Georgia manual on uniform traffic control devices for streets and highways, March 1954

GEORGIA
),1 allua] all
Uniform Traffic Control Devices
for Streets and Highways
~IARCH 195/.
A dopted by the State Highway Board of (~eorgiH
for use by the State Highway Department of Georgia
and the Counties and Munir.ipalities and all other jurisdictions within the State, in accordance with Article Ill, Section 31, of Act ~ o. 8.54 approved .January 11, 19M, (Georgia Laws 19.53, :November-December Session, pp. 556-623).
Printed alld distrihuted hy STATE HIGHWAY DEPAHTMENT OF GEORGIA
x o. 2 Capitol Square
Atlanta 3, Georgia

RESOLUTION OF THE STATE HIGHWAY BOARD OF GEORCHA
ADOPTING THE MAl\TAL A:\D SPECIFICATIONS FOR THE FNIFORlVI SYSTK'vI OF TRAFFIC CONTROL DEVICES
(~eorgia, Fulton ('OIll1ty.
Whereas, the (;eorgia General Assembly in its i\Tovember-December, 19.5:3. Session adopted, and the Governor of the State, on January 11. 19,54, approved Act :\0. 854 Cniform .4.eI Regulating Traffic on Highways; and
Whereas, Sedion :31, Article III, of the Act directs that: "The State High\\'a~' Board ::;hall adopt a YIanual and Sper'ifications, as recommended by the Engineering Division of thp State Highway Board, for a uniform system of traffic-r'ontrol dpvices consistent with the provisions of this Act for usc upon all highways within this State. Such uniform system shall cOlTelatp \vith and so far as possible conform to the system then current as approved by the Amerir'an Association of State High\\'ay Officials."
Whereas, the Engineering Division of the State Highway Department has recommended through its State Highway Engineer that the attached Manual on Un~form Traffic Control Devices for Streets and Highways in Georgia, March 1954, be adopted in compliance with said Act No. 8,54,
IT IS THEREFORE RESOLVED, AND IT IS HEREBY ORDERED, That the said Manual on Uniform Traffic Control Devices for Street8 and Highways in Georgia, March 1954, be and the same is hereby adopted by this Board as directed by said Act, and same is declared
to be the official manual and specifications to control and govern any
traffic control device or devices erected or to be erected, installed or
III

to be installed, placed or displayed, on any street or highway within this State. Recommended this 24th day of March, 19;')4.
::-ltate Highway Engineer Approved this 25th day of March, 1954.
STATE HIGHWAY BOARD OF GEOHGIA Chairman Member Member
iv

RESOLUTION OF THE STATE HIGHWAY BOAR;) OF GEORGIA
ADOPTI NG THE REVISIONS TO MANUAL AND SPECIFICATIONS FOR THE
UNIFORM SYSTEM OF TRAFFIC CONTROL DEVICES
Georgia, Fulton County.
1r1hereas, the State Highway Board of Georgia did on March 24, 1954, adopt a Manual and Specifications for the Uniform System of Traffic Control Devices in accordance with Section 31 of Act No., 854, the Uniform Act Regulatin~ Traffic on Highways, adopted by the Gene=a':' Assembly of Georgia at its November-December Session 1953, and approvec by the Governor of the State on January 11, 1954j and
Whereas, it has been deemed expedient that said Manual be amended in order to conform more closely and correlate with the System now current as approved in 1954 by the American Association of State Highway Officials as required by said Act:
IT IS THEREFOP.E RESOLVED, AND IT IS HEREBY ORDERED that the following described parts of the MaDual adopted March 24, 1954, be and they are hereby amended as described in each instance.
/'! Recommended.this 6th day of April, 1956.
.. '.,' /Ih)~'~-'1"'" ~ '-'~ .'~ ( <.,t...:.: J, J:</,/..-{.-.(/-vState Highway Engineer Approved this 12th day of April, 1956.
STATE HIGHtt\JAY BOARD OF GEORGJA



_._",".t

*,,\

--

Member

Revisions to
GEORGIA MANUAL ON UNIFORM TRAFFIC CONTROL DEVICES
For Streets and Highways Dated March, 1954 Revised April, 1956
Adopted by the State Highway Board of Georgia
for use by the State Highway Department of Georgia
and the Counties and Municipalities
STATE HIGHlf\TAY DEPARTMENT OF GEORGIA
No.2 Capitol Square Atlanta 3, Georgia

RESOLUTION OF THE STATE HIGH.~AY BOARD OF GEORGIA
ADOPTI NG THE REVISIONS TO MANUAL AND SPECIFICATIONS FOR THE
UNIFORM SYSTEM OF TRAFFIC CONTROL DEVICES
Georgia, Fulton County.
V~ereas, the State Highway Board of Georgia did on March 24, 1954, adopt a Manual and Specifications for the Uniform System of Traffic Control Devices in accordance with Section 31 of Act No., 854, the Uniform Act Regulating Traffic on Highways, adopted by the Gene=al Assembly of Georgia at its November-December Session 1953, and approved by the Governor of the State on January 11, 1954; and
Whereas, it has been deemed expedient that said Manual be amended in order to conform more closely and correlate with the System now current as approved in 1954 by the American Association of State Highway Officials as required by said Act:
IT IS THEREFORE RESOLVED, AND IT IS HEREBY ORDERED that the following described parts of the Manual adopted March 24, 1954, be and they are hereby amended as described in each instance.
~1 Rec~~this ;6/~h day of April, 1956.
/L <:::>( .;h./' /l- 0- .1-/&.~ State Highway Engineer Approved this 12th day of April, 1956.
STATE HIGHWAY BOARD OF GEORGIA

REVISIONS TO GEORGIA MriNUAL ON UNIFORM TRAFFIC CONTROL DEVICES
FOR STREETS AND HIGlMAYS
APRIL 1956
PART I - SIGNS
Standardization of Position.
On raJe 7 delete th?refrom the fifth and sixth unnumbcr0d parasraphs and substitute therefor the following:
"Signs in rural areas should normally be mounted at 3 heiJht of 2t least 5 feet above the crown of the pavement to the bottom of the sign. However, where parkin] is likely tc occur, or where oth0r C~[t~uctions are present, the height should be at least 7 feet to the bottom of t~e sign. In business and in resid0ncc districts signs should be mounted at least "/ feet high to the bottom of the sign."
Design of Stop fi.9.D....
On page 13 delete in its entirety and SUbstitute in lieu thereof the following:
"Owing to the importance of Stop signs they are given a distinctive shape (actaeon) and color (red). The r0d color is consistent with the accepted use of a red light as a Stop signal and of the color red as a special warning of danger.
- 1-

The Stop sign shall be octangonal in shape, shall have a red background, and shall carry the word STOP in white letters at least onethird the height of the sign.
The Stop sign with yellow background and black lettering now in position may remain until replacement or refinishing is required, with full legal status. All Stop signs erected hereafter will have a red background, and white letters."
Reflectorization or Illumination.
On page 14 delete therefrom the first and second paragraphs and substitute therefor the following:
"All Stop signs shall be illuminated or reflectorized at least in the lettering. Illumination may be by floodlight or by fixed white light in the letters. Reflectorization may be by white or clear reflecting units or reflecting coating in the letters, with or without a red reflecting coating on the background. In addition to such illumination or reflectorization, a flashing red signal, in operation both by day and by night, may be incorporated in the face of the sign or placed just above it."
Speed Zone Ahead Signs R-6, R-7
On page 22 add thereto after third paragraph the f~11owin9 paragraph:
"If the speed zone exceeds three miles in length, the sign shall indi~ate its approximate length."
-2-

No Passing Siqn R-16.

On pages 26 and 27 delete said paragraphs in their entirety and substitute in lieu thereof the
following:

D0
NOT PAS S
R-l6
24" x 30"

"Do Not Pass Sign R-16 The Do Not Pass sign may be used on two and three-lane roads at the beginning of a zone through which restricted sight distance makes overtaking and passing hazardous. It shall have black letters on a white b~ckground, and be of a minimum size of 24 inches by 30 inches. There will be a 5/8" black border, 3/8" from edge of sign. It shall be erected at the right-hand side of the roadway at a height of 5 feet to the bottom of the sign, not less than 6 feet nor more than 10 feet from the edge of the roadway. Because a driver about to pass a vehicle ahead often has only restricted view to the right, an additional sign on the left-hand side of the road may be desirable.

The sign normally should be supplementary to standard pavement markings as described in Part II, Section B, Pavement and Curb Marking, Page 103. Where pavement markings are well maintained, and weather conditions are not likely to hide the markings, the Do Not Pass sign need not be used."

-3-

End No Passing Zone Sign R-17.

On page 27 delete therefrom all of said

paragraph in its entirety and substitute therefor

-'--, the flollowing: PAS S I I WIT H
J CAR E

"Pass With Care Sign R-17 The Pass With Care sign may be used at the end of a no-passing zone where Do Not Pass sign has been erected at the beginning. It shall be of the same size and color, and shall be erected in the

same manner as the Do Not Pass Sign."

R-17 24" x 30"

Location of Warning Signs.

On page 39 delete therefrom the second paragraph of said section the height of 4' of said sign and substitute therefor the height of 5' so the amended paragraph will read as follows:

"In rural and residence districts where no parking occurs, Warning signs shall be erected not less than 6 feet nor more than 10 feet from the edge of the pavement or traveled roadway, with the lowest edge of the sign not less than 5 feet above the roadway, except as hereafter indicated. In any location where they will obstruct sidewalks or pedestrian paths, however, they should be mounted at a height of not less than 7 feet to the bottom of the sign.

-4-

In residence and business districts where parking is frequent, they shall be so set that the bottom of the sign is not less than 7 feet above the top of the curb and lefthand edge not less than one foot back from the outside edge of the curb."
PART III - SIGNALS
Meaning of Color and Arrow Indications.
On page 133, for subti tIe "Yellow alone or Caution when shown foHowing the green or Go" there is substi tuted:
"Steady Yellow alone or Caution when shown preceding red or Stop."
For subtitle "Red alone or Stop" there is substituted:
"Steady red alone or Stop."
For subtitle "Red with green arrow" there is substituted:
"Steady red with green arrow."
Accident Hazard.
On page 163 delete therefrom the second numbered warrant in first said paragraph and substitute therefor the following:
"2. Five or more reported accidents of types susceptible of correction by a traffic control signal have occurred within a 12-month period, each accident involving personal injury or property damage to an apparent extent of $50 or more; and"
- 5-

-~eneral Design Requirements.
On page 200, delete therefrom the sec-ondlpproved design for pedestrian control signals, )eing the second of the, two number 2 paragraphs lear the top of page and substitute therefor the :ollowing:
"2. A Rectangular box-type signal in which the words WALK AND DON'T WALK are properly illuminated. "

~w Signs to be Added to Manual Ordered by Georgia
~
Throwing of Trash Sign (Information-6)

THROWING TRASH-GARBAGE
ON HIGHWAY PROHIBITED
MAXIMUM $1,000 FINE . AND/OR IMPRISONMENT
1-6 36" x 36"

The Thr1wing of Trash Sign will be 36" x 36" in size, black lettering on white background. This sign is not reflectorized except in a few special locations near or on edge of cities. These signs will be placed on outer edge of shoulder at right angle to roadway with message facing approaching traffic. Lettering sizes are: First four lines 4" Series "0" letters and the last two lines, 2" Series "0" letters. Sign will have a 3/4" black border, 1/2" from edge of sign and sign will oe erected so that the bottom of sign is 5' above center of pavement. These signs will be placed facing
~raffic leaving each incorporated ~0wn or city and at other locations where the traveling public is using high'tlay right-of-way to dump trash or garbage.
- 6-

Limited Access Highway Sign (Information-7)
-
The Limited Access Highway Sign will be 30" x 24" in size with black lettering on white background. This sign will not be reflectorized. Letter sizes are:

Lines 1 and 2, 2" Series

"C" letters, lines 3 and
---------- - - - 4, 1" Series "C" letters,

LIMI TED-ACCESS

lines 5 and 6, 1-1/2"

HIGHV'JAY

f Series "C" letters,

I lines 7, 8 and 9 are 1"
INVESTIGATE LAW BEFORE PLANNING Series "Gil letters, and

IMPROVEMENTS TO ABUTTING PROPERTY line 9 will give location

L l STATE HIGHfJAY BOARD OF GEORGIA CONTACT DIVISION ENGINEER STATE HIGHWAY DEPARTMHJT G~I

of Division Office. These signs will be erected on

or near right-of-way line

1-7

parallel to and facing

24 1t x 301t

roadway. These signs will

be at least 5' from bottom

of sign to ground line.

These signs will be located at frequent intervals

alternating from one side to the other along the seg-

ment of roadway which has been designated as Limited

Access.

-7-

CONTENTS

yoreword

Page

~___________

1

State Highway Board to adopt manual of uniform traffic control devices_ ___ 1

State Highway Board to sign all State Highways ________________________ 1

Local traffic control devices "

_

""_______

2

PART I-SIGNS

A-Introduction:

Legal authority-

"- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - :{

Classification of signs

" ____ ________________________ :~

Excessive use of signs . _____________ _______ _ _________ _________ 4

Standardization of signs __________

"_ ___________ _________ 4

Sign shapes __ _- _- _- _- - - - - - - - - -

-" - - _- _- _- - "

4

CoioL _- - - - - . Dimensions ___

--------

----- - -

,')

- _- ________

5

Symbols __

. - _- _- - - - - -

- - - _- - _- __ 5

Word messages _-

- _- - - - - .

- - - - - _- _- _- __ 5

Lettering

- - - - - - _- - - - - -

Illumination and reflectorization ____

-------_

(j

_________ _____________ ()

Means of illumination_ ________________

_____________ {)

Means of reflectorization __ - _- - - _- -

- _- ________ (j

Sign borders

- - _- - - - __ - - _- _-

- _- ________ ()

Standardization of position

- _____

_. _ ________ 7

Standardization of application_ ____

Erection_ ___ ____ _

-

__" _________ 8 ___________ 8

Materials__________

!)

Sign posts and their foundations_ ______

!l

Maintenance __

___ . _______

!l

Height and lateral location of signs.

10

B-Regulatory Signs:

Application of regulatory signs_

12

Classification of regulatory signs_

12

Design of regulatory siiI1s

_

12

Other regulatory signs_ _______ _ _

13

Stop sign ___________ _ _

1:{

Design of Stop sign

_

1:3

Refleetorization or illumination

14

Warrants for Stop sign_ ____ __

14

Location of Stop sign

_

14

Size of Stop sign to be used __

15

Yield Right-of-Way signs

_

](j

Warrants for Yield Right-of-Way signs_

19

Location of Yield Right-of-Way signs _

H)

Speed Limit sign

_

20

Location of Speed Limit sig;IL _ _

_

2\

Speed Zone Ahead sign_

_

.

22

Turn Prohibition signs_

_

_

22

v

Page

No-Passing sign

-

End N 0-Passing Zone sign ____ ___

-

-

____________ _

_ 26 _ 27

No Passing ~hen Yellow Line is Right of Centerline sign

_ 27

Keep Right Except to Pass sigrL __

______________

Keep Right sign _________ _____

___________ __ _

Do Not Enter sign___ __

_

One-Way sign _______________

_______________ _

Two-Way Traffic Ahead sign _______ ______ ___________ _

Parking and Stopping signs ____

______________ _

No Parking on Pavement sign _____ _

Pedestrian Crossing signs ______ _____ _

_____ ___ 27 _ 28 _ 28
_ ao
_ :~O _ :~2
_ :~:~
_ :3a

Road Closed sign_ _ ______________ __________ Stop for School Bus Loading and Unloading _______ _

__ _ _

_ 34
:H

Traffic Signal Speed sign ____________________________ _

_

Load Limit sign ____________________________________ _

Other Regulatory signs _____________________________

_

:34 _ 35 _ 35

C-Warning Signs:

Application of warning signs

_

:37

Design of warning signs

_

:37

Location of warning signs_ ___________ _

_

3~l

Curve sign ____ _____ _

_

:~g

Turn sign .. ___ _ _

41

Reverse Curve sign __ _

_

41

Reverse Turn sigrL __ ________ ___

42

Supplemental Curve and Turn signs __

4:~

Winding Road sign __

4,~

Stop Ahead sigrL _

45

Signal Ahead sign

4(j

Hill sign_

47

Bump sign_

47

Dip sign

_

47

Pavement Narrows sigrL ___ __

4\l

Two-Lane Pavement Ahead sigrL

4!l

Two-Lanes (with 4 arrows) sign

52

Divided Highway Ahead sigrL __

,52

Divided Highway Ends sign

.~;)

Narrow Bridge sign

_

54

One-Lane Bridge sign_

54

Pavement Ends SiglL _

,55

Low Clearance sigrL _

56

Fresh Oil sign

.57

Men Working sign _

57

Soft Shoulders sign_

58

Slippery When Wet SigrL _. __

58

Double Arrow sigrL

_

.58

Railroad Advance Warning sigrL ___ _

_

59

Railroad Crossbuck sign

_

60

Crossing signs

_

61

Advisory Speed sign _

62

Cattle Crossing sign __

62

Watch for Cattle sign ___ _

_

64

Detour Ahead sign __

64

VI

Draw Bridge Ahead siglL _

Draw Bridge sign

Cross Road sign _

Side Road sign ______

_

T Symbol sign

- - _- _- - -

Y Symbol sign _______

_

Business District SiglL ___ _____________________ __ _

Residence District sign ________________________________ _

Roadside Park sign

---_ _

-

_

Other warning signs -- - -

--

--

-

_

Page
64 65 66 _ 66 _ 67 _ 67 _ 68 _ 68
68
68

D-Guide Signs:

Application of guide signs________

_

_ 69

Design of guide signs __ - _- - - _- - - - - - - - - - - _- _- - -

-

69

Route markers and auxiliary markers

- ______________

_

_ 6f)

Junction sign __ - - - - - - - - - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - _- __ 69

U. S. Route Marker- - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 70

State Route Marker. -- - - - - - - - - - - - - - - - - - - - - - - - -

- - - __ - -

_ 70

Confirmation and Reassurance Markers ______ ___

_

_ 70

Directional Markers_ - -- - - - - - - - - - - - - - -- - - - -- - - - - -

- - - __ - - - - - 71

Destination Markers_________

------ ---

_ 71

Distance Marker _- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - _- 71

Ends Marker 24" x 18"-

- _-

- _____ _

_ 72

U. S. Oversize Route Marker- - - - - - - - - - - - - - - - - - - - - - - _- - - - - _- __ - -

- 74

Georgia Oversize Route Marker __ - - - __ - - _- -_ ________ _

Directional Arrow Panels _______

_

Ends Marker 13" x 10"

- ____

__-

_ 74
_ 75 _ 75

Temporary Marker

-------

- _- - - - - _-

-

- 75

Alternate Marker _- _- - - _- - - _- - - - - - - - - - - - - - - - --

- _- _- __ - - _- _- _- 75

By-Pass Marker.

- _- _ _

- ______

_

_ 76

Business Route Marker. ______

_

_ 76

Cardinal Direction Marker. ___

_ - ______________ _

_ 76

Secondary Destination Marker _

_

_ 77

Information signs_ __________

_________ _

_ 77

State Line sign ____________

_

_ 77

City Limit sign__ __________

_

_ 78

County Line sign _________ __

_

_ 78

Unincorporated Village sign

_ 78

Right-of-Way signs

_ 7!l

Guide signs for major junctions and intersections

_ 79

Junction Assembly _________________ _______________ _

_ 79

Route Direction Marker Assembly ____ _

_ 80

Route and Destination Assembly ___ ______________

_

_ 82

Confirmation Marker Assembly' ___ ___ ___________ _

_ 84

Rural Reassurance Markers

_ 85

Guide signs for secondary routes and intersections:

Application of Secondary Guide signs Design of Secondary Guide signs
Secondary Route Markers and Auxiliary Markers Secondary Junction Assembly Secondary Route Direction Assembly Secondary Route and Destination Assemblv Secondary Junction PaneL __________ .

_ 85 _ 85 _ 85 _ 87 _ 87 _ 8f)
89

vii

Page E-School Sign Standards:
School Zone sign_ _____________________________ __ ___________________ _ 92 School Crossi~ sign _____________________________ ____________________ 92 School sign_ ___ ___________________________________ _ __________________ 93 School-Speed Limit signs_ _____________________________________________ 93 No Parking School Hours sign ________ ________________________________ 94 Portable School sign_ _________________ __________ ___________________ 94

PART II-MARKINGS

A-Introduction:

Functions and limitations of markings_ ________ ________________________ !J7

Legal authority

- - __ _ - - - __ - - _____________ 97

Standardization_ ____________________________________________________ 97

Types of markings ___________________________________________________ 97

Materials ___________________________________________________________ !l8

Color8_________________

_

100

Types of striping _____ _______________

_________________ 101

Width of lines

- _ _________ _____________ 102

Reflectorization_ __________________________________ __________ ____ 102

Maintenance __________________ _______________

_________

102

B-Pavement and Curb Markings:

Center lines

-_

Center lines on rural roads

_

Center lines on urban streets _

Lane lines

- - __ - - _- - - _- - - _ _- _- _- _- _-

Lane lines on rural roads

- -_

Lane lines on urban streets_ ___ _

No-passing zones

-

_ - -_

No-passing zones on two- and three-lane roadways

Warrants for no-passing zones_ _ __

_

_

Pavement edges

'_

Pavement-width transitions_

Approach to an obstruction _

Streetcar clearance lines __

Turn markings

_

Transverse lines _______ Stop lines_ _____ _

__- -_

-

-

Cross-walk lines

_

Route direetions

_

Approach to railroad crossing __

Parking space limits_ ______ ___ _

_

Word markings_ Curb markings for parking restrict ions

lQ;~

1O;~

lQ;~

104

104

_

104

105 __ 105

107

107

110

110

1l:3

114

114

114

116

116

116

118

118

_

11\1

C-Object Markings:

Application of objeet markings _______ __ _______________________ _ 120

Objects within the roadway

_ 120

Lighting or refiectorization of obstructions_ __

_______ __

121

Object markings on curbs

_

121

Objects adjacent to the roadway __

121

viii

Page

D-Reflector Markers:

Application of reflector markers _______________________________________ 123

lIazard markers

123

Delineators _____ _____________________________________________________ 123

PART III-SIGNALS

A-Introduction:

Definitions_ ________

_ - _-

- ______________ 127

Value of signals_ ___

-

- - ______________ 127

Standardization- - __ __- -

- _ - - __ - - - __ - - ______________ 128

Legal authority - __

- - _-

--

--

129

Classification-

-

-

- __ - - __ - -

- - __ - - __________ 12H

B-Features Common to Fixed-Time and Traffic-Actuated Signals:

General aspects of signals __ - _- - - - - - - - - - - __ - - - - - - - - - - - - - - _- - - __ - - - __ 131

Design for future needs __ - - - _- - - - - - - - - - - _- - - - -

- - - - -. - - - __ - - - __ 131

Number of lenses per signal face - - - - - - - - - -

- - - - _- - - _- - - __ - - __ 131

Color and position of lenses __ - - - - _- _- _

- - - - ______ _ _ 132

Meaning of color and arrow indications_ - -

- - - - _- _- - - - _ 1:~2

Shapes and dimensions of lenses - _- - - _- - -

_- - - _- - - __ - -_

1:~5

Lettering on lenses __ - - - - - _- - - - - -

- - - _- - -_

13,5

Illumination of lens _- - - - - - - - - - -

- - - _-- - _- - - _- 13G

Visibility and shielding of lens - _- _-

--- - -

_ lin

Auxiliary illuminated signs - _- _ _- _

I:n

Number of signal faces

- _- _- - - -

- - - _- - - _- _- _

lin

Limit of signal-controlled area __ - _- - - - -

- - - _- - - - - - - _-

1:38

Location of signal faces at intersections_

- - - __

138

lIeight of signal faces

-

--

_ 1:3U

Pointing of signal faces

-

--

_ 141

Location in relation to curb lines

-

_ 141

Location in relation to the pavement or traveled surface.

_ 141

Removal of confusing advertising lights or display of unauthorized signs,

signals or markings_ __________

_

_

142

Provision for future installation __

142

Types of mounting for signal heads _____ _ _

14:~

Installation of underground conduit or cable __

14:~

Selection of cable

_

144

Insulation of cable

_

145

Cable positions and clearances

_

145

Messenger wires

_

145

Efficiency and continuity of operation _

14.5

Length of cycle _____________________ __

146

N UIp.ber of traffic phases

_

14G

Rotation of intervals ________ _ _

147

Traffic movement intervals proportioned to traffic requirements_

___ 147

Unexpected conflicts during Go intervals __

148

Vehicle-clearance intervaL _

148

Adequacy of maintenance _

14\)

Signal lamp replacement. _

14!l

. Cleaning___

_

_

\.'>0

Maintenance of controllers __

150

IX

Painting records ~iaintenance

Page 151
151

C-Comparison.,n Fixed-Time and Traffic-Actuated Control:

Relative adaptability to normal intersection requirements

152

Special merits of fixed-time controL ____________________________________ 153

Special merits of traffic-actuated controL _______________________________ 153

Other factors governing selection of type of controL

154

D-Fixed-Time Signals:

I>efinition

156

Advance engineering data required _____________________________________ 156

Warrants for fixed-time signals

-

- __________________________ 156

Minimum vehicular volume -

-

- __________________________ 157

Interruption of continuous traffic_ ___ - _- -

"

159

Minimum pedestrian volume

161

Coordinated movement

162

Accident hazard

163

Combination of warrants-other factors_ _______________________________ 165

Selection of type of fixed-time control mechanism

165

Nonsynchronous fixed-time controller for isolated intersections

165

Program type of fixed-time controller for isolated intersections

166

Synchronous type of fixed-time controller for isolated intersections

166

Controllers providing for coordination

166

Signal timing in accordance with traffic requirements

167

I>ivision of total cycle timc

167

Coordination of fixed-time signals

169

Types and selection of coordination

~_ _

169

Simultaneous system _________________________________________________ 169

Alternate system_ ____________________________________________________ 170

Simple progressive system_ __________________________________ __________ 171

Flexible progressive system_ ___________________________________________ 172

Conditions affecting efficiency of signal system __________________________ 173

Manual control

173

Speeds for progressive systems_ ________________________________________ 174

Signs indicating timed speed __________________________________________ 174

Coordination with railroad crossing signals_ _____________________________ 174

Rate of f1ashing

175

E-Traffic-Actuated Signals:

Definition

176

Warrants for intersection controL

176

Warrants for nonintersection controL __________________________________ 178

Types of traffic-actuated control, and factors governing selection

178

Semi-traffic-actuated control_ _________________________________________ 178

Full traffic-actuated controL

179

Coordinated control

180

Pedestrian-actuated controL

181

Speed control

182

One-way restricted zone controL ______________________________________ 183

Detectors and controllers _____________________________________________ 184

Types of detectors ___________________________________________________ 184

Pressure-sensitive detectors ___________________________________________ 184

x

Page

Magnetic detectors_ _______ _ - -

Sound-sensitive detectors_ ___ _____________________ _

Light-senitive detectors_ __ _

-

_ 185 _ 185 _ 185

Pedestrian push-button detectors _______ _____________________ ____ ___ 185

Types of controllers

-

-

~

_ 185

Two-movement, semi-traffic-actuated controller with time extension

_ 186

Two or more movements, full or semi-traffic-actuated controller with time

extension

_ 186

Traffic-actuated speed control for nonintersection loeations

_ 187

Two-movement, full or semi-traffic-actuated controller with speed controL __ 187

Two-movement, full traffie-aetuated controller with automatic adjustments

of periods with respect to traffic volume, relative density, and elapsed time_ 187

Two-phase, full traffic-actuated control for one-way restricted zone

_ 188

Additional flexibility for controllers used in coordinated systems _

188

Provision for manual operation _____________ _

_

_ 188

Installation of traffic-actuated signals _________ _

_

188

Distance of vehicle detectors from stop line

_ 189

Location of vehicle detectors from center line_ . _________ _

_

191

Installation of pedestrian detectors

-

_ 192

Installation of streetcar detectors

- ________ _

_ 192

Operation and adjustment of traffic-actuated signals_ _ _

_ 192

Continuous operation __ - - - - - - - - - - - - - -- - - - - - - - - - - - __ . - - - - -

- - - _ 192

Time intervals and adjustments - - - - - - - - __ - - - - - - _- _- - - - - _- Interval sequence_______________________________ _
Rotation of phases_ _________ ___ -

_ 19:~ _ 196 _ 196

F-Special Pedestrian Signals:

Definition

- - - - - - - - - - - - - - - - - - __ - - - - - - _- _- - - - -

-

_ 198

VVarrants

-

_ 198

Type of controL

--

-

--

_ 199

General design requirements

_ 199

Meaning of indications

_ 200

Location

_ 201

Operation

_ 201

Phases and intervals

_ 202

G-Other Special Traffic Signals:

Types of special traffic signals

_

Flashing beacons and signals:

Definition and application

_ 20:~

VV a r r a n ts

_ 20:~

Types of controL ________________ _

_ 204

I)esign

_ 205

Location

_ 205

0peration

.

_

205

Lane-direction traffic signals:

Definition and application

_ 206

VVarrants
~~~~:~~~~~~r~~-~~~~~-~~~~~~-~-~-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~_~~~

206 206 207

Location

_ 207

Operation

_ 207

Xl

Page

Traffic signals at drawbridges: Application _____________________________ ____________

_ 207

Warrants _~_ ____________________________________________

.. _ 208

Design

. _________ 208

Location_ _

. 208

Operation_ ___________________________________________

_ 208

H-Train-Approach Signals and Gates:

Railroad grade-crossing protection

_

209

Train approach signals: Classification and definition _______ ___________________ _ _ Warrants

Types of controL

I)esign

Location

Installation

Operation

Maintenance_ __________________ _

..

_ 209 _ 209
_ 209 _ 209 _ 210 _ 210 _ 210
_ 211

Railroad-highway grade-crossing automatic gates: Application_ _________________________________________________ _
Warrants

Types of controL

Design

_

Location_ _________________________

_

_

1nstallation_ _______ _______________

_

_

Operation

._ _

_

Maintcnance

..

_

_ 211 _ 211 _ 212
212
212
212
212
21:~

PART IV-ISLANDS

A-Introduction:

Function of islands

215

General engineering requirements_ _____ __________________________

21.5

C lassification_ ________________________________________________

2H\

Standardization_ _________ _______________ ___________

2H\

B-Loading Islands:

Legal authority_______

_

218

Functions_ _______ ______________________________________ __________ 218

Warrants___________

__

_

218

Location ________ _ ______ _____

____________________________ 218

Access_.

2Hl

Elements of design_ ___

219

Designation of arca ____

219

Dimensions ____ _. _____

220

End protection_ ______ ___

220

Approach-end treatmenL_______

_.

_ __

221

Side protection_ __ _______________

222

Illumination and reflcctorization_ ___

________

_ .__ . _ 222

Dircction of flow_ Signs _________ _ _________

_

. 223

___ ________ _______________ __ 2Z~

Markings

.. ___________________________________________________ 223

Summary specifications for loading islands_ ____ ___________________

224

Xli

C-Refuge Islands:

Legal authority _ Functions _

\Varrants _

Location -

Elements of design.

Designation of area

_

Continuous median strip_

Dimensions - _- - - - - - - - - - - - - - -

End protection- - - - - -

Approach-end treatmenL __

Side protection - - - - - - - - - - - - - - - - Illumination and reflectorization

Signs __ - - - -

--------

Markings __ - - - - - - - - - - - - - - - - - - - - - - - - - - Summary specifications for refug(; islands __

D-DivisionaIIslands:

Legal authority- - - - --

Functions

---

Warrants - - - - -. --

Elements of design __

Designation of area _

Dimensions

- _- -

Curbs

_

Approach-end treatment __

Illumination and reflectorization _

Signs

- - - _- __ -

Markings _________ __ ________ _

_

Summary specifications for divisional islands_

E-Channelizing Islands:

Legal authority _ Functions_ __ __________ _________ __

warrants_ Elements of design __ _________ __

Designation of area_

Dimensions

_

Curbs_______________

_

_

Approach-end treatmenL ___________

_

_

lIIumination and reflectorization_ __ _ __________ _

_

Signs _________________________________

__________ _

Markings

Summary specifications for channelizing islands_

_

_

22,5 225 225 226 226 226 227 228 228 22D 22D 229 22fl 22fl
2:~0
240 240 240 240 241 242 244 244 244 _ 244 _ 245 245

APPENDIX A

Glossary of traffic signal terms

_

_ 246

APPENDIX B

Illustrated index for signs and markers

_

250

Xlll

ILLUSTRATIONS

Page

Figure I.-Stop signs-typical installations

_

17

Figure 2.-Tytifcallocations for Stop signs _______ _____ _______ _

_ 18

Figure 3.-Turn Prohibitions signs-typical installations.

.

_

2:~

Figure 4.-Typical installation of signs at end of one-way street __ . .

24

Figure 5.-Portable turn prohibition signs-typical installations _

25

Figure 6.-One Way signs-typical installation .

.

_

29

Figure 7.-Parking signs-typical installation

.

_

:H

Figure 8.-Curve signs-typical installation. _______ _ . ______ _ __

38

Figure 9.-Reverse Curve signs-typical installation .

_ 40

Figure 1O.-Typical sign installations-transition from 2-lane to 4-lane

highway _____________ _____________ ___ _____ ___________________ 48

Figure ll.-Typical sign installation-transition from 2-lane to divided high-

way

. _________________________________________ 50

Figure 12.-Typical sign installations-transition from 2-lane to divided high-

~-ay__________________________

51

Figure 13.-Detour signs-typical installations_ _ _ _ ___________________ 63

Figure l4.-Typical installation of guide signs for major routc intcr-

sections..

.

. _.

. . opposite n

Figure 14A.-Typical alternate installation of guide signs for major inter-

sections (for one dircction of travcl only)

.

.

opposite 73

Figure 15.-Typical installation of guide signs at "Y" intmsection _ 73

Figure 16.-:\'Iethods of erection for destination markers

_ 83

Figure 17.-Spacing of routc markcrs in rural areas

.

_ 86

Figurc 18.-0versize statc and U. S. directional route markers

_ 88

Figurc 19.-Typical installation of guide signs for ~econdary route intersections_ 90

Figurc 20.-Standard location and ercction of school signs

.

95

Figure 21.-Position of signs in rural and urban areas

. . _ 96

Figurc 22.-Standard pavcment markings for no-passing zones

_ 106

Figurc 23.-Method of locating and dctcrmining the length of no-passing zones

on vertical and horizontal curves _________ _____________ _____ __ ___ 108

Figure 24.-Typical pavement-width transition markings

. ___ 109

Figure 25.-Approach markings for obstructions in the roadway

...

III

Figure 26.-Typical designs for turn markings on pavements__________

112

Figure 27.-Typical urban pavement markings, showing center lincs, parking-

space limits, and route markings. __ _____ _

.

115

Figure 28.-Standard pavement markings at railroad crossings_ _______

117

Figure 2\J.-Typical markings on objects in and adjacent to the roadway

122

Figure :~O.-Arrow lens design; Institute of Traffic Engineers

. ______ 136

Figure 31.-Location standards marked "Ped" apply to intmsections where pedestrian volumes equal or exceed the warrant values_ ______________ __.. 140

Figure 32.-(Above) WALK lens design, Institute of Traffic Engineers. (Be-

low) A typical WAIT lens design

201

Figure 33.-WALK-WAIT signal installation

.__

_ 202

Figure 34.-A raised loading island with no protection other than pavement

markings. No turns are permitted at this intersection

_

216

Figure 35.-A raised loading island in business district. Also serves as a protec-

tion for left turn movement

217

Figure 36.-A concrete loading island with end protection provided by a con-

crete buffer, six-inch red reflectors and concrete painted with black and white

stripes. The white stripes reflectorized, this panel warns drivers of approach-

ing vehicles of the island's presence __________________ _____ _

221

XlV

Page

Figure :37.-A raised refuge island

_

226

Figure 38.-Combination channelizing and refuge islands. The center islands

extend into but not entirely across the cross walks

_ 227

Figure 39.-Combination divisional, channelizing, and refug~ islands with

desirable tapered shape, and overhead illumination

_ 227

Figure 4O.-Channelizing islands and pavement markings at a complicated inter-

section. The raised islands also scrve as refuge islands

_ 228

Figure 41.-A paved median in a suburban area. The width of the second island

is reduced by combined acceleration and deceleration lanes provided for

vehicles making left turns to and from the divided street.

_

Figure 42.-Separate lanes for left turns. The roadway is illuminated and

traffic signals control movements at the intersection

_

Figure 43.-At this channelized "Y" intersection, with irregular-shaped islands,

traffic signals regulate the principal crossing movement. _

23.5

Figure 44.-Separation to permit the addition of central islands was an im-

portant factor in the channelization of this intersection. High-visibility

curbs were used and an overhead traffic signal regulates the principal crossing

movement. ___ _

- - - - _- _-

- - - - __ - _ _

- _- - -

- -- 241

Figure 45.-This channelized "T" intersection has stop control for crossing

movements_

_____________________ _

_ 242

Figure 46.-Channelizing islands of various sizes and shapes are used at the

terminals of highway grade separation ramps

_

xv

FOREWORD
This il1anual on Uniform Traffic Control Devices for Streets and Highways in Georgia has been correlated with and conforms, as closely as conditions will allow, to the system now current and approved by the American Association of State Highway Officials, and approved as an American Standard .June 2,1, 1948.
Such modifications as required to fit local requirements, and to incorporate in these specifications the most recent material accepted by this Department, have been made in this Manual.
Reference is made to the detailed provisions of Act X o. 854 as they may apply to any traffic control devices described herein and as to the authority and responsibility of the Governmental units having separate jurisdictions within the State.
The following eXcOI'pts from Act No. 854 of the Kovember-December 1953 Session of the General Assembly, approved .January 11, 1954, indicate the legal requirements governing all agencies or parties in the State in the installation of any traffic control device:
Article III
Traffic Signs, Signals, and Markings
Section 31. State Highway Board to adopt manual of uniform traffic-control devices. The State Highway Board shall adopt a manual and specifications, as recommended by the Engineering Division of the State Highway Board, for a uniform system of traffic-control devices consistent with the provisions of this Act for use upon all highways "'ithin this State. Such uniform system shall correlate with and so far as possible conform to the system then current as approved by the American Association of State Highway Officials.
Section 32. State Highway Board to sign all State Highways. (a) The State Highway Board shall place and maintain such traffic control devices, conforming to its manual and specifications, upon all State high\"ays including those within all municipalities and counties, as it shall deem necessary to indicate and to carry out the provisions of this Act or to regulate, warn, or guide traffic, and shall remove or direct removal of all traffic-control devices which it shall deem unnecessary. All traffic-control devices shall conform to those adopted under the authority of Section 31.
1

(b) No other authority shall place or maintain any traffic-control devices upon any State highway under the jurisdiction of the State Highway Board except by the latter's permission.
(c) The dl'Sregard or disobeyance of the instructions of any official traffic-control device or signal, placed in accordance with the provisions of this Act, by the driver of a vehicle, shall be deemed as prima facie evidence of a violation of law, without requiring proof of who and by what authority such sign or device has been erected.
Section 33. Local Traffic-Control Devices. (a) Local authorities in their respective jurisdictions shall place and maintain such trafficcontrol devices upon streets and roads under their jurisdiction as they may deem necessary to indicate and to carry out the provisions of this Act or local traffic ordinances or to regulate, warn, or guide traffic. All such traffic-control devices hereafter erected shall conform to the State manual and specifications.
2

Part I
SIGNS
A-INTRODUCTION
The commonest device for controlling, safeguarding, or expediting traffic is the traffic sign. As in the case of any other type of traffic control device, signs must be used only where necessary and where justified by facts and field studies. Signs are not needed to confirm well-known or universally recognized rules of the road, such as that requiring drivers to keep to the right but they are essential where special regulations apply at specific places or at specific times only, or where traffic or road conditions require alertness. They are also needed to give information as to highway routes, directions, destinations and points of interest.
Legal Authority Traffic signs shall be placed only by the authority of a public body
or official having jurisdiction for the purpose of regulating, warning, or guiding traffic. Xo traffic sign or signal, or its support, shall bear any commercial advertising.
It is essential that signs be installed only under public authority. Otherwise they cannot be enforced and violators will be dismissed in court. Signs placed without authority by private organizations are often poorly placed and maintained, and are not legally binding. All unofficial and nonessential signs should be removed, as they weaken the value of the necessary signs.
Classification of Signs Functionally, signs are classified as follows: Regulatory Signs, giving the highway user notice of traffic regulations which apply at any given place or on a given highway, disregard of which constitutes a misdemeanor, and which would not otherwise be apparent. Warning Signs, calling attention to conditions in or adjacent to a highway or street, which may require slowing, stopping or some other maneuver. GUide Signs, showing route designations, destinations, directions, distances, points of interest, and other geographical or cultural information.
3

Excessive Use of Signs Care should be taken not to install too many signs, especially those
of the Regulatory and Warning type which, if used to excess, tend to lose their autihority. A conservative use of Regulatory and Warning signs is recommended. On the other hand, a frequent display of Route Markers and Directional signs, judiciously placed, will not lessen their value.
Standardization of Signs Modern highway speeds and increasingly complex intersections and
interchanges require that highway signs be recognized and understood at a glance. Uniformity and simplicity in design, position and application is of the greatest importance in aiding recognition.
All signs hereafter installed on any highway shall conform to the standards set forth in this manual. In situations where messages are required other than those herein provided for, the signs shall be of the same shape and color as standard signs of the same functional type.
Sign Shapes The significance of sign shapes has been standardized as follows: The octagon shape shall be reserved exclusively for the Stop sign, which requires that the driver shall stop near or at the point where the sign is located before proceeding cautiously. Equilateral triangle shape shall be used exclusively for the "Yield Right-of-Way" sign, which requires the driver to yield the right-of-way to any traffic approaching intersection from right or left of the intersection roads or streets ,vhich are so close as to constitute an immediate hazard. The round shape shall be used exclusively for the advance warning of a railroad crossing. Diamond-shaped signs shall be used only to warn of special conditions either in the roadway or adjacent thereto. Regulatory and Informational signs shall be rectangular. Information signs, as a rule, are rectangles with the longer dimension horizontal. Regulatory signs are ordinarily vertical rectangles. Special shapes are also reserved for other special purposes, e. g., the shield or other characteristic shape for Route Markers on U. S. and State Highway routes, and the crossbuck for railroad crossings. If other shapes are desirable in rare cases they may be used only with the approval of the official authority having jurisdiction.
4

Color Warning signs (including the round Railroad Crossing sign) and
Stop signs shall have a background of "highway yellow" with black symbols or lettering.
Regulatory signs, other than the Stop sign, shall have a white background and black letters, with the exception of Parking signs which may have red or green lettering, depending on the type of restriction imposed.
Guide signs shall be black and white. Route Markers and Auxiliary ::Vlarkers including Junction, Turn, and Directional :VIarkers shall have black letters or symbols on a \\'hite background. Destination, Distance and Information signs shall have black letters on a white background or, optionally, for enlarged or oversize signs, 'Yhite letters on a dark background.
Dimensions
The sign dimensions shown in this manual are to be regarded as the minimum standard. Increases above this minimum are permissible and desirable where investigation has shown that a large sign is needed for adequate emphasis. Hmyever, "oversize" signs should be used sparingly, in order not to weaken the effect of smaller signs.
In determining whether an oversize sign installation is warranted, consideration should be given to such elements as highway speeds, the degree of hazg,rd (as appraised by a field survey of sight limitations, intersection complications, etc., or as revealed by accident records) and the competition offered by other signs, lighting, or displays. Generally the use of oversize signs cannot be prescribed on the basis of arbitrary "warrants." Each installation is a special case for study and decision.
In the enlarging of signs, standard shapes and colors shall be used, and standard proportions shall be retained, so far as practicable.
Symbols
Where practicable, symbols are used to convey sign messages mstead of words. A simple conventional symbol like the curve arrow or the intersection diagram is instantly recognized. Symbol designs shall in all cases be essentially like those shown in this manual.
Word Messages
Most sign messages, particularly those of Regulatory and Informational signs, cannot adequately be conveyed by symbols. 'Word messages should be as brief as possible. Where applicable, standard wordings as shown in this manual shall be used.
5

Lettering
Sign lettering shall be in clear, open capital letters of the type approved by the Joint Committee on Uniform Traffic Control Devices and its sponforing agencies as illustrated.
In no case shall lettering be smaller than that shown in the sign illustrations and in manual appendix.

Illumination and Reftectorization
All \Varning signs, including Railroad Crossing signs, all Stop signs, all other Regulatory signs with the exception of Pedestrian signs and Urban Parking signs, and, on state highways and local roads, all Guide signs, shall be illuminated or reflectorized.
Exceptions to the general rule are the School sign and similar signs which have significance only during school or daylight hours and the Men 'vVorking sign and other temporary signs, if u8ed only during daylight.

Means of Illumination
Illumination may be by means of: ]. A light, within or behind the sign illuminating the main message or symbol. 2. An attached or independently mounted floodlight or floodlights, directed on the face of the sign.
Ordinary street or highway lighting is not regarded as meeting the requirements for sign illumination. However, such lighting can aid visibility to an appreciable degree and if present should be taken into consideration in selecting the exact points at which unreflectorizcd signs are placed.
All illuminations 8hall be by white light, except that a flashing light incorporated in a sign installation shall be yellow \vhen displayed with a \Varning sign or red when displayed with a Stop sign.

Means of Reftectorization

Reflectorization mav be bv mean8 of:

"-'

oj

I

1. Reflector buttons or unit:,; set into the symbol or message or

2. Reflecting coatings, either on the sign background or where a

black background or panel is used, in the symbol or me8sage.

All reflecting elements shall reflect white light, except that if a reflecting coating is used as a background of a colored sign it shall re-

flect colored light.

Sign Borders
With rare exceptions, shown in the illu~trations, all signs shall have a narrow border, of the same color as the message, just in:,;ide the edge.
For 24-inch signs the border shall be from :~/8 to % of an inch in width,

(i

set 1ll ineh from the edge, and for other sign sizes approximately in proportion, On metal :;Jgns, eorners shall be l'Ounded on a radius of
]16 im'hes,
Standardization of Position
S1<lndanlization of position ('allllot alln\~'s be at (ained in pnl<'tiee, because sign" nw"t in all eW:ies be plaeed in the 1l1Ost advantage-ous po"it ions, and mllst be aeeolllmoda ted to h igll\Y<IY de8ign and alinement, The gene-ral rule i" to loeale "igns on the right-hand side of the roac!lray, \vherf' the driver i" in the habit of looking for them, Signs in ;l/lY ot her posi tion "hould ordinarily be eonsidered only as sllpple-
r meni:! ry to signs in the normal location, nder some eirellmstances
sign" may be phl<'ed advantageously on ehannelizing islands, or overhead, or (al" on sharp elllTes to the right) on the left-hand I"houlder of the road, direetly in front of approaehing vehielel", In such eases the supplementary sign located on the left of the roadway is often helpful on a three- or four-lane road, or on a one-"'ay road \\'here traffi(' in 1he right-hand lane interferes with the driver's view to the right.
;\ll signs shall be mounted approximately at right angles to the diredion of, and facing the traffie that t hey are intended to SetTe.
Hefk(,toriz('d signs should usually be turned a little tmnml the road
to keep the ineident angle of the headlight beams near no degrees
throughout the range of useful visibility. Where mirror reflection from the sign faee is eneountered in sueh degree as to reduce the legibilit y of the signs. both non-rcflce(orized signs and thosp refleetorized wit 11 but tOilS should Iw turned slightly a\yay from the road, At eurved alillellwlll s the angle of placement "hould be dctcnnlned by the eourse of appro;lehing traffic, rather than by the roadway edge at the point whel'(' t}w sign is loeated. On grades it may be desirable to tilt a sign fonr;lrd or b;lek from the "ertieal. to improve the yiewing angle.
Signs Oil the road shoulder should be not less than () feet nor mon' thall 10 fep! from the pdge of the payement, or traYehnly, except whel'(' ('ollditions do no! permit Of "'here other requirements arc specifjpd \"itll h'gard to particular signs e!se\\'llcrp in this manual. \Vherc a raispd ('mb is pn'"en! a sign should ordinarily be plaeed adjaeent to the ro;l(!\"ay. \\'ith its nmre"t pdgc at lpast OIl(' foot baek fl'Om the curb lillP,
"Signs in rural areas should normally be mounted at a height of at least 5 feet above the cr~vn of the p~vemGnt to the bottcm of the sign. However, where parking iS,likely to occur, or where ot~er ob~tructions are present, the helght s~o~ld be at least 7 feet to the bottom of. the sign. In business and in resid~~: districts signs should be mounted at le3st" 7' 'feet>blgh to the bottom of the sign."

Overhead "ign", whether in rural or urhan areas. shall he not Ie"" than 14 feet (j inches above the road surface.
\Yarning signs are generally placed in advance of t he condition to \yhich they"'call attention. Stop signs as near as praetieable to the point \yhere the stop is to be made.
Other signs arc plaecd as required, in all ea"es as spceihed in the seetion of this manual dealing \yith indi\'idual signs or das"es of "igns.
Standardization of Application ImpOl'tant as is standardization with respect to design and place'-
ment, uniforrnit:,' of application is at least equally important. Identical conditions should always be marked \\'itlt the same type of sign". irrcspeetive of \\'here thosc particular conditions oceur.
Each sign shall be displayed for onc definite and speeific pmpo"e only.
Thi" manual sets forth eriteria for the application and \1,,1' of ail type" of sign", It is impo"sible, however, to set up speeifieations th:\t ean apply to e\'ery ease. Tlw proper signing of higll\yays depends to a "ery great extent on the experience and good judgment of the t'llgineer responsible for the plaeement and maintenance of signs,
r rban eonditions differ from rural in respe(t to 10\yer speeds, short
blocks, eongcsted traffie, parking, eompeting lights and displays, etc., and in many in"tanees signs must he different ly applied ancl loea ted, \\'here practieal, therefore. this manual set" forth separate speeifications for rural. residence, and business distrit't".
Before any nc\\' higll\\'llY or any ddo\l]' 01' temporar~' route is opelled to traffie all necessary signs shall he in place,
Change" in the traffic charal'teristies of a higll\\'ay nUl~' at an~' 1ime ('all for a reappraisal of local sign requiremcnts,
Signs required by road eonditions 01' restrictions "hall beimmedi:1 tel:,' rem(wed \\hen those conclitions eease to exist 01' tl1(' re:-;triction,; are \\'ithdrawn, Guide signs diret'ting traffic to and on ternporar~' I'Olltes or detours shall 1)(' ],(moved \\'hen no longer applieablE'.
Erection ~ ormally signs should he individually erected on separate po"ts,
except \\'here one ,;ill:n sHpplements another, or \\'here route OJ' direct ional signs must be groHpeel. T\\'() signs for different purposes ,;boule! not llP placed doseI' together than 100 feet along the high\y;)\' if it ean be reasonably avoided, Exception" to this rule are sonwt imes necessary, particularly where space is limited. but the pl'iJl('iplc is sound. Two signs closely adjacent are difficult to read at high speed on two-lane roadways.
This general role applies to signs facing in opposite direction,;, which
to minimize distn-action, should not be placed immediately opposite each other on each side of the roadway.
8

Materials
Metal treated with a rust-resistant coating shall be used for permanent signs. Wooden boards may be used fot temporary signs for special occasions or emergencies.
Such other materials as may have been accepted by the State Highway Department may be used when supplemental provisions for this manual are properly approved to that effect.
K on-corrosive bolts, screws, and washers shall be used for attaching permanent signs to their supports, to avoid discoloration.
Sign Posts and Their Foundations
Sign posts and their foundations shall be so constructed as to hold signs rigidly in a proper and permanent position, and prevent them from s\yaying in the wind, or from being turned or otherwise displaced by children or irresponsible persons.
. A portable or remoyable type of mounting is desirable for ::Vlen Working, School, and similar signs used temporarily or intermittently. Such a mounting should be heavy enough not to turn over in the wind, and its base should not be appreciably ,,'ider than the sign.
Maintenance All traffic signs shall be kept in proper position, clean and legible at
all times. Damaged signs shall be replaced immediately. Signs poorly maintained lose their authority as traffic control de-
\ices. Damaged, defaced, or dirty signs are ineffective and discredit the agency responsible for them.
To insure adequate maintenance a suitable schedule for inspection, cleaning, and replacement of signs should be established. All signs should he inspected regularly and any that are defective should be deaned, touched up, or replaced and taken in for repair and refinishing or 8crapping. Employees of the Highway Department, Traffic Police, State Patrol and other governmental employees whose duties require that they travel on the highways should be instructed to report any damaged or obscured sign at once.
Special care should be taken to see that weeds, shrubbery, construction materials. and snow are not allowed to obscure the face of any signs.

HEIGHT 8 LATERAL LOCATION OF SIGNS

STOP SIGN RURAL DISTRICT

WARNING SIGN RURAL DISTRICT

'-
..........."
4.... .

,;1010'

_

REGULATORY SIGN BUSINE SS OR RESIDENCE
DISTRICT

.~:":::" : .... -~..' .: ~:. . . ' ! ' . :.:.:.: . ..
REGULATORY SIGN BUSINESS OR RESIDENCE
DISTRICT

:":, lJ

TURN MARKING ASSEMBLY
BUSINESS DISTRICT

liTh
[BJ
NO"t I LESS 1 HAN
"

10

.4. ~,

,"
",',

. '

, ,

0 '."

'' ,'

''''''
..... ,.;,

CONFIRMATION ROUTE MARKERS
BUSINESS OR RESIDENCE
DISTRICT

LOCATION OF SIGNS

IJUNCTION I

~ Unl.cllFir ~! JUNCTiON ASSEMBLY RURAL DISTRICT

~

r

iI
I

l >-,

I

,'" j ".-------1 sl

\:{:<;,o;~"~'c-=n -_:l

C,

TURN MARKING ASSEMBLY BUSINESS OR RESIDENCE DISTRICT

--;:)j:Q;(1:9:1;"~T.H~O=M=AS.T=O=N-;-------------~ ATLANTA-+
OVERHEAD DESTINATION SIGN

II


B-REGULATORY SIGNS

Application of Regulatory Signs
Regulat0J] signs shall be used to inform highway users of certain laws and regulations enacted to promote safety and convenience upon the streets and highways, the violation of which would constitute a misdemeanor.
These signs are essential to indicate the existence of legal requirements that would not otherwise be apparent. Great care must be exercised to see that they are erected wherever needed to fulfill this purpose, but unnecessary mandates should be avoided.
Regulatory signs shall be erected at those locations where the regulations apply and shall be mounted so as to be easily visible to the motorists whose actions they are to govern. The message on the signs shall clearly indicate the requirements imposed by the regulation. Signs which have been erected but which are no longer applicable shall be removed.
By establishing uniform standards of application, location, size, shape, color and dimensions for different types of Regulatory signs the motorist can always recognize them quickly and be governed accordingly.

Classification of Regulatory Signs
Regulatory signs are classified in the following groups: 1. Stop series. 2. Yield Right-of-Way series. 3. Speed series. 4. Movement series. (a) Turning. (b) Signal. (c) Alinement. (d) Exclusion. (e) One-way. 5. Parking series. (a) Prohibition. (b) Restriction. 6. Pedestrian series. 7. Miscellaneous series.

Design of Regulatory Signs

With few f:1xceptions, Rlgulatory signs are rectangular in shape with

the longer dimension vertical. With the exception of the Stop sign

and the Parking signs, they are white, with black lettering and border.

Stop signs and Yield Right-of-Way signs are "highway .yellow" with

black lettering and border, while Parking signs may be white with

red or green lettering and border as specified.

'

12

Minimum dimensions are p;iven for each sign here specified. Where conditions require greater visibility, or where the required message cannot be accommodated on a smaller area, larp;er signs may be used, in which case all dimensions shall be increased in proportion.

Other Regulatory Signs

l I .

Regulatory signs other than those specified ab~Ye may be required

to aid the enforcement of other laws or regulations. They should be

of adequate size, and designed with black letterillg on. a white back-

ground, on rectangular plates with the 10ngeJ;., dimension vertical. They shoul~ be mounted in accordance with the general requirements

for sign position.

Typical miscellaneous Regulatory signs are Tractors With Lugs

Prohibited, Road Limit 10 Tons, Wet Paint, Do :\ot Cross Line, No

Dumping Allo\\wl, X0 Hitch Hiking and X 0 Fishing From Bridge.

The uses for such signs are sufficiently obvious to require no detailed

specifications.

Stop Sign R-l
It is commonly provided by law that State and local authorities, \,"ith reference to high\yays under their respectin=' jurisdictions, may designate through highways and erect Stop sip;ns at specified entrances thereto, or may designate any intersection as a stop intersection and erect like signs at one or more entrances to such interseetion.

Design of Stop Signs
,- .
"ONing to the importance of Stop signs they are given a dlstinctive shape (octagon) and color (red). The red color is consistent with the accepted use of a red light as a Stop signal and of the color red as a special warning of danger.

The Stop sign shall be octangonal in shape, shall have a red background, and shall carry the word STOP in white letters at least onethird the height of the sign.
The Stop sign with yellow background and black lettering now in position may remain until replacement or refinishing is required, with full legal status. All Stop signs erecteti hereafter will have a red background, and white letters."
13

,

ill tl\(, it b"elll'e of :IIlY ('( lIldu"i q' l'Y idel\('(' "hu\\'i ll~ itt 0 he h',;,; erfe(' ti\ t hall the yellO\\',

1)nfln"tnr;",tion or T1lnminatiol1

"All Stop signs shall be illuminated or

~eflectorized at least in the lettering.

=llumination may be by floodlight or by

fixed white lIght in the letters.

;eflectorization may be by white or clear t~flecting units or reflecting coating in the

:etters, with or without a red reflecting

~oating on the background. In addition to

:~ulcahshiilnlgumreidnastiiognnaol,r

reflectorization in operation both

a by

day

end by night, may be incorporated in the face

'Jf the sign or placed just abOve it."

i . .l.lll..'Cl,--\.\ .. \I\'11 , , .
applicatiull of tIl(' 1l<ll'IIlHI right-uf-\\:lY mil' i,; ullduly hazardou,;, 'J llltcr"p('tioll uf n ('()\lI\ty road u!' ('it~, ,,-,tn'l't \\'ith :l :-,t:l((' routt: :), IlltcrH'l't iUll of t\YU maill high\\'a,Y'; \dw)'(' llU trafti(' "igllal i, p)'('';Pllt, 1. ~tTPPt plltl'l'ing a 1hruugh high\yay or _,-,t rl'('\_ d, l'nCii!l:llalized illtl'r,'-'e(,tiull ill a "igllaliz('d area,
n, Haill'oad ('l'(I""illg wh('\'(, a :,to]! i" required b~' b\\' ur I)y urde!
of the authority ha\ing juri:-;diction O\'er the highway or "tree! j, Ot!wr illtcrsection where high speed, restricted view, or seriull,;
aCl'ident record indicates a need for control by the Stop sign, ~top sign" "hould not ordinarily be erected at inten3ections where traffic signals are present, The conflicting commands of l\yO typP'; uf ('ontrol device" are confusing. If traffic is required to stop ,,'hpll the operation uf Stop-and-Go signal is not warranted, the signal should 1)(' Pllt on Ha:-;hing operation \\'ith the red Hasher facing the nat1i(' that must stop. TIw "Four-'Vay Stop" installation, ,,'hel'e legal, has been found u"eful Wo; a safety measure at some location", Bpt'ause of its dPlayinf2. effeet, it should be sparingly used, It should not he used unlp,;s the volume of traffic on the intersecting roads is about equaL \\,\1(']'(' t here is any considerable v'olumeof traffie, a traffie-signal instcllJatioll is the more satisfactory solution,

Location of Stop Signs
Stop signs shall always be erected at the point where the nhil'l( i, to stop 01' as near thereto as possible, In no ease shall a Stop fiign 1)( plaeed farther than .50 feet from the intel'seeted roa(h'a~', ,\" 11 gell-

let

eral rule the distance should not xceed 15 or 20 feet, particularly in built-up areas.
In rural districts the top sign ;;;hall be placed not less than 6 feet nor more than 10 feet from the edge or the approach pa\'ement, it shall be mounted so that it bottom \\'ill be not Ie. s than 4 feet above the pavement,
In residence and business district, and at any place \\'here parked "ehicles may frequently obscUl'e the Stop sign, the sign hall be mounted 0 that its 10\\'er edge will be 7 feet aboye the top of the curb, The left edge of the sign shall be not less than 1 foot nor more than 3 feet back from the face of the curb, "-here there i a marked crosswalk on the pavement the sign shall be erected 4: feet in advance of the crosswalk line nearest to approachi ng traffic,
At an intersection "'here a wide throat exists on the " top" approach the obset'Yance of the Stop sign may be improncl by the erection of an additional 'top sign on the lert side of the approach road.
t certain channelized intersections top signs may be effecti\'ely placed on channelizing islands.
ize of Stop Sign to be Used
The size of the top signs shall he: H-IA 30" x 30", R-IB 36" x 36", R-IC"1 "x -1 " and each size shall he used as follow, See fig. 1.

USE R-IA (30)
1. On unpaved county road llltersecting state high"'ay,
2. On county road intersecting lhrough county road. On city treet intersecting lhrough cily street,
4. n city treet interse ting tale highway.

R-1A 30" x 30"

USE R-lB (36)
I. On paved county road inter~ cting paved tate high\\'ay in rural area.
oJ On unpaved state highway in-
l to. cting paved state high\\'a ' in rural area.
3. n tat highway or city lr inter ecting through .lal highway in urban area \\'h r 30" x 30" is in~de qual .

R-IB 36" x 36"

15

STOP

USE R-IC (48)
1. On payed tate highway intersecting through payed state high\my in rural area.
2. On state high\my or cit? street inter 'ecting through state highway in urban area \rhere smaller sign is inadequate.

R-1C 48" x 48"
In the event the yisibility of a Stop sign at any location is restricted, the ign shall be located a' pecifie 1 and a top Ahead sign (W-G) shall be erected not less than 300 feet nor more than 500 feet in advance of the Stop sign.
Figures 1, 2 and 15 shm\' typical Stop ign installations.

YIELD RIGHT-OF-WAY SIGNS R-2
There are some intersections \"hich, from the nature of their desio'n and the comparatiye spacing of traffic on the main road, and the les important connecting road, "'here the use of top signs would unnecessarily delay flo'" of traffic which might through the use of Yield Right-of-Way signs move more satisfactorily. While thi is true, it must be kept in mind that the Yield Right-of-Way sign could cau e trouble unless conditions are such that rea onable dri\'er rare would as ure of safe operation on the "yield" basis.
Yield Right-of-Way signs should not supersede top signs except at locations where condition \"ould render their successful control of traffic practically fool-proof.
These signs have been adopted by thl:' Joint Committee with recommendation that they be accepted by the cooperating agencie , and already the use of the Yield sign has been made legal in several municipalities through ordinances, and Georgia's Act No. 854 authorize its use on the roads and streets of the State, in Article IX, Section 72 (c).

IG

STOP SIGNS
TYPICAL INSTALLATIONS
STATE HIGHWAYS, COUNTY ROADS. CITY STREETS

CD
8 R I-A

8 "R 1-8
GJ
~TO~
II Ii
R I-C

FIGURE I
17

TYPICAL LOCATIONS FOR STOP SIGNS

Locotlon of STOP sll)n In large surfaced intersection orea. Right turns moy be mode 10 right of STOP sign

Location of STOP s.gn when surfaced area IS relatively small

~--=c,---,o'8TOP

.~.

~~

:::--...".
\\ I,l; \\ II/,

/','WI',
//' <?o

Location of STOP sign in lorg8 surfac~d area of TEE intersection. Turns may be mode 10 flgh I and lett of STOP sign.

FIGURE 2

II
Lacollan of STOP $lgn$ at TEE intersection \Wlfh island

18

Yield Right-of-Way signs hall be in

shape of an equilateral triangle, with the

point rounded off to IP1-inch radiu , and

baving minimum length on each ide of 30

inches before rounding corners. The Yield

sign will be displayed with one of its point

downward. It is recommended that the

sign be at least 36 inches on each side,

ince the message of the sign should be

clearly visible at such distance that will

permit drivers to move toward the inter-

etion under proper peed control and

alert to ob erve approaching traffic in all

R-2
36"

other lanes.

The sign will be yellow with black letters,

and reflectorized for night visibility.

WARRANTS FOR YIELD RIGHT-OF-WAY SIG S
.\.t no place bould Yield Right-of-Way signs be used unless (a) th r is relatively light traffic entering the heavier traveled road from th intersecting road; (b) or where the cros ing or merging traffic . t!'cam at an inter ection are about equal in volume with frequent inter":11 in each that permit safe crossing and merging movement of \'chicles; (c) and where there is good visibility in both or all direction ; (d) and unless it is clearly shown that traffic will b effectively controlled through the use of the Yield Right-of-Way signs. When('\' r th re is any doubt as to the effectiveness in its use, install Stop .ign or other controls instead.

LOCATIO OF YIELD RIGHT-OF-WAY SIGN
Yi lei Right-of-Way igns hall always be erected at the point where th v hicle must come to a stop if the right-of-way should be yielded to v hide in another lane, or as near thereto as possible. The distanc from the intersected highway should not exceed 15 or 20 feet !lnd n v l' more than thirty feet. In built-up areas it should be a minimum of 12 to 15 feet.
In rural area. the Yield Right-of-Way sign shall be placed not Ie s
than .re t nor more than 10 feet from the edge of the approach pave-
m nt; It f;hall be mounted 0 that it bottom will be not less than 4
r t aho\' the pavement.

19

In residence and business districts, and at any place \yhere parked vehicles may frequently obscure the Yield sign, the sign shall be mounted so that its lower edge ,vill be 7 feet above the curb. The left edge of the'~ign shall be not less than one foot nor more than three feet back from the face of the curb. Where there is a marked crosswalk on the pavement, the sign shall be erected 4 feet in advance of the crosswalk line nearest to approaching traffic.
At an intersection where a wide throat exists on the Yield Rightof-Way approach, the observance of the Yield Right-of-Way sign may be improved by the erection of an additional Yield Right-of-Way sign on the left side of the approach road. At certain channelized intersections, Yield Right-of-Way signs may be effectively placed on channelizing islands.

SPEED LIMIT
60
5 5 TRUCKS
UNDER
5 0 10000 LBS
10000 TO 16000 LBS
4 5 OVER
16000 lBS
R-3 30" x 42"

SPEED LIMIT SIGN R-3
The Speed Limit sign R-3 shall be a vertical rectangle not less than 30" wide by 42" long in size, having black letters and numerals on white background. They shall indicate a daytime speed for automobiles of 60 m. p. h. and nighttime speed of 50 ffi. p. h. For trucks under 10,000 Ibs., a daytime speed of 55 m. p. h. shall be indicated and a nighttime speed of 50 m. p. b. The change from day to night speed limits may be indicated on the sign by using proper type of reflecting material to show the correct night speed while the day speed would not be reflectorized and would show the correct day speed limit in daylight only.
The sign shall indicate that speed limit for trucks weighing from 10,000 Ibs. to 16,000 Ibs. is 50 m. p. h. ~o change from day to night, and the limit for trucks weighing over Hi,OOO Ibs. is 45 m. p. h. with no change from day to night.

20

LOCATION OF SPEED LIMIT SIGN
Speed Limit signs indicating statutory speed limits shall, "'hen used, be located at the point of change from one type of speed zone to another, and at intervals not to exceed 10 miles bet,Yeen speed districts.
In rural districts on r. S. and
State numbered routes Speed Limit signs indicating the statutory speed limits shall be erected at the entrance to the state and boundaries of metropolitan areas. A special oversize sign shall be erected at state boundaries.
Signs indicating altered speed limits shall not be erected until the altereel speed limits are approved and officiall~ authorized. In such cases a Speed Limit sign shall be Im'ated at the beginning of each section where the speed is altered and at appropriate intermediate locations. At the end of such sections there shall be erected a Speed Limit sign showing the next speed limit.

SPEED LIMIT
50
5 0 TRUCKS
UNDER
5 0 10000 LBS
10000 TO 16000 LBS
4 5 OVER
16000 LBS
R-3
30" x 42"

SPEED LIMIT SIGN R-4, R-5
The Speed Limit sign (R-4) shall be a vertical rcdallgle 1I0t Jess than 18// x 24// in size having black letter,.; and numerals on a white back~round. Jklmy the ,yards "Speed Limit" the speed limit ill miles per hour is shown in large lIumerals. The speed limit shall he the speed limit established after appropriate engineering and traffi( inn'stigatioll according to Imv. The sr:ed limit ,.;hall he shmm in multiples of 5 mIles.
The Speed Limit sign (H-;j) shall he 24// x 30// antI shall be used where deemed necessarv" to designate t11(' ,.;peed limit established aft;r appro~riate enginecring and traffic investigation accordmg to la\\'.

SPEED LIMIT
25
R-4 18" x 24"
SPEED LIMIT
55
R-5
24" x 30"

21

SPEED ZON[.. AHEAD
R-6 IS" x 24"
SPEED
ZONE
AHEAD

SPEED ZONE AHEAD SIGN R-6, R-7
The Speed ZOlIP Ahead sign may be pla<:ed ill advauee of an authorized speed zone to inform motori"ts that they arc entering a seetioll where the statutory limitH have been altered.
It shall have hla('k lettering on a white baekground and it shall be 18" x 24" 01' 24" x :30". In rural districts it shall be placed not leHs thaI, ~OO feet nor more than ,')00 feet in adnlllce of the speed zone. In all cases it shall he erel'ted in the same manner as the Speed Limit sign.
This sign must always be followed by the regular Speed Limit sign erpetcd at the beginning ot the zone wh,erp the altered speed limit applies.

"If th'? speed zone exceeds three miles in length, the sign shall indir:;ate i t.s ii?prozimate length."
TURN PROHIBITION SIGNS R-8 TO R-15, INCLUSIVE
Turn Prohibition signs shall be used at interseetions to indicate regulations prohibiting the types of turns speeified.
No U-Turn sign may also be used between intersections on a wide roadway where dangerous U-turns might he made. Where r-tUl'1lS are prohibited by statute throughout a given area, it is unneeessary to erect Prohibitory signs at or between intersections as preseribed aho\"!'.

NO
RIGHT TURN
R-S lS" x 24"
R-9 14" x 9"
NO
RIGHT TURN
R-SA 24" x 30"
22

NO
LEFT TURN
R-10 lS" x 24"
R-ll 14" x 9"
NO
LEFT TURN
R-IOA 24" x 30"

NO
U
TURN
R-12 lS" x 24"
~ TURN R-13 14" x 9"
NO
U
TURN
R-12A 24" x 30"

NO
TURNS
R-14 lS" x 24"
[]&] TURNS
R-15 14" x 9"
NO
TURNS
R-14A 24" x 3D"

TURN PROHIBITIONS SIGNS
TYPICAL INSTALLATIONS
PROHIBITED

INOllo"NI TURNS

I =~lo~l= :II:

1

~

~

Z_

II
. Ii

Ii

11 :0: Imnl I
INO/ ON
TURNS
1/ ALL TURNS PROHIBITED
FIGURE 3

23

TYPICAL INSTALLATION OF SIGNS AT END OF ONE- WAY STREET
II
aV3HV JIJJVMl ~
AVM OMI
=---=_--- ~~-- -1-----~-.-
II
j, \
jI
)II
FIGURE 4
24

--- --- ----------------------~
PORTABLE TURN PROHIBITION SIGNS
TYPICAL INSTALLATIONS
I NO
LHT TURN
- - - - - - ) ~~------
~\

"~'F~/,t'_E ~~:R~ SiGNS MAY BE USED WHEN ,,\ EFFECT AT ALL TIMES, OR TO SUPPLEMENT PEAK THAFFIC PERIODS
FIGURE 5

TURN PROHJBJTIONS ARE NOT PERMANENT TYPE SIGNS WRING
_ _ _ _ _ _ _ _ _ _ _ _---J

25

TURN PROHIBITION SIGNS R--8 TO R-15, INCLUSIVE-Continued
Turn Prohibition signs shall be 24" x 30" in size except that where mounted blBow pedestal type traffic signals where vertica\ Clearance is limited they may be 18" x 24" in size. The 14" x g" sign: may be used on overhead signals where vertical clearance is limited. The~' shall have black lettering on a white background. Figures 3, 4 and 5 show typical locations for Turn Prohibition signs.
'Where required at unsignalized intersections, the ?\0 Hight Turn sign shall be placed on the ncar right-hand and far right corner. 'Where No Left Turn, No C-Turn or No Turn signs arc required, two shall be used, one at the far right-hand and one at the far left corner. Such signs shall be mounted, facing traffic approac'hing the intersection, so that the bottom part of the sign will be not less than 7 feet nor more than 10 feet above the top of the curb and so that no part of the sign will be less than 1 foot back from the face of the curb. ,\t signalized intersections the signs shall be mounted just below pedestal type signals, and additional signs should be placed as necessary, at or in advance of the intersection. If advance signs are used, Care should be taken that no alley or driveway exists between them and the intersection where the turning movement is prohibited. At an interseetion ,,,ith a one-way street, whether signalized or not, the One-\Vay sign (R-22) should be used, rather than the Turn Prohibition sign.
A. Turn Prohibition sign mounted on a traffic signal installed directly over any roadway shall have a clearance of at least 14 feet () inches above the roadway.
When the movement restriction applies during brief periods only, the Turn Prohibition sign shall be mounted on a movable pedf'stal and placed in the roadway adjacent to the curb or in the middle of the intersection only during such periods.

,,--o-0--1
NOT
P A ~_s_J
R-l6 24" X 30"

NO-PASSING SIGN R-16
The 00 Not Pass sign may be used on two and three-lane roads at the beginning of a zone through
which restricted si9ht distance makes overtaking and:pqssin,g hazardous. It shall_~aveblack letters on a whitebi3,ckground, and be of a minimum size of: 24 ..
inches by 30 inches. There will be
a 5/8" black border, 3/8" frOlllcedge of sign. It shall be erected at the right-hand side of the roadway at a height of 5 feet to the bottom of the sign, not less than 6 feet nor more than 10 feet from the edge of the roadway. Because a driver about to pass a vehicle ahead often has only restricted view to the right, an additional
sign on the left-hand side of the road may be desirable.

The sign normally should be supplementary to

standard pavement markings as described in Part

II, Section B, Pavement and Curb Marking,

Page 103. Where pavement markings are well .

mtoaihnitdaeinethde,

and weather condition markings, the Do Not

s are Pass

snl.gont

lnlekeedl)

not be used."

The sign normally should he supplementary to standard pavement

markings. \Vhere pavement markings are well maintained. and weath-

('I' ('OlHlitions are not likely to hidet!le markings. the No-Passing sign

111,{,d not, hp n""d

- .... .~ --~--_
PAS S

"Pass With Care Siqn R-17 -
The Pass With Care sign may be used at the end of a no-passing

WIT H
i
i CAR E

zone where Do Not Pass sign has been erected at the beginning. It shall be of the same size and color, and shall be erected

.
._-~--------
R-17

in the same manner as the Do Not Pass Sign."

24" x 30" ;"u PA~~lNG WHEN YEL-

LOW LINE IS RIGHT OF CE~TERLINE SIGN R 18

NO PASSING

The :'\0 Passing When Ye]1m\" Line bHight of Centerline sign shall he reflect orized. It shall be placed at JO- to Lj-mile int('l'\"als on each side of any

WHEN
YELLOW LINE

higlmay \\'hieh has been marked with ydlO\\' ":'\0 Passing" or "Barrier" lillPs. This sign nUlY

IS RIGHT OF

he used in place of sign R](j in hill~' ('oulltry \\'here "BaITi"r" lines are I 00 numerous to permit the us,, of sign !{-](i.

CENTERLINE
R-18 48" x 60"

KEEP RIGHT EXCEPT TO PASS SIGN R19
TI1P !\:(.,'p ltight Exeept to Pass sign may be uspd on mull iple-l~lIH' pa \"('nwllts wl)('re motorists
Hre J'('quir,'d to kl'ep in the right Jalle exeept
when passing, I t should 1)(' ereeted :300 feel from tl)(' ])('gi!lllillg of a multiple-laIH' pa\'(~nl('llt.
and at 01 her 10('a t iO!l,; when' i here is a hmdellc\" on the parl of ill(' mo1orists 10 drive in tIlt' iJ~ sidp lane or laIH''; \\"}lP!I not pas,;ing.
This sig!l ,;hall be a \'prtintl l'(~('tallgle :21" x 30" in sizp. wil h hlad; Ipttpring on a white hack~oulld. It shall 1)(' pla('ed on the right-hand I SIde of til(' road \\'a.\", faei ng approach ing t raffi(',

KEEP RIGHT
EXCEPT TO PASS
R-19 24" x 30"

KEEP

with the hottom of the ",ign at tL height of 4 feet abon~ the edge of the pan'ment, and noi less than li feet 1101' more than 10 feet from the edge of the pavement. See fig. 11.

RIGHT
-~ R-20 24" x 30"

KEEP RIGHT SIGN R-20
The Keep Right sign shall be used within and ll,t the ends of Il?tedian strips, parkways, loading islands and refuge islands, at traffic islands \yi~h eurbsin,ore thl1n 3 inches high and at underpass piers wltrr~ tr;tff}s~ is required to keep to the right of such obstructions.

The sign shall be a vertical rectangle 24" x 30" (oversize sign 48" x GO" may be used where necessary), with black lettering and arrmy on a ,Yhite hackground. It should normally be mounted at a height of 4 fpet to the hottom of the sign.

On a median strip the Kpep Hight sign should he mounted about 2;'') feet 1leyond the approach end of the island. On a pedestrian island

or intersection dwnnelizing island it should be mounted at the upproueh end or as close thereto as praeticable. It should he mOlll1t c'd on the faee of 01' just in front of a pier or other o11struetion in the CC'Iltel' of the roadway.

~Where traffic is permitted to pass to either side of an island or other OhHntetion in the road\"ay, the Double-Arrow ~Warning sign (W-:!l)

may be used.

DO NOT
ENTER
R-21 24" x 24"

DO NOT ENTER SIGN R-21
The Do ::'\ot Enter sign shall be ('onspic\1oll",I~' placed at the end of a one-way roadway or ramp to prohibit traffic from enterillg the restrieted seetion. It should he 24/1 x 2c1" ,,'ith hlack ll'ttt~ring on a white haekground. It slw II be mounted on the right-hand side of the roackay. faeing trafEc entering the roadway 01' ramp in the ,\Tong direction. III rural di"tri('b i1 shall normally he erected at a height of not 1(''';''; than 4 feet to the bottom of tIl(' sign and as ('lose to the pavement edge as practicable. In residence or business districts or ,,,here a low mounting will not give adecluate visihilit~, it shall he mounted not less than 7 feet nor mon' than 10 feet above t.he curb or roalhnty.

28

ONE WAY SIGNS
TYPICAL INSTALLATIONS

-

I

m j mm

(1 I

- - - -

--

--

~-_.~

I I

f1

--_ - -

..- - - - - -

- - ,....

--------.----- _-- --~---_..

------.---

I

mm' 'rn

INTERSECTION OF ONE - WAY STREE 1 WITH TWO-WAY STREET

filM 3NO J

- - -- ----~- ~ ~

c

m

,m
------ - ~
-~-~
J'A.'VM 3ND~

INTERSECTION OF ONE- WAY STREET WITH ONE- WAY STREET
FIGURE 6

29

ONE-WAY SIGN R-22

t:ONE WAyl
R-22 36" x , 2"

The One-Way sign shall be used to indicate streets upon which traffic is allowed to travel in one direction only. It shall consist of a white arrmv symbol on a black horizontal rectangle 36" x 12" in size. Centered in the arrow shall be the words "One-\Vay." The sign must be made in "rights" and "lefts."

One-Way signs shall be placed as shO\vn in figure G. Where the intersection is signalized, the signs shall be placed above or belO'v the appropriate signal faces. One-Way signs shall also be placed parallel to the one-way street directly opposite the exit from the drivevvays, alleys and other publicly accessible places. A One-\Yay sign should always be used, where applicable, rather than a Turn Prohibition

sign.

At unsigrmlized intersections the One-Way sign shall be mounted not less than 7 feet nor more than 10 feet above the top of the curb or pavement, and "'ith no part of the sign less than 1 foot from the

curb line.

TWO-WAY TRAFFIC AHEAD SIGN R23

TWO WAY
TRAffiC
AHEAD
R-23 24" x 30"

The Two-Way Traffic Ahead sign shall be used on a one-way street in advance of an intersection beyond which the one-way traffic regulation does not apply. It shall be a vertical rectangle 24" x 30" in size. with black lettering on a white background.
This sign should not be used on a O!H'-\my ('onnecting ramp or channelized road\vay, or at the end of a di\'ided stretch of street or a1 a T intersection where a one-way street ends.

The Two-Way Traffic Ahead sign shall be placed on both the right and left-hand sides of the strc~t. not less than 50 feet from th(' intersected street. It shall be mounted not less than 7 feet nor more than 10 feet above the top of the curb, and with no part of ttl(' :-;ign less

than 1 foot back from the face of the curb.

30

PARKING SIGNS
TYPICAL IN STA LLAT IONS
(

~
~".i'l

l

[~E:!=
q

GJr.I;::~~=IC:::C:::CII~:r:r::J::J=~J~~;r'i
r'H'J =i1If~ ~]dt~,

FIGURE 7

I

31

PARKING AND STOPPING SIGNS R-24 TO 31, INCLUSIVE
Parking signs and other signs governing the stopping and standing of yehicles .[;.0\"81' a yery "'ide yariety of regulations and only general specifications can be laid do"'n here, Typical examples are as follows:

NO
PARKING
ANY TIME
R-24 12" x IS"

NO
PARKING 8 A.M. TO 4 p. hi
R-25 1l" x 1S"

NO ANGLE
PARKING
R-26 1l" x lS"

NO
~TOPPING
OR
STANDING
R-27 12" x 1S"

ONE HOUR
PARKING fROM 9 AM TO 7 P1\
R-2S 12" x lS"

NO
PARKING BUS STOP
R-29 12' x lS"

NO
PARKING mE TO CORNER
R-30 12" x lS"

NO
PARKING LOADING
ZONE
R-31 1l" x 18"

Other \rarding,. ma~' be used to fit local conditions, The legend on Parking signs shall ::;tate \rhate\'er regulations apply, but the signs shall conform to the standards of shape, color, location and usc,
Generally Parking signs should display such of the follo,,'ing information as is appropriate from top to bottom of the sign in the oreler listed: See fig, 7,
]. Hestriction of prohibition, 2, Time of day it is applicable, if not at all hoUl's, 3, Days of \reek applicable, if not eYery day.
Where parking is prohibited at all times or at .-pecified times, Parking signs may haye red letters and border on a \rhite background (Parking Prohibition signs), and where only limited time parking is permitted, or \\'here parking is permitted only in a particular manner, the signs may haye green letters and borders (Parking HestrictioD signs),
'Vhere parking is prohibited during certain hour and permitted under a time limit at other periods of the day, tIro Parking sigru should ordinarily be used. the red abO\'e the green; but, as an alterna tiYe, both messages, in different colors, may be used on a single plate ,,'ith the sign lengthened yertically, if necessary.
In residence and business districts, Parking signs shall be L2" x 18' in size. Where seYel'31 restrictions 01' qualifications mu:;t. be set forti
32

the yrrtieal If'ngth of th(' sign ma)" be in(')'('a,,('d a" n('('e""ary. Whl'IT ne('e",,:1I"y thl' size of tlw sign may he inneased to 1S" x 24".
Parking "igns in re"idenee and busine"s district" shall be mounted not less than 7 feei nor more than 10 feet abon- the lOp of the eurh. all<!\\'it h no pari of the sign Ie"s than J foot h~l<'k from tIl(' faee of the eurb.

NO PARKING ON PAVEMENT SIGN R-32

In mral districts :\"0 Parking on Pan'll1pl1t

"ign (l{,;32) may he used to ('lnphasiz(~ the pro\isiolls of law that no !wrson "hall "top. park. or lean' ,;tanding any ,'ebide upon thp paved part of the higll\n1Y ,yhpre it j,; prach('al to leaye swh \'ehide ofT ,;uch part of the highway.
The ,;jgn should be u,;ed primarily at point,; of s('cnie beatity or other points of intprest. where

NO
PARKING
ON
PAVEMENT

\'iolatiol1" are prevalent. and ',",)pre stopping or parking on the payement ohstt"1wts the norma] flow of traffie. If npeessary tlw ,;ign may he

R-32 24" x 30"

made io read ":\"o Stopping 011 Ptll'ement."

These sigm; shall be 21" x ~30" in size. They shall IJP mounted at

right angles to the p'lTement, faeing approaching trnffie and not les"

than () feet nor more than ]() fept from the edge of the pavenwnt.

They should ordinarily be refleetorized. Where Off-plIH'nH'nt parking

is likPly to occur, they should he 11101l11ted not Ie"" than 7 feet nor

more than 10 feet ahove the pavenlPnt level. If parking is not prar-

tical. they should be at a height of not le"s than 4 feet to the hottom

of thp "ign. They should be lOl'a ted at thosc point" \\'here haza rdou;; parking i" likel:-' to oc('UI'. and at neeeSS~tr)" intelTab t h rollgholl tan)"

;;;cetion \\"hpl"!' j he ('ondition exists.

PEDESTRIAN CROSSING SIGNS R33, R-34
Pedestrian ('ro;;"illg sign" may Ill' used to supplemPllt trafti( "igllul control. or to aid ill limiting pelJc.,,trialls l'I"ossillg: to "afp plal'e". '1'11<'1' will ordinarily hp
~I\lired ollly ill hll;;ill('''s di"tri(t" or at signaiizPd
mt'I'!;('c,t ions"
Y('<.!pst riall ('ro;;"illg ;-;ig:n,.; ;;hall Iw J 2" X 18" in "iz('. With hlllc'k !c'Upr" Oil :I whitp haekgrollnd. Thev shall he rf('rtpd to fu('p )led(,,,trian,, ahollt to (']"0"" thl.: roadway, at.lI IH,jght of :I)lJlroximatel:-" 7 f('('t to the hottom oI f th'r SIl/.:n' ,rll('!'(' "g']"'1 laI" aJ"(' pre8ellt.. an appropn.ate OC&hon II' on tIll' )lost "lI)l]lortillg the signaii'.

CROSS
ON
GREEN LIGHT ONLY
R-33 12" x 18"
USE
CROSS WALK
R-34 12" x 18"

ROAD CLOSED SIGN R-35

ROI\O
CLOSED
R-35 36" x 24"

The Road Closed sign shall be used to mark roads which have been closed to all traffic (except the contractor's equipment and such vehicles as may be permitted to enter for access to residences on the closed portion of the road) either because of construction or maintenance operations or because of a temporary emergency such as high water or a land-

slide.

It should not be used where traffic is maintained or where a route is detoured several miles in advance of the actual construction or block-

ade.

The Road Closed sign shall be 36" x 24" in size, with black lettering on a white background. I~ shall be illuminated or reflectorized.

The sign shall be mounted on a barricade in the center of the roadway or directly facing traffic on the right half of the roadway, at a height of 4 feet to the bottom of the sign. See figure 13 for placement.

STOP fOR
SCHOOL
BUS
LOADING UNLOADING
R-36 18" x 24"

STOP FOR SCHOOL BUS LOADING AND UNLOADING R-36
The Stop for School Bus sign shall be placed along the highway where school buses travel. They shall be erected at intervals of 3 to 5 miles.
It shall have black letters on a white background, and be a minimum size of 18" x 24". It shall be erected at the right-hand side of the roadway at a height of not less than 4 feet to the bottom of the sign.

SIGNALS SET fOR
25
M. P. H.
R-37 18" x 24"

TRAFFIC SIGNAL SPEED SIGN R-37
The Traffic Signal Speed sign, reading "Signals Set for (25) M. P. R." may be used to indicate the beginning of a section where the traffic control signals are coordinated into a progressive system and timed for a specified speed.

The signs, 18" x 24" in size, with black lettering on a white background, should, if used, be mounted on, or as near as possible to each signal face where the timed speed changes, and at interv2tls of two blocks throughout any section where the timed speed remains constant.

34

LOAD LIMIT SIGN R~38

Due to seasonal weakening of the road ::;\11'face, obsolescence of bridges or pavement, or other impairment of a roadway, it is often nece::;sary to limit the load permitted on a road\ray. The Load Limit sign, reading "Load Limit (10) Tons," shall be used to indicate such restrietions. The sign "hall be 18 inche" by 24 inches in size, with black lettering on a white background. It shall be located immediately in advancc of the bridge or other structure to which the restriction applies. In the case of an extended length of road, the sign shall be placed on the righthand side of the restricted roadway approximately 25 feet from any intersecting road 011 which the restriction does not apply, so as to be dearly visible from all vehicles turning into the restricted roadway. A supplemcntary si!!;n may be necessary on the left-hand side of the roadway. If the limit applies at an intermrdiatc point wherr there is no alternate routing. a special sign should be provided to diYf'rt heavy \'ehides at the nearest interseetion where a suitable detour is available.

LOAD
LIMIT
TONS
R-38 18" x 24"

Load Limit signs in rural districts shall normally be erected at a hei!!;ht of 4 feet to the bottom of the sign, and not less than 6 feet nor more than 10 feet from the roadway edge. In residence or business districts wll('re a low mounting height \rill not give adequate visibility they shall he mounted not less than 7 feet nor more than 10 feet above the eurh or road\yay. On entrance ramps or channelized roadways, or where a ('mb is present, they shall be as dose to the pavement edge as practieablC'. ,,'ith a minimum of 1 foot to the nearest edge of the sign. :\t bridges they may be mounted on the bridge structure.

Other Regulatory Signs
Hegulatory ::;ign::; other than those spccified above may be required to aid til(' enfoJ'('C'ment of other Imvs or regulations. They should be of adequate ::;ize, and designed with black lettering on a white background, on reetan{o!;ular plates \yith the longer dimension vertical. The~ should br mounted in ac(~ordan('e ,,'ith the general requirements for SIgn pm,ition or as neees::;ary to make them mOi'lt effective.

35

Typical miscellaneous regulatory signs are Tractors With I~ugs Prohibited, Wet Paint-Do Not Cross Line, No Dumping Allowed, No Hitch Hiking. and No Fishing From Bridge. The uses for such signs are stfl'ficiently obvious to require no detailed specifications.
36

C--WARNING SIGNS
Application of Warning Signs
Warning :5ign" shall be used for the plll'pose of warning traffic of hazardous conditions cit her on or adj acent to the road. \Varning "igns rcquire caution on the part of the motorist and generally call for reduction of speed in the interest of his cy\\"n safety and that of other motorists and pedestrians. The use of \Varning signs should hc kept to a minimum. Too frequent use of them tends to breed disrcspeet for all signs.
Typical locations and hazards that may \\"unant the use of \Yarning signs arc:
I. Turns. 2. ClIl'Yes. 3. He\'crse turns and curves. 4. SlH'cessions of ClilTes. with or without short tangents. ;). Tnten.,ections. 6. Ad\'ancc warnings of stop signs and traffic signaI:-. 7. (;rades, dips and bumps. 8. Changes in pavement widths. 9. ;\arrow roadwayR. bridges and other pointR of limited
clearance. 10. Hoad construction or repairs. II. OtllPr temporary road conditions. 12. Pedestrian iRlands 01' similar obstru(,tions. 13. School zones. 14. Hailroad crossings. ];j. Entrances and crossings. Determination of the sign to be erected shall be in accordance with the criteria s('1 forth in the follmving pages. When doubt exists as to which sign to usc, the one requiring the minimum restriction shall be ereeted. Warning signs shall be applied only as specified in this manual. Those spc('ified herein cover most conditions tha t arc likely to be met.
Design of Warning Signs
Wuming signs ('onwy their message IJy legend or symbol, color and shupe. All ;;lIall havc a "highway yellc)\\'" background, with black lett('l'in~ or ;;~-mbols. They shall be diamond shaped (squarc \vith one diagonal \'crl ica!) \vith the exception of the Hailroad Advance W~ming ;;ign, \\-hidl shall be circular, and the Ach-isory Speed sign. which shall be squarE'.
All W.arning signs shall be reftectorized. unless otherwise specified. The Sizes of sign;; here shown are to he regarded as minimum sizes.
Where conditions require greater visibility or emphasis, larger signs
37

I,~

CURVE SIGNS

TYPICAL INSTALLATIONS

~ [f1~

3:
/~~-
VIV'I-


.0., II

.0 45' W' MPH II
I

~"

~~ 'II II'"

<$>.,

15

j-L

M P I"t

FIGURE 8

II

38

should be used with symbol or legend enlarged approximately in proportion to outside dimensions. (The dimensions are measured along' the side of the diamond, not diagonally.)

Location of Warning Signs
Since Warning signs are placed primarily f~)I' the protection of the driver who is unacquainted with the roads, it is very important that
thought and care be given to their location and erection. Although it
is pecified herein at what distances the signs shall be placed in ad-
yance of the hazards warned against, there will be many instances
where physical conditions 'will require different distances. Trial runs
hould be made by day and by night to determine the most effective
location and erection characteristics for each installation. In cities,
II"here speeds are relatively low, Viarning signs should usually be placed
nearer to the points of hazard than on rural hig!J.wa s.
"In rural and residence districts where no parking occurs, Warning signs shall be erected not less than 6 feet nor more than 10 feet from the edge of the pavement or ... .,' traveled roadway, with the lowest edge of the sign not less than 5 feet above the roadway, except as hereafter indicated. In any location where they will obstruct sidewalks or pedestrian paths, however, they should be mounted at a height of not less than 7 feet to the bottom of the sign. In residence and bUSIness districts wnere
parki n9 is frequent, theY" s!1all be so set
that the bottom of the sign is not less than 7 feet above th~ top of the curb and lefthand edge not less than one foot back from the outside edge of the curb.'"

'ither to the right or left shall tw u: I to mark a curve in the lin ment of the highway.

. II 'u['\,e sign shall be reft torized.

ThE' 'un' 'Ign hall be erect-

not I." than 300 feet nor

m than 750 feet in advance

th h ginning of the curve

W-l



'

24" x 24"

Thhfrobm'(ogtItltohmehalO dlfgbeteheomf o.Itguhl1ne,tepadanvdneomntoeltnetsl.essstThtahhnea

6 feet from n 6 feet nor S'Jgn should

the pavem .more than be erected

ent 10 at

39

REVERSE

CURVE SIGNS
INSTALLATIONS

TYPICAL

.

,. ~.

<t>W0 3

40

'" P Ii
I

W-28

-10

such height in excess of the llliillll1Uill requirements to be the most effective at the greatest distance.
On curves having a safe driving speed of less than 60 miles per hour the Advisory peed sign (W-28) should be mounted below the CLuTe ign and shall show the safe peed that the curve can-be dri,'en. See
fig, 8.

TURN SIGN W-2
The Turn sign (W-2) 36" x 36" showing an arrow bent at a 90 angle either to the right or I ft shall be used to mark a right-angle turn in the alinement of the high\yay. See fig. 8.
All Turn ign shall be reA torized.
The Turn sign shall be erected not Ie than 200 feet nor more than 7 0 feet in advance of the turn.
It hall be mounted so that th b ttom of the sign will be not Ie than 6 feet above the puyement surface, and not les thun 6 feet nor more than 10 f t fr m the edge of the pavem nt.
The .\ hoi ory Speed sign (W:! I 'hull be mounted below the Turn .ign and shall how the
fc sp<, d that the turn can be drivE-no

W-2 36" x 36"

'ER E RVE SIG W-3
Th HE-verse Cuwe sign (W-3) _'I" .' '21" -hall be used where t\\ 0 ('IlrWs in oppo ite directions
purat d by a tangent of than -l00 f et. It shall show n rrow ('un' d twice in oppo-
I di~tion"
11 Htvcrs(' '\I n' ..igns shall ft toriz('(l.

W-3 24" x 24"
41

W-4 36" x 36"
42

The sign shall be erected not less than 300 feet nor more than ~50 feet in advance of the beginning of the first curve.
It hall be mounted not Ie s than 6 feet from the bottom of the sign to the pavement sur face, and not less than 6 feet nor more than 10 feet from the edge of the pavement.
On reverse curves having a safe driving speed of less than 60 mile per hour the Advisory
peed sign (W-2) shall be mounted below the sign and shall show the safe speed that the curves can be driven. See fig. 9.
REVERSE TURN SIGN W-4
The Reverse Turn sign (W-4) ize 36" x 36" shall be used where two turns in opposite directions are eparated by a tangent of less than 400 feet. It hall show an arrow bent at 90 angles in opposite directions.
All Reverse Turn signs ball be reflectorized.
The sign shall be erected not less than 300 feet nor more than 750 feet in advance of the turn.
It shall be mounted not I than 6 feet from the bottom of the ign to the pavement urface, and not less than 6 feet nor more than 10 feet from the edge of the pavement.
The Advisory Speed sign (\\'28) shall be mounted bela\\' t Reverse Turn sign and sb show the safe speed that th turn can be driven.

W-IA 48" x 48"
W-2A 48" x 48"
PPLEME TAL CURVE AND TURN SIGNS W-IA, W-2A. W-3A AND W-4A
ur... and Turn igns (W-IA, W-2A, W-3A and W--4A) 48" x 48" tx- uMe<l to upplement Curve and Turn signs (W-l, W-2, W-3 ) on ur\'e' which require a substantial reduction in speed.
43

They hall be placed at the point of intersection of the curve i

direct line with approaching traffic. See figs. 8 and 9.

n

The sign.s shall be mounted not less than 4 feet from the bottolll
of the sign"1,0 the pavement surface, and not Ie than 6 feet nor more

than 10 feet from the edge of the pavement.

_-\1I Supplemental Curve and Turn signs shall be reflectorized.

W-3A 48" x 48"

W-4A 48" x 48"
44

DI G ROAD SIGN W-5

Th Winding R oad sig~ sho~

in lin arrow bent four tlIDes ill

pp()~"1"(c dir ctions h" all b_ e used

"mIolercn'

(here i (UJ'Il' or

a senes of b or cur~es, as defined

in (h \I'arrant for Turn and

(ur\"{' "ign, eparated by tan-

enl di,tance of less than 400 I If the fir t turn or curve

.ret:, th right, a right Wincling I oml ~ip;n (W-5-R) shall be
I and if the first turn or
II.
(,u["\'c i" (0 the left, a left Wind-
in!/: Ron I sign (W-5-L). All

Winding Road signs shall be

reflcdorized. Additional protection may be

provided by the installation of road ddin ation markers by use

W-5 36" x 36"

of the Advi ory Speed sign (W-

:? l. Where there are fewer

Ihun ,) curve in succession, one

or more Re\'erse Turn or Re\'f'~c C1I1Te 'ign should be used.

'I'll(' Winding Road sign shall be erected at the beginning of the first

. ri . of curves. In advance of Uti sign either a Turn or a Curve

.j n 'hall be erected howing the direction of the first curve. The e

ijtn . shall be erected in accordance with the general pecification for

IIII' pll\('ement of Warning igns.

TOP AHEAD SIGN W-6
Th . (op Ahead sign shall be II,,('I! in acl\'ance of a top sign which i' not visible for a suffi(,iml distance to permit the dri\, r (0 bring his vehicle to a lop at. (h top sign, Obstruction of "ie\\' due to horizontal or \" rt i('al curves, parked vehicles, or foliag and high approach :pced hould be considered in df'termining the need for the (("t>(,tion of this sign, In some I'll: it may be used for em-

W....{; 36" x 36"

45

pha is where there is POor observance of the Stop sign.
The Stop Ahead sign shall be erected not less than 350 feet nor more than 750 feet in ad. vance of the Stop sign and in accordance with the general specifications for the placement of Warning signs. In cities it may be necessary to erect the sign less than 350 feet in ad. vance of the Stop sign in order to have it within the same blOCk. See figs. 2 and 15.

SIGNAL AHEAD SIGN W-7

The Signal Ahead sign shall be used at any rural signalized intersection where the signal is not visible for a distance of 400 feet in advance of the intersection, or at any signalized interection where the prevailing approach speeds or conditions of visibility are such as to justify an advance warning.

se of the ign i \Yarranted

where horizontal or vertical

curves limit the sight distance on the approach to traffic ig-

W-7 36" x 36" 48" x 48"

nals, or where lights or illuminated signs at the intersection may distract the driver's atten-

tion from the signal.

The ign hall be erected not Jess than 400 feet nor more than 750

feet in advance of the intersection and in accordance with the general

specifications for the placement of Warning signs. In cities it may be necessary to erect the sign Ie s than 400 feet from the ignal in order to have it within the same block.

46

HILL SIGN W-8
'here f ty demands a det of the grade in intermedin or (0'" gear, the Hill ign
rna\" be us d. j"lH' Hill ign hall be located
Dot 1('0 . than 300 feet nor more than i50 feet in ad"ance of the
inning of that part of the dowl\~radc "'here conditions require 11 r duct ion of speed f?r
fl,t\.. It hall be erected III s('l'o;dllncc with the general JX'l'ilication for the placement
of Warning igns.
B MP SIGN W-9
Th Bump sign shall be used to ~i\' "'arning of sharp rise in the pr fil of the road that i ,uffieicnlly abrupt to create a hllzllrdou condition, to cause l'(IIl..id rable di comfort to pas. 0l':el", to cau e a shifting of the Cllrgo, or to deflect a vehic'(r from it true course when ('rcl:',('d at peeds 25 pel' cent gr ater than the normal driving pl'l'tl f r that ection of road. The Bump sign shall be located not les' than 300 feet nor more than 7-0 feet in advance of the hazard and hall be erected in :u'('ordance with the general p cifications of the placement of Warning signs.
DIP SIGN W-IO
1'h Dip ign shall be used to h'c warning of any sharp depre i n in profile that is sufficiently abrupt to create hazards of the type described in connection wi.th ~he Bump sign (W-9). Th DIp Ign shall be applicable and u d'III the same manner as the Bump sign.

W-8 36" x 36"
W-9 36" x 36"
W-l0 36" x 36"
47

TYPICAL SIGN INSTALLATIONS
TRANSITION FROM Z LANE TO 4 LANE HIGHWAY
rI!i
I
iI I
TIT
FIGURE 10
48

TIU' USC' of the Dip sign ~t a

ort .'tr teh or depressed ahn'\ement that may, momentan y

bl'd(' 11 m nlIl'<I,

\'

hide 'uch
'

IS a notcanredci'tol,Omn-

huuld he treated as a no-

inl!: zonC',

p \"EME T ARROWS IG W-ll
The Pay ment arrow sign Iulll h u, ed to give advance n Itil' of a reduction in the idth of pavement (a from 22
f t to 1 feet), The ign hall be located not . than 300 feet nor more than f t in advance of the point h rc the reduction in width ins and hall be erected in rcordanc with the general
perification for the placement of' arnin igns.

W-l1 36- x 36-

2-LANE PAVEME T AHEAD SIGN W-12

Th 2-Lane Pavement Ahead ign shall be used to give ad\'ance I\uti('c f the approach to a two-lane from a three-lane or a four-lane hi hway.

W-12 48- x 48-
-:1:9

TYPICAL SIGN INSTALLATIONS
TRANSITION FROM 2- LANE TO DIVIDED HIGHWAY
I~
FIGURE II
50

TYPICAL SIGN INSTALLATIONS
TRANSITION FROM 2 LANE TO DIVIDED HIGHWAY

0

o

'0

2

0

5?

o .'."..
FIGURE 12
51

The ign shall be more than 750 feet

4 1/ from

X4 the

1/ and point

located of tran

not ition

Ieandthfaacnin3g00apfpereotacn~~

ing traffic. See fig. 10.

?

2 LANES (WITH 4 ARROWS) SIG W-13

The 2 Lanes (with 4 arrow) sign shall be used at the point of tran'i_ tion of a four-lane to a two-lane pavement and shall be erected to fac~ traffic entering the two-lane pavement from the four-lane pavement.
ee fig . 11 and 12. The ign shall be 4 1/ X 4 1/ and reflectorized and shall be erected in accordance with the general specifications for the placement of Warning signs.

W-13 48" x 48"
DIVIDED HIGHWAY AHEAD SIGN W-14 The Divided Highway Ahead sign hall be used on the approacbe:; to a ection of highway where the oppo ing flow of traffic are separated by a median island. It shall be 4 inches in size. It shall be located not less than 300 feet nor more than 750 feet in advance of the dividing island and in accordance with the general specification for the placement of Warning sign. See figs. 11 and 12..
52

W-14 48" x 48"
DIVIDED HIGHWAY ENDS SIGN W-15 Thl' Di\'ided High\my Ends sign shall be used at the end of a sectiol\ of di\'ided highway as a warning of two-way traffic ahead. It hall he -I " x 48" in minimum size and shall be reftectorized. The i II ~hall be located not less than 300 feet nor more than 750 feet in dnllH' of the end of the median island and shall be erected in ac'onllll\('l' \,"ith the general specifications for the placement of WarniIII/: ~ip;I\~. Rec figs. 11 and 12.
W-15 48" x 48"
53

NARROW BRIDGE SIGN W-16 The Narrow Bridge sign shall be used to indicate a bridge bavin a roadway clearance less than the width of the approach pavement Additiona1' protection may be provided by the use of reflector mark~ ers. The Narrow Bridge sign shall be erected not less than 300 feet nor more than 750 feet in advance of the structure, and in accordanc
with the general specifications for the placement of Warning signs. ~
W-16 48" x 48"
ONELANE BRIDGE SIGN W-17 The One-Lane Bridge sign shall be used to mark all bridges havjn~ a clear roadway width of less than 16 feet. It may also be used on bridges having roadway widths of less than 18 feet, when commercial vehicles constitute a high proportion of the traffic using the structure or when the alinement approaching the structure is poor. The sign shall be reflectorized. The One-Lane Bridge sign shall be erected not less than 300 feet nor more than 750 feet in advance of the structure.
54

W-17 48" x 48"
PAVEMENT ENDS SIGN W-18 Th Pavement Ends sign shall be u ed where a pavement surface chall!!:e' from a hard-surfaced pavement to a low type surface or an rth road. It hall be erected not less than 300 feet nor more than 750 feet in d\"llIlC of the beginning of the lower type surface and in accordance "ith thc general specifications for the placement of Warning sign, "
W-18 48" x 48"
55

LOW CLEARA CE SIGN W-19

The Low Clearance sign, indicating low overhead clearance a d

showing; the exact amount of clearance at low bridges, underpa. Il

and other"""overhead structures shall be used at all points where clea
ance i less than 6 inches greater than the maximum height of vehic~!'

and load permitted under the tate la,v and in any case, Where th

clearance is less than 14 feet. The actual clearance shall be Shown of'

the sign to the neare t m. eh.

II

The state law ets a maximum height of 13 feet 6 inches for vehicle

and load. Hence any clearance less than 14 feet should be marked

regardless of state law.

'

On rural highways, the Low Clearance sign shall be 48" x 4 1/ in size. Because low clearance is not always apparent, especially at night, it is e sential that the sign be reflectorized on all but the rno:t unimportant roads.

In rural districts the ign shall be erected not Ie than 300 feet nor more than 750 feet in advance of the substandard clearance and in accordance with the general specifications for the placement of Wam. ing igns. In urban districts it should ordinarily be located nearer to the point of hazard.

In the case of an arch or other structure under which the clearanee varies greatly, two or more signs hould be used on the structure itself to give accurate information as to the practical clearance Ol'er the entire roadway.

W-19 48" x 48"
56

FRE H OIL SIGN W-20

F'troe

h Oil (or Fre warn traffic of

h Tar) sign shall resurfaCl.l1g opera-

which render the surface of the pa~'e-

nt

tem P

rarilv J

hazardous,

and
.

whlCh

. i .. I'au' ,h obJ' eetionable plashmg on v. eThi . ign, like the Men Workll1g

is intended for temporary use on

hl(' mountings. 111(' ;;ign 'hall be erected on the rigbt-

d ' id<' of the road, or on a portable up-

rt in th center of the road>;my if the

'dth p('rmit. It should be located not

than 300 feet nor more than 750 feet

~.

alh'ane f the section being treated approach of the roadway affected.

at

MEN WORKING SIGN W-21
The ::-'1 n Working sign shall be used primarily f r the protection of men workin on the road in the path of traffic, or for the protccLion of traffic when the natun' of th(' work it elf is such as to create
hazard . . Il'n Working sign shall be placed approximately 350 feet on each ide of the tion where men are at work. The sign hall he mounted on sub tantial portable apport , not easily knocked over or blown down and placed in the center of the road 11/11 ..~ the width of pa\"ement, poor shouldl'rs. or other conditions make thi inad\i.. hie, in which case they shall be placed adjac'ent t the roadway on the shoulder IIf th r ad. They hall be in place as long . there arc men working on the road, or thl'rc i.. any piece of equipment in the roadway, ct ., but shall not be left up during !hc lunch p riod or at night or on holidays If the road i free from hazard at that time. .\n 1 " x 18" red flag should be di played ahove ach ign and if used at night a red lant rn or bomb torch should be placed I . id it. The signs should be moved forward a. any work progresses so that there

W-20 24" x 24"
W-21 24" x 24"
57

W-22 24" x 24"
W-23 24" x 24"

is at no time a distance of more than 1.000
feet between the sign and the wOl'kmen.'
SOFT SHOULDERS SIGN W-22
The Soft Shoulder sign shall be used where soft shoulders present a hazard t vehicles that may get off the pavement This sign will usually be warranted o~ newly seeded shoulder Ol' on roadway where shoulder are dangerou ly 150ft due to weather conditions. The ign should be removed when the hazard no longer exist
Soft Shoulder signs shall be erected i,; accordance with the general pecification for the placement of Warning sign. One sign shall be placed at or near the beginning of the soft shoulder conditions and other signs shall be placed at intervals through. out the length of the road where the con. dition exi t .
SLIPPERY WHEN WET SIGN W-23
The Slippery When Wet sign shall be u ed to warn traffic of an extraordinarilv
i lippery Ol1dition when the pavement
wet. The use of this ign should be kept to an absolute minimum, and upon correction of the slippery condition the sign should be removed.
The sign shall be erected in accordance with the general specifications for the placement of Warning signs. On rural highway it should be located 500 feet in advance of the beginning of the slippery section and at not greater than 2-mile intervals on long sections of uch pavement. In urban districts the e distances should be greatly reduced.

DOUBLE-ARROW SIG W-24 The Double Arrow sign showing a double-headed horizontal arrJW shall be used at loading and refuge island, traffic islands with curbs more than 3 inches high, and obstructions in the roadway, where traf fic i permitted to pass either side of the island or obstruction.
58

. hould normally be mounted at a height of 4 feet to the

Igfn th ign. On an island it should be mounted at the ap-

m d r a closeO thereto as pra' ctlCable.

hhoenuld0 be

mounted.

on

t.he

face

f
0,

or

J. ust

m.

f r~nt

f
0

a

'pI.er

or

I I ob truction, m whlCh case the standard strIpe markmgs on

rl.l.lr~gtruttion should be d"Iscontmued to Ieave a 3-'mch space around

OU"

.

ut 'id of the sIgn.

o u e an obstruction in the line of traffic is likely to be obscured

mbo' uvn(t.A'a_h.,.I1..(-Ide ir, ecatlysecaobnodvesitghne

of the same design should ordinarily be standard sign with its lowest edge 7 feet

ho\'(' th pavement.

.

.

n('rt' traffic must keep to the rIght of the Island or other obstruc-

. the Keep Right Regulatory sign (R-20) should be used. t10Tnhe Double Arrow S.ign 48" x 48" may be used at T m. tersections.

W-24 48" x 48"

RAILROAD ADVANCE WARNING

SIGN W-25

Recau e railroad grade crossings present
a :[X'eial type of extreme hazard, Warning i~I' of distinctive designs are prescribed for them.

The Railroad Advance Warning sign

'hall be ('arrym. g

a yellow disk 30 a "Crossbuck"

iXnchaensdinthdeiamleettteerrs'

"RR" in black. Every Railroad Advance

Warning sign shall be reflectorized.

W-25 30" diameter
59

The e;ign e;hall be ue;rd in advance of en)rv railroad ('I'oe;e;illO'

.



.

,'"

if C'\ '('11

prote(ted by e;lgnale;, gates, or flagman. exeept III the' l()ll()wi!Io' .

e;t,an('ps:

" Ill-

1. .\t a minor siding or spur \\'hich is iuf'requpntly ue;('d and \\,hl"b

I.e;'~gual'( Ic'c 'I \\'lH'n'muse 1ly a mem1)pI' 0 f' t l w tr'am ('1'('\\.

(I

,) I n the hue;inpss distriet of the large cities \Y!ll'l'(' tlte ('rossings arp fully protected all(l tlw phye;ieal condition" an ~llch th

('WII a partially ef'fecti\'e display of the e;ign i" im!l()e;e;iblc. at

In l'\Iral distriets this sign shall Ilormally br placed 7,-)() f,'p! in ad.

\'ance of the ('I'oe;e;ing, although local conditions, s\[('h as grad,'s. curves and limitpd Yi"ibility may makc' e;ome intermediate die;taJl"(' 1)('t\H'e~
:300 feet and 7;')0 feet more sati"factory. In any cae;e till' die;tall('e shall

he great rnough to permit \'ehi('lee; at prentiling sprecls to 1)(' brought

to a complC'tp stop before the (Tossing is reached. TIIP e;igll e;hall he

C'rected on the right-hand side of the roachmy in a('('cmlan('(' i"ith the

general specifications for the pJacempnt of 'Waming signs.

In re:,;idence or business districts \\'here 1m\' sjweds arc' jln'\'alent the sign may he placed a minimum distance of 100 feet from lIw ('l'OSs~
ing. If there i:,; a street intersection within 100 fpet, an addi! ional siglI

or signs should he so placed as to wam traffic approaehing t II(' cross-

ing from each intersected street.

Railroad :\ch'anee \Varning signe; are usually off the rail mad right.

of-way and are properly the n'e;pOlI"ibility of the hi!!;Il\ray 'l\Itltorities.

RAILROAD CROSSBUCK SIGN W -26
Tlll' de:-;ign of the commonly u:,;ed Hailroad Cros:-;buck, \\'it It .\uxil. iary sign :-;howing ttl(' number of tra(ks. has been e;tandardi;r,c'd by the .Joint Committee OJI Grade Crossing Protection of tlll' A"e;(wiaiion of .~nwriulll Hailroad:,;. The C'ros:-;blwk sign ie; furni:-;hed and illstalled by the railroad company, and i:-; usually 10('ated OIl tlw railroad rightof-way to :-;hm\' the loc'ation of the tnu'ks and the numlwr of tracks.
Detail:,; are shcmn in Bulletin ~ o. :3, Railroad [fiUll/my Grade ('rossing Protection . .\ssociatioll of American Railroade;.
The ('roe;sbll('k shall be \\'hite \\'ith \\'ords "I{ailroad Croe;"illg" in black lettering. If there are two or more tra('b, indllding "itlings. the nurn)wr of track:-; e;hall be indi('atec! on an Allxiliar~ sign of ill\'erted "1''' shape mounted below the (ro"e;IHlck. The di:-;tallce that e;llOuld he a:,;sumed to :-;eparate tracks hefon> an additional Crossing "ign is eonsidered i:,; 100 feet, Ilnb.;e; local ('clllditione; require otheI'\Yie;('.
The practiee in :-;ome loealitie:-; of placing the Hailroad (')'(N:!mck sign all a pedestal or island in the ('enter of the roadway ie; e;ll'Ongly disapprm'ed. The sign shall 1)(' erected 011 the right-haml side of the roadway on eaeb approach to the ('ro:-;sing, not more than l;j fc(,t from the center line of the nearest track and not ke;s than () feet no)' more
GO

10 f('Ct from the edge of :he pavement. The height hould be

\" htI.:'amI)<.l~"

the level
I)" \'aried
c

of the highway to the center of as reqUI.red by locIa dcon"ItlOns.

the

crossbuck,

W-26 9"' x 48"' 9"' x 60"'

RO ING SIGNS W-27

Th

ing signs, indicating

type of crossings, as

hool rossing, Truck Cros ing,

Ped .trian rossing, Cattle

"ing, Deer Crossing, shall

be u I at hazardou crossing of

th typ indicated. The sign

mayor may not be of a tempo-

rary 01' ea onal nature, but

ould b r moved if and when

the hazardou condition ar

tt'mlinated.

In mral area the sign shall be

located n LIes than 300 feet

nor mol' than 750 feet from

th era ing. In urban areas a

hort I' di tance will usually be d~.irabl. The sign shall be

<>r('('ted in accordance with the

<>nf'ral . pecification for the

phwrm nt of Warning signs.

In .muny in 'Lance it may be

de.lrabl t.o define the crossing

hy pm-cmenL markings.

W-27 36"' x 36"
61

W-28 18" x 18"
W-29 24" x 24"
62

ADVISORY SPEED SIGN W-28
The Advisory Speed sign i s~all plate 18" x 18" square' with the message "- M.P.II ,: in black on a yello.w background. It may be used m conjunctio
with any standard yellow Warn~
ing sign to indicate the maxi. mum "safe speed" around a curve or through a hazardou location. When used, it hall be mounted immediately below the standard Warning sign and on the same post, with its lower edge not less than 4 feet abo\"e the pavement. The speed shown shall be in multiple' of 5 miles. In no case shall such a sign be erected until the afe speed has been determined by accepted traffic engineering procedures and officially approved. Because changes in surface characteristics, sight distance, etc., may alter the safe speed, each location should be periodically rechecked and the Speed sign corrected if necessary, as shown in figures 8 and 9.
CATTLE CROSSING SIGN W-29
The Cattle Crossing sign is to be placed 300 to 500 feet in advance of any point where cattle are regularly driven across the highway. For maximum effectiveness, this sign should be a portable sign. When responsible persons are not available to place and remove this sign on each crossing of cattle, permanent signs should be installed. This sign is not to be reftectorized.

DETOUR SIGNS
TYPICAL INSTALLATIONS
ROAD CLOSED TO TRA FFIC I
L------:---~.:-.--------""--~--,.~--~ -_.-J~ LOCAL TRAFFIC MAINTAINED FIGURE 13

W-30 36" x 36"
W-31 36" x 36"

WATCH FOR CATTLE SIGN W-30
The Watch for Cattle sign is to be reflectol'ized and placed along those sections of highway where fencing is not provided to keep cattle from the right-ofway. The e sign should be placed at sufficient intervals wherever such conditions exist.
DETOUR AHEAD SIGN W-31
The Detour Ahead ign shall be used as advance warning of the approach to a point in the highway that the traffic is diverted from the route.
The sign shall be erected not less than 100 feet from the intersecting detour and shall be followed by standard Route and Directional Markers as shown in fig. 13.
On highways where speeds are high an additional Detour Ahead ign may be erected 1,000 feet farther in advance for added protection.
Placemen t shall be in accordance with specifications a outlined in this manual.

DRAWBRIDGE AHEAD SIGN W-32
The Draw Bridge Ahead sign hall be used a an advance warrun of the approach to a draw bridge and located not less than 500 feet nor more than 1,000 feet from the bridge.
The ign shall be 4 " x 48" and shall be reflectorized. Coloring and placement hall comply with specifications as outlined in this manual.

64

W-32 48" x 48"
DRAW BRIDGE SIGN W-33 The Draw Bridge sign shall be reflectorized, placed at the extreme I'nd of the draw bridge preceding protective gates and placement hall comply with general specifications as outlined in this manual. Th ign shall be located not over 100 feet in advance of the bridge Oil hath sides facing approaching traffic. It shall be mounted not 1(':' than 4 feet above the pavement.
W-33
48" x 48"
65

W-34 24" x 24"
W-35 24" x 24"
66

CROSS ROAD SIGN W-34

The Cross Road tical cross symbol,

sign, shall

showing the be erected

~'er.

through highway of a cross road.

to I

tisnduisceateshtohueldprebeennele!.

stricted to intersections with road t~e.

are improved to such an extent that
there is likely to be a fairly large vOlu~t

of traffic entering or crossing the through

route and where unusual features, 'uch

as poor sight distance or obscured en.

trances, make it advisable that the inter_

section be called to the motorist's atten.

tion. It should not ordinarily be u ed

where Junction signs or Turn Marke

are present. Too frequent use of the

Cross Road sign should be avoided.

More complex intersections, or oblique crossings, may be shown by appropriate diagrams.

If there is a considerable difference in the importance of the intersecting road" the more important route should be shown by a heavier line in the diagram. Since this requires the stocking of se\,eral different designs, however, and since a turn in a numbered route is shown by Route Markers, the use of different widths of line is not mandatory.

The Cross Road sign shall be erected not less than 300 feet nor more than 750 feet in advance of the intersection, and in accordance with general specification for the placement of warning signs.

SIDE ROAD SIGN W-35
The Side Road sign, showing a sideroad symbol, either left or right, and a an angle of either 90 or 45 degrees, shall be used in advance of a side-road intersection according to the same warrant and specifications as set forth for the Cross Road sign (W-34).

T YMBOL SIGN W-36

T ymbol ign shall .be used. to

traffic approaching a T llltersectlOn road that forms the stem of the
1. ;0 o wh rc traffic must make a turn r th right or to the left. The

all not be used on an approach

traffic i required to stop before 'ng the intersection, ~or at a T
tion that i channelIzed by traf-

oland" nor, generally, where J unciR'I' or Turn Markers are pr~sent.

I' lati\'e importance of the llltering road hould be shown by differ-

n

'idth T

of line. ymbol

sign

shall

be

erected

I . than 350 feet nor more than 500

I in advance of the intersection, and

an IK'cordanc with the general specifica1 for the placement of warning signs. I may b de irable to place an addition-
l' :'ymbol ign at the head of the T di tly in line with approaching traffic.

Y YMBOL SIGN W-37
Tht' Y ym bol sign shall be u ed to rn m tori t approaching a Y intertion on th road that forms the tem tht' Y. It hall not be used at a Y int -tion that is chatmelized by traffic i land, nor, generally, where Junction 'ign' or Turn Markers are pre ent. Th(' I' lativ importance of the intertinll: road should be'shown by diffeI'nt width, of line.
Th Y ymbol sign shall be erected not 1(' than 350 feet nor more than 500 f t in advance of the intersection and
)
t~ accordance with the general specificatIOn for th placement of warning signs. It may be de irable to erect an additionI Y int l' ection sign at the fork of the Y dir eUy in line with approaching raffie.

W-36 24" x 24"
W-37 24" x 24"
67

BUSINESS DISTRICT
W-38 18" x 12"

BUSINESS DISTRICT W-38 This sign shall be 18 inches by 12 inches in size, with black letters on a white background. These signs will be no wider than the Speed Limit signs upon which they are mounted. These signs will be erected on top of the Speed Limit signs only after authorized by the Director of Public Safety in business districts.

RESIDENCE DISTRICT
W-39 18" x 12"

RESIDENCE DISTRICT W-39 This sign shall be 18 inches by 12 inches in size with black letters and a white background. These signs will be no wider than the Speed Limit signs upon which they are mounted. These signs will be mounted on top of Speed Limit signs only after authorized by Director of Public Safety in residential districts.

W-40 24" x 36"

ROADSIDE PARK W-40 This sign shall be 24 inches by 36 inches with white letters on green background. These signs will not be reflectorized. They shall be mounted at right angle to the pavement facing approaching traffic, and not less than 6 feet nor more than 10 feet from the edge of pavement. They shall be erect-
ed one mile and >i mile on each side of
entrance with mileage posted on bottom of sign, and the third shall be at the entrance of the roadside park. These signs will only be erected for roadside parks built and maintained by the State Highway Department. All other roadside park signs will be erected off of State Highway right-of-way.
OTHER WARNING SIGNS

Warning signs other than those specified above may be required under special conditions. They should in every case conform with the general specifications for shape, color and placement of Warning signs as set forth in this manual. Typical miscellaneous Warning signs are Playground, Bridle Path, Hospital, Crosswalk, Tunnel, Uneven Tracks, Rough Road, High Water, Range Cattle, Factory Entrance and Slides. The applications of such signs are sufficiently apparent as to require no detailed specifications.

68

DGUIDE SIGNS

pon of Guide Signs

"I.Lr.oI_._ilJu.'IA(1.I-'tdueU .<hehs,riel,d,ismea(tt1ooe:ra.".'.altI.lCgIo.lnnlnfaIO,s',;.0l,;t'l''Iina'Ito'Il(I"in'es,"sh,\ie\m'" "l"st,1nos'\dc'o.n.i1fgdtIli'eic.,lnnt!nhttec. ler1trayosmlel'' v, cngo,tueslt.ialtoc~ lr'!gsPbgI;ym1.r. ,\to'Ephnu'leve}k1,cs1.'m,r,md,s]o.,]t':to(,o;s~uctretrd"ihJes.rmat(~I.meIIIa,,tlst'hlo,oor[nc.mup.gl'raanrptkeIO.Ostsiot',lnal''Jbfclrohll.i,i:lrt'e;se.y.ls\l\!'l:1o','1d;1r,

ne>TPhe s,Ign Hou t e

s.'I\,'H',IIe'khD,Ie,'r~,e,'lcnod.n,s"AIduexrl,eh,da,rJ'vIl

three maJor :\Iarkel's.

groups:

De:;tination and Distance slgn",

Informat ion sign"" . , " "

"

,.

'I'k other typcs oj slgnl'J, GlIlde l'Jlgni'l do not lose effedlveness hy

l nI e frequen t I 1'M" .

,Yhcn there is any IIonI)t a" to t1te a<Iv'isaI)J'I'ltV oj, any

"

,

.

,

llUeh sign. it ~Il(luld he eredel!.

J)esign of Guide Signs

All Houte :\[arkC'r~ and Auxiliary :'Iarkers used there\\'ith shall be

designed with a ,,'hite background. on .which ylC lettering 01' symb.ols and border ~hall he hlack. Dest1l1atlOn, DIstance and InformatIon

signs shall he hlack 011 \\'hite, or, optionally, for enlarged or over"ize

signs, whitc on hhll'k.

,

.,

.,

Except for HOll t r :\Iarker~, \rlueh arc ot speCHt! shapes as speCIfied

hereafter, all C;uide ~igllf; are reetangular, with thf' long;er c1imen~ion

horizontal. Houte :\[arkC'r~ and Destination sig;ns shall he rdleC'iorized or il-

luminated.

Route Markers and Auxiliary Markers
HOllte :\Iarkers are important to identify numbered highway routes, hut to accomplish their purpose they must he supplemented by variOilS types of Auxiliary Markers and signs to indicate .Junctions, Turns llnd Directions thereof as well as Temporary, Alternate, By-Pass, Business Houtes and Detours. Except where used as "confirming" or as "reassurance" markers as hereinafter deserihed, Houte ::Uarkers llre always mounted in conjunction \"ith Auxiliary signs to form .Junction .h~emhlies, OJ' Directional .:\'Iarking Assemblies.
r. S. Houte :\[al'kers shall be displayed only on the U. S. Numbered
Highway System or the approaches thereto. State Houle N[arkel'~ ~hall he used onl~ on state numhered routes and their appl'Oaches.

JUNCTION SIGN M~l The Junetion sign shall be a horizontal reetangle 48" x 18" in size. It shall haY(~ hlack letters on white hackgl'Ouml and he mflel'torized.

(\9

The .Junction sign shall only be used with Route:'lhrkers (:\'1-2 and/or M-3) as shown in flgs. 14 and )5.
[JUNCTION I

M-2 24" x 24"
M-3 24" x 24"
M-4 16" x 16Y,"
M-5 16" x 16Y2"
70

M-l 48" x 18"
U. S. ROUTE MARKER M-2 The l~. S. Houte :'IIarkcr (:\1--2) shall be a :,;quare sign 24 inche::: in :::izc. "'ith the federal shield outlined in blaek and earl'ying 1he route number on a white baekground and shall he reftcetorizcd. It shall be used at rural and urban illtersec_ tion:,; and as reassurance marker through urban areas, and at these locations continuously on the route through the state. See fig. 14.
STATE ROUTE MARKER M3
The State Houte ::Vlarkcr (1\1-3) shall be a square sign 24 inehes in size ~\\"ith an outline of the state forming the shield symbol.
The sign shall be refteetorized with t he symbol and numeral::: black on white backgJ'Ound.
It shall be used at rural and urban intersections and as reassurance marker through urban areas and at these locations contimlOm;\~' on the route through the statp. See fig. 14.
U. S. AND STATE ROUTE MARKERS M-4, M-5 FOR USE AS CONFIRMATION AND REASSURANCE MARKERS }'he C S. Houk Marker (1\1-4) shall consist
of a shield-shaped plate Hi" x lli.I /' in size, carrying the state name, the Jetters "{ 'S" and the route number. The sign shall 1u1\(' a white background with black lettering.
State Route Markel' (:'II-oJ) shall c()\lsist of a sta((~ shield-shaped plate Hi" x W! '!." carrying the letters "GA" and the route number. The sign shall 1u1\"e a \"hite background \"ith black lettering.

DIRECTIONAL MARKERS M-6, M7, M-8 AND M 9

T.her

D


I

,(,(,t
I.

'IC)n,tl '.

~ "\I"arkers

shall

be

t directIOn ot the route and

24" x 18" in size \yith

.

.

.

shall be rdlectol'lzed.

an

alTow

to TInhcelcma ael.ke.]..;;:e'.llall

be.

mounted ~

directly.

below

a

Route

i'darker

(Ivl,

2

or .'1' -3). See fIgs. 14 and 1;).

-

t

M-6 24" x IS"

M-6S 24" x IS"

M-7 24" x IS"

M-S 24" x IS"

M-9 24" x IS"

DESTINATION MARKER M-IO The Destinat ion :Uarker shall be 72" x 24" in size with either the L. S. or state shield, two city names and directional arrO\ys in black on white background and shall be reflectorized.
@t- THOMASTON
~ ATLANTA-+
M-10 72" x 24"
DISTANCE MARKER M-ll The Distance "\Iarker shall be a horizontal rectangle GO" x :36" in siae, carrying til(' names of three incorporated cities, villages, or to\yns, and the mileages (to the nearest mile) to the centers of those plaees. Lettering shall be black on \yhite baekground. The top name shall be that of the next ineOl'pOl'ated lllunicipality along the route. The secowl name shall be that of the citv in which the greater portion of the through traffic is interested. 'In the case of
I~ routes, the 100\'er name may be varied on successi\'l~ signs, alter-
Dating hetween seH'ral city, village or town names.
71

NEWNAN

36

'LA GRANGE 66

MONTGOMERY 186

1.1-11 60" x 36"

However, if the route is approaching a large city with no other cities near, the name of the large city should be repeated on successive signs. On Interstate Routes, as a second objective, the name of a city in the adjacent state may be shown.
Distance signs shall be erected on important routes leaving municipalities and just beyond intersections of numbered routes or at approximately lO-mile intervals along the route. They should not be used on any but U. S. and State Routes.
Distance signs shall be placed approximately 500 feet outside of the municipal limits on the right-hand side of the road, facing traffic leaving the municipality, or at the edge of the built-up district if it extends beyond the corporate limits. Where overlapping routes separate a short distance from the corporate limits, the Distance sign should be omitted at the corporate limits and should be erected 100 feet beyond the junction of the two routes.
Distance signs shall be mounted with the bottom of the sign not less than 4 feet above the pavement and not less than 6 feet nor more than 10 feet from the edge of the pavement. Figures 14 and 15 show typical use of Distance signs at rural intersections.

ENDS
1.1-12 24" x 18"

ENDS MARKER M-12
The Ends Marker (M-12) 24" x 18" shall be used with Route Marker M-2 or M-3 to indicate that the particular route terminates at the intersection.
This marker should be mounted as outlined for Directional Markers.

,"
72

TYPICAL INSTALLATIONS OF GUIDE SIGNS FOR MAJOR ROUTE INTERSECTIONS
Figure 14

'~50

GRADE

FIGURE 14

TYPICAL INSTALLATION OF GUIDE SIGNS
FOR MAJOR ROUTE INTERSECTIONS

TYPICAL ALTERNATE INSTALLATION OF GUIDE SIGNS FOR MAJOR INTERSECTIONS (FOR ONE DIRECTION OF TRAVEL ONLY).
Figure 14A

ROUTE US
57
\rl~ it

ROUTES
---==:.:.=.:.:J --=-::.:J US 47 -S-R--I2-.0.

p . -;;;;;;;;;;:;::::=;;:;:=;:;:::::;::::=; ROUTE US 47

I
?f III~O..~~.~57
I~
J, ".i.n.
STATE
=~-~-)
ROUTE
154

ROUTE
US57

CT
\ ~\154

FIGURE 14A.-TYPICAL ALTERNATE INSTALLATION OF GUIDE SIGNS fOR MAJOR INTERSECTIONS

(FOR ONE DIRECTION OF TRAVEL ONLY)

'

TYPICAL

INSTALLATION OF GUIDE
"Y" INTERSECTION
~ bT

SIGN S AT

73

U. S. OVERSIZE ROUTE MARKER M-13
The 17. S. Oversize Route Marker (M-13) is to be placed at a junction where a F S. Route diverges from another l'. S. Route or a State Route.
rt may also be placed at hazard-
ous locations where emphasis is necessary to advise of a turn in the route.
Curve or vertical arrows may be substituted for the horizontal arrows when necessary. Sec fi!!;s. 1.5 and 18.

M-13 36" x 60" 48" x 72"
GA 83

GEORGIA OVERSIZE ROUTE MARKER M-14
The Georgia Oversize Route Marker (M-14) is to be placed at similar location as the M-3A
si!!;n on State Houtes. rt may
be used in conjunction with a similar type of U. S. Route
Marker where a r. S. and a
State Route intersect.

M-14 36" x 60" 48" x 72"

M-6A 13" x 10"
74

M-6AS 13" x 10"

M-7A 13" x 10"

M-8A 13" x 10"

M-9A 13" x 10"

DIRECTIONAL ARROW PANELS M 6A, l\17A, ~1 SA, M 9A The Jlirediollal\lTO\\ PaJwb (\1 (j,\ :\17,\, \I-So\, \1 9,\) shall he 13" :\ 10" in "ize Iyilh an arJ'() II' 10 illdi('ate Ilu' direetion of the mute
:lnd slwli he rdlect oriznl.
The p:llwl "Jwll he mOlllllpd directly hekl\\ :1 HOllle \l:trKt'l' (\[1
or :\1;)1, ~e(' fig, 1\),

ENDS MARKER M 12A
TIll' Elld~ \[arKer (\1 12.\) I:r' :\ 10" "hall 1)(' II"ed Ilith gOI!iI' \IarK('r (\11 or \1 ,)1 to illdil'all' that till' route II'rmilwle" :11 till' iliter"('I't iOIl,
Thi" marld'l' "lll>ltld 1)(' mO'lIItPd ;10' 1>llllilWd for
Ilin'diolla! .\1:lrK('r",

M--12A 13" x 10"

TEMPORARY MARKER M 15

TIll' Tpm p"rary\[ aller "hnll ,'a1TI' Ilw \\1 'I'd "Tt'mporar~'" ill hl;wk leI tel''' Oil n Ilhitl' pialI'
21":\ !I" ill "iz(', It "Iudi 1)(' mO'lll1ed imnll'dintp!y al,()\'(' a I((>lill' \[nrKer (\1 2, \[ ;.\) 10 illdi-

ITEMPORARY I
M-lS 24'" x 9'

(';I\(' t'it her:

(:11 ,\ J'Illlte t('mpor:trily de"igllat,'d 1111t llt,t illll']lC!I,d a" ;I ]H'rlll<l-

lIelil p:lrl of a rq!;lll<lrly IIllml)(']'('d 1'0111(', or

Ihl .\ temp"r;lry dl'lollr fmm :Ill e"t:lhli,,,lwd mUll', dill' to 1'11)('1'-
g('/WI' "I' Illajor 1'I'('OIl"t ni<'l i011.

WllI'n' it i" plallll('d to ]'(,IOI'atl' a mull' :11 " I;lt<'l' dall', ll"" of til(' "'!'('mporary" dl'~i,t!;Il;llioll II'ill orll'll Iwlp 10 al'oid fUI'm' mi"II'ld('r,talldillg alld ill f"I'lillg, Oil 11ll' ollll'r !l:111t1. Illl' u,,,,' of "Teillporary"
III"tl'"d of "1l,'IOIII'" :lloid" I Ill' "ugge'''1 iOIl or poor mad t 11:11 i" a""'lI'iatl'd ill th,' pltl,Ji" IlIillll Ililh IllI' Jalt,'r IPI'lll. '1'1)(' t,'mporary rOllll' lIlal' h,' all"tlll'r t' :-:., or ~Iale 1l'lmlJ1'!'ed rOllI", :I "OUIII,I' road, or ,'ill'
-I rl"'t.

TIll' '['I'mp!)rnr,\' !t"llle .\","(mhlie," "hall 1)(' u""d Oil II'mlmr:lr.\' r"utl',alld "hall \1(' l!)call't1 :11111 ('('("'lI'd ill a('('ortl;JIWI' Il'itll Ilw "!H('ifi"al iOII.~
...1 f"rth f!)r "talld:ml "()III (' lIlarKI'r", Tlw.\' "h:dl Ill' J'('lIlo\'l,d promptly "1"'11 Ih(, tl'll1!lI'l':ln' "()llll' i~ :1!):II"jOIl('t1,

ALTER\'ATE :\1ARKER M 16

TIll' ,\It1'I'II:ltI' \l:ll'k,'I' "hall (':lIT\' Ihe \\1)('(1

",\,I.I.N.II'lt('" '111 I)I.\('I,, I,'11,'1''' ()II :1 11'I11:1" pIal,' :! I "

l J III ."iz,,' . II ,,I la II I1(' 1I]()llllt!'( 1 I.ml1ll'(l.l"le!Y

al."\,,, a I: "III I' .\ [,.\1.,\1, '1 , " \ I .l.

\1

.)

to dl'''. lglla'll'

:\/1 a 1&11011

lt"nla
~'r" I

ll" r"lI

1"lItl.ll~' tl'.

I
1('

,
)11""11

111'0

pO"lllt"

!)II

:I

[ ALTER NATE I
M-16 2-1' x 9"

,,)

Thl' _\\\('l'IIaj(, Hout(' .\""('Illhly "Iw\l 1)(' u,,('(\ ill (Il(' "allll' lllallll(~r :1" a r('g:ular HOIlt\' :\IarK('r alld "hall 1)(' lo('all'd alld (,I'1'('(('d ill a(((jrd. all('(' ",ith (11(' "all\(' ,"pl'('ifi('al iOI\.'-',
.;,,'"
Th(' d('"ig:llatioll of all all('1'Ilat('l',~, Uout(' "Iwlll,(' ill ;\l"'O)'l!:i1I('e Ilit h till' (""(;\hli,,ll('d poli",I' of the ,\llH'ri":1I1 ,\"HlI'iatioll oj' ~lal(' 111g:!l. Ila\" ()tli('iab. a" H'I fOl'th ill tlJ(' "I!III) 1('1'('1'1'1(('(' Book" of thai ,\8''';'lI'ial JOII. \:0 :dl('l'llal(' [', ~, Hout(, llla~' 1)(' de"ig:llal('d 01' llllll'ked Ilitholll tilt' :\Pp]'ol':d of til(' EX('('uti\"(, ('ollllllil\('(' of llJ(' ,\"",)('ial1"II,

BY-PASS MARKER M 17

BY-PASS
M--l? 24"' x 9'

TIlt' 1)\,-l'a"" .\Ial'k(']' ,..;hall ":11'1'.1' \ lit, \Imd
"I)y-I':I";";" ill hl:ll'k I(,\{(,I''' 'III a II'hi\(' pl;1 " :!-i"
\: !I'! ill";IZ('. 1t..;ll:dl 1)(' lll'lIlIl\(,d illl111\'>llatel\'
:illl'l'!' :1 Houl(' .\lal'\.:('l' (.\1 :!, .\1 :ri 10 d";~lIate
~I rou\(' Il'hil'll hl'alll'lle" fl'l'lll Ill(' I'('g:u!:l I IlIlm-
l)(,l'l'd mill!' lh]"IIIg:h a (it,\". hy-p:I"".(',,; IIii' ('it\, alld )'l'joill" th(' )'l'g:ul:11' Ilulllh(,l'l,<I mUI(' 1('~'()lId the ('ity,

Tlw 1).\'-1'as..; Houl(' ,\""('l11hly "hall lJ(' 11,,('d ill 1h(' "allW 1lI.',lllle]' as II l'q;ular [(oute .\lark('I', :Illd "hall \J(' jO(':ll(,d alld ('1'('('I(,d ill :I((ord. al\(T IIith Ihe "all\(' "p('('ili(alioll".

BOSINESS ROUTE MARKER M 18

BUSINESS
M-18 24" x 9'

'I'll(' J)u"ill('"'' 1(0111(' .\Iark(,I' "lwll 1,11'1'.1' the Il'onl "J)\1"ille",," ill l,la('k 1\'11('1''' '>II Ii I\'hite plal(' :!-II! x !II! III "iw, It "Iwll h(' llHI!lllled im. llwdiat('ly ah(ll'\' a l(oUl(' .\Iark(,1' (\1 :!. .\1-3) to d('"ig:llale all auxiliary I'OUll' 11lli'!1 ill'alll'hes fJ'()1ll a 1'('g:\11:11' 1\\1mh(']'('<1 l'Illl1(' tll]oll!lh a I'ity to dil'(,('\ traMi(, thr()ug:h til(' \l\billt'"'' portion of ill(' ('it~.

TIll' l)\1"ill('"'' I{out(, ~\",,('mhly "hall lw u,,('d in th(' "alll(' nWIlllPr as :l regular \(O\lt(, .\[arkt'1' and "hall \)(> lo('atl'd alld ('\'('('l,'d ill a('('ord

,lIl('e wilh lhl' ';:l\11l' Sjw('iti('alioll".

NORTH
M-19 24" x 9"

CARDINAL DIRECTION MARKER M-19
Thl' Cardinal Din,(,tion .\Iark('1' ,..;h:dl ('any the wonb "\:0I't1l, 80\1th, 1':a"t O!' \\(',1" in black: Jelll'!''' on white plate 24" x \11/.
It may rH' monnted dire('t h :Iho\'e Haute!
l .\Iarker (:\12 0]' :\[-:3) to illdi:':ll" the genertl1
dire(,tioll of tile routl's. Tt should II(' u~ed onl1'

iG

where motori,;t,;. ill t nlll,;t'crrilig from OIiC rout C to allothcr. might be eOllfu;;ed a;; to thc dirc('(ioll ill Iyhidl lh(' illtcr;;('c!cd routc 1l'(lIdd
take lIl<'m, :-\('(' fig;;, I L 1.-) alld IS,

SECONDARY DESTI~ATIO;\i MARKER M lOA
The :-\ccolldary I )C,;1 illat iO!1 ~Iarker (~I Il!.\! ;;Iwll 1)(' :3(;" '\ Ii" ill ,..;ize \I'ith 011(' I'il.\' Ilall](' :llId mile:I,!2:I' ill hlack I('j 11'1''; O!I Ilhit(' aJ'l'II\\ alld ,;hall hc 1'('-
1!e('lllrize(I,

(CAMAK
M-l0A 36" x 6"

15 ]

I~FORMATION SIG~S IlIf()J'mat ilill ..;igll;; aI'(' \'al'i~lhlc ill ..;ize ~llld ill ml'..;..;agc Tlwy illl'ludl' "lwh illf()J'll1:1t ilill a;; II a111('."; oj' I'i\'('r,..; C!'o";";I'd, ('it,\', \'illagl'. 01' t011'11 limit", ('OUllt,l' lillc;;. ;;tat(, lillc..;. ('In'alioll";, ('1(', IlIfol'lnatioli ";lgll"; "hall I,(, hmiwlltal l'('I'tallgl('", Thc,\' ..;hall ha\'(' h];l('k Ictt(,l'illg Otl a white I,a('kgrlllt!ld, 'I'll<' ,;ize of I('tlel'ittg u;;('d "hould hI' ;;I[('h a" to
I!in' ad('qllall' I('gihility fol' tIl<' purpo,;c to 1)(' ;;cl'\'('d. :-lilll'(' thc,,('
"igll'; an' 1'01' illf(\rmalioll plll'pO';(';;. alld do 1I0t ordillarily "I']'\'C to I'('gu-
!atl'. Ill' guidI' lr;tfli(' {l'XI'Cpt pcrhap,; ilidin'ltly ill t hc ('a"e of ('it.\, lim-
it:,. ('tl.1 Ill<' Il('cd for 1Il1ifol'lnity itl dc,;ig!1 to ill';lll'C autollwtic 1'('. ;;Pllll;;p i;; IIllt ~t111Igclhcl' (,,;,,clltia!. TIl<'Y ;;lwuJd. hOI\'('\'CI'. Ill' of ,..;talldard ;;happ alld ('1l11 )J',
III rural di,;tril'1...;. tIl<' IIIfol'lnatiOll ;;igll'; "holiid Ill'dillarily 1)(' mOllltt-
cd fwm Ii til III 1'('1'\ from thc pa\'('n1l'llt cdgl'. alld \Iith till' hottom 1I0t !f'l',."; thall Ii ft'('1 ;Iho\'(' thc pa\'('Il1l'II1. The lJ:UlW of a ri\'e]' IlW,I' 1)(' O1Olll1tp<l OIl til<' (,tid of a hl'idge t l'lt"". III 1'('"id('II('(' and bu,;itll';;'; di,;tript:, til(' IIl\YI 'l'lll 0;;\ cdgc ,;1101I1d hc 1I0t Ic,;,; than I feel ahovc the ('urh, alld 110 port iOIl of til<' ,;lgll ,;Iwuld be lc",; 1hall I foot !>fu'k from the ('urh,

STATE LINE (INFORMATION 1) 72" X 36" Thc ~tatc LillI' "igtt ,..;hall bc phH'ed at lhe ,;tatc houndary lillc Oil all ldt'atc and 1'. ~. hig}I\\'a' \',;, alld. 011 ';l\(h I' 'OUII!Y hig"h\y.ay,; a,; ma.y 1)('
Ift'('t('(! hy t IH' allt ll()rit ic;; of ('oullti(',; ",hiph border ot!wr ,;laU',;.

71

GEORGIA
STATE LINE

1-1 72" x 36"
CITY LIMIT SIGN (INFORMATION-2) The City Limit sign shall be 24 inches high by variable !<'llgth (depending 011 length of city's name) using 8- and -!-indl letters. The sign shall be rcfleetorized and placed along state and '-. S. high. ways at city limit line_

ATLANTA
CITY LIMIT

1-2 24" x Variable

FULTON COUNTY
1--3 24" x Variable

COUNTY LINE SIGN (IN FORMA.

. TION3)

I

The COllnty Line sign shall be 24

inches high by variablP length (cleo;

pending on length of COllllty name)'

using letters (j inches h i g h . :
The 8ign shall he rcfl(,(,t orized an~

placed along 8t ate and '-. ;-;. high,YaYl,

at the cOlmty line.

I

I ABERDEEN I.
I 4 18" x Variable

UNINCORPORATED VILLAGE SIGN (INFORMATION--4) 18" VARIABLE
The j-nincorpomted \illage si!\l1 shall he placed approximately l,t:dj feet in advance of the approxima"l
limit8. of an unincorporat('d ,-illage. l

78

IwaIT-OF-WAY SIGNS (I:\,FORMATION 51

." (' ltil!:ht-o!-\\';IY .~igll shull \)(' :{O illdll',~ hy :.? I iII('J](',~ Ill~iz(' lIil.h

'I, I'kIk, tl('rilll!: ilil 11I1'11(' \l'I(I"grollillI. '1'1I'I" ,~"Igil ].~ 1101 rdl"l'I'1orlz('d.

l1l,}1l'' ~1' ,,'1-("II.~ '~11'.l11 Ill' IJ]'\('('d alollg ,h(' riglil-of-lIu\,, lilli' ill an',I" ,,J]('r('

1l1:l~' il\.~1,dl ,~igll" t1wl',t'

,
1

1.','.11'1"'

" 'I 11'lld"III'\' to huild up alollg ,1](' righl-of-II'a,' 01' til an'a"

I'
I' .'

II"I~' ]I

,II'' I'Id. >1I1,~h. IH'lllg

dUll11)('d

Oil

.

'.

rlght-o!-II'a,\,:

.
III

II'}]('I'I' IIII' p1l1ili,' 111'('lb 111 hi' illfol'll1('d of (lip pJ'()I('I'tioll

11I]('n'
o11wl'
of il.~

I'Ll, ' t'.I1"\\'. (1111('1' jllri"dil,tioll"

"ill1ilal'

a" dl'I'llll'd

rlt! 1t -II

<.

1;1'1"('.":,";:1 r.\".

STATE

HIGHWAY

RIGHT OF WAY

EtjGROACHMENTS RESTRICTED

PERMITS REQUIRED "OR

<TA TE H'C,HWAY DEPARTME NT o~ GEORGI A
1-5 30" x 24"

Throwing of Trash Sign (Information-6)

The ThrJwing of Trash Sign will

be 36" x 36" in size, black lettering

on white background. This sign is

TIflONIUJ
TRASH~RBAGE

I
I

! :tl HIGHWAY

I ffiOHIBI TED

"'11~ $1,000 FINE \1

AIIll/OIl 1MI'll I SONMEN1

1-6
36" x 36"

not reflectorized except in a few special locations near or on edge of cities. These signs will be placed on outer edge of shoulder at right angle to roadway with message facing approaching traffic. Lettering sizes are: First four lines 4" Series "D" letters and the last tWQ lines, 2" Series "D" letters. 2ign will have a 3/4" black border,
1/2" from edge of sign and sign will
~e erected SQ that the bottom of sign

1s 5' above center of pavement. ~hese signs will be placed facing craffic leaving each incorporated ~0wn or city and at other locations

Where the traveling public is using hi rjf..lIay right-of -way to dump trash or

These .

garbage.

alt sl~ns will be loc~ted at frequent intervalS

lD('netrnofatlna-' f r m oo ne 'SIde to the otn. er along the 509-

ACcess. roadway which has been designated as Limited

JUNCTION
fere with viHibility, the height should be not less than '( feet. abo~e the pavement. In rural areas the a~sembly shall be not less than 6 feet nor more than 10 feet frorrr the edge of the roadway, exeept where Hhonlder width reqnireH closer mounting. In urban areas the assembly shall be not less than 1 foot from the curb.
Figures 1-1 and L"i show typic'al applieatiom; of Junetion Assemblies.
ROUTE DIRECTION MARKER ASSEMBLY The Houte Direction ::Ylarker c\sHembly. consisting of a Houte ::Ylarker with direl'tion arrow placed ])('\0\\". shall be placed in advance of 80

',',,'J, :1.l.r...

III ,ftlill IIII' IIJ"(Tlitll' tlf l'tllI\('" 11'I,i"l] 1111'11 til' Iftl' di"I"'-

~ if ttl .Ir j t- .. ,' _ ..

,._

II" lililr, III 'IJI"r""I,'d rllllll'''. :--1'1' fig.". I I iliid I.).

"'Il' 1:"111,

1)1', .
""111111

\

I ,.

. ""III "Ii"

.
IIII'

.dl

1'111111'"

,-II:! II

I )('

I
Illtlllllll'1

,lIl

"lllp..n
It

II it I II
. I II'

:"'1.""

II I \'

IIII'

1'111111'"

.
11"""l1g

, 1('11

ttl

1
I Ii'

I(''It,

I
;111'

......lllrrlllll.: ri~IJI III 1111' . II.

When two Route Direction Assemblies are required they shall be placed side by side on the same support. Where there are more than two assemblies a combination horizontal and vertical arrangement may be used. "~
In rural districts the Route Direction Assembly shall be placed approximately 500 feet in advance of the turn or intersection. Height and lateral distance shall be the same as the Junction Assemblies.
In residential districts the Route Direction Assembly shall be placed approximately 250 feet in advance of the turn or intersection. The assembly should not, however, be located so as to turn traffic into an alley or secondary street in advance of the proper turn. Height and lateral distance shall be the same as the Junction Assemblies in residential and business districts.
1" THOMASTON
ATLANTA'"
M-10 72" x 24"
ROUTE AND DESTINATION ASSEMBLY The Route and Destination Assembly consisting of two or more (M-lO) panels showing the route number, name of two towns and with directional arrows shall be placed at intersections of numbered U. S. and State Routes. This assembly shall be located on the far right side of the intersection facing approaching traffic and as near as possible in front of the right traffic lane. See figs. 14 and 15. The panels of this assembly shall be arranged insofar as possible to read from left to right and top to bottom as follows: (1) Straight Ahead Routes, (2) Left Turn, (3) Right Turn. See fig. 16. In rural areas the Route Destination Assembly shall be erected so that its lowermost part shall be not less than 7 feet above the roadway. It shall be not less than 6 feet nor more than 10 feet from the edge of the roadway. In urban areas where visibility is restricted the assembly should be erected over the pavement. This may be accomplished either vertically on a single post or horizontally on a mast arm. In either case the overhead clearance of the assembly shall be 14 feet 6 inches.
82

1--

METHODS OF ERECTION FOR DESTINATION MARKERS
, --------==-c----~~--~~-___,-__11

I
lJ

FIGURE 16

GRADE

83

CONFIRMATION MARKER ASSK\IBLY

TIll' ('onlil'lI1al ion \[al'kl'l' '\~~('I11I>l~' ,.;hall 1'011";]";1 01' ''iI'' or more
i \[ :2 alld or \[ :)( markl'r,.; :ll'l'angl'd :1"; ~hu\\'11 IltHI 101 'ill',j Ilot Irs; lhall :200 1'''('1 h,,~'on,j lit" ilil('r";('I'tioll 10 1'('11";,.;11]'(' Ih" Illl>l1>,i,.;t,.; of the
]'(lllt(' Il('ing I rll\'l'1('d, ~('(' fig", 11 :lIld I,)'

T\lI' l\[ :2 ulid. or \[ :) i HOlltl' \[,ll'k('1" ,.;1t:l!1 I,(! 1l"I'd i(( litis a,":,rm
hl~' tlt]'(lllgh 11rhan an'II"; alid ,11 t}l(' lir,.;t lU('lltiuli hr'\'Jlldlllll'I':'l'I,tioIJ>

ill rl11'l11 an'IIS,
[ll IIl'hln ,Jj'('II"; tlti" :I,~,~l'll1hly ,~h,dl )11' 1l1011IlI('d nol

Iltall i ic-et

aho\"(' tIl(' pa\'('I1l('nt lind liot II''';''; thilli I fool fl'Olll IIi\' (dgc of the

('I\rh. In nIl'll! ,In'a,.; thc a";";l'll1l,l,\' ,.;hall hi' 1l10\IIII"d Ii' '.." I' thl' grl'at-
",.;1 yi,.;ihilit~, IJlII in nIl 1'11."1' II''''' thalli 1'1'1'1 fl'Olll Ill<' "i1lom of the
a"";('lI1hl~' II' tIl(' pa\I'Illl'll1.

IWIUL REASSliRANCE :\IARKERS
Th(' !tlll':,1 !t1':I~~lIr:IIlI'(' .\lul'k('1' "\,";'~I'Ill)'h' l'IJIl~i~IJIlg "f ;'11(' "I' I1WI'C
'II I :llld III' 'II ,-)1 [10111(' .\1:ll'k,'I'~ ~h:11l 1)(' J(lI':lll'd :11 11111 I,,~~ Ih:11l :2mill' illl('I'\:lk :-'1'1' Iiglll'l , 17 :illlllg I Ill' Ilig]m:I,\',
Thi~ :1.-;,I'lltld\' _"kill ),(' 11l1l1l1ltl'd Illlt II'.",,, 111:111 1 1'1"'1 fl'<l111 til(' 1"J111l1ll
"II'"f till' ]1l11 ,'IIlH l"t 1I1:1I'k1'1' III till' P:I\TIlll'1l1 :llld Illlt k,;~ lh:llI Ii f(,1'1 fnllll ('dgl' "f ill(' P:I\I'I)1I'Ili, \\'111'11 :1 t' :-" :111.1 :-'1:111' It"lIll' fllllll\\ Ih,' ';:11111' hi,ldl\\:l\' 1I)lh, 111('
\', ~, \1:11'\"'1" II ill 1)(' 11,-;(,.1 ill 1hI' :1~';I'IllI)h',
GrIDE SIGNS FOR SECO:\'DAI{Y IWCTES AND INTERSECTlO:\,S
Application of Secondary Guide Si~ns
~("'()llIl:II'." (;llidl' .,igll'; ~h:lll ),1' 11.~I'd 1111 n'I:lli\'I'I." 1IllilllPIlI'1:lllt l'.~, :llld ~1:lt,- 1('JlIII'~ \\hl'l'I' 11':l1!i1' \'"llIlll('~ :1l'I' lllll :111.1 ~pI'I,d i~ I'P,tri"t('d dll(' 111 1'Il:ld l'lllldit illll",
Design of Secondary Guide Si~ns .\11 ~"I'lllld:II'." (; II idl' "igll .; :llld 1Il:ll'kl'I''; ,;11:1 1\ h:' dl',~iglll'd Il'i I II :1
whit(' hal'kgl'lJlllld 1111 \Ihilh till' 1I'IInillg 011 ,"."mhll!." :111.1 ),lll'dl'l' -;h:ill
I~ hl:II'].;,
.\11 ~('I'1l11l1:II',\' ( ; II idl' ,;igll" :llld 111:1 I'k I' 1''' "h:11 I 1)(, 1'1'111'1'1 Ill'i 7,1'.1,
Secondary I{oute \Iarkers and Auxiliary :YIarkers
Hllllt(' \[:11'].;1'1', :11'(' jllIPIlI'I:l1l1 III ldl'lItif." 1111IllI)('I'I,d high\\':I." 1'11111,'';
"lit to a""Il!llpli,,,11 tll(,il' plll'p""1' Ihl'\' mll,;1 1)(' "lIppll'llH'll1l'd h." \':ll'i-
ou~ tYJl('~ Ill' "\lI:\ili:ll'\' .\1:ll'k('I''' :111.1 "igll" III illdil,:t11' jUlIl'lillll.'" tllrll" and din'I't illll~ of rllil t (',;, }-;XI'l'jlt 11'111'1'1' 11"I'd n,; ('Ollti rmillg Ill:! 1'].;1'1'';, H"outp \['II'k (')'~ :11'1' :1 I11':1.".; m1l1l1l1,'1 1 'III 1'lllI..lUIlIII,(JIl 1\'1'1I 'I .\ IlXI'I"J:!r\' ~IRTl~ to flll'lll .11111('1 ilill ,\~';I'mhlil'';, Ill' I )i)'('(' I i<l1wl .\Iurkillg '\""l'm)'li('~,
:-;,-)

SP~CING OF ROUT E MARKERS IN
RURAL AREAS

COUNTY ROAD

FIGURE 17
86

TIIl'

~1'I'1l1l1I:11'\' ,111111'1 i'lll
,,!t:111 l'IlII'I',1II') II

,\,,'~I'('-

...>nll>ly, Jill II 'I ill I I 1'1) II I' I I' Ia I 'I '( I

tlll
I

l\:lf.\ ,\'1'

III

' II

,

I' Il

1\\ I 11'1'

I"\ "\ II (

,\1'\,1'1, -

l\" \1 I Ill' \1 ,'I')IIl\\ill;,( lh('

l>r'." I.

1 ", III IIii' 'IIIH'l'''('('\-

nl ll tl' 1111111 )11

llll!

f

i

l

II

I' 1'

,

-

,

'';1

'I'

I"I", -

II"I

'I'j1"\' ,'I "' "' I '1111'\ ,\'" II: (II 1)(' 1'1:II'('d

,\'Il1'III'h'

l\ppf'"\
\1I11t'l'

I l t''

til"l'

,-,1)1) 11'1'1 III
'
Illll"',I','111l11.

adII

..IUl II

\1

i

)1'1\\'l1h'
<.

!>I'

nl"'II'd


"Il

'I till' 11l\\TrJ11 1l,1 1'111'1 \\'ill 1)('

t ):11
nllt

I(:,-"-:--

111''111

I 1'1"'1

a!>II\'!' 11)('

,.Uft',,II 'I' "I' till' I'llI I " 1111 '\ :llld ,,!ta II

1M' lI"t !t',"" l!tall Ii 11'1'1 11111' III I I!'I ,

Ihllll III 1'1,('1 fl'lllll 11)(' I'd;,(' Ill'

thl' fllllt!,
Fil!lIn' I~I"III)\\' 1\l'il 'al appli-
"a!illll" Ill' :-'1"'1)11,1111'\' .flllll'lillll

.\""l'mhlil''',

JUNCTION

SECO:,\DARY HOt TE D1RE(,TIO~
ASSE:\II~LY

Thl' :-'I'('ont!al',\ 1:1l1111' Din,(,tion :\,,-

>'{'mhly (',m"i"l ill;,( "I' I (Illlt(' .\In I'k('1

1\11 IIIld .\[ .-) \\itll DiJ'('('tiollal .\1'-

filII' (.\1- 1;.\1" ,,!t:I1! II(' p1;l('('d approxi-

:mo IIlllt('ly

1'1'('1 ill Ilflnllw\, of tlw

intl'f"l'('tioll III ,,,!JIl\\ the diJ'\,('tioll uf

thl' illt ('f"l'('t iIl;,( IIlIIII',';. IIl'i~dlt IIIlt! 1:111'1'111 di"talll'I':-i ,;hall
hi' tltI' "11111(' a,; 1'.)\' .flllll'tioll .\,;,;('m-

hli('".

OVERSIZE STATE AND U. S.
DIRECTIONAL ROUTE MARKERS

---

o0:
S'"
V>

.'~."..
V>
FIGURE 18
88

~E(,O:\"DAI{Y .J CX('TION PA"'EL
Th(' :'1'I'fJlldaly ,lillii'I i"ll I'nllvl ,,11:t!1 !Jv ;1 Ii"ri.ontal n'l'tallgle :21" \ ~I" ill "i ,f,(' , It "lin!1 Ila\(' bbl'k 1('llvr" Oil \\ liil'- 1':I('k,grtllllll! :llld ,,11:111 II('
r"'II' -Iori zet!, TIll' .J\llj('tilill 1';111"I-;JI;dl II(' \I"l,d "Ill\' \\'illi
ItOIlII' \Iarkl'r" (\1 I :llld or \1 ,)) ;1" ,,1i"\\1l ill til( I~ I,

IJUNCTION I
M-IA 24" x 9"

TYPICAL INSTALLATION OF GUIDE SIGNS FOR. SECONDARY ROUTE INTERSECTIONS
:,.~
( ~ T . '" ~"',~
c
~
;;;
0 o.

":==J'--------S.'R:. =13'-

t

t

I---- ,," I

500'

~ I b ~

r :;

C - - - 300'

_I ZOO'--1

---, '-----~SR-;;-'3-,;-65.R;:;;-.-:7->,.

90
...

nJ~ ~
FIGURE 19

E SCHOOL SIGN STANDARDS

. \ k\l'! r( nl!'nl of Puhli(' ~afpjy !ta" i"sued sp('C'd zonlllg ",'""e (,;c.or'~1l"a ill!' s'pt'pd oj.\"(,'llI(,le.; tran'\l.II.g on !t.lg!tlyay" and "treels
~ .-Lo'l'!lh1l1l11Ol1O""()-foo( I':ldius oj'(. 'n~r, y "I'I100I 'In (III' ':-;t a t (' oj'(,, ('or'gl:!,

S.,tjtlJbIldOll.r:dl ".'1m1"1d,\\.pC,!

]H,('n :lp a('('Iu::nt

pro\('d seltill!!:
'.'
01 :-;('hoo] "lgn

f "

orth
Oil

sjwl'ifi('al iOll" 11,1gll\\'a~'" and

for tIll' ,,1 n'pl"

dl" ap-

,;,n. U:'C', I \ril hin 1IIl',se ,,('!too] ZIHH\S.

dUll!! ,11l(
pfOll, I'lrds

;11'('

~1, \'C'1l

.'
III ddall

. III

.
t!te

..

.

tollo\\'lllg

pa!!:e":

Thl'''c "t.lll( ,

....

.

1

\ Z ...:('hOCl ... <lIH';'"lO':-'l-l"

(."~ .\)_

('I, n'

to

h-~e"'

e- n'"('t-e" d-

_III

'ldY'IIl('('

01.,

(

of

till'

. '...(I' Ion\.JZ')]1l' I,) ,o....,'i\'C' (!I'in'r" adnull'e noti('!:' of the ZOlle,

oJ

" I )1 ..... (' If Ie

('I'()';';lrl'" ' . :--

"I~ns c,'

(:-;--:!i

arc

to

he

elTded

ill

alh-allel'

of

all

;'''tahli,.;lll'd ('!'l"s\I':ilk \r!t('n> ('hildrell no"" t!te !tigl1\ray or

"t 1'('('( .

3, School "i~n,.; i:-; ::\1 an' to 1)(' pl:ll'ed ill a(l\'alwc' of the "l,!tool

~'aroliuonndos f

Illwn it a s(hoo]

i" dl' on a

"!itriaghh\kla~o'r

Ill'('I'""ar~' to llc-"igllall' II'i( hin :1 s('hoo] ZOlle.

11]('

10-

4. Spel'd Lilllit.;igl\.'; (:-' 7) II'i1l1 AlI:\iliary S('hool Palle!" (8 -Ie) :)r IS ,il an' tl) 1)(' ('rel'led at Ih(, hl'gillnillg of lhl' ,,l'!100] zonl' to inforlll drlll'r.; of (he "]H'l'd limit I\'il!tin til(' ,,('!too] zone .

.i. \'0 Parking :-,('hoo] I [ollr" "igll" (Slii arl' to hi' lI"ed II'111'n' parking Oil 1hl' hi!!:hlray or "treel adjal'elll 10 111(' ,,('hoo] PJ'()-
duc('s a h:IZ:1 rdolls ('olldilioll,

fi. Spcl'd Li III i1 ,.;j gn" (8 71 are to h(' 1:l'c('lcd at t !tc' ('nd of 1he ZOIH' t'a('ing I raffi(' km'illg 1111' zone (0 "hOlI' lhe mO(()J'i,,( (hat
he !tas rl':ll'lll'd 1II(' l'nd of ,,('!too] ZOIl(' :llId to ."1'1 for(!t Ih(' '''!J('ed li III lI h('Yond 1he ZOIlI'.
I. l'or(ahk :-,('hool "ign" Il'ith AlI:\ili:II'~' ~lop PallP] (8 S) arC' optiona] and n1a~' lip u"ed at a, "chool lTo""ing 1\'hNP ('ollliition,.. makC' it lJ('(I'.;"ar~' to stop t raffle at a definite poin1 in the highway or "I n't'l.
~. Portahll' ,";('\ll){.1 "dgn" \I-il h Auxiliary Speed I'anl'l (S-D) are
optional :lIld may be u;,:ed at a point in the higlll\'[IY OJ' "tn'l'1 1I'!tC'I'(' it i~ 1l(,('p"S:Jr~' to ,,101\" namc to a 1011'('1' limit than Il:l~
heen pSbldishpd for tlw entin' /lOW',

!II

5-1 36" x 36"
5-2 36" x 36"

SCHOOL ZONE SIG
The School Zone ign i. to give advance notice to dtiv that they are appr achin chool zone.
The chool Zan e ign hall placed 100 feet to 500 f('N advance of a school zan .
This sign shall be 36" x and where condition warr an oversized sign 4 " x..j " be used.
The lettering shall be bla'k yellow background and i. not be reflectorized. See fi<rur .and 21 for location and pi ment.
SCHOOL CROSSING BIG.
S-2
The School Crossing i!!;11 used to give advance notice drivers of a school cro ing within a school zone.
The School Crossing ign be placed 100 feet in advanc'(' a designated crossing.
Crosswalks should be plainly marked by white lines painted on the pavement. See fi . 20.
This sign shall be 36" x 3 with black letters on yell background and is not to reflectorized.

92

COOOL SIGN S-3

~('h00I .\'o"'n shall be used

.It'

'. I~

(10
,

irable

or necessary
.

I,gnate th 10catlOn of the

I n . . .n.

hi"hway

or street ~

.
11\

a

.,,('h

01

zone.

L sually

'\I not b needed when

III

I. gns are used.

Th

ign shall be

I 100 fec to 300 feet in

f th chool ground.

T\ h1l'11'(~'('h

"
I si"n shall be 36

," wi h black letters on yel-

h:,('k"round and not reflect-

\. ::- fj".:21.

5-3 36" x 36"

000 PEED LIMIT SIGNS S-4, S-5

The' 'I d Limit signs shall be erected at the

JOdaric,' of the school zone to inform drivers

the I tal 'pced limit within the zone. Til ~p I Limit sign shall also be erected at
t.h nd r th chool zone to indicate the legal

I limit on the highway beyond the zone.

fi~,... :..0 amI 21. Th ~I (' d Limit sign shall be 1 " x 24" with

llsl.k IttI'. on \I"hite background and i not to

ref! ct riz d. 2-1" x 30" peed Limit sign

may b u. d if th i . larger sign i needed.

Tit ,'ch 01 Panel shall be used only in con-

juncti n \\"ith tandard peed Limit sign to in-

dirat that the speed regulations et forth by

h ' p l . i n are imposed for the protection of

hool children.

Tit ign hall be horizontal, rectangle in

~nP<' and 9" x] "and 12" x 2-1".

Tit 9" xl" School sign is to be used with

Itl' 1 " x U" peed Limit 'ign, and the ] 2" x

:!t" .' It 01 ign is to be used \\'ith the 24" x 30"

,'1 I Limit sign.

Tit ~ igni:i shall have a i It IllaC'k letters and are not

white to be

l'beaAcekcto~'ll''Oilzlefcild.

ISCHOOL I
SPEED LIMIT
25
5-4 18" x 9" 18" x 24"
(SCHOOL}
SPEED LIMIT
25
5-5 24" x 9" 24" x 30"

93

NO
PARKING
SCHOOL HOURS ~
5-6 12" x 18"
~TO~
5
C
H 0 0
L
5-7 12" x 51"
a?J
5
C
H 0 0
L
5-8 12" x 51"
94

o PARKING SCHOOL HOURS SIGN s;
The No Parking School Hours sign may b used to prohibit parking in school areas Where parking obstructs the motorist's view of Choo~ children at the edge of the highway.
It shall be 12" x 18" and shall have black
letters on ,,"hite background and is not to be
reflectorized.
PORTABLE SCHOOL SIGN S-7 The Portable School sign with Auxiliary Stop sign hall be used at locations where the hazard is particularly great and hall be set in the roadway at a point where enforcement of top necessary. See figure 20 for location and de ign. The Portable School sign hall be erected a the beginning of and be removed at the end Ii the school day. The School sign hall be 12" x 4' 3" and Auxiliary Stop Panel shall be 12" x 12". These signs shall have a yellow background with black letters and are not to be reflectorized.
PORTABLE SCHOOL SIGN 8-8 The Portable chool sign with Auxiliary S Limit sign showing the established afe limit shall be used where conditions \ra slowing traffic at a particular point in the roadway. See figure 20 for location and design. The Portable School sign shall be erected the beginning of and be removed at the end the school day. The School sign shall be 12" x 4' 3" and Auxiliary Speed Limit Panel shall be 12" x 1 These signs shall have a yellow backgro with black letters and are not to be reflectori

,mmm~"'L

l'

r~. .,.,::~'~;. :'~~~N.~. ~__ ~ ~;;:;:;~;;:~~.~;;,~~~:~:.~~

~ 'j~ ~l"'~:,1~~~~:,:,

I.

,;

_~~~~~~...J'-.,..,I

SGt400l. CROSSING 6 1'(lRT,t,8l.E SCHOOL $IG~ TO IE EIIEGTE!) IF NEUiED
. ~ ~ffi

POSITION OF SIGNS IN URBAN AREAS
.~~ sOCO"S ( TO U E"l.eEO .,T .. -.oTtQOO 00 "lO~ ><01llSS I ... ~ 1 aBOVE _E"llO' UR8AN AREAS '~11 "Ot LUS I"'" ,11 ,_UKI O' 'tOo.o-.,

nW w
.,...~: -= .-;;::::::::::::::: ,:~'! ~ ~
~--+-wl

.",_. . . j iT~: _$ .. .1"11 O]]dS OJ .,'$~ j

~~j. ~. .

~ll

b
j
~.
j

FIGURE 20

STANDARD LOCATl~ AfIID ERECTION OF
SCHOOl SIGNS



95

.~. r

POSITION OF SIGNS IN RURAL AREAS
WIoiERE Pl,RKING 00($ NOl OCCUR All. SIGlfS
ARE TO at ,11;'0 WIT" !OnOi4 or S(ilj1lOf
LESS TOlAN 4-0 AllOVE PA,VEIoI[MT 9UIlFIQ ""0 "'~ 6~'O' FIlO,,", PAV[IoIEHT EDGE

IF PMIKING OCCURS, SIGNS "'Fl.[ TOeE [!l(CTtI A1 7FOOT tlEIC~T ABOVE PAVEMENT:

",~,,~~ -

.'

" ."

.bT

~5:5:

24 "

T

POSITION OF SIGNS IN ~BAN AREAS
AlL SIGtiS ... It TO IE [llttTED "'nil 10TToo. Of SIGN NOT LESS T10IUI T' AeOVE P"'V[IIIIEM IN URBAN
AREAS .1\"'0 NOT LESS TltA/'1 In fllCIot EDGE Of" 1l0AO'WAT

";e!
.?';e;

~

,...~

e

,,-

.. -" ~ _

. 20 2 .-

"."'"

",

. y'

FK;URE 21

96

Part II

MARI\:INf;S

A-INTRODUCTION

Functions and Limitations of Markings

'ilirkin/!:~ h;l IC definite tunct ion~ to pprtol'11l in a proper ~chenH' oi

'ffie cont 1'01. I 11 ~OIllC ('lISe" tlIPy a reo uSl'd to su pplemcnj the regu b-

lIir,oons 01her

(1(I'I, I1.I;",ItI''mI' clciI~l"" ". j~ heojy" , oojbIl, teaI'm(I('r\''eI(~'PuhSs. ."11s('oII]ea' hs' tomn. ft"tH,h' e"I.Ir'gn01s1'1o1r

Sl'gTI .I;I "',. I n n1Cl'lt,s, that

not 1)('
rthane'- !o'er\"('

obt:till(,d a.; It ler.Y

bdyl..etdheI.H1'I

"e oj a
mcan~

n0y1" coothne\'re.dnneng. ccpe. rt

aIm.n

s\[('h C{L.;('" reguIat'lOlls

and \\':lrnin/!:" tllat I'ouhl not othel'\lise be made' clearly UIHkrst andn bl('.

~llIrkin/!:" :tbo ha\'(' deflllitp limitat iOJls, especially 11'11('11 ~lpplicd t ()

pa,-empnt and curl)i', \I'hel'(~ thry Illay lw entirely oblitenticd by :':IlO\\.

are not clcarly \'i~iblc \I-hen wet. and arc not ycry dumble whrn paint-

ed on surfacc~ (;:\l)()~rd to traffic \\"f'al'. I n spite of t heS(' limitation.s,

howe\-pI', the~' hllYP the adnmtage under faYo!'able l'OIlditiollS thai

they Clin conn'~' Ilaming or information to the \'phi(]P Ih'i\"('r withont

diverting hi~ att l'1I1 ion from the road\I'n.\,.

Legal Authority
~llIrkings shall be placpd onl.\' h~' thp ;luthorit y of a publi(' body or offieilll h:l\-ill/!: .imi~didion for thl' pUl'!)OSP of regulating, 11:tl'lling. or ~lIiding traffic.
Pan'ownt nnd ('mh lllarking~. bf'illg ('X('lllsinoly Iyithill th(' hOllndari('8 of puhli(' hi\dl\\a~'~. should IIP\'('I' 1)p ill~tallpd ('XCPpt hy plddi(' authorit.\,. Iklin('lllor" ,111(1 markillgs on ohjP('h H~ a \Imnillg: of thpir hazardous lo('al ion .; an' also norm,l!ly IYithin the high\\ay rig:ht-ofwsy, and should 1)(' ~ld)j('d to lll(' "ame ,imisdidional J'('glliatioll.;,

S&aadardization

~llIrkillg~, II,h('n' lI~ed, .;11;\11 he lIlIiform ill c!e"igll. po.;ilioll. allc!

appli('ation, .\.; ill til(' ca.;e of all othel' traffic ('Ollt wi dl'\'i(,(',.;. it i.;

aimndJXU>lrladtpi\r'(~,t

that ood

ilml..:;ltrlkililtlll.0~,';

1)('

1IIIifol'ln

~o

that

they

ma\'

he

n'('ogllizpc!

Types of Markings ~larkings as ddilll'd 1'01' tIll' purpo~('s of thi~ 1ll11llllal :11'(' or :1 lI11In!J('r
Ilf tyJX>s:

97

I. Panmwnl marking,.;: (a) ('enler lim',.;. (h) Lane lilll''';. I,u-l :\ o-pa;.;,.;ing-zol\(' mark ing;.;. (d J Pan'llwnl edge,.;. (e) Pan'llH'nt-\\'idth tran,.;ition,.;. (fl .\pprwwh to oh.-.;tnwt ion,.;. (g I :-'In'pl ('a r ('\ea rall(T line;.;. (h) Tmn marking,.;. Ii 1 :-'t op linp;.;. (j 1 ('ro,.;;.;-mdk lille,.;. (k\ BOIIII' din'dion,~. (II .\pprwU'h to railroad no,.;,.;ing. (ml Parking ,.;ptU'e limit;.;. (n) Word marking,.;.
.J ('IIr1, marking;.; for parking n';.;tridion,.;. :). (lhjel't marking,.;:
(a I (lhjpd,.; \\ithin tlll' rua(hm~'. (hi Ohjed,.; adja(,Pllt to llw road\la~. +. l(<'Il('I,t or markpr,.;: (al IIazard marker,.;. f.hl ]lplineator,.;.

Materials

TI\(' Illo;.;t ('I)JllIllOII Ilwt hod of applying 1)<[\Pllwnl. "\11"1" and object

Illarkillg,.; i.- I,~' lllPalh of paint. ,\ 1""ltinuou,.; imprll\"llll'nt ill paint.

and ill 1''1UipnH'llt alld Ilwtllild;.; of appli('alioll ha,.; n'~liltl'd ill a \"ery

lI'idl' U,.(, of pa\Tnll'111 markillg,.. Equipll1Pllt i,.; ill 11"(' 1kll i,. capable

of pl<J('jllg ,.illgle, douhlp, or triple ";lriping "n a hi!.!:!III;!\, ill different

('olor,.;, alld of ,.;olid Ill" hrokell lype of linp, lI'hill' OP('I':II illg at a Rpeed

of to to \.", mill'.- ])('r 11IlIlI', Iland e'luipJ1H'111 ('till I", II.-pd to pIal'\'

I ran";\'I'I>I' or ,.;pe('ial marking,., at interH'I,tioll"; or 1'\";"\1 !II'I'I', at a rea

,.;olla hll' 1'0,.;1 .

.\ rplali\'I'I,\' n'('l'nt dl,\'plopmPllt in pal'l'llll'llt m:lrkill!.!:"; i,.; tllP use

of minlltl' gla,.;,.; "heal!,.;" (al'tuall\' tn\(' ,.phen''';j I'mhl'dd('d in the pare-

ml'nl marking material 10 prudll(,1' a rl'1 rodin'('t in' rdl('('] ing ,.nrfaee,

'1'1](' gla,.;,.;-I'I'alkd ";lIrfa('I' n'tul'1l"; a gn'at!y inl'l'l'aH'd pllIlll,rtioll of the

illl'ident lighl !Ja('k in the direction of it,.; ,.Olln'I', alii I (','In'';I'''; thl' mark

illg,.; II' appl'ar hlillinou,.; al night IIIHlI'r Illll"mal hl'adlighl illg, While

the hl'ad,.; marking,.;

han' litl!I' or 110 I'fll'd in lhe hy night i,.; gn'all,\' impro\'l'd,

da,\\'tlilllhHo'u~h11111'1](l'i,.1;1il1,!itliiati\'

of the co,.t of

~u('h rpfi('I,torizPd marking,.; j,.; con,.iderahly highl'r tl];(I, lor ordinary

traffi(' painl, a nUIllI)('r of higl1\\'a,\' departml'lIt,; han' rl'l",rtl'd that the

illl']'('a,.;pd lifl' of thl' markillg,;, l',;pPl'ially at hpa\'ily-lr:II('ll'd locations,

mo]'('thHlI ('Ompell,;ate,; for tIll' diffl'rPIII'e ill l'O,;t,

'k'II"~ ma\" abo 1)(' ill Illl' form of "mall 1lllit, of 1ll('lal

I 111'11 I",'

.

Pa"rn1l'11 ':'1 '11:lI'llt'd to or ,,('I ililo 11](' pa\TIllI'111 ""l'bl'I' :-'lll'h

nl'\I<'II,1 ,I

.

_ othtr .', ' rt'I't:11112:1I1:11'. l'olllld. 1'1' of "]H'I'I:Ji "Iwpl', alld Illay })(' a"-

anJ, lll
11 ...... l

n1\'':l1\111
('(.

H
0

~'ol

id or 1'1'

),I'OkCII ill lIlt'

I'111(''',
pa\'PIl]('111

"llrla, l'l' "wI II

)('

n1'

j H'1'I1l:l1 11'1 II

.".'.a..l

111111" '1 f' I fi1 ll' p'I\'1 Cm l '1I11 l11a l, 'k II 112;';. alld "hall \)(' "1'1

.'0 lIwI

. tlll'll'

, ('llklr.'

'\' "1)('1'1 1 1

" 'lIr.t:ll'I'~"

rt
,I

.

'("1~I''lIliall\"

'

.

.

flll"h

. \\'llh

till'

pa\TI11I'1I1

. ""l'lal'l'
,

upPf'r, l'I'l.d ill l'ilIIIIIIIlOII" 1I,llla(t, or ,,('pal'alcd 1>y "Illall

.I.Ill'\" ~'pal'c. "

_~. I~' ~I',I'h' I'li ll:tl lil pp1't1.XIII1.1,1 . ,.d 111]1'1'"

lIlt' 1t-II1.!:Ih
a "011.1 I I"1111'

of a "illgl(' IlIlil. 1:ith('1' \'\'J)(' of
I" P\'('''I'I'.I\)(,' I 'III I Il'l~ 111:IIIIWI. I 'al'-

Ii.nr n1,'\.\'

II' II~I 'hollid

I",

1:lkcll

10 "c,'

thaI

:llilll'I11('111

:lIld

'pal'illl.!:

an'

tirtJ1M I':t rl' ~

, til ill"III'l' :1 gillHI appparalll'l' .

.....un1lt . . . 1'1' ~h'lll \11'\:1 I 1I1~(' ~. ,

h:I\T :1

""1'1:.11'1' I Ilat
.'

\\'1'11

\'('IlWI.II

1ll'll..!:III
.

11111 11'1' II ]I'

'. of tr:tflil'. Ihll' 'illltl'a"tllll.!: \\'1lh till' I'olill' 01 lI\\' pa\IIl]('III.

ac. llol1 'II' , ill"PI'I" ,hail IH' 0'1 ))('I'lllall('111 1'0 \or:, a" "p""1.f'11'1 1 l.or pa\'I'-

\olln]('1 ,

.\

'kIIill"~

111,"1'1" "hall \H' IHl1 I""" IlwlI I illl'llI'" ill di:lIl]('t,1' if

1I11'llt I'tIlJllI

111:11 ",' '
I, 0 \. "I'''1)lll

. l'o\,llIl

al"h' .

. 1''1 III \'al''111 .'

an':,

IlIo! mOI'(' I!J:III \" 111l'1ll''' apart.

. '. .
II ,I! 011]1'1' "haIH.
"1'111('1' 10 "1'1111'1'.

:llId "hall Oil Irall.~-

l hc' ~p:t"'II'I1II'~

11ll!' mill'"

. IIJ:lIl :\(; 1I11'1\\'" apal'l

..

.

Oil IOlll.!:lt lIdlll:Ji lillI'"

\c'rot'

..

.I. I I I ' \ '
.

!'hall halT 1'1l1l11,lt-d ,111'1':)"1'''. pn'''Plllilll.!: a "llllH,th "01110111' 10 II\\' \\hlI,I,

u( whi .. k", alld "h:lii 111>1 pl'lljl','1 1ll1)j'(' Ih:lll 1l111'-1J:l11 illl'h ahll\'(' tIll' W\'l'! "i till' P:l\'I'Ill"III. Thl'~' ,,11<111 ])(' !)(,I'IlW 111'11 I 1\' li:\l'd ill p!;Il'I' 1,\,

snch"l' },,,Il~ Ill' .~illlil:11' 1'1'1'1'1'1 i\'I' dl'\il'I'';. :'imilarl~. IIIlit \,'111'1'''. "."1111>111,. Ill' "ll'ipl'" 111<1,\' ]1(' :ltl:II'hl'd III Ill'

!'C'l illt" thl' p:I\TIIII'111 "lll'fal'I', a" :III alll'I'llal i\ I' l\'])(' ,>I p:I\'I'I1]('111 markillg. Thl'''I' ~holJid \)(' 1'''''I'1I1ialh' f111."h \\il1J Illl' pa \Tll](, I II .~l1l'fal'I.

sntl "h,,"ld II II! \"""'1111' l11l1ItJiy,lippl'l'y \\1JI'1I \\1'1. ('''pl'l'i:t1ly if II)('.\'
sn' "i "IlIl"idl'I':l1>II' :11'1':1. TItI'Y ,~hOllld \1(' \,1' pl'I'IlI:IIIl'111 I',,jlll" :l~ ';pl'l'l-

tit'\\ i,,1' pa\TlIll'lll 11I:II'kill.i2:"
:\ll'1al alld pl:I,1 ii' ill"I'1'1" :11Id II:tI 1ll:ll'kl'l' 1111il" ill Ill' 1111 tlll' pa\'I'-
Illl'llt "lII'fal'l' al'l' 11~Id pl'illl'il':tll~' ill lId,:111 :11'l':I". \\1JI'I'l' 1ll':I\'\' II':dli, rapidly dl'''II'll~'~ p:lilllld Ill:ll'killl.!:". alld \\'Ill'I'l' 11'1"i1II'lil l'I'pailllilll.!: 111,1

lIlIly i" 1'11"11." },111 (':111"1'" lll1dlll' Irafli,' dl'la."". III I'IIl'al :11'l'a" "))('I'd II!

lIpplif'atillll l1\akl'" P:lilitilll.!: 11](' pl'l'fI'ITI'd 1'1l1'1ll III Ill:ll'kllig :'III'I'f',,~illl l':\pl'l'illll'III" ha\'(' 111'1'11 l'I'plll'll'd \\ilh J)(,I'IlWIII'111 hllill-ill
\llIYl'mf'1l1 J11al'kill12:~ 0\ \\hill' Ill' 11l!III'ld "Il]II'I'I'tl' Ill' ilJi:lid !llil!;.' Ill'

l,jlH'b.
TIll' 1I,~1' IlI1 IIII' p:I\"IllI'111 ""1'1':11'(' of ,;llIall 1l](,lal Ill' pLI'1 it "I lid, \\ith ill'I'l'll'd l'l'fl""11l1' hillto]\.; i,; 1I0! l'l'I'IIl11Il1('IIIII'd. 1-::\ pi 'I'i I 'I II'" 1Ja'"
-hOIlIl Ihat llll'y ":11111111 hI' kl'pt ,ll'all alld 1'1'1'1'1'1 i\I'. :11 III )Ill'~ :11'l' :1

h:wml III 1111111l1'l\,1,....
Lal'gl' "J11l1"III";lllil" },"111111". Ill' hal'''. 0\' 1':t,,1 il'lll1 01' "oll"I'I'I"~I'\'I'l'al

' I I I :111'111". hio: -h. \\'11 1 I (l! ' \\J'1 I lOl11 1'('. {'('ttl\':-;, I'19I lt~. ~\'nl1)i)~, Ill' n1(\-..;~ag(\;-.;.

i~I:tlld., an' ia\Il!'ld ill "" III I, ,ilil'" 10 l11ark )H'dl'''ll'i:t11

or 111 :t'"i-:t ill

f'h:lllllpliz.ill''"" I]':1 JI'II'. 1II I. )](.,H' :tpp111'':1"1 111I\.; t 1ll'." :11'1'. I.II ('I '1' (,,'1. ('III'1l~

or islands. They are not a suitable alternative to signs or pavement markings. They should not be located where they constitute an unexpeeted hazard for motor vehides, and their use on rural highways is strongly disappJiflved.
Object markings are ordinarily painted direetly on the surface of the obstruction. If the surface will not retain paint readily, some flat surface of wood or metal should be painted with the proper marking and attached to the obstruetion. Where a refleetorized coating is desirable, it will often be necessary to use a separate surface for satisfactory application. Reflecting buttons or clusters may be attached directly to the obstruction or installed on separate posts immediately in front of it.
Delineators and hazard markers may consist of single reflectors,dusters or reflectors, or small panels of uniform shape covered with a reflecting coating, mounted on separate posts. To be effective they must be of retrodirective character and of adequate brilliance.

Colors

Pavement markings shall be either white or yellow in color. The correct color for yellow traffic paint is the same as that specified for. highway signs.
Bright metal buttons are to be regarded as the equivalent of white paint in pavement markings.

White shall be used for:

1. Center lines on two-lane rural roads and city streets.
2. Lane lines. 3. Pavement edges. 4. Streetcar clearance lines. 5. Turn markers.

G. Stop lines.
7. Cross-walk lines. 8. Parking space limits. 9. Route directions. 10. Word markings.

For the following markings it is recommended that yellow be used, but white is permissible:

1. Double center lines on multi-laned pavements.

2. No-passing barrier lines at:

(a) No-passing zones on two- and three-lane roads. (b) Pavement-width transitions. (c) Approaches to obstructions in the center of the roadway. (d) Approaches to railroad crossings.

The markings for which yellow is recommended are all solid guide lines or regulatory lines to the left of which it is unsafe or illegal to travel when they are applied as prescribed in this manual. Yellow is favored for several reasons:
1. It contrasts with the normal white center or lane lines and thus gives emphasis to the hazard.

100

2, Ycllow lw" hl'pn ac('ppt ('d ;\" a ,.;ym holic Il'a rn IIlg ('0101' in ";Ign,~

:Ind sigllu],.;.

It i,.; ('Oll.,.;i";1<'llt Il'jlh thl' ,,.;Iundurd for no-rJ:l,.;sing-zone Illurk-

3, , (f' hithert" appro,'('d h~' the ,\n1('riC,11l .\,.;,.;ociatipll of ~Iaje

1II,,:-
High,ru,"

Oflici:i1,.; ulld

"
In

11,.;e III

nl:ln~' ,.;Iat(',.;,

r('urII Ill,'1I.Kl'ill""'''; t" ,.;holl' purking pJ'()hihilion,,.; ('ol'{'r"d h~' ";Ign,.; or
'(H'(' ,.;h:i11 iJp \TllO\\. Of{'l1:Ill,r1'lkI'Ig:"- "n 1'('l't ical ";11I'fa('(',.; of . ohj"cCl,.; Il'it hin (h(' rO:ldIIU\, 01' dan.gc]'<lu:-,I.\, ('1,)'"(' I11('rpl0 ,.;hall ('''ll'';l"t ot :t11el'lw1e iJ!:tck and Idlite

6triJX'l!~' I' '1(IJ"I('('nl 10 1he 1'0:i1!1I',I\,. "nch u" guard raib. (ree", illld

( lj('(':-' '

.

',.' .

.'

.k~ Illa\' hp p,linled \rhlt(, u,.; a u,.;plill g\lldp 10 nlgh1 t r,dlll',

rO(I~ 'rrflc'!'t()j' m'lrkcr,.;, deJinl'ulor,.; ,,.;hull 1)(' II'hi1<', ,~nd Ill:lrkcr" indi-

rat in!! thp ]"(':11 i"n (If haz:trdon,.; oh,\('('I" ,.;Iwll 1)(' II'hlt(' 01' yplloll'.

Types of Striping :\ hrok!'11 linc ,.;llall 1)(' n,.;('d for ('pn('1' or lane lill('''; \\'lle\'(' Ih('s(' lines
are only guidI' lill('''; 1hut ll1a~' 1,(' ('l'o,,;,,;('d ,II tlJ(' di"nNioll of Ih(' dl'i\'('r. Sin('(' Ill"";! ('('IlL'1' and lall(, litH'''; a]'(' only f(lr gnid,\ll('(" Ihe ,.;a\'in,!2:
in paint thl'llugh Ih(' n,.;p of !)rok('n Jim's i,.; :111 impol'1:mt ('conomy, HijtlH!l(,pd ,.;t I'iping machi tlPS han' hP('ll ('Oll"! 1'l1l'1 ed tha I a]'(' ('apa 1>11' (J repainting hJ'()kpll lill('''; a('('lll'alel.l ,Illd npa11y, pl'l'I11ilting a "a\'ing (J more thull (iO P('\'('('lll in paint. Iri1h Idtl(' ()j' no in('l'ra";I' in tl1l' cost.
(J applicati"n. :\ broken line, IIi1h .~egm('nt,.; alld gap,.; \Iell proportioned, ,Ipppars
to he a,.; eHedin' a,.; a ,.;olid line for gnide purpos('s. Oil I'llra] llighll'uys ('ommonl~' \1H'd ,.;1 :Indard i,.; \;"j-foot ,.;egnwllI s Il'dh :'?;"j-foot gap,.;. In the applicatioll of :1 gi\'Pll gallonage of paillt P('I' mill', ";\lI'h \'('lali\'('I~' mort ,.;rgnH'nt" Irill gil'(, :1 het tel' Jilll' th:1l\ if ]ullger ,.;egmpnl,.;, with l.'OJTei;pondingl~' longer ga ps, are lIsed, On t lip ot her hand, \'ery ,.;bort eegment,.; and gap,.; ha\'p heen found to cau,.;e an lInpleasant fiickerin~ eensation,

On urban strret,.; tl!(' liI!(' segment,.; :md gap,.;, especially the latter,
mould he con"i(kra hly ]'('dllcec! in length. Short spet ions of broken
line, such a,.; a)'(' lI,.;ed for interspction appl'Oac1ws, requirp the Ibe of Ibort segments, c!o,.;e]y ,.;paeed.

Broken lines are al,.;o prpsnilled for street ear clearanc(' lines, and for tum markings.

A solid line sball alll'ays he used for longitudinal markings where
::: line is ~f a reglll:ttory ehara~ter and is not ,to lw crossed, that is.

center hnes of II\'O-I\'l\" mllltl-Ianpd roads WIth an evpn number of

lanes. and for lines indicat'ing IIO-passing zone,.;.

.

. In.a comhination striping of solid and hroh'n lilH'S, the ,.;olid 01' barher hne has significan('(' only if it is on the right-hand sidp of the com-

101

bination stripe, as viewed by the driver, i. e., in or adjacent. to the trafli

lane to which it applies.

1

Width of Lines

Longitudinal pavement lines shall be from 4 to 6 inche" wide.

The most common width is 4 inches, but 6-inch lines, favored b
a number of highway departments, provide added visibility. ~a:

rower 3-inch lines have been used as a means of economizing in pain;

but they are not regarded as adequate for standard use.

\'

Transverse lines on pavements must be much wider than longi.

tudinal lines to be equally visible. Stop lines may have to be as wid

as 24 inches where approach speeds are high.

e

Reflectorization Reflectorization for better night visibility is desirable for almost all
markings, but it is neither a practicable nor necessary requirement in all cases. Reflectorization is of doubtful value on well-lighted city streets, for example, and it is not ordinarily essential for center or lane lines where there are no special hazards. At lea"t the following mark. ings should normally be reflectorized:
1. Center lines on multi-Ianed pavements.
2. No-passing barrier lines at:
(a) No-passing zones on two- and three-lane roark (b) Pavement-width transitions. (c) Approaches to obstructions in the roadway. (d) Approaches to railroad crossings.
3. Striping on vertical surfaces of objects in and adjacent to the roadway.

Maintenance
All necessary markings shall be kept in good order and dearly visible at all times. Unless this is done they may create seriou8 hazards by giving a fal8e sense of security, espeeially in the case of cross walks.
The frequeney of repainting depends on the type of surfaee, composition and rate of application of paint, climate, and volume of traffic. Particular care should be taken, espeeially in the case of broken lines, to paint over the old markings as exactly as possible, otherwiHl they will appear increasingly ragged after suceessi"e repaintings.

102

B_PAVEMENT AND CURB MARKINGS

ter
(',ell

Lines t' line

is

used

to

designate

the

center

of

the

tI:a\"E~led

portion

sCJtJIa)Ia.l~creoesun'1e"'I1I\'1S\'If',l'l,I.t"te. rC,'I''ol]lflTa,t"Vhinee.gmpet.arnvat-fe\fm\i'Cl'ed1n'tlItl1,

b. o't}1 eI'lrecj transi"tIOn,
On all m

J,Ons., 1, !H" 1 er 'sOllle C''ll'C'UIll-

I,t

nee(I

not

}
)t'

at

the

g-eo-

ajor l'lIral high\n1vs having

(rica (e

,.

.

.

'. .

alInIertes n\t

' eIIIInIllb'"r of rural roads,

lanes, a,nd .o.n man.v, urban streets and ]Pss nllcenter Imes arc necessary and should he applied

po hout the C'ntire length of the pavement. In urhan locations

thrdoiol/n-!: some r11ral roaeIs \Vh. ere a contJ' nuous cent.er I"me 1S not reqUl,re(I ,

:ort sections of center line are u~efuI, on ap?roaches to busy inter-

_tions, marked cross walks, or railroad erossmgs, and around elllTes o,'er hillcrest s, \Vhen so used, 1he center line seITes both to mll'll

:; any unusual condition and to organize and eontrol traffie through

a hazardous or congested zone,

A line marking the eenter of a one-way roadway is a lane line,

Center Lines on Rural Roads
The eenter linc on a two-lane paved rural hig!l\\'HY shall be a broken line, not less than -I nor more than () inches wide: white paint on hlack pan'ment or hlack paillt ou \"hite pavement, Line segnwnts Lj feet in lenp:th. \\'ith ~;j-foot gaps. are re('ommelH!ed,

Center Lines on Urban Streets
Ccnter lil)('s on city stTeets shall 1)(' broken lincs. not Ir"" thallt illl'IJ('s nor mol'(' than () inches "'ide: \"hite paint on blae].;: pan'nwllt or hlac'k paint oll\\'hite p,wenW1I1, To presen'e the dIed of eontiHuity \dwre t rattic' i,; }wa\'y. speed,.: are 1()\\', 0]' hloek" short, 1he line srgnwnt,;, ,Ind e"pec'iall~' the gap,;, sho11ld he relatin'I~' "hor1.
Long "cc'l ion,; of ';\I('h line,.: "'!Onld not he u"cd on Cit n'p!s j)nl\'iding IPss than II\'() lilJ(''; for f]'ee-mo\'ing 1raflie in eaeh din,(,tion, ('xC'iu"ivc of parking lane", Thi" minimum "tn'et width doe" not apply to the lISC' of sho]'t sedion" of c'ent(']' line" a]'()\llld (,l1ITC", on']' hjll(,\,c'.~1s. or on app]'ml('he" to imporU!nl intcr"e('tion,.: and marked ('m"" \\'aII, ", Shorl sec't ion" of ('en leI' line for r('gula ton' pn rpOH'" "ha 11 1)(' of sol icl drsign,
:-'mal1 unit" of llH'tal or other mate]'ial atta('lwd to or ,,!'t into thc pa\'C'llwnt ,.:urfac'( an' frequently uscd in eitie" a" an altel'llati\'(' to painted markings,
On \\'iek. high-,;peed honl('\'I\l'cb. and on ('cJlItl'olled-ac'c'pss higll\n1~''': in mban an'as, ('c'nler-lint' st andards shall lw the ,;anw a" thosr for rmal highways,
.\ppli('ations of ('pntel' line" arp ShO\\'ll in \'IlriollS illustrations herein, partieularly figure,.; ~~, 24 and ~7,

1m

Lane Lines

Lane lines are helpful in the organization of traffic in it~ prope channels, and in increasing the efficiency of the use of the roadwa; surface at Qflngested locations. They should be used:

I. On all rural highways with an odd number of traffic lanes.

2. In addition to the regular center line, on all rural highways of four, six, or eight lanes.

:3. At important intersedions, at cross walks, and in dangerous

locations, on both rural high\vays and eity streets.

\

L At congested locations, particularly on city streets, wh(,l'e the roadway will accommodate more lanes of traffic than would be the ease without the use of lane lines. These include: (a) Locations between loading islands and sidewalk curbs. (b) Other locations where the normal laJlC width is decreased. (c) Approaches to widened intersections.

,J. On important one-way streets or highways where maximum efficiency in utili,mtion of the roadway is desired.
Applications of lane lines are illustrated in figures 24, 2;) and '27.

Lane Lines on Rural Roads
Lane lines on rural roads shall be broken lines, not less than 4 inches nor more than (j inches wide; white paint on black pavement or black paint on white pavement. Line segments l;j feet long, with 2;j-foot gaps, are recommended. The transverse spacing of lane lines, that is, the lane width, should not normally be less than 10 feet.

Lane Lines on Urban Streets
Lane lines O!l city streets shaJJ be broken lines, !lot less than 4 inches nor more than G inches wide; white paint on black pavement or black paint on white ptwement. Due to relatively lower speeds, tllP line segments, and espeeially the gaps, should normally be shorter than in rural areas. In limited sections of lane lines, as at intersection approaches or between loading islands and sidewalk curbs, the line selSments and gaps may be as short as 4 feet and of equal length.
The lane ,,,idth defined by lane lines eihmild not normaJJy b(' less than 10 feet, but a minimum of 9 feet is permissible where a maximum number of lanes must be made available, aei at a signalized intel'eiection where provision must be made for the mOeit efficient storage of stopped vehicles in a street \\'idth reduced by the presence of a loading island.
On wide, high-speed boulevards and on controlled-access high Ilays ill urban areas the standards for lane markings shall be the samp as 1hose for rural highways.

104

N~1.\Poa_psassi:n'g;inZg onZOels1(':'; :.;hould be e:.;tabli:.;hcd at yertieal or horizontal

U;yes and e!se':'here on tm)- ~nd three-lane hig~,Yays ~d1ere .pa:.;sing

Crnustthcbre

prohibltcd be('au:.;e hazardous ('onc}"ItlOns.

of

dangerously

re:.;tr]('ted

Sight

chstanees

or ~ no-paH3ing zone shall Iw marked by a solid barrier line placed as

h' right-hand element of a combination stripe along the center or
t ~e line. This barrier line shall be yellmY.
!ThIe cl omhlina.tl011 I'nle may eOll:';'ls.t 0 f "eltlWI' 0 f' tIwfo' ]mlY'lng. as 1'11 us-

trated in figure :2:2: I. ,-\ normal broken "'hite center or lane line continuing through the no-passing zone, \yith the solid harrier line placed to the right of it. \Vherc no-passing zones in opposite din'c,tions O\'erlap ou a two-lane roachnly there ",ill he a solid barrier line on each side of the hroken c'enter line. \Vhere the nopa:.;:.;ing m.,tridion applies only in t he opposing direction, the harrier line ",ill appear to the left of the broken eentel' or lane linc amI ",ill not 11a\'e any eontrolling effect ex('ept OIl traffic in the opposing direction. 2. A douhle line replacing the single hroken center line un a tm)lane roadway, of which the right-hand stripe is the sulid harrier line. \Vlwre no-passing zonc:.; in opposite directions oyerlap, there 'Yill be a double :.;olid linc, and \yhere the no-passing re:.;tridion applies only in the opposing direction the solid line \yill be to the left of a broken line and will not ha \'(' an~' controlling effect.
The harrier line shall be not less than -t nor more than (j inl'lw:.; ,Yide,
and shall be separated from the adjacent stripe by a space of not less than :2 nor more than -1 inches. It should normally be refledorizcd for increased emphasis.

No-Passing Zones on Two- and Three-Lane Roadways
On a t'H)-laue roachnly the combination no-passing line shall follow the center line throughout the no-passing zone. On a three-lanc road the combination line shall start from the left-hand lane line of the ('elltel' laue and :.;hall ext('nd at an angle of not kss than 20 to 1 across the center lane to the right-hand lalle line at ilw beginnillg of tlw llOpassing zone, and thenee extend along the lane line to the end of the zone.
::\o-passillg-zonp ",igns (J~--1(i, H.-Ii) may he used to ",upplement the pavement marking", here prescl'ibed.
It is a",sumed that on higll\H1Ys of four or a great('\' eyell lluml)('r of lanes it i", not I1c('es",ary to ('I'OS", til<' ('el1ter line to O\'ertake amI pas", other vehicles. '::\0 ",pecificatic)J]s, therefore, are p]'()"icled fol' the markillg of 110-pa",sing ZOl1es 011 such high,ntys. The double (,(,l1ier

I();)

is to be regarded as a continuous no-passing marking, consisting
~~wo barrier lines which must not be crossed from either side.

warrants for No-Passing Zones

The warrant for the establishment of a no-passing zone depends on

the assumed design sp~ed of the road and t~e min.imum sight dista~ce

essarv for safe passmg at that
necrve is'the distance at which an
eUrface can just be seen from ano

speed. object

4S~lgfhetetdlasbtaonvcee

on the

ther point 4~ feet above

a vertlCal pavement the pave-

S~Uednet,tearsmiilnleudstriant

ed in figure 23. similar fashion,

Sight distance on a horizontal curve measuring around the embankment

Jr
Ao

other curve

sohbaslltrwucatriroanntthaant oc-uptasssom.ffgthzoenve,ieawndonshtahlel

inside of the be so marked,

curve. when

the minimum sight distance for the assumed design speed is equal to

or less than that listed below:

AIinimum siUht

Design speed (miles per hour):

30

_

distance (feet) 500

40

----------------------------------

50 _- - - - - - - - - - -- - - - - -- - - - - - -- - - - - -- -- - - - - - - - -- -

60

---------

----- ---------

70

----- ---

-----------

600 800 1,000 1,200

The beginning of a no-passing zone, point a in figure 23, is that point at which the sight distance first becomes less than that specified in the above table. The end of the marking, point b, is that point at which the sight distance again becomes greater than the minimum specified. In no case shall the marking be less than 1)00 feet in length. If the actual no-passing distance is less than 500 feet in length, the additional length of marking shall be added at the beginning of the zone.
On urban streets it is not ordinarily necessary to mark no-passing zones. Speeds are generally low, and a normal center line is usually sufficient to keep vehicles in line. On boulevards or parkways, where no-passing zones may have to be marked, the standards should be the same as for rural highways.

Pavement Edges
Line markings on the pavement have sometimes been used along the sides of the roadway, especially Oll bridges, to indicate the limit of safe approach to the edge of the pawment. Experience has shown that such lines are easily mistaken for center or lane lines, with the result that drivers attempt to pass to the right of them and so r\lll off the road. They are therefore not reeommended. Reflector markers are much preferable for the purpose intended.

107

VERTICAL CURVE

0,0' Begin no-passing zone
Sight distance becomes less thon minimum measured between points 4~ feet above pavement

b, b' End no passing lOne Sight distance again eKceeds nWirrun

No1e: No-passing lones in opposite directions mayor may not overlap, depending on Q1intmeM.

HORIZONTAL CURVE

I

I

I

I

(),o'()~

. ~ l,O~e~\.co,e~ :

~~\~

,t>

~o ,\.of\

I

~o' ~/.t.V

t

' " \\f\

:

I I I I

0, 0' Begin no-passing lone

Sight distance becomes less thon minimum measured between points on center line (or on right-hand lone line on three lone rood'>

I

I

I

I

~"'O-h

I ftl) ass//"

I

Oij.~Cli 'g I'O'J~

I I

c 0..,''.'Oi

~

0'
'o/),

I I

:

01t!(/) "

I

I

I

I

I

I

I

I

b, b' End no- passing lone Sight distance ogoin exceeds rrinimum

No1e: No passing zones in opposite directions moy or may not overlap, depending on olinement.
Figure 23.-Method of locating and determining the length of no-passing on vertical and horizontal curves.

108

jI
FROM 4 LANES TO 2 LANES
Figure 24.-Typical pavement-width transition markings.
Ion

Pavement more than 6

edge lines shall be solid white lines, not less than inches wide. When used, they shall supplement

r4atnh~r

than replace standard center and lane lines.

r

Pavement-Width Transitions
Line markings should be used to indicate points where the pavement width changes to a lesser number of lanes. There are a number of situations possible, as illustrated in figure 24, depending on which lanes must be offset or cut out, and the amount of offset. One or more lane lines must be discontinued and the remaining center and lane lines must be connected in such a way as to merge traffic into the redUCed number of lanes.
I-ines marking pavement-width transitions shall be not less than 4 nor more than 6 inches wide, and of standard center- or lane-line design. Converging lines shall have a length of not less than 20 times the offset distance.
Through the transition area, in the direction of convergenee, the line separating the opposing directions of traffic should be of nopassing-zone design, either the double solid center line of a multi. laned road or a normal broken center line with an adjacent harrier line as preseribed for no-passing zones. Such no-passing markings should normally be refleetorized.
Pavement-width transition lines, in themselves, are not a sufficient warning at such loeations, and should be used only to supplement standard signs, guardrails, or delineators.

Approach to an Obstruction
Pavement markings shall be used to warn of the approaeh to a fixed obstruetion within a paved roadway.
Obstructions within the roadway are hazards that should not 1)(' permitted to exist if avoidable, but where they eannot reasonably be eliminated everything possible should be done to prevent vehicles from colliding with them. An obstruction may be in the eenter of the roadway, in whieh case all traffic must keep to the right of it, or it may be so located as to be between two lanes of traffic moving in the same direetion. The markings in either ease must be designed to defleet traffic away from the obstruction by a diagonal line or lines of unmistakable meaning.
Obstruction pavement markings shall eonsist of a diagonal line, or lines, extending from the center or lane line to a point 1 foot to the right side, or to both sides, of the approaeh end of the obstruction. See fig. 25.
The length of the diagonal markings should be determined by the
formula L = S x W where L equals the length in feet, S the design
speed in miles per hour, and TV the width of the obstruction in feet.

110

L~

L

Figure 26.-Typical designs for turn markings on pavements.
112

rIanl

no case areas or

shall the diagonal line .50 f"eet III urIJan areas.

be

less

than

1;")0

feet

in

length

in

ruIf traffic is required to pass only to the right, the diagonal line shall

be marked to the right and shall be of one of the follO\'.:.ing designs:

1. A normal broken center line flanked by a solid barrier line, as specified for no-passing zones. The barrier line shall extend along the center line in adnmce of the diagonal line for a further distance equal to the length of the diagonal line.

2. On a roadway not marked with a continuous center line, a solid line which shall be extended, on the roadway center line, a further distance in advance equal to the length of the di-

agonal line.

3. On roads of four lanes 01' more a simple continuation of the double center line prescribed for such roads.

In addition, a solid \yhite diagonal line may be extended to the left of the obstruction, to outline the triangular area from which traffic

must be excluded for safety.

If traffic may pass either to right or left of the obstruction, there shall be two solid \\'hite lines di\'Crging from the lane line, one to either side of the obstruction. In advance of the point of divergence a single solid line shall be extended in place of the normal broken lane line for a distance equal to the length of the diverging lines.

All lineH used in obstrm:tion approach markings shall be not Ie"" than 4 nor more than (i inches wide. They should preferably be reflectorized.

As an added Hafeguard it is desirable, especially where traffic is permitted to ptU3H to both right and left of an obstruction, to place broad transYerse. diagonal, or longitudinal lines in the triangular area between the guide lines. aH shown in figures 25 and 29.

Similar marking" are desirable at channelizing islands not so designed as to diYert traffic naturally from them.

Obstruction approach markings shall be used only to supplement adequate markings on the obstruction itself.

Streetcar Clearance Lines It is often desirable to mark lines on the pavement to indicate the
limits and the clearance of the overhang on turning street('ars,
Streetcar elearance lines shall be broken white lines, with Hegment"
and gaps of equal length not exceeding 2 feet. They shall he not Jp""
than 4 nor more than 6 inches \vide.
On curves of short radius it is necessary to usc verv short dasll<'''
and spaces, to preserve the appearance of ~ontinuity in' a bro\';'('ll line,

Turn Markings :\larkinp;s to restrain drin~rs from starting left turns befol'(' reach.
inp; the intersection, or to guide turninp; vehieles, are sometimes used at intersect,i,(ms. Such markings han~ not been satisfaetorily stand. ardized, but if use~ they sl.lOuld b: so desig~lCd as to indicatl' the prop. er course for turmng vehIcles "lnthout bemg needlessly COllllUiing to through traffic or traffic makinp; other turns. Typical designs are shown in figure 2G.
Lines used in turn markings shall be hroken \yhite lines. !lot less than 4 nor more than G inches "lyide. As in the case of street car clear_ ance lines, they Hhould be made IIp of Hhort dashes and short Rpaces.
Transverse Lines
Because of the 10\\' angle at ,,"hich pm"ement markings are \'ieWed from an approachinp; "I"ehicle it iH necessary that all tnms\"erse lines be proportionately \yidened to giYe visibility equal to that of longitudinal lines, or to ayoid appan'nt distortion where lonp;itudinal and trans_ verse lines are combined in symbols or lettering. This applies particularly to Stop lines, cross-walk markings, railroad-crossing mark. ings and word markings.
Particular attention must be given to the maintenance of trallHverse lineH which, because of their position on the pavement, are subject to constant wear hy en'I".\' vehide that paHseH.
Stop Lines
Stop lines (or Limit lines) should be used in both rural and urban areas only where it is important to indicate the point hehind which vehicles are required to stop in compliance ,,'ith a Stop sign, traffic signal, officer's direction, or other legal requirement.
Stop lines shall be solid white lines, not less than 12 nor marc than 24 inches wide, They shall extend across all approach lanes, usually to the center line,
On urban streets where speeds arc not high a width of 12 to 18 inches is usually sufficient.
Stop lines, where used, should ordinarily be placed 4 feet in adnmce of the nearest cross-walk line, In the absence of a marked cross walk, the Stop line should be placed at the desired stopping point, in no case more than 30 feet or less than 4 feet from the nearest edge of the intersecting roadway.
If a Stop line is used in conjunction with a Stop sign, it should ordinarily be placed in line with the Stop sign. Howeyer, if the sign eannot be located exactly where vehicles are expected to stop, the Stop line should be placed at the stopping point.
The word STOP shall not be placed on the payement in advanee of a Stop line, unless every vehicle is required to stop at all times.
114

Figure 27.-Typical urban pavement markings, showing center lines, lane lines, stop lines, cross-walk lines, parking-space limits, and route markings.

Cross-Walk Lines
Cross \\"tllks should he marked at all int(']'"eltions \ylwl't, thel'l' is material ('onfli'fot hetween yehi('ular and pedestrian moyemE'nt. :\larkl~d (TOS" walks should abo he pl'Oyided at other appropriate point" \y!Jne there is "uhst ant ial ])('de"t rian mo\"('nwn1, a" at long loading isla nds. or \yhere pedestrinn" an' permittP(l to ITO"" I)('t \ypen intel',,(~(t ion" or \\'he1'E' pedestrian" ('ould not olhen\'i"p 1'('I'ogllizp the ]lrOIH'1' pla"l' to (']'oss.
('ro",,-\yalk line", in hoth rural and \lI'han an'a". "hall 1)(' solid \,hite line", mal'king holh edgl'" of tl\(, (TO"S \\alk. Tlll'~' "IUlll he 1111\ less thanJ nor more than 12 inl'lll's I\idp (tig, :.tll. If no alh'aJH'l' ~tll\lline is pr()\'idpd. it nla~' \)(' de,sirnhk to in(TI'a"e the \\idth of thl' ('ross\I',llk line on the appmal'h "idl' to :1" nH1I'h a" 21 inl'!w",
()nllrhan "tl'eet". Iyhel'e "peeds an' I'dati\'pl~'I()\y, a \\'idth or Ii 11\('!leo is u"uall~' :lIlioq\\a te.
'I'll(' \\'idth of the (TOSS \yalk het\\l'I'n ('I'O""-\\'alk linl's i,s US II,t1ly c1I,\('1'l1lilWd h~' t hl' \yidt h of thl' "ide\Yitlk" so ('OIl1l('('\('d, Tit, \\iclth "hall in no ('asl' 1)(' k"s t h:11l () fl'pt,
To f:lI'ilitnte ]H'llio"trian ('oopl'I':t1ion in tralIi(' l'egulatioll, ]H'dl',stl'ians "llOuld kno\\' exa('tl~' \yhe1'(' tlH'\' an' to (Tnss tIll' ,st 1'1'1'1, and.;iliJ\dll feel n'a"onah1P sl'l'llrii~' not only again"t \'(,hil']ps :lppl'o(\I'hinll ! 11<' inter"e('tion, hut a1.so again"t those tU1'lling within it, :-,ingl(,-lil\(' ITOS,"-
\yalk marking" fail in thi". and :\\'(' st 1'Ilngly disappl'o\'('11. T\\o lines
are n('('l's"ar~' to ddinl' 1111' I']'O",,-\\,:tlk an'a, and "IHllild :illl;I\S lit' noed,

Route Directions
.\s a s\\pplenwllt to standard roule markel'S. or \I'IH'1'(' dlll'I,tions cannot he sati"fal'torily indi('atl'd h~' an~' other n1l'im.~, "]H,(,j:11 dirl'l'tional marking" ('an sometin1l',-- Ill' l\.,-;ed on the pa\'l'mpnl. Tli('~(' nU1~' con"ist of (ml' 01' more alTO\\'", \\'ilh or \\'ithout 1'0\111' nUl\l\)('l's, in thp ccnIN of tlll' lane, .\ t~'pi('a] example i" illnstl'at"d in ligll\'(' '27,
Din'('t ional markings ,--hall ])(' white in ('olo!'.

Approach to Railroad Crossing

Pa\'cment markings ('onsisting of n I'ro"s. thl' \1'111'1''' lUt it no-
passing I'l'nler line, and ('I'rtain tl'an:-\'('rse liIH's ,~h:tll li(' pl:\(,pd on all
pa yed approal'h"s to railroad (')'os:-ings, ex('"pt ;\ \ nUlior :-idings ~
"purs or in ul'han an'a" \\'he1'1' olh('1' protl'(tim} is al'!'ol'dl'll. Swh mark-
ings :-hall be \yhite eXl'ept for the no-pas:-ing ]li\lTi('r lilH', whil'h should

prefE'rahl:v he yello\\'. These marking" "hould nOrIll:dl\ ])(' refle('\orized. The design of railroad-l')'os:-ing paypnH'nt l11ilrkin,gs shall bp essell'",
tially as illustrated in fignl'l' 28. Thl' ,,~'mhol nnd Il,t t('1':- arp elongated

to allo\\' for tll(' loll' anglE' at \\'hil'h they an' \'iel\pd,

,

dt '''hill' these markings haye nlltll' as a nWillls of n t t rtH'ting the.

tl'ntion of tilt' dri\'()1' to the pl'Oximity of a I'nilrlJild gradp cr0ssi4

IHi

hf'('ause the:,' are distindin'I:,' differpnt from all other IHlYP!11('nt murk ings, (hey aI'(' only auxiliary 10 nIP standanl signs or signaL- whil" must I>e inst al1('t1 in e\'('r:,' ('as(',
Parking Space Limits
'I'll(' marking of p<lrking S])<I('e limit:-; on url>an s(reet:-; tends 10 1'1('\'pnt elleroa<'llllwnt on fin' h:"dranl zones, jlll:-; :-;(op:-;, loading Zl>"('S, approacll('s \() ('Ol'ners, and ckaralwe space:-; for islands, Such Pi: t'king :-;paee limits may he indic<l(ed on Ill(' p<l\'('men( 1):,' lit\(,:-; nlll: ked
perpendicular to the ('urI> a1ll1 exll~nding into the rO<ld\\'a:,' n\(, \\ idth
required h,Y a park('d Yehi(:l(', u:-;ual1:,' 7 feet, ,\:-; <I further rdilll'lllpn\ <I lin(' ma:,' he pl:\('ed pamllel to (ll(, ('urI> ('Ollll('(,ting the Sll'('('\ ('Ilib of the:-;(' ])('rpendicu1:lr lines. indi('<1( in/.!: the outsidp I>oundary of t hi' P:ll-b:ing Z01le, Th(, W!W may 1)(' di\'i(kd into stalls I>y the use of litH" ])('1'!lendi('ulal' to til(' ('urI> and so "p;j('ed lhal e<l(,h "tall is long CII')II~h to a('\'ommodate onc park('d Ychicle, Ilslwlly 20 feH, [n this (''1,,(, " short Jil\l', parallel (0 the ('urI>, Illay \)(' p1:lced at tl\(' end of c:l<'h,,: 11 line, in plaee of thc c(ltltinuous line cxtpnding' the \('ngth of (II\' pllrking ZOIH', See figu 1'(' 27,
The marking of is(alb i:-; (':-;IH'eially hell('licial \Y!\('re p:ll'kir,,", meters are u:-;('(I.
.\n/.!:k parking i" g(-nerall:,' no( desirahle, t!tough ()l'easiollillh' it lIlay he justified <liS, for example, on an ull1liSually \yi(k ])1\\ ('III('II( \\'here IJassing (raH'ie is light and rl'lati\'el:,'slo\\' mO\'ing, Wll<'J'(' :tilde parking is ppl'lIlitted tbe marking of lines to indicate til(' lilllll-- of staIb pnahlps all drin'r" to park at th(' :-;anll' angle with a IIllnllllillll of \\'aste spal'p,
All lilH''' for parking iSpaeps shall 1)(, solid \\'hit<> Iinl',--. 11", I""" than 4 nor mOl'e than Ii inl'!lPs \\'idp,
Word Markings
"'on I marking" on tlw pan'nH'nt may he u"l'd for IIii' ])urpose of guiding, warning, 01' n'/.!:ulatin}.!; tralfie, They ",hould 1" limited to as 1'(-\\' \\'ords as possihle, IIl'\'er moJ'(' than thre;-',
"'01'11 markingiS shall !\()( he niSed for mandat(lr\ Illl'ssages except in IiUpport of standard sign". TIIP:" slwlJ he \\'hitl' ill ""lor.
The 1l'lIeriS should Il(' greatly elollgakd in til' din'diem of traffir mo\'pml'nt h('('alltw of the 10\\' angle at \\'!rieh th,'\ :11'(' \'ie\\'cd hy 3Pproaehiug drivers,
On high-speed road", ('spe('ially wlwn' t ralii" i" 11(':1 \'y, messal(es tJ
more than one line an' umlesirahle and "hould l!.flli'l':llly be :l\'oided. It is diffieult to read and understand a nwss:ql;l' \\hen the \"ords ':: neeessaril:,' spn'ad oyer ,"'0 /.!:reat a distalleE' that tl",\ are not allleF:1 at (l!le t illW,
liS

Where pn'Yailing 1mlnc ~pepds arc grc<ltpr than ;'~5 milps pel' hour J:lrgr ]r11p]"s and numprtds should 1>r llsed, ;;; fpet or !l101'(' in lwight: and, if the !l1essagp con"ists of morp tlHln Oll(' \rord, it shollld read "U])," i, c" the first mml ShOllld 1>e nettrest the dri\'pr,. Thr space hetm'en Jines shOllld he at lea,s1 fOllr lime" t he heigh t of the ('hamC'ters,
On ilIP olhn hand, ",here ))J'e\'ailing 1ratfic s])eeds an' ;~:) milp,s ))('1' hour or less, i1 is ])o"sihk to USP smttller ktters and 1ll1l1l(,],<ll.s, and 10 "pa('p the lines closer 1ogPl!l(']' "0 thtt1 an (ntire llless<lgp of as mallY as threr line" n1a~' he "een and rpad III one lilll<', In this case, <I me"sage of t\\'() or 1hree lilles should 1>e alTangpd 10 ]'('ad "dmn!." i, c .. \rith the fir"t \\'ord farthest from 111(' drin'I', The spa('ing het \\'('pn the lines should Il(' eqllld to 1hI' lwight of the charaders,
The \\'onl STOP "Iwll Jl('\'(']' llP llsed Oil the pan'!llcn1 in ad\'tllH'e of a StO]) line, lin less e\'('r,\' \'ehip]p is )'('quirpd 10 stop nt all times, Curb Markings for Parking Restrictions
Curb markings nla~' he llsed to sho\\' \\ here ])tlrk ing is proh ihi t ed :11 all timps, They "holl]d not lw ll"ed e,,('p])1 (J)) ('III'hs along \\'hich parkin/!: is kgally pmhihited, either hy g('lwral ordinmH'e, as al tin' hydrants, adjacent to conwrs, and oppositc loading i,slands, or hy t!lt-' erection of stnndnrd no-parking signs,
Thp cmb marking shall }w of a solid ~'pllo\\' color, ('O\'pring the face and top of j he curh,
E"prrience has sho\\'n thttl the pllhli(' does not easily llndcrstand a color code \\her8 several eo]or" arp m;ed in ('\Irh marking to indicate' different types or dpgrpes of parking rest riet ions, Curh marking" are' accordingl~' !'l'commcw)ed only 10 shOll' that parking is prohibit ed a I; all times, OJ her rest rictions should he ShOll'll b~' st andard parking signs,
119

C OBJECT MAHKINGS

Application of ~bject Markings
Ph~'~i('a] o!J,.;ll'l1('tiun" in ur n('ar 'I mad\yay that ('lln"litull' "1'ri"ll> Iwz,lI'Ib to traH11', in('!ndillg in~tall,ltiun" dl'"igll('d fur tIl(' 1"lIl( rid 'If 1rnlh(', ,.;halll)(' ,ld(''1Ualp!y markpd,
T,\'pil'al oh"tr\ll'lion,.; of thi,.; ('har:\('I('J' al'l' hridg(' "upporl,.;. 11I11\IU11l('nl". I ralli(' i"lanl!";' 111'al'llIl ur "ignal ,.;upporl~. ]'Iading i,.;lalll!". I'ifniI'ad(',.; 1(1 I'!o"(' road". railroad and dra\\'hridgp gall'''. pnd po"t.~ 1>\ liarI'U\\' hridgl'''. ulId('rpa"" pi('r" alld ahut 1lH'llh. ('\\1\'('1'1 ]w:lIl \\',dk "-liard rail", "igll p'I"\";, pU!('.~, 1n'('", alld m('b, :lIld ,,1 1'\1('t \\n'" 14i\'ing 1'1"1 lil'l('d 11\'('rhl'ad (']Paranl'(',
()nl\' "I!I'h il1lll1()\'alll(, oh"tl'ltl'lilln" a" hrid14(' "\\pporh and 1II'(r~"ary i"\;md,, ,.;hould h(' p('rll1ilt('d to ]'('main \\'ithin th(' rO'lIh\'I.\. I:\"n al j]\(' pn''';1'1l1 lin1(', oj)"1 r\\('t ion" an ol'('a"ion,dk pla('('d in I'il:rrhya~'.,
nndl'r tI\(, llli"Llkl'n hl'1id that l!W,Y' \\'i11 "1'1'\'(' a,.; aid" to 1)". ,'ontrlll
IIf tr,d-!i,', ~11('h ilHallalion" inl'!ud( "i14ll,d ]H'd('"jal" ill th, ("nll'r of ill(('r"('I'\ ion,.;, "ign or "ign:d ])()"t,.; ,II railm,ld ('m""i 1112> , ::lld Iargp "mll.~hroom" hul1111l"; ill :1('li\'I' tr,dhl' an',I', Thl'"'' .~hllllid lll\ariahly 1)(' \'('II\II\'I'd fill' ,afl'ly .
.I\\dgll\l'nt 1111\,,1 Ii(' (':"I'I'I'i."I'd ill tl\(, markillg IIf IIh.i""I~ I Iltl'road\\',I\' hut it ma\' hi' nut('d th'l\. ('\'I'n \\'hprl' thl'~' aI'!' lhi'("'('llr':d]~' at a ",11'( di"lal\('I' frllm til(' ma,l\\a\', marking thl'lll Il\il.\ 1'(I'\"lil "I'rillll:' ,1"i'iljplll~ ,md fa"ilitnll' night dri\'ing,

Objects within the Hoadway

()h~1 l'Iwl i'lIl" in t h(' mad\y:!.\' .,,1 li\ II hi' mark!d II Ii Ii Itl,l II'."" Ihall

ii\'I' ,dl('maling h\;\(,k and \\'hilp "Irip('" Thl' "trip,>, ,ililll ,Iopl' dllwll-

\\'ard al ,In allg](' of L-) dq!y('(', (iI\\:1l'I1 tl\l' ."idl' Ill' it\{ ,l!l"tl'lll'litill Oil
\\'hi"h tralli,' "hall pa"" TI\(, altl'l'Iwl(' ~trip,',,,~h:,)1 i", Ul\it'1Il'111 lind
110\ ks.~ lhanl iu<'1I('s ill \\'idth, Thl',\' 1I1i1.\' h, ::" 1111\,11 I"idl'r a, may hI' \l("'I'.~..;ar~' lu m:II':'I' a 14011l1 appl'ar:lI\(,(, alld 11\ \iill\\dl' ,.;\tflil'i('nt "i"i hilit.\'. dl'p"I\lliug ')11 t h( ,iZl' I\f tI\(, uh.il"'1 :ll\d ~11i'!,d 1\1' ilPPI'iI,ll'hin~

Irillli!'
.\ ('\Ir1, al Ihl' ('ud of illi i"land \\u\lld ul\l 1',''1\11\'' '\ I'IP('~ of 111t11'1' thllll t I\(, -l-iu<'1\ minim\lll1 \\idt h. \\hill' iI largl' "UI'I':\I'I, ,(wit ii' :1 hrid!!(' pier. might l'l',!11il'l' "lripl'~ of l:l-inl'il 01' gl'l'al('r lIilhll d"/l('lIdill/2: 01\ it~ aJ't'l.

Th( lI'idl'r '"Irip,''' ill'!' I'",.;il'r ,\lid k"" (':"])('I\"i\',> til :Ipph'.
[f dll' IIh"II'\!I'til\g uhj(,(,t i" ~\1I'1i that il dl\!'> 11111 I,'nd it"l'll n'adi/1
J,lla:. to Ihl' iI]I]l1i('al illn ,)f ]ll\i1l11'd 1I1'lrkill.i2;";. I h, -11'ipll\g Illil\' II{'
,)1\ ,\II indl'l)(,I\I!1'1I1 '\Irfill'(' iltl,Il'h(,d III 1\1' 1\11\\111\1,,1 ill1llli',liilli'I~' 1U

\.,\11,'(' of Ill(' ohj<.i't,

sit1IiI ,\ P]ll'llPl'.lilt'l' ,"1g:U~ l I,':")0.

\\'

:!-I)

1j'11'1'1"1111.l!.

Il'iI II',,'

II)

I .,
I) \'

or

hoth

Ill' til(' oh"II'\Il'1iol\ "hould a1";1) hI' \1"1'11. :Ie- ilppli,,d>i,.

I:lO

III ;ldditillll III 111(' 1I1;1l'kill!l> "II Ilw fat',", "I' :til llh"tl'll<'tillll ill Iltl' ro;lt!l\";I.\' 1\";ll'lIillg llf :lppl'll;1('1t tll I Ill' 1t;lz:1J'(1 "Iwll 1,(, gi\"plI II)' lilli' 1l1:ll'killg" llll I Itp pmT!llIIlI. ;I," ,1t"111I ill figlll'l' :!\l Lighting or I{etiectorization of Obstructions
,\" It 1'1'1' :III ()h,,,tl'll<'tillil lip,; ill tlt( dil'l'l,t liIll' lll" 11,;tffit,. Iltl' llI1.,;tnll'1i()])
:llld lll:tl'kill,i.!> tll('l'l'llIl ,,;ltllllld, if pll,;,;il,Jp, 1,(, illllllliIl:ltl'd I,.\' :1 r!lllld-
ligltl ,;" 1(1l1.--tl'lll'1pd IIt:lt it \\"ill ;ldl'!I\I;llt'!." liglll Iltl' lll',il'l't Illil II"ill
n()t Iltrll\\" ;1 ;;1:11'1' ill til(' 1";1('(' "I" Ir:lffi(' ,lppl'll;I('ltillg fl'll!ll l'il!wl' dil'l'C'-
lioll, '\"11('11 fI()lldligltt illg i" Jllll pr:lC'1 ':t!, Iltp 1llljp('1 1ll:ll'klllg,; "ltmdd
hI' I'tTI"'ti\'I'!.'" I'dll'I'(lll'izpd, "' l'I'r!l'C'1illg l'll:liiIl;; ,;11()ltld 1)(' :tpplil'd 1(1 tlte IIltli,'--il'ipp,; ()I' tlll'I'I' ,;1t()\lld 1)(' pl;I('I'd tlll Iltl' lll,,--ll'll<'lillll tllll' lll' m()J'(' 1:11'.12:1' yl,llll\\ rdlpl't()I''; "I' (,III,;t 1'1', "I' \'pll"l\ l'(flpI'1 iIlg Illil I llll" ;11
11':I"t 10 11Il'!1I''; III di:lllwtl'l'"
Object \Iarkings on Curbs ,\!tI'III:II(' 1,]:lI'k :llld I\hill' ,;tl'ipl,,;,,ll(lltid I,:, pl;l('pd ()II til(' 1'lIl'h,-- tit
:tli i,;l:llId- ItI(':l1pd ill t II(' lilli' "I" lr:tffi(' 11,,\1" Tit,,), Ill:l)" :ll,;" 1,( It(,lpfill (,n ('\11'1,-- dil'l'('th' :lhpad ,,! tl':tfli(' :11 T alld ()lbl'l iJltl'l',"('I'ti"II,-RI'I'all';(' ,,! Iltl' ()l'diIl:ll'ih' IllII Itpight til' 1'lIl'h,;, till' ,,,t I'ipp,-- "llIlltid IJI'
Il'l'ti(':tI tin ilil' ('urh f:t(T" 1':ltltl'l' tll:111 ,--I"piJlg :1-- till lltlll'l' ,,11.--11'l1l'Iillll:',
,,1,- "'It I' J'(' tll(' ('111'1, i,; 1l:111Ir:tll~" d;lrk, "llffi('il'lIt ('<JIIII':l,--t may IJI'
lainI'd II)" p:lilililig tlllh" tlt(, \\ItII""ll'ipl'",
Objects Ad jacl'lIt to the Roadway
In ,'1'1111' (';(.,1''; IIhjl'('1,-- 1ll:1)' II lit III' :It'tll:lll\" III IIi{' rll;ld 1\':1." , Illil lJl:Iy he ,() (,10';1' II' till' ,'dgl' of tll(' I'lJ:ll!lI:I\' :1.-- to "lllHilI111':1 d"llllilp 11:lz-
anI. Th(,,;p illl'lildl' :'I!I'1t l'lJI'I'IJ;II'IIIIlI'Jlh a:, IIlJdl'IV:I,--:' pil'I',-- alJd ;tlllllmenl,;, alld ('lliI,'I'1 111'ad \1;i1k '1'111'\" ,~IHlllld 1,(, IIl:ll'k(,d II"it It t hI'
diaJ.(oll:tl "tl'ipl' dl'''lgll 11I-'''I'I'illl'd pl'l'\"i"II"ly, Oth,,\, ad,ial'l'JlI ol,.!(,!'t,; 111:11 :11'1' 11 .. \ likl.J.\' 10 IJI' lilt IlItll'--" :1 \'(,hi!'l"
run" \\"1'11 oil tltl' 1'0:11111:1.\", ,--IIt,1t :1.__ gllal'dl':lik 11'('1''', :llld l'l",k" IIl:I\" Ill'
pain"~I ';01 id IIIt iI ('"
1:!1

figure 29.-Typica' markings on obiects in and adiacent to the roadway.
122

D-REFLECTOR MARKERS
APplication of Reflector Markers Reflector markers, consisting of single reflecting buttons, clusters
of buttons, small panels covered with reflecting coatings, or similar devices, are widely used in marking obstructions and other hazards, or in series, to indicate alinement of the road. In the latter applicati~n they are known as Delineators. Although, like signs, such reflecting units are mounted on posts and convey a warning to the driver, they are much more closely related to obstruction markings or guide lines, and for the purposes of this manual are treated as such.
Hazard Markers Reflector markers may be mounted on or immediately in advance of
obstructions, or at sharp changes in alinement, to indicate the presence of hazards. Hazard :Vlarkers should be of such design as to be clearly visible under ordinary atmospheric conditions from a distance of ,500 feet when illuminated by the upper beam of standard automobile headlamps.
Hazard Markers should reflect yellow light. They should be mounted at a height of approximately 3~ feet above the pavement, except when they are applied directly to a hazardous object which by its nature requires higher or lower mounting, such as a limited overhead clearance or a low culvert head wall.
Single small reflector buttons are not ordinarily effective as Hazard Markers. Clusters of buttons arranged in suitable patterns, small plates covered with reflecting coatings, or other units of characteristic design should be used. No single standardized design has been developed for these markers. Since their meaning is nonspecific, however, the important thing is that they be large enough and brilliant enough for clear visibility. For obstructions closely adjacent to the roadway, markers having three l~-inch buttons arranged vertically, or their equivalent, are recommended. For obstructions within the roadway larger clusters or reflecting areas up to 12 inches in diameter may be desirable. Similar large units may be used at the end of a dead-end street, directly ahead of traffic at a T intersection, or on the outside of an unexpectedly sharp turn. On overhead structures, or on curbs in the line of traffic, rows of buttons, suitably spaced, or strips of reflectorized coatings may be used. Standard signs (R-20, W-24) should also be used, where applicable.
Delineators
Road-delineation markers are effective aids for night driving. Delineators are to be considered as guide markings rather than warning devices. They may be used on long continuous sections of highway
123

or t,hrough :<hort stretclw:-; whel'(' t here an' dUlllge" ill Yert ita! or hmizonta! alinement, particularly \\'here the alinement might Iw COIIfusing. An ifi'rportant adnmtage of Delineator". in cpr1ain area". I" that they remain \'isihle wl}('n there is SllU\\' on the ground.

Ddineator:-; shall ('on"ist of rdlpetor unit" mounkd on suitahh' "lIpports, 1he units bping ('apahk of rdlecting light of the "arne eoItl!' as
that of the "OUJTe and Iwing (!Parl:,' \'i"ibl(' under normal ntmo"ph"rie ('(mditions from a di:-;t aIIC'e of 1,000 feet \\'hen illumina ted hy t Ill' upper ]wmn of standard ~l1ltornobile !lPadlamp". The lwads or l'(,n,(to!' unih "hall bl' not mol'(' tl\1\11 :~ il\('lll''' \\'ide and J() i!le!wCi high nt" Ips" 11wn 2 indwii \\'id(, and (i indws high. 'I'll(' rl'f12l'torizing eLnwJil.s OJ' surfar'p may ('onsist of glass or plastie ll\ltions. a glass-l)('~\d rdi<'ding; eoating. or other sui t abk lAke! ing mat erial.

\Vhen uspd on long eontilllHHl" ,scel ions of lllldi\'ided l'tl:lt!\\:IY, hi-

din(tiona! J)plinpntor" (i. e.. /)eJinentm" \\'ith hHJ fa('(s. \i.sihk from

oppo:-;iip dire(,tion". or t\\'O Iklinpalor" mO\ll\t\'d haek 10 h;l('k ,hall he

in"tallpd on both side" of Ill(' I'oad\\'ay, WI1('n u"pd on diYid,d roari-

waYii and at ((rtain isolatpd loeaiion" smh as P:\\TJ\)('nl-\\idlh transi-

tion,.; not indude(] in ;1 ('on! il\\ltlll" ddinea\(d "p('lion td' rnonodirpetional delinealor,.; ,.;hall be in";lalkd, ()11 di\'id('r!

!l,i)i~"d'\h\'w;~';l'\.';

"\lch lllonodirP(tional (!Plin('alor,.; shall 1)(' 1l~('(1 on hot h ,~id(" of pa('h

rO:Hh\'a:,<, .\1 isolated paH'J\)ent-\\,idth iran"ilion," lJI\':" ~bll he u,,('d

onl:,' on that ,.;idp of tl1\' 1'O~lth\'ay affpeled h:,' ,.;nt'll a tl':lll"ili'lI\.

1ldineators "haJl hp in,.;lalled al a lwi!!:ht "lll'h ihat tit" ,'('\1\('1' of the rpf!eeting head i", :3 J :2 feel ahoye illP 1\pal' pa\'pmenl or \'Il;(thay pdge. They shall in no r'a"e lw mol'(' than 10 fpl't nor le,,~ tha\l :2 I'pet oU1side the road\yay or paH'men( cdge. tIl(' mo~t (!p"imbk ]t)(,:lli'llI Iwing uniformly 8 fed, Jpaying a eh'ar ,.;!JouJdpr \\'ide ('nough fm I hI' parking of a Yehide, ()n 1'Oarh'ay~ \\'ith ,;]101l1dl'],s le~" than X f(,(t \\idp, Drlineato]'~, if u"cd. "hall 1)(' installed at thp ,.;hmIldrr pd~(' ,\Jong curbed sections of l'Oad\\'a:,', ])elineato]',.;, if n,.;ed, shall lw platTd not ]p"s than :2 feet nor more than ;; fept from tll(' purh filef',

:\ormally, I)dineator" should he sp:wed 200 h't,t :qlHrt. \Yhere sueh spa('ing i" interrupled !,y driH'\Yu:,'s, ('l'o,.;,.;rn;lIk 1'1(' .. and where,
un(Ier the normal spacing, a Dpjineator \yo\Jld fall wil hin "\Jch an area.
that Delineator may he J\)o\Td in eitllPr din,(tio\l :\ di,.;talllP not exceeding one quarte~' of the nurma! spaeing. Ifs\leh DcJineator still
falls \yithin that area, it "houlel be eliminated.

()n the approaches to and throughoul horizontal ('II1'\'e8 the spacUCi

should 1)(' "ueh a:-; t () makr fin' Dclineatm,.; al\\;\ \'S "i"ihlp to the rigb&;

of the penter line of a two-Jane pavement. or (;1' 1hp right-hand -

nIP line of a multi-luned paH'mcnL Tah!!' 1 "ho\\''';

recommendell

spacing of horizontal Cll1Te".

124

Thp ]'('('0111111P])(/P<1 ,;pa(,lIlg for yprj iell I CUlTes IS "lImnl III tab!p ')
Table I.-Spacing' for highway delineators on horizontal curves

:--:p:wiJl).!
OIl <'11 ryl'

:,11
I TIll' tilt' ('\1I'Y(' 10 til(' 1ll':\1 oI,'lIlI"'a ,or

1"/'/ ,I !lJ
.-l:~
JI :{.-)
'11 27 2-1 :!:! :.!(J lH 17

/-",,1

200 200 200 :W()
181; Hi:! . I J4
l:L] 12(J
IIj 102

Table 2.-Spacing I for highway delineators on verticol curves (summits)

:\.1"t'fJrai(' dinl'l"'l'I~'(' in 1)('["('('111
pf l:r:ld(

100 2011 :100

100 .",00 1i00 SIHII.0001.2IHJI."01l1.1100I.SII1I2.11I1I1

o.t,
I.IL l.il
2.lL
:?.'i
J.n
4.0
.i.n
6.0 i.O 9.;')
12.0
)0
17.0 19.:'. 24.0

I 1:1 I/;S 200 :zOO :!OU :ZOO 2110 :lO() 2110 :lOU :!(J() :!()()

1"1 11:1 11:1 l{iS I ~ I() :!OO 2011 2110 21111 ZOO 21111 :200

;-)/

S!J 11:1 I:q 1,")'2 IfiS ]\)7 :200 2011 200 '200 21111

-w
:111

/7;--"1

\1.") 11:1 1:2 ~ I Ij:l lliS I ~ l( ) 2110 2110 2110 21111

S:1 HH 11:) J:2fi I"S

lSi; :!()(J :WO 2110

:1-1

.")(

7,~

S\l 1111 Il:l I:JI

11;8 IS:! 1\17 2110

'27 -Ifi (i]

71

Btl

0;-) II:, I:2H 11:1 I ;j( i J(;S 17\1

22

:~! j

.j:{

(il

7-1

s;~

HO II:! l:2fi \:{'i IIS I.-)S

:{--1
:111

Jii -1-:2

;-)( ,->I

(iIi ;-j!1

7-1
1;7

S~l 101 II:! 1:2-1 1:1" I""

SO

\1:2 10:{ II:! I')') 1:11

;2:{

;-);{

II

IS

.).-)

li(;

iti

Hli

\II

J()~ 10\/

'17 :H

II

-lli

,"')/

fili

/t

R')

oS!1 !I;)

:.?:~

'J.!I

.j;)

11l

,)()

;"'),s

li(i

7'1

7\1

K)

'J.()

'J.li

:11

:{fi

41

,"')'1

;-)jl

li;-)

71

77

'1;)

:2S

:u

41l

-17

;-)-1

fiO

fi;-)

70

'J.:)

'27

:Jl

4I

-Hi

,-)'2

,"')/

(i1

:!OO
2(11)
2110 21111 :200 21111 1!1I1 IriS 1,"):2
j:{!l
Ill;
IIlI !IO ,s'J. 7;"')
lit)

"94 " I TIll' ,... p:u'inl-':, ,\ 011 1Ill' YNli(':\! ('\11'\(' to llw:\irnlllll of 'J.()(J f('dl I."'"' f()lInd fr()ll] (])(' il'l'llllli:l' 1. I; -:20 \dwl"(' 1> i." 1111' ]pn!!! h of Clln'(' in lJ\lwln'(!::: of f('Pl :lllcl I; i::: tIl(' alj2J'!)r:II(' 1Iirt'l'!Tnt'f' in

~~~J(:L7~~I/,~~' Tlw

:Id\:\[l('(' to IhL' !ir~l 11(liIH':1 r or ill

of

:ITl(l In til(' {w:\1 fi.""'. hilt IHlt j(,

tIl(' ('111""(' ~d\()ll]d 11(-

125

Part HI
SI(;NALS
A INTRODCCTION
Definitions
lIig]l\\a~' I raHic~i!!:llttl~ i'll'lwlc ~t11 111:11l1Iall\', I!ll'i'!llillii'ldh fll' 1,1"1'tricalh' o[Jl'r;lled Iralfi(' Cfllli ml d,'\'iCi',~, 1':\I'i']>1 .,igll'" h~' llliic!J Irltllil' i~ wal'lll'd ;11' i, din'I,tl'd to Illki' ~OIlH' ~I)('('ific 1ll'lilllL .\ glll.';';:II',\' fli
traffic ~igllal li'rm,; lIill 1)(, IOlllld ill a]>IH'lldi:\\,
ralue of Signals Thl' 1I'ltfli(, ,;i!!:II:t1 i.~ <l \'ali1ltldl' d,,\'il'l' lor tl\(, "1lIlI1'\11 Itll" .;alc f;ll'i1i
tation of \'l'liicle alld ]>cdt''';II'ialllr:tlfic, Iki'llll";i' of it, arl,itl'ary Ill' trafficin"llt'l'd a,;,.;i!!:I1IlH'1l1 of ri!!:hl-llf-I\'a~' Ifl Ihl' "arioll"; 1ll0\'1'1lH'1l1, nf'cr~sary a1 illtprspi,tion.~ ;In,1 at (11111'1' ~tn'pt 111111 liig;III\':I~' 11)("llillll~,
till' traflil' .;ig;llal e:\pr1..; a ]>mfolilld illfillpllI'p Oil lr;dfil' 11011', ] II lllo~1
('asps, a ,.;ig;llal ill,;tallation \I'ill opl'mtp 'iUile dl'finill'ly "illH'r to the a<!Ytllltage or disnd\'alllaw' Ill' Ihe \"hil,les Illld lH'rSOIlS ('fill I ]'()III"I.
('on~eq\lentl~', it is of 111(' utlllos1 import:lI11'(' lh'll th(' ,.;e]..('1 iOll ,mil \II'P of s\lI'h :11l importallt "OIl1l'ol di'\'il'l' 1)(, pr('('l'dt-'d hy Illo]'()u!!:!J study
of ro:l<!\l'ay :111.1 trafii(' 1',mdi1iollS II\' :lll 1';,;pl'ri(,IlI'(d 1'Il!!:ill(,('I', Eljually
urg:elll i,; thl' 1l1'Id for dH,('king 1I\( dfi,'i('nl',\' of a tr:tllil' sigll"I, 0111'(' in o!wralilJll, to a,s('('rlain tlii' di'gn'l' III \Ihidl II\(, t\'))(' of installation and thl' timillg program Ilw('1 thi' n'ljllin'IllI'Il\'; of Ir:dli(', and to pnmit intdlig('llt o[Ji'l'Hting adjustn1(>ll(,; 10 hi' ll1adi' in tJ1(> ('ol11mk
(nf'ckhack,; ari' of \'ahli' not only 10 tIl(' parI il'ular in,;t:dl:tljoJl ('on-
eemrd hut in t Itl' KI']p('lion of proppr I'qllipnWnl aJld oppl':lting plan,.; for futul'(' in,;tallal iOIl~ as \\'pl1.
Highway t raffi I' ,.;ignals, pro])('rl~' op(l'alld, UKllally kl\'p mil' 0]'
111011' of tIl(' follO\I'ini!: ad \'[1I\t agl'';:
1. Tll('y pro\'idl' for onkrh' 11l()\'('lllpllt of tndtil',
2, Tll('~' rpdul'l' t hI' fn'qll(';H'Y of ('cr1 ain 1ypp,; of ;l!'l'idpllls, 3, TllP~' ('an 1)(' l'oordinaled to prm'idc for i'oJltimlous or l\('arl~'
('ontinuou,; IllO\'pmcnt of traffic at a definite ,;ppcc! along a gi\'('n rou t (',
4, Th~'y ('an hI' {!Sl,d to l'ol1trol ,;peed on through highll'ays and
malll route,;,
5. T~ey ('an hi' u,;('d to intel'l'upt hpa\'~' traffic' at interntl~ to prr-
mit other traHi(,. ]1l'de';1rinn 01' \'(.hic:u]al'. t () n08S,
127

G. They represent a considerable economy, as compared With manual control, at intersections where some defini if' mean
S
of assigning right-of-way first to one movement and then t
anothg is required by the volumes of vehicular and pedes~
trian traffic, or by accident conditions. There is a belief among laymen and some engineers that traffic sig_ nals are the answer to all traffic problems at intersections. This has led to their installation at a large number of locations where no legiti_ mate factual warrant exists. This stereotype plan of imt:dlation should be avoided. Many signal installation:-;, even though warranted by traffic and roadway conditions, have been ill-designed, ineffectively placed, improperly operated, or poorly maintained. The consequences have often been excessive delay, disobedience of signal indications, use of alternate routes, and, often, increased accident frequency. The same difficulties are often found ,vhen signals have been installed under conditions that do not satisfy the minimum warrant8 set fort h later on in this manual. A careful analysis of conditions at a large number of traffic :-;ignal installations, coupled with the judgment of engineers with long experience in the 8ignal field, has provided a series of minimum ,varrants that define the conditions under which a traffic signal installation may be justified. These \varrants are p!'psented in this manual for the 8everal signal classifications. Separate valups are given for \nurants for rural and urban areas, in recognition of differenc'es in the naturp and environment of traffic in these two general area classP8. Drivers in !'Ural areas arp ('cmditioned to relatively light traffic, and intersections \vith only modPl"ately heavy traffic' volumes have greater' potentials in terms of congestion and hazard than do similar intersections "'ithin a ('ity area \rhere heavier volumes predominate. An urban area is here considered to be a metropolitan region having a population of 5,000 or more. All other places, for the purpose of these warrants, are regarded as !'Ural areas.
Standardization
Because of the increasing range of traffic circulation, it is of primary importance that there bc national standardization of those feature" of traffic signals that effect public participation in traffic mo\'Cm(']lt. De8ign, application, location, and operation all lend themRelves to a certain degree of standardization, and standard8 for 8uch features :1re presented herein.
The increasing use of and need for train-approach signals and automatic gates at railroad grade cros8ings heighten the importance of standardization of this type of equipment. The principal features of
128

design and open.lt ion that haw' .lwen .standardized by the ASi:iOcia tion of AmNican HaJlroads are set jorth In the pOl'tlons of the text deal. g with train-approach signals.
III
Legal Authority
Traffic signal indications \\'ould he unenforceable if plaeed hy other than public authority. l'nottieial trattie signab should be legally prohibited in all jurisdictions, The erection of signs or other de\'iees that hide from vie'" or interfere \\'ith the dfcetiveness of any t rattic signnl should likP\\'ise be prohibited. It is imperati\'e that traffic signal indieations be Htrictly observed and enforeed.
Articl(' III, Seetions 31 through 38, of A.d 8,)-J. of the :\'m'emherDecemher ] D5:3 Session of the (;eorgia (;eneral,\HHf'mbly provide lrgal anthority for installing and enforcing restrictions of mm'enwnb of traffie hy use of :'iignab, and other traffie control devices,
Seetion 32, Articlc' Ill, of "\ct 8;)-J. prOl'icb., that "All trafhc ('ontl'ol devices shall conform to tho:'ie adopted under the authority of Seetion 31," \\'hieh :'ieC'1ion reqni]'(~:'i that the State' High\vay Board shall adopt a manual and :'ipeeification:'i for a uniform Hystem of traffie control devices for n:'ie upon all higl1\HlYs \vithin this State,
Prior to the mandatory adopt ion of this manual a number of trattie control signals not meeting the requirements and specifications of this mannal had lwen installed in some areas in the State. All :'ilH'h signals shall be replaced as soon aH practieable. \Vhen a major repair is necessary, on any signal, snch as motor replacement or replacement of signal head, complete replaeement :'ihall he made. and only "'ith eqnipment that meets the reqnirement:'i and speeifications of thi:'i manual.
Any installation of a traffie control signal made sub:'iC'quent to ~Ian'h 12, 1\)54, shall conform to the requirC'mC'nts and specifications ineluded in the J! anllal on l'nUurm Tra./fie Control /)CI'z'CI'8, adopted hy the State Higlmay Board on :\Ianh 25, 1\)54, or amendmentH th(']'C'to as may thereafter hC' adopted b~' the Hoard.
Hefereme is made to Act 8;)-J. (Georgia La\\'H 1g,):). :\' o\'emherDecC'mber SeHHion, pagE'H ;),)(i-H2:rl for more eomplete information.
Classification
In the elasHifica tion of t rattic signals i ha t f01l0\\'H, tlJP distinetion iH made on the basis of operating function and noi tbe traffie signal unit itself. It is common praetiec to usc the term "signal" to describe the complete inHtallation, and that practice will he foll{med in this mannal.
IIigl1\\'HY traffic signals are daHsified as foUo"'s:
1, Traffic control signals (Stop-and-Go) : (a) Fixed-time signals.

(b) Traffic-actuated signals: (\110) Full traffic-actuated signals. (2) Semi-traffic-actuated signals. (3) Speed control signals.
2. Special pedestrian signals. 3. Other special traffic signals:
(a) Flashing beacons and signals. (b) Lane-direction traffic signals. (c) Traffic signals at drawbridges. 4. Train-approach signals and gates. (a) Flashing light and \vigwag signals. (b) Automatic crossing gates.
130

B -FEATURES COMMON TO FIXEDTIME AND TRAFFIC ACTUATED SIGNALS
General Aspects of Signals The featnres of traffic ('ont 1'01 ,.;ignal,.; in \\"hil'll I'ehide oppnllor,.; and
pede,.;trian,.; me interp,.;tpd, nall1pl~. tlw location. design. indication,-. and Ipgal signifiearl('(' of the signab Ihell1sdns. a )'fiden t i('al in fixedtime and traffic-al'tna t I'd ,.;igna /.-. tlw difTerp!H'(' h\'tIH'pn thC' two 1."IW"; being in the mechanisms that op('nll(' them. :-\talHlardizalioll in those dE'sign faetors that affect t 1)(' namc to he l'0I1trolJed is e'-lweialJy iI1lpOltanl, ThE' sC'(tions of this subdivi"ion ('ontain alJ standards and requirement" of this !WIIII'(' thai an' eqnally applicahle to the ill'o typP" of sign:l!s named, :-\tandards applicahk to Illil OIW type, inl'lndillg design fc:tiurps and mPlhods of operation. arc pn',;('nlpd in .';IJ1l,.;eqlll'nt S\lbdi I'i_ions,
Design for Future Needs Tmtfic conlrol eqllipml'nl shonld :d lVay.- he pnrdw,s(d Ivitll the 1'11-
ture in mind, Flexibility 1l']ridl may no! inllllPdi:lll'ly he' con"idered nel'pssan' Il'ill often hl' found de,;irahj(, Ivithin thl' life of 111(' C'Illipmellt, EqllipnlPIlI thtlt Ivill gil'(' long et'fectin life Il'ill :dllltl,-t ~d\\:\,I''; pro\'(' an ('conom~' ('I'en if tJlt' first ('o,;t i" lllod('r:Jtel." higher' than that of equipmelll of inferior qllaliiy.
Number of Lenses per Signal Faee Each sign:d f:u'p shall Iwl'(' nt ]I'asl 1!t)'(,1' Il'll,;('S ),l'd, Y('HOII, and
green, It 1ll:II' 1l:II'(~ additionnl Ien,.;I',- a,; illdit'~lt(:d 11I'l'('i 11 , EXjlel'ip!]('(' Ita,- sltOll'n tlw t thI' ~'('lloll' illt lit'at i, 11I ,-('1'\'(''; S('I'()':1I iIll-
port:ml trafiic control function" Ihat (':llIIltJI ,';:lti,;f:l<'to)'ily h(' "':(']'I'I.'d by a tII'O-Ie!I'" ",i,gllal fal'p, Thesp a)'(':
I. Tltl' ~'('IJ()\I' ,;igll:ll ac(,; :t.- a cU"ltit>ll at t \1(' ('lld of t It(' (;() illt('ryal and \1':lJ'IIS :qlJJI'oill'hing tl':lfiit, of a <'Ilang(' ill ,-ignaJ indie:ltion,
,) ('aI's Il'illtin all illll')',-pl'tion 0)' otlll'), ,-ignnliz,d an'a, a,S Il'ell a,; tho,,(' nppmac!lillg ,_0 dos('].I' tltal to stop \I"l1dd h;' liaz:lrdolls. a)'(' gil'('ll :Ill ojl]lO)' I 1I1lit Y 10 c!(':l)'.
3, Flashing .\'eJloII' i" imjlortallt a,- a c;lutioll ,;i\;ll:d 1I'II('n 111(' ",ignal is not I!('in,g o]lcnIU'd :1" ;I :-,lop-:llld-(;o d('I'i('(',
. ArrOlI' indica1ions ,;h;lJl hI' ,.;hOII'1I at in11'r,-eciiolls whc)'(' "igll:d,s for individual tUl'Ilillg 1ll00'('IIWllis a)'e ])}'()\idC'd. Th,sl' inc'ludl':
I. f'traigltl-thl'llllgit al'J'OII. 2. Left-t Ill'll a ITOIL
~3. Hight-lurn anOl1 for thp cOllt)'o] of jll'dl'snian" Illay ;lbo hI' added to paclt sign:d
I:-j I

Color and Position of Lenses

All !en",es ::;hall Iw ananged in a "tmight and prderahl~' YNt inti !il\<' and "hall 1)(' in tI;~ following o]'(kr, from lop to hot tom or from ]('1'1 to
right:

J'osdiol/:
.)
Ii
-,

SiUllol indicotiol/ Hed YdIO\\
( ;1'('el\
:-1t migh t-t hrO\\ ,1lTO\\
r,dt -turl\ arrO\\'
I~ight-t.\lrU alTO\\' Wait (or Don't Walk Walk

..\11 arrO\\'" shall he green on an opaque baekground. \\'alk-\\'ait lenses \\'hieh are il)('orporated in ",tandard signa] h)('p", shall hi' ,f the design de,'inilwd in Gpnpral Dp,'iign Hpquiremenls,

The colors rpd, ycllo\\", ,md grepn ",hall eonform 10 t hp ad,inslahleface lJ'Hffle con1rol "i~,!;lwl head standard" of the Institutp of Traffic Engine(']'",l appro\'(>d ac' an AnH~ripan :-1tandard hy Ow .\merie;11\ ~tand ard", A"s()ciation (I) 1O.I-HH2).

In addition to the foregoing len"e". "pecial Iwde"trian "igJwl", mOllntpc! apart from the traffie :-iignal head may he prm"ided as s!)('('ified in anot!wr section.

Meaning of Color and Arrow Indications .
('0101' and alTo\\" indi('ation;-; in traffic ('ontro! "ignal" "h"ltld have the meaning", a",eribed to them in thi" ",petiou and lIO othpr lIwanings. In no ea"e, hO\\"(;\'pr. "hould a dri\"er he permitted to en1 PI" or proceed through an intersection \\"ithoul due regard for til(' "are!y of other per;-;on", \\ilhin thp inter"ecjion, regardk"" of "ignal indi(';ll ion".
Sati:,f[[ctory result;.; from traffi(' signa] operation l"I'quin' a uniform under"tanding of their color indication;.;. Tho"e hcnin ~pt forth are in [[econl with Artieje Ill. :-1cction :32, of Act 8;)L TIt( :-imultaneous illuminil hon m overlapping of different eolm indje[[tions. except where
green arrows are shown 10gpther with the ejrcular l'(d indication, or
where pedestrian len"e" are irwolved, is not ]"(>(oIl1mcl1llpd.
This "eetion applieH primarily to traffie control "ignal" at interaec-
tions, but appropriatp intprpretation can be rpadily made for use of
signal:-< p18e\yhcre, such a" at ;.;('hool no",singi:i, fire "ta1 iOlls. and draWbridge;.;.
The meaning" of the indieatio!i":, \\'hieh should !H' j hus pn'scribed by law. are as follO\\"s: -', it dj".'<!uhle Face Trajfic ('all trol 8'if/l/u{ fI ewl ,",lul/du nk '!'t.dllli,,:[1 Ht'port ~o.l.g . IIH,jitutp of Tratti" EnginpPl"s.

13:2

I, rdlil'lll:11' Il':lffi .. hl'lll~ III(' 'I~II~II, 1'''I'I'pt \\11('11 pl'ollil,iJI'd 1,\ ~I
,'lIllt'I'Il'1' 1't'~I1I:11 jO!I, IIlII\' PI"I('I'I,d '1I'IIj~111 IlIl'oll~1I 01' 1111'11 I'I~hl
01' 11'l't 11111""" :1 ,igll 111'11<'11 pllll'" pl'ohil,it" "IUI"I' '111'11 IIIi'll Hilt \'I,III1'IlI:11' 1I'IIflil', 1llI'lilllill,g \'I,hil,II', 1111'1I111,g l'ighJ 01' 11'I'~, ,,11:111 \'i"ld Ill<' 1'1~III-ol-\\:I\' II' ,,111<'1' \1'111"[1" 111,,1 II' l)('dl"II'IIIII'
111\\'1'1111." \\'1111111 III<' IIIII'I','I'I'IIO!I "1'1111 Ildjll""lll ''1'"" \\111" 1111111 I illll"IlI'II'I~II:1I i" 1,,,IIi1,il,,d
1'",I,',ll'illll.' 1'IIl'IIIg III<' ,I,t!,11111 JIlII\' PI'I}('I'I,d IIl'I'I"" 111l' 1'('III!I\lt\'
l\ill1ill :111\' 1I1:1111,d ,I!' IIlIiIlIll'kl,d ''1'0,',' II:dk
:sady
}",!!uli'iI!mll III "('Ilit/IUII" II'!IIII "!IIIII'lIlo!!u(('!!/I!!!/I I!I'/,,, III "(;11'

\'I,lIil,\tlllI' 1l':lflil' I'liI'illg IIii' "lglllIl I' 111<'1'11,\' 11:1/'111'.1 11I1I1 IIII' 1'1'11
III' ...;Iop ,igll:t! I\ill 1)(' ""llilllll'd IJIllllI'diIIJ,'h' 1111'11'11111'1'. 1I!1I1'III'L \1hi,'III:II' 11':1f11" ,,1I~dl IloJ "1111'1' II!' I}(' "I'''''''lllg till' illll'I',I'('IIl'!1 \1/1('11 till' 1't,d II!' ~J'lp "igll:11 I.' 1,,,lIil'II,'d " \11 p"d,,"ll'i:111 LII'III~'"i'II,igll:Jl "IIIII[ 1'/111'1' 111l' I'Olld\\:I\ Illill! 1111' ~/'("'II 01' "( ;,," 1,,1/01\'11 :tI"III', Illdl",' :llltli<II'ii:J'd ,'" III d" 1,\ iiII' l}('d""II'I~111 "\\'ltI""lgJI:d TIl(' \1,1111\\ 11'11' i, l'I''1llil'"d III ,~IIIII,l:il'd "i\.!,lIlt1 ~lppIII'IIIII, 11,1' III(' 1'1'11-
'''II,' illcli"III,'d 1I1~1','II'11I "II 11111111)('1' "I' It'II,'I'> ,Pt'I' "lgtl,tI 1'111'1' ('011-
fll,illil Itl'> fl'l'IIIII'III!I' Ill'i,('11 1l'''lIl III(' 1111"11,1' "I' I hi, il'II' \\'/11'11 IIii'
11'1I~lh III \'1,11,,1\ It,hll'll'-I'\,'III'IIIII'I' 11111'1'1'111 i, I'''IT('!'I, '1IId III(' ,llllld:\1'1! 1I11'~III,lll\.!, ~Ih"\,, dt,,,"I'il)(,cI h \.!,1'III'I'~tll\' ,,1"'I'n'l,d 1II"'I'>,~III'\> flllll'-
tillll' (If 1IIII'IIIIIg 111111 ,'!I':ll'illg IIII' 1111"1','1'.'11"11 III'" PI'l'i.II'llli'd I,\, 1111.'

intl'nll],
teady
Hecl"!"1I1 (/ "'''/O!i'':
1, \'('hil'II]III' Il'lilli .. flll'lll~ IIII' ',gll,iI "II:lII'!1l1' 1111'111'1' 1'lill'I'III\.!, IIii'
"I'II",~ 1IIlIk Ilil till' 111'1/1' "idl' "I' 11\1' ]II!"I',,(,.'I illil 'II', II' "'1111', 11\1'/1 1,,,1'111'" "llll'l'1ll~ 1)11' IlIt"I',,(,.'IIIIII, :llld ,hldl 1'1'llllllll >1111IIIIlIg II!II II
a ~1'I'1'11 ,i,t!,lIld i" ,,!I()\\'II
" \11 P,'d(',ll'i'"1 flWill\.!, "11"'1 "igll~iI "lildl "/111'1' IIII' 1''':II!1IU.'' lilltii

Ihl' 1!:1'I'1'11 Ill' "( ;,," i,,,,; ,,,hO\\'1I :iI"III' 1IIdl'''" U ,'I'I';[I':t!I' \\:llk illlli(';I-
1il III i" ,,1i1l\\'11

('lIl1fll"jllll '11111 "I'l'ioll" h:lz:ll'd 1'I''';ltI! I' 1'0III 1:11''' of 1111lf"I'IlI "llI'dil'III'" to l'i,d "i~llak '1'111' I"'d illdi"ulioll ,,!loltld :1/1\':1\',; 1111':1/1 Ihul "U"'I \'('-
hil'JIl hilall ,lop Itlld "lwll lIot !l/'o"I'"d f:t1'111I'1' '1IIItii U (;" "j~llul :lp-

!l"al'" 111"1'''" ")II'1'ili"lilh' :llIthol'iz"d II\' 11111' III' 1/11' :l1I"i 11;1 1'\' illdii'1l1 iOII"

\Il'~:ril'l'd 11l'1()\\,'

,

,

ifill /l'it!, fil'l I 1/ 1/1'1'1111':

1l1:1~' I. \','ilil'ldal' 1I'Iillil' f;willg ""I'1i ,...;i\.!,IWI

..alii iOll"ly ('III "I' 1h('

11I11'/''I'I'liOI I "I"Y 10 Illllk" til<' Ilw\,(,IlI,,"1 illlli('at"d 11\' ,'llt'h :,/'-

1'11\\, hilI ,..;hal! \'i"l<I IllI' I'il!:hl-of-\\u,\' 10 P"d(','ll'iall' 1:1\\'fltll."

I :~:;

within a cross ,valk and to other traffic lawfully using the inter_ section. :2. X 0 pedestrian facing such signal shall enter the roadway until the green .~r "Go" is shown alone unless a separate walk indica_ tion is shown. Permitting vehicle operators to make right or left turns during the showing of the red signal without a modifying arrow is bad practice It weakens the single meaning of the red indication. The practic~ cannot be permitted at all intersections, and, therefore, cannot be followed uniformly. It adds to pedestrian hazards and inconvC'nience. and creates hazards and delays for vehicle movemC'nt. The appropriateness of right and left turns proceeding durillg the Stop period is exceptional and therefore these mm'ements, whun neces_ sary, deservC' a specific modifying indication, as is prm'ided by the right- or left-turning arrow lens. If such turning arrows are shown ,vhen through movement is stopped, they should ahmys be illuminated in conjunction with the red signal they modify. ShO\m alone, they create doubt as to whether other movements are forbidden during the indicated interval. Furthermore, drin~rs approaching an arrow indication may mistake it for the customary (io signal. This is especially likely where strange driyers are involw'd and where the nrrow signal is poorly designed. The utility of alTo\v indications depends considerably upon I here being a lane consistently available for the movement indicated. Such lanes should be clearly marked on the roachmy surface at all tinH's. A circular green indication shall be given only when it is intenclf'd to permit traffic to proeeed straight ahead or turn in either direction. \Vhenever it is intended to permit traffic on a certain thoroughfare to make certain movements and prohibit it from making others. the regular eireular red lens fa('ing that traffic shall be illuminated together \vith a separate green alTOW for each permitted movement. The foregoing is not intended to prevent prohihition of tUl'I IS. at all times or during certain periods of the day, by the erection of signs. The plan has been tried of prohibiting certain movements, suC'h as a left turn, 011 the regular eircular green indication hy signs stating that those movements are allowcd only on separate green arrow indications. Thi:,; has not been sati:,;faetory, however, becau:,;e driH'l's fail to comprehend the apparent conflict in instructions and pro('ecd to make the prohibited turn on the circular green indication.
Pedestrians walk and WaI:t signals: Whenever :,;p('('ial pedestrian-control signals exhibiting the \Hlrds "\Valk" or "\Vait" arc ill phwe :';1\eh sigIlals shall indicate as fol1mys:
(a) \Valk-Pedestrians facing s1\ch signal may proeeed across the roachyay in the direction of the signal and :,;hall be given Ihe right-of-\\'ay by the drivers of all "chicles.

(b) Wait-Xa pedestrian shall start to cross the roadway in the direction of such signal, but any pedestrian who has partially completed his crossing on the walk signal shall proceed to a sidewalk or safety island while the wait signal is showing.
Flashing red (Stop signal): When a red lens is illuminated by rapid intermittent flashes, drivers
of vehielcs shall stop before entering the nearest eross walk at an intersection or at a Stop line when marked, and the right to proceed shall be subject to the rules applicable after making a stop at a Stop SIgn.
Flashing yellow (Cantion signal): When a yellow lens is illuminated with rapid intermittent flashes,
drivers of vehicles may proceed through the intersection or past such signal only with caution.
The use of steady yellm\" as a caution signal is not recommended.
Shapes and Dimensions of Lenses Traffic control signal lenses shall be cireular with a visible diameter
of not less than 8 inches. A green arrow lens shall show an alTo\Y so designed that its shape
will be distinctly visible at a distance of 200 feet. An arrow to indicate straight-through movement shall be pointed vertically upward. and an arrow to indicate substantially a right-angle turn shall be horizontal.
Where the turn is substantially different from a right angle, the arrow may be pointed obliquely upward on a slope appropriate to the angle of the turn.
It is essential that approaching drivers be able to recognize the green arrow shape at a suffieient distanee to goyern their actions accordingly. Some arrow lenses now in use fail to meet this requirement and should be replaeed with properly designed lenses as promptly as possible. Figure :30 shows the details of an arl'JW lens design developed by the Committee on Standards of the Institute of Traffic Engineers from numerous field tests under both day and night conditions.
Lettering on Lenses Lettering shall not be used on lenses. This does not apply to special
pedestrian signals. The practice of embossing GO on green lenses, CArTIOX on yellow
lenses and STOP on red lenses reduces the effectiveness of the lenses. With the spread of uniform meanings and positions, the need for such lettering is constantly decreasing.
135

PAINT MUST EXTEND OVER THIS EDGE TO BACK OF LENS.
NOTE'
ALL LENSES SHALL BE KOPP DR CORNING
g~AAS:P~~~~' ~~'0~~~~E":~;,MATIC DIFFUSING

THE LENS GLASS SHALL BE OF APPROVED

COLOR CONFORMING TO I.TE. SPECIFICATIONS

FOR THE PARTICULAR FUNCTION OF THE LENS,

NAMELY. RED. AMBER OR GREEN.

'

ALL LENSES SHALL BE GIVEN ONE COAT OF

BLACK OPAQUE ENAMEL OF A THICKNESS SUF.

FICIENT TO TOTALLY OBSCURE LIGHT OF IOO-WATT

JLAMP PLACED BEHI ND IT. THE ENAMEL SHALL

BE FREE FROM ALL PIN HOLES.THE ENAMEL

:... IS TO BE APPLIED ON THE OUTSIDE SURFACE

I ., OF THE LENS IN SUCH A MANNER THAT WHEN

I

THE LENS IS IN USE,THE ARR<:NI SHALL BE lli

:

ILLUMINATED PORTION OF THE LENS. THE EN-

I

AMEL SHALL BE BAKED OR FIRED INTO THE

:

GLASS. THE ENAMEL SHALL BE HARD AND ~

I

ABLE AND SHALL NOT PEEL OR FLAKE OFF

I

WHEN SUBJECTED TO THE HEAT OF A SIGNAL

LAMP WHEN THE LENS IS IN USE OR WHEN

THE LENS IS WASHED.

THE ARROW SHALL BE REPRODUCED ON THE LENS IN CONFORMANCE WITH THE DIMENSIONS AND SHAPE SHOWN ON THIS DRAWING.

figure 30.-Arrow lens design; Institute of Traffic Engineers.

Illumination of Lens
Each lens shall be illuminated independently of any other lens. The illumination shall be by a clear lamp of not less than 40-watt capacity, especially desip;ned for traffic signals.
This provision is not intended to preclude the use of other properly designed light sources, such as those utilizing gaseous mixtures, which produce an equally effecti ve signal lens indication.
Independent illumination of each lens is essential to permit uniform position of lenses, give satisfactory brilliance, and provide the necessary flexibility in signal indications. Special lamps with sturdy filaments and other appropriate characteristics have been designed to meet traffic signal requirements. A 50-watt lamp has been most generally used, but 57-watt and 40-watt traffic signal lamps arc also available.
The 40-watt lamps are economical in current consumption but should be used only when the lens transmission factor is sufficient to give a conspicuous indication and when there are no confusing background lights or sun glare.
For most effective indications, traffic control signal lamps should be operated at full voltage, rather than under voltage. \Vhen lamps rated at a higher voltage than the actual voltage at the lamp socket are used, longer lamp life results, but at the expense of light output and signal brightness.
More desirable than the above practice is the use of higher wattage lamps which will give the equivalent light output with a longer life. To serve this purpose the 67-watt traffic signal lamp has been developed and made available. Though consuming slightly more pOiver for an equivalent light output, its life has been considerably extended.

13li

Visibility and Shielding of Lens

Each lens, reflector, and visor shall be of such design as to render

the signal indication, when illuminated, dearly visible to the traffic

~oghnttroalnl edda bt my otshpahte rfiaecec oantd iatlilo ndsi set axneecpe st

from dense

10 to fog.

300

feet,

under

all

Each signal faee shall, to the extent praeticable, be so shielded by

visors or hoods that an approaehing driver can see only the signal in-

dications intended for his observanee.

Confusion results if signals are so loeated that operators see two

signal faees gi\Oing different indieations. IITegular street design fre-

quently necessitates so plaeing signals that there is a comparatively

small angle between their beams. Sueh cases require especial care in

shielding so that the driver will be sure which signal he is to obey.

Shielding also reduces the tendency of drivers who see the yellow

indication on the cross street to "jump" the Go indication.

Auxiliary Illuminated Signs
Signal heads and auxiliary mounting equipment should be designed so that auxiliary signs can be attached and illuminated either above, below, or on either side of any signal fa(e.

Number of Signal Faces
In rllI'al areas there shall be one or more signal faces visible to traffic on each approaeh to the intersection, except in those eases where the minimum pedestrian volume \yarrant is met, when a minimum of two faces shall be used for eaeh appl'Oa(h.
In urban areas there shall be two or more signal faees visible to traffic on each approach to the intersection.
The advantages of having at least two faces for eaeh appl'Oach roadway are believed suffi('ient to warrant making this a general requirement in urban areas. Trueks and busses very frequently obscure oneface installations, lea\'ing the drivers of \"Chides immediately behind uncertain of the signal indication as they approach. Two properly located faces will, at practically all intersections, provide drivers with a signal indication sufficiently in adnmce to insure their proper reaction to eonditions at the intersection. High speeds and other traffic considerations \vill frequently \yarrant the use of t\\"() signal faces even in rural areas.
The adnmtage to pedestrians alone justifies the installation of two signal faees at many locations, sinc(' it prO\'ides indieations within reasonable range of the normal line of sight for all persons on foot. If one of the signal faces is to be on the near side, however, a total of three faees will be needed to provide adequate pedetitrian indications. Satisfactory enforcement of pedestrian regulations is diffi(,ult unless signal faces are clearly visible for all lines of pedetitrian movement.

137

Limit of Signal-Controlled Area
A signal shall control traffic only at the intersection where the in. stallation is located.
Depending 00 signals at a few intersections to control traffic at i termediate nonsignalized intersections is an uncertain and hazardo: practice. Under such conditions, drivers on cross streets at nonsig. nalized intersections must often enter the cross walk to see a signal indication on the main street. Strangers are likely to enter nonsig. nalized intersections unknowingly, which is obviously hazardous.
Location of Signal Faces at Intersections
Signal faces shall be located so as to give drivers and pedestrians a clear and unmistakable indication of the right-of-way assignment from their normal positions on the approaches and as they enter or pass through the intersection area. Where signals are installed on the basis of the pedestrian volume warrant, or where the pedestrian volume warrant is equalled or exceeded, a vehicle or pedestrian signal face shall be installed at the far end of each cross walk.
One of the more controversial points in the standardization of traffic signal practice has been the matter of signal-face location at intersections. The advantages of far-side, near-side, mast-arm, and centersuspended locations have been sufficient to induce the choice of all these locations for various types of situations. \Vhen asked in a recent poll to express their preference as to signal location, a group of 36 outstanding traffic engineers could not develop a majority for their first choice for either rural or urban intersections, although the greatest number of votes was cast for the center-suspended location in rural areas and for the far-right-far-Ieft location in urban areas.
Because of the diversity in practice and the lack of agreement among qualified engineers on signal location, the above requirement does not specifically fix the points of signal placement. Instead, the engineer is held responsible for a study of the visibility conditions on each intersection approach and the subsequent positioning of a signal indication conspicuomily within the normal line of view of drivers and pedestrians using the intersection. Although this individualized selection of signal location seems the most desirable, undue variation in location from intersection to intersection along the same street is to be avoided, as this may create confusion and hazard.
The need for pedestrians to have a signal indication directly before them ,,"hile proceeding through the intersection area suggests the advisability of having signal faces at the far side of the intersection. With all far-corner signals, two signal faces per corner will provide a signal at the end of each pedestrian cross walk, whereas three signal faces per corner are needed to accomplish the same results with one signal on the near-right corner. (See sketches in fig. :31.)

'fhe near-Hide location haH merit in that the HignaJ ('an be placed at r near the Stop line. the point of obedienec. The near-side location,
~ a general way, iH alHo a more eonsistent and uniform position with
JDspect to the approach lanes than iR the far side, eR)f>cially where irreregular types amIf'orms af'mtersertlO. nH are m. voIved .
The trend tmnm] the use of signals suspended dirertly over the tra\'eled \yay, either on mast armR or on a span wire, has IJPcn increasing in recent years. ThiR loration is especially effective at rural intersections where speeds are high and maximum prominence for signal indications to drivers is needed. Another fartor contributing toward more frcquent use of over-thp-roadml,V signals is the growth in brilliance and color of illuminated adycrtising signs in shopping areas. Where such background lighting is likely to be a serious hindrance to the effective display of traffic signal indications consideration should be given to the mast-arm or suspended loration for at least one of the signal-face locations.
Pedestals in the roadway to carry signals are driving hazards and are not recommended, despite their obvious advantage as conspicuous signal locations. This is not intended, however. to preelude the use of signals on pedestals or posts within the area of properly dpsigned ehanndizing islands or in t he median strip of divided roadways.
Where physical conditions prpvent a vehidp driver from having a continuous vie\\' of at leaRt one signal indieation through the :300 feet immediately in ad\'iUlcP of the Stop line, an auxiliary signal location shall be used to providp this visibility. If physical eonditions make it impossiblp to provide any location whieh ean bp seen for 300 feet, a caution Rignal or a Signals Ahead sign shall IlP erected in a suitablp position to warn approaching traffir.
Height of Signal Faces
The bottom of the housing of a signal face shall be not less than R feet nor more than 10 feet above the sidewalk or, if none, above the pavement grade of the center of the highway, except that where vehideR must pass under a signal housing, the height to the hottom of the hOllRing shall be at least 141~ feet but not morp than 15H? feet above the roadwa)T surface.
~faximum yisihility is the guiding prineiple in def~iding signal height. Signal faces should be high enough not to be obstrueted unneeessarily by passing vehides and pedestrians. On the other hand, especially in urban territory, the signal faees Rhould bp low enough to he within easy range of tIl(' average pedeRtl'ian's and \\'aiting motorist's eyes. Grades on approaching Rtl'epts may he important fadors in determining the mORt effectiyp hpight.

The clearance required for 8ignal hou8ing8 mounted over the road-
waY is con8i8tent with general highway requirement8 for overhead structures.

pointing of Signal Faces

-

Each signal face 8hall be so adjusted Yertically and horizontally

that its beams 'Yill be of maximum effectiYeness to t11P approaching

traffic for ,Yhich it is intended.

In general, signals should be pointed 80 as to haH' a maximum dfec-

tivenes8 in the u8ual p08ition of approaching drin'rs at a distalH'e frum

the Stop line equal to the ayerage distance they mJUld moYe "'hill'

reacting to the Stop indication and stopping their vehicle8. The in-

fluence of CUlyeS of grades should also be considered in the aiming of

signals. For an average urban intersection where the normal 8peed of ap-
proaching traffic is 25 mile8 pel' hour, the point of maximum effectiveness for aiming the 8ignal \\"Ould be at the height of a driver'8 eye8, about 6 feet to the right of the eenter line of the paycment and about 75 feet baek from the Stop line.
Frequently poles on which signal faces arc installed arc not exactly vertical. Brackets or other mounting fixtures used 8hould be of 8uch a design that it will be p08sible to adju8t the signal face both horizontally and vertically through a considerable angle.

Location in Relation to Curb Line
Signal face8 mounted at the roadside 8hall be located as near a8 practicable to the curb line of the street wh08e traffic they control. They should be about 3 feet from the crOS8 walk of the intersecting street, or from the plaee where a cross ,Yalk would normally be located. A signal or its support 8hould not ob8truet the cross walk.
In order to present to the driver a maximum of effectiveness, a post or bracket-mounted signal face should be kept close to til(' curb line. However, for the protection of the equipment from damage by passing vehicles, it i8 not cle8irable that any part of the signal head extend within 1 foot of the curb line.

Location in Relation to the Pavement or Traveled Surface
Hegardless of the street or highway eros8-section de8ign, a 8ignal face shall not be more than 10 feet to the right of the pavement or tra\'eled surfaee.
In the case of rural higlnnty8, the 8houlder \\'idth may create a problem in signal location. So long as the signal faee is not more than 10 feet to the right of the pavement and is not hidden by foliage or other sight ob8tructions, it should be 8atisfactorily yisible. Experience indicates that signals mounted on poSt8 near the eurb in urban areas are generally effective although, "'ith parking at the eurh, the right side

141

of approaching vehicles is normally about 12 feet laterally from such signals, which roughly corresponds with the distance specified above as a maximum. The vehicle operator usually gives his major attention straight ahead, and a signal indication more than 10 feet from the edge of the moving lane is not likely to receive proper attention.
This rule has important bearing on both first cost and maintenaIH'e outlay, for if a signal can be post-mounted within 10 feet of the improved surface, the advantages of lmv mounting height and simplified maintenance result. However, if the shoulder width or some similar condition requires that a mast-arm-mounted signal or a centersuspended signal be used, costs are increased, mounting height is greater, and maintenance is more difficult.
Removal of Confusing Advertising Lights or Display of Unauthorized Signs, Signals or Markings
Section 38, Article III, of Act 854, Georgia General Assembly, approved January 11, 1954, provides:
"(a) No person shall place, maintain, or display upon or in view of any highway any unauthorized sign, signal, marking, or device which purports to be or is an imitation of or resembles an official traffic-control device or railroad sign or signal, or which attempts to direct the movement of traffic, or which hides from view or interf2res with the effectiveness of any official traffic-control device or any railroad sign or signal. This shall not be deemed to prohibit the erection upon private property adjacent to highways of signs giving useful directional information and of a type that cannot be mistaken for official signs.
"(b) Every such prohibited sign, signal, or marking is hereby declared to be a public nuisance and the authority having jurisdiction over the highway is hereby empowered to remove the same or cause it to he removed without notice."
Provision for Future Installation
Signals should always be installed so that future traffic growth and other later requirements can be as readily met as possible. Outmoded, worn-out equipment and materials constitute serious handicaps to extension or improvement of existing signal systems. The type of mounting selected, the choice of wiring and accessory equipment, and other seemingly minor details of a signal installation play an important part in the reliability and effectiveness of signal operation during their service period. These elements should be carefully chosen for the particular duty they are intended to perform, and with a view toward obtaining uniformity and standardization of equipment, so that exchange and replacement operations will he simplified.
142

Types of Mounting for Signal Heads
Types of signal-head mountings include the following: 1. Alongside the roadway: (a) Posts 8 to 10 feet high. (b) Short brackets attached to poles (at same Ileights). 2. Over or in the roadway: (a) Long brackets or mast arms extending from poles off the roadway. (b) Cable suspension. (c) Posts or pedestals on islands.
Group 1 has many advantages, including simplicity of design, ease of access and maintenance, and better conformity in height to the needs of traffic. Of the two types in this group, post mountings are preferable. Where an existing pole is at the position desired for the signal faces, however, it is generally used. New poles may be installed to provide necessary support and clearance for overhead cable.
Mast-arm and cable suspension involve considerable lateral strain. Cable suspension may interfere with fire fighting and requires overhead maintenance equipment. Both of these types involve difficulties in cleaning and maintenance, besides placing the signals too high for best visibility to waiting traffic and to operators of vehicles close to the intersection. Suspended signals are desirable, however, at locations where side-mounted signals are apt to be overlooked, as at isolated rural intersections; where high-speed routes enter built-up areas; or where advertising signs and other distracting lights interfere with visibility of signals mounted along the roadway. To improve the effectiveness of the signal indications to waiting vehicles and pedestrians, post-mounted signals may be used to supplement overhead installations at such locations.
Signals on posts or pedestals on islands are justifiable only in certain large, channelized, or irregular intersections. Under these conditions, the signals should be well protected by properly designed islands and signs and by night illumination.
Any mounting should be substantially constructed, with a strong foundation, preferably eonnete, and should be able to withstand all weather conditions.
Installation of Underground Conduit or Cable
Underground conduit or cable, though considerably more expensive than overhead wiring, is generally preferable, especially for urban intersections. In certain zones it may be legally required.
Before the underground wiring is installed, governmental units and utilities that may have underground structures or facilities at the location or may later place them there should be consulted. Much trouble and possible damages may thus be avoided. Furthermore,
143

sueh organizations can glVe valuable advice as to how such work should best be done.
A large proportion of the eost of underground installations Cun b ' avoided if traffic c<futrol conduit is installed when the intersection e s.lgnaI Iocatl.On.IS torn up f'01' some otIleI' purpose, sueI 1 as'for puvinor repairing, or utility underground installations. Loeal authoriti g, should antieipate future signal requirements and take adnmtage : any sueh opportunities to install eonduit, even if sueh installation is in advance of the need. Though conduit is normally used, direct burial or "parbvay" eable has also been employed successfully.
Selection of Cable
The cable is an important element in the sueeessful and eeonomieul operation of a signal system.
Quality.-Experienee has proved the desirability of using eable of high quality for all but purely temporary installations.
Rome good traffic signal cable specifications (fOl' use on 11 0-120 volt service) eall f()]' a (JOU-volt cable with at least three sixty-fourths of un ineh of 30 pereent para rubber insulation and good quality doth-braid eovering on each conductor and with a eable covering suitable for the intended use of the cable. De\'Clopments of the lust fe,v years have provided several other satisfactory types of eable, for whieh speeifieations are obtainable from cable manufacturers. :\0. 12 or Xo. 14 B. & S. gage wire is often used at intersections. The size of conductor required for a mastcr control cable in a coordinated system should be computed.
Color code.-A standard color code should be adopted for traffic eontl'Ol cables. Sueh a code identifies eaeh eonductor with a parti(~u lar eolor or eombination of eolors in its braid eovering, aecording to the funetion served by that eondueto1'.
The advantages of a standard eolor code arc eonsiderable. Any person familial' with the color eode ean install, test, or replace controllers quiekly beeause the fumtion aeeompanying each color seheme is known. Color eoding generally eliminates the need of tagging the leads. One of the diffieulties with tags 01' numbered bands is that they are likely to eome off.
Spares.-lt is generally sound economy to prm'ide several spare conduetors in each local intereonnceting and master eontrol cable. From time to time, for one reason 01' another, conduetors in a eable may den~lop defeets and be no longer suitable for use. In sueh cases, the provision of spare eonductors eliminates the cost of loeating the trouble and making repairs, ()]' of installing ne,\' cable. Spare condutton, alim permit adding new features, sueh as a pedestrian dearanee period, 0]' an illuminated sign.
144

Insulation of Cable Adequate cable insulation shall be provided throughout the entire
"tallation, conforming to fire \lIHlel'\YI'iters' specifieatiom"
m~
Cable positions and Clearances positions for traffic control cables shall be sueh as not to interfere
with utility structUl'es and \vires or with position:,; reserved for them, suitable clearances agreed upon hy all intere:,;ted parties :,;hall be pro\,jded in all ease:,;,
In most eommunities the utility companie:,; and appropriate governmental agencies han~ agreed upon certain position:,; on poles and certain positions underground for various :,;trudures, eonduit:,;, and wires, Much trouble can be anlided if thODe in eharge of traffie signal installation \rill consult ,,'ith tIl(' affel'ted groups concerning loeation problem:,;, Where a pole is used for se\'eral type:,; of cable it i;.; most important to maintain clearaIH'eS satisfactor~' to all parties im'oh'cd,
Messenger Wires All overhead cable shall be ;.;upported hy a suitable acrial mes;.;enger
wire ",hcnever there is a span of more than :)0 feet. The use of aerial messenger wire in sueh eases removes the strain
from signal ('able:,;, and reduees the likelihood of eablc trouble, I' nsupported eable is apt to develop trouhle at tlw ends of l'tlhle spans,
It is good c('(momy to provide high-grade aerial messenger \rire, sueh as that ,,'ith a eopper ('overing ,,'elded to the steel by the molten welding proeess. The size and strength of messenger wire depends on the load to he eal'l'ird, but five-sixtcenths-ineh "'ire ,,'ith an ultimate strength of not less than fi,200 pounds is ui'ually satisfal'tory for a 12-eondul'tor signal eable.
Efficiency and Continuity of Operation The full utility of t raffie :,;ignals is realized only when t!1('y arc op-
erated in a('('ordanee with aetual traffie rcquirerrH'nts. lrH'onvenicnec, disobedicnec, and hazard follO\v ImnC('essary, arbitrary, or inaeeurate operation. The operating standards eontained herein provide for a reasonable pffieieney in thp op('1'ation of signals at \varranted loeations,
It is desirable that a person approaehing a traffie signal :,;hould presume it is funetioning unles:,; he i:,; ginm a ('.on:,;pieuous and spceific indieation to the eontrary. Benee it is requirecl that all :,;ignals in use be "live." When not operating a:,; a Rtop-and-Co deviee, the :,;ignal should be operated as a flashing c1eviee.
During s(~a:,;onal shutdO\vn:,;, when it i:,; not de:,;irable to operate the signa]:,;, tlwy :,;hould be hooded, turned, or taken down so persons will Iw under no mi:,;apprehension that a lamp may be hurned out,
145

Length of Cycle
Considerable dissatisfaction with traffic signals may be attributed to improper timing; and selection of cycle length. It is important therefore, that the 'predetermined and constant cycle length for f1xed~ time signals be accurately related to traffic requirements. The cYcles of traffic-actuated signals, on the other hand, vary and tend to adjust themselves to the demands of traffic. In this case, the total cYcle length is partly or wholly dependent on adjustment of those time controls or cycle components that regulate the reaction of the signal_ timing mechanism to vehicle or pedestrian actuations. Obviously the correct adjustment of these time controls ranks in importanc~ with the selection of a proper cycle length for fixed-time signals.
The cycle shall be as short as will accommodate the necessary movements.
Short cyles encourage observance of the signals by pedestrians and vehicle drivers. Unfortunately, no entirely satisfactory formulae are as yet available for an exact determination of proper cycle length.
For city conditions, a cycle length of from 35 to 50 seconds is generally satisfactory for the usual intersection. Rural intersections, heavy traffic volumes, or complex control problems may make it desirable to use r,50mewhat longer cycles.
Changes in cycle length for different traffic conditions during the day, while requiring special equipment, are oftentimes justified.
Number of Traffic Phases
The number of traffic phases or group movements of vehicles and pedestrians required to obtain proper and efficient operation at an intersection varies with the composition and direction of the traffic flows as well as with the number of entering streets and the general intersection lay-out. A two-phase cycle in which the right-of-way is successively assigned to all movements on one street and then to all movements on the other will suffiee for the majority of inkrsections involving two streets. Intersections having a large and concentrated volume of left turns or unusually heavy pedestrian movements, and those with more than four entering traffic streams, however, will frequently require a division of the total time cycle into three or more phases or grouped traffic movements in order to eliminate major eonflicts between vehicles or between vehicles and pedestrians.
The traffic information collected should be most carefully studied for all intersections where the above-named conditions exist, with a view toward keeping the number of phases to a minimum consistent with needs. In determining whether a given intersection should be operated on two-, three-, four-, or multi-phase control, it should be kept in mind that certain unavoidable delays are added as each additional phase is introduced. Where one street carries a low volume of
14ti

raffle and it is evident from the physical lay-out and the traffic patt rJl that more than two phases are needed, it is often possible to as-
!.? n one Go or movement period to the low volume ~treet while the
o81tgher streets arc gI. ven t,,o such,G 0 pen'o(1s.

IWtation of Intervals Each interval provided for traffic movement should generally be
given once and only once during each cycle, but extraordinary conditions may warrant the duplication of an interval in anyone cycle. With certain types of traffic-actuated control equipment, it is possible to omit from the cycle those traffic movements for which no demand has been registered. It should be understood that the movement of one particular line of traffic may continue during several intervals. No special indication or interval should be used in a signal cycle until its need haR been definitely established by tr-lffic counts and observa-
tion. Following are typical illustrations of the sequence of intervals in
simple cycles:

Simple Cycle Without Pedestrian Interval

Interval number

ilJain street

Cross street

L

.

Green_

Red

2___

Yellow_..

Red

3__

Hed.___

Green

4.

Red_____

Yellow

and repeat.

Simple Cycle With Combination Pedestrian Intervals

"~ain street

Cross street

Interval number ~~~--~~~~-

Yehicles Pedestrians Vehicles Pedestrians

Green_

WALK __ Red_

WAIT

Green_ _ WAIT

Red _ WAIT

Yellow _ \VAIT

Red_

WAIT

Red

WAIT _ Green __ . WALK

Red

WAIT. Green __ WAIT

6__

Red

WAIT. Yellow WAIT

and repeat.

Traffic Movement Intervals Proportioned to Traffic Requirements
Cycles should be divided into intervals proportionate to the time required by the traffic which will enter the intersection during the signal intervals. \Vhere time requirements of the different movements vary widely during different hours of the day, provision should be made for changing the percentage of the total cycle allowed for each interval to accord reasonably well with these requirements. Where the time requirement~ of the different traffic movements do not vary

14i

materially during the day, the percentage;.; allowed the different inter. vals should normally be tllOHe that mOHt accurately accord with the requirementH during the heavieHt traffic hour.
Traffic moves iJl'lanes, and the more lanes in use, the shorter is the time required for a given volume to paHS through an interHection assuming that the intersection has adequate diHcharge capacity. In~ tervals should not, therefore, be proportioned purely on the basiH of relative volumeH entering in the different directions unleHH there is
0; the same number of moving laneH on each entering Htreet. En'n then
streets carrying conHiderahle proportions of slow-moving vehicles, streetcars and bUSHes \yhich must load and unload at intersections, will require more time to diHcharge a gi"en volume than streetH where the traffic is made up largely of passenger automobiles. :\djuHtment for such differences will often he necessary.
Traffic frequently diHtrihutes itself among the antilahle lane" so that ea('h lane requireH approximately the "arne time to discharge its load. l'nder certain conditionH, hO\yever, this may not be true. A given lane, beeause of turning moYements, the preHenee of commcreial vehicles, or other factors, may require a greater amount of time than others. This then becomes the eritical lane and should be the OIl(> eon-
Hidered in proportioning intervals. r sually the volume of traffic per
lane entering the intersection on a Go inteJ'\'al will not be equal from the t\H) directions on tl)(' samc street. The per-lane volume of traffic entering from the IH'avier diredion, therefore, should generally determine the time required for the interval.
Unexpected Conflicts During Go Interval
:\0 movement which may involve an unexpeeted erossing of pathways of moving traffic should be permitted during any Go interval, pxcept under unusual conditions, when:
I. The mO\'ement invoh'eH only slight hazard; 2. HeriouH traffic delayH are materially reduced by permitting the
conflicting movement; and :3. Traffic Huhjected to the unexpected conflict is effecti\'ely
\\'arncd thereof. When such c(mditionH of possible unexpeeted conflict exist, \Yarning may be given by an illuminated Hign or, under certain conditions, by the use of a flashing signal instead of a green Go Hignal. The foregoing applieH to ,'ehiele-pedeHtrian ccmflietH as well as to vehiclevehicle ('onfl iet s.
Vehicle-Clearance Interval A yellO\\' \'(~hieIe-e1earanee interval shall be used following each green
interval. In no case shall a yellow interval be diHplayed in conjunction with the change from red to green.
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In general, the vehicle-(Iearanee interval should be not less than 3 seconds, nor more than i,., reasonably ne('es,.,ary to clear the intersection of traffic. At inters(~etion,., \yherp approaeh speeds are 3{i miles per hour or more the elpararH'p internd on the_ ,.,treet or street,., ha\ing this approach ,.,peed ,.,hould u,.,ually hp at least D seconds. -
While elearance interval,., longer than ti ,.,econd,., may occasionally be neee,.,sary at very \yide intpr,.,('(:tions or under other unusual conditions, they are apt to eause impatience among drivers awaiting the signal change and consequent starting before the green indication appears.
Theoretically, the display of yellow after red ha,., the effect of advising the waiting motorist to prepare to start. In practice, it has frequently induced waiting drivers to start forward in advance of the green indication.
The usc of the yellow elearance interval as a period during which pede,.,trian,., are ,.,upposed to walk is disapproved. The function,., of the yellow interval should be exelusively those of warning approa<:hing driw'r,., and clearing the intersection.
Some authoritie,., feel th~tt a short all-\YaY re<1 interval of about 3 second,.,' duration immediately after the normal yellow clearanee interval has merit at ,.,ome intersections in that it provides a brief additional ckaranee p8riod "'hich permits the slower moving pedestrian to eomplete his crossing 'Yithout vehide interference.
Adequacy of Maintenance
:VIuch of the authority and re,.,pect that traffic ,.,ignals have may be traced to their elear-eut eompelling indications. Signals with impaired efficiency eannot be expeeted to eommand the neeessary degree of respeet. Proper maintenanee i,." therefore, of primary importanee from thi,., funetional vie,vpoint, and ,vill pay other dividends in inerea,.,ing the effeetive life of the signal equipment.
:VIaintenanee should he an important eonsideration in the design and pllrehase of traffie signal equipmpnt. If low first eost is follO\Yed hy high maintenance eo,.,ts or by ,.,eriou,., los,.,es of efficiency, it i,., obviously poor eeonomy.
The ,.,tandards ,.,et forth herein are intended to pnn'ide the essential feature,., for an adequate maintenanee program.
Signal Lamp Replacement
Burned-out signal lamps convert traffie ,.,ignab to the role of a traffic hazard. Immediate replacement of ,.,neh lamps, or scheduled replaeement of lamps short of their antieipated lifp, is an extremely important maintenanee funetion.
Hemotene,.,,., of signab from maintenance faeilities entail,., delay in replacement of bllrnpd-ollt lamp,.,. In maintenance jllrisdietions where
149

this condition exists, a regular lamp replacement schedule is advised

Such a schedule should provide for replacements slightly short of th'

life expectancy as determined from consideration of the folIowin;

factors:

,~

1. Theory of probabilities of lamp failure as applied to mass

production and manufacturers' rating.

2. The effect of differences between socket and rated voltage.

3. Failure due to vibration and handling.

Actual hours of illumination for lamps vary according to lens posi.

tion and timing schedules. For example, main-street green and side-.

street red will require replacement more often than side-street green

and main-street red. These latter in turn will require replacement

more often than the yellow.

Cleaning
The reduction in brilliancy of a signal indication resulting from even a moderate amount of dust and dirt is generally very much underestimated. Signal lenses, reflectors, and lamps should be thoroughly cleaned at least once every 6 months. Lenses and reflectors should always be cleaned when lamps are replaced, unless the last regular cleaning has been very recent.
The frequency with which cleaning is required will vary according to the location of the signal. A signal located on a bridge over railroad tracks may require cleaning once a month.

Maintenance of Controllers
Every controller shall be kept in effective operation in strict accordance with its predetermined timing schedule.
Lubrication.-Controllers shall be carefully lubricated, in accordance with a lubrication chart furnished by the manufacturer, at least as frequently as is specified by the manufacturer and more frequently if experience proves it necessary.
Different controllers often require lubrication at widely different intervals.
Timing.-A careful check of the correctness of timed operation of the controller shall be made frequently enough to insure its operating in accordance with the planned timing schedule.
The checking as to timing can be done effectively in connection with cleaning, lubrication, or overhauling. The length of each interval should be recorded for at least two complete cycles. These should then be checked against the timing sehedule, a copy of which should be posted in the control box housing.
The necessity for checking timing arises from the possibility of mechanical or electrical misadjustments or unauthorized changes in timing.

150

Painting Signal heads, brackets, poles, posts, control boxes, housings, and
conduits above ground should be repainted at least every 2 years, and as much oftener as may be necessary to prevent corrosion and to maintain the good appearance of the equipment.
The frequency with which repainting is needed will vary with the paint, the condition of the surface to which it is applied, chemicals in the atmosphere, and other conditions. Maintenance Records
Detailed maintenance records should be kept and analyzed at regular intervals to determine future policies as to equipment purchases and the maintenance program.
Good maintenance records are valuable in a number of ways: 1. Careful analysis will assist in determining whether or not the maintenance program in use is satisfactory. 2. Analysis of costs will aid in deciding upon types of equipment to be purchased and improvements in maintenance methods. 3. Maintenance records will frequently be needed by the courts in connection with accident cases.
Maintenance records should indicate the necessary time required and costs of cleaning, lubrication, retiming, overhauling, lamp replacement, painting, and similar items, for each signal installation and for each specific controller.
151

C-COMPARISON OF FIXED-TIME AND TRAFFIC. ACTUATED CONTROL
Relative Adaptability to Normal Intersection Requirements
Each of the two 'principal types of traffic 8ignal control, fixed-time and traffic-actuated, posseS8es certain advantage8 not afforded by the other. The choice of equipment should be made only after a review of the relative merits and adaptability of the two types to the particular requirement8 at the location prop08ed for 8ignalization. While fixed_ time control has had by far the wider application up to the present and will very likely continue a8 the more popular choice for reasons which will be discus8ed later, the use of traffic-aetuated control for certain 8ituations is increasing. The following discussion i8 intended to bring out the basic difIerence8 in the two types of control. in80far as their operating characteristicI' and suitability for variou;,; traffic requirements are concerned.
With fixed-time control, a consistent and regularly repeated sequence of signal indications is given to traffic. The total cycle length, or time required for one complete sequence of signal indications, is a feature of fixed-time control which can usually be adjusted from a minimum of 30 seconds to a maximum of about 120 second8. A cycle length is selected, based on the traffic demand, and divided into the intervals necessary for handling that traffic. Signal indications then appear in accordance with the predetermined sequence unless changed to other timing schedules by automatic or manual means.
This regularity of timing is both an advantage and a handicap. It permits maintenance of an e8tablished time relation with other signals in the area so that vehicles can move through the signalized intersections with a minimum of delay. It does not, however, recognize the short-time variations in traffic flow. In most cases, this means excess or wasted time when cars on one street are required to wait for a signal change although there is no traffic using the other street. The;,;e time losse;,; are small but when they occur frequently may cau;,;e considerable delay, inconvenience, and reduction in intersection capacity.
With the traffic-actuated type of control, the cycle length is not predetermined or fixed at any definite value. Similarly, the intervals are usually self-adjusting within certain limits so that they more accurately fit the need8 of traffic. The sequence of intervals normally remains the same, but the time for a complete rotation or sequence of intervals will vary widely. This type of control has a considerable measure of flexibility and some of the time and capacity los;,;es inherent in fixed-time control are automatically avoided. This is especially true at intersections where the traffic load shifts from one street to the other during the period of signal operation. Because of the flexibility characteristics of traffic-actuated control, its principal appli-
152

cation has been at locations not inten:onnected with other signalized interseetions for progressive traffic movement.
Many operating yariations arc possible with traffic-ad uated ('ontro!. Interseetion" may have semi-traffic-actuated or full trafficaetuated control. In the former case, the right-of-way or green "ignal is normally giyen to the major street unless a side-street actuation is recei\"ed, at ,,,hich time the right-of-way ,,,ill be temporarily assigned to the side street. This type of control equipment has its principal app!ieation at isolated signal locations ,,,here traffic on the <TO"S street or route is light and arriye" at irregular intelTals but, unles" aided by signals. is unable to enter and cross the prineipal route safely without long waiting periods. \Vith full traffic-actuated control. vehide" on all approaches affect the operation of the "ignal and the assignment of right-of-,,,ay is made substantially in accordance with the demand" on the "everal approaches. Complieated inter"eetions often require this type of control to permit a reasonable degree of operating efficiency to be attained.
Special Merits of Fixed-Time Control
Fixed-time ('(mtrol is. as previously mentioned. the more commonly used of the t,,,o types of equipment. This i" due largely to (1) the simplicity of the equipment, (2) the fact that it prm'ides I)()"iti,'e speed control in a signal system, and (3) at many intersections it does an adequate job in controlling intersection traffic. The fixcd-time tyP(' of control. if carefully timed, can approach very dosely the f'fficiency of traffic-actuated control at intersections where mm'ement" are ,,-ell balanced by direction and ,,,here traffic ,'olumes do not \'tlry ,,,idel~' during the day. The equipment is abo more easily "elTiced and maintained than the more complex cireuit" of the traffic-actuated controller. The constancy of the cycle length is of obvious advantage ,,-hen "ignals are interconnel'ted for obtaining progl'<'s"ive movement and ('entralized control.
Certain additional flexibilities ~tyailable in fixed-time control permit thc u"e of a different time cycle. cycle division, or offset to meet more preci"ely the requirement:-; of traflic during the pcak and off-peak hour". Thi" change in timing each clay may he regular or on a differing program. depending on the requirements encountered. Sueh programming of control timing is elf considerable vah\(' and makes for more efficient handling of intersection and system requirement".
Special Merits of Traffic-Actuated Control
The volume of traffic approaching most interseetions is a continuously and often ,,-idely fluctuating quantity. YIaximum efficiency in signalized inter"el'tion control is attained "'hen the "ignal indication"
j;i3

are timed so as to reduce to a minimum the delay to traffic Using the intersection.
To approach this condition as closely as possible, control meehanisrns must be able to regulate".the signals in accordanee with ehallging demands of traffic. Means must therefore be provided for detecting the presence and volume of traffic, both vehicular and pedestrian, in the approaches to the intersection; and the controller must IX' able to apportion right-of-way time with maximum effectiveness.
Traffic-actuated control signals operate upon this demand principle. There are two general types of traffic-actuated control: (1) Sernitraffic-actuated control, in which traffic-actuation devices are installed in only some of the approaches; and (2) full traffie-actuated eontrol
in which such devices are provided in all approaches to the inter~
section.
Among the special advantages of traffic-actuated control are the following:
1. Delay and inconvenience are not great at traffic-actuated controlled intersections because traffie is passed through the intersection in a manner closely approximating the natural approach pattern. Any reduction of delay operates to increase the capacity of the intersection.
2. Traffie-aetuated control is especially effective at multiple intersections, or at intersections with traffic requirements that vary considerably during different times of the day.
3. At problem loeations in progressive systems, traffic-actuated equipment will usually handle speeial conflicting movements more expeditiously than fixed-time equipment, particularly if these special movements vary in time requirements at different hours.
4. The full safety advantages of eontinuous Stop-and-Go operation during low volume periods are retained with trafficactuated control, whereas fixed-time signals often are switched to flashing operation under these conditions to avoid exeess delay in traffic.
5. Traffic-actuated control may, in some instances, minimize the tendency of traffic to avoid signalized intersections, and thus result in the use of more logical routings.
Other Factors Governing Selection of Type of Control
When the problem of choosing between fixed-time and trafficactuated control equipment is presented, the factor of cost has often been a decisive one. Mainly because of the need for installing deteetors in or adjacent to the roadway and the more complex timing circuit in the controller, traffic-actuated signal installations are considerably more expensive than most fixed-time control installations.
154

Due to the wide range in types of fixed-time and traffic-actuated equipment it is not possible to state comparative costs with any exactness, but the more complex types of fixed-time control are the only ones that approach the cost of the simplest traffic-actuated controls. It is most important, therefore, that a careful study be made of the intersection requirements to determine which type of control will be the more appropriate.
If investigation shows that the physical lay-out of the intersection presents no unusual difficulties, that traffic is of substantial volume and reasonably well balanced by direction on both streets and does not change its time requirements too greatly throughout the day, and that no severe pedestrian or turning-movement problems exist, it is likely that fixed-time or traffic-actuated control would be almost equally satisfactory. If the location is close to another signal with which it may now or at some future time be desired to make interconnection for progressive movement of traffic, the fixed-time installation will probably be preferable. However, in cases where the intersection is quite isolated from other signalized intersections, with no interconnection contemplated, and more than two streets or widely varying traffic loads are involved, a traffic-actuated installation will be likely to result in less delay. If, for some reason, a signal has to be installed at a location where conditions do not appear to warrant signalized control, a traffic-actuated signal should be employed because of the lesser delay normally caused to traffic by this type of control.
Dealing with traffic-actuated control in coordinated systems, such equipment can be employed in interconnected progressive systems by superimposing a background time cycle on the control unit. Under heavy demand, the traffic-actuated signal tends to get into a regular schedule of operation resembling that of a fixed-time signal.
Extreme care should be used in selecting both fixed-time and trafficactuated equipment so that proper features for present and future operation will either be obtained when the controllers are purchased or can be added at a later date when the need develops.
155

D-FIXED-TIME SIGNALS
Definition
A fixed-time signal is a traffic control signal by which trafflc is aI J ternately commatded to stop and permitted to proceed in accord: ance with a predetermined time schedule.
Advance Engineering Data Required
The installation of fixed-time signals at intersections should be preceded by a thorough study of traffic, roadway, and accident condi. tions. Among the facts that should be obtained are the folloWing:
1. Complete vehicle volume counts, including right and left turns and classification by vehide type. These counts should include the periods in an average day when the signal would appear to be most needed, and in all cases should be at least 8 hours in duration.
2. Pedestrian volume counts on each cross walk during the same periods as the vehicle counts.
3. Speed and classification of vehicles on approaches to the intersection.
4. Details of the physical lay-out, such as roadway width, channelization, grades on approaches, corner sight-distance restrictions, bus-stop locations, parking practice, and location of railroad grade crossings. These data are of most value when assembled on a condition diagram.
5. A summary of accidents by type, location, vehide or pedestrian, direction, time, etc. A collision diagram covering a year or more of accident experience should be prepared from this information.
Warrants for Fixed-Time Signals With such information as will be provided by the above studies, it
is possible to appraise the need for signalization in terms of the warrants given below. If the warrant conditions stated are not satisfied and there still appears to be need for signal control, consideration should be given to the use of traffic-actuated equipment.
The warrants presented for fixed-time signals are intended primarily for typical intersections of two two-lane, two-way streets or highways.
In some cases separate values are given for city and rural locations, and in other instances the warrants arc qualified for special problems such as those which arise at intersections near railroad grade crossings, schools, industrial plants, stadiums, and similar points of public congregation.
Fixed-time traffic signals shall be installed and operated only where and when one or more of the following warrants.
156

1. Minimum vehicular volume. 2. Interruption of continuous traffic. 3. Minimum pedestrian volume. 4. Coordinated movement. 5. Accident hazard. 6. Combinations of 1 through ,)-other factors.
Minimum Vehicular Volume The minimum vehicular volume warrants are intended for applica-
tion at locations where no special conditions exist and where the amount of intersecting traffic is the outstanding reason for intersection conflicts. As previously stated, the warrant values apply to the intersection of two two-lane, two-way street:-; or highways. Yehicle volume warrants for intersections of roadways having two or more moving lanes in one direction should be :-;omewhat higher than the \"allles given belmv. Obviously, more traffic can pass through an intersection in a given time in two or three lanes than in one lane.
The minimum vehicular volume \varrants are as follows:
In Crban Areas: 1. Total vehicular volume entering the intersection from all approaches must average at least 7;"";0 vehicles per hour for any 8 hours of an average day, and 2. Total vehicular volume entering the intersection from the minor street or streets must average at least 175 vehicles per hour for the same 8 hours.
Jn R1iral Areas: 1. Total vehicular volume enterinll; the intersection from all approaches must average at least 500 vehicles per hour for any 8 hours of an average day, and 2. Total vehicular volume entering the intersection from the minor highway or highways must average at least 125 vehicles per hour for the same 8 hours. On important rural highways, traffie during the hill;hest 8 hours of
the average day will usually amount to one-half to two-thircl:-; of the 24-hour total. This mean:-; that a total of 6,000 to 8,000 vehides entering the intersection on an average day is the approximate equivalent of the minimum vehicular volume warrant stated above for rural areas. Peak tr'affic on summer holidays and Sundays may frequently be twice as high as these values and for approximately half the days of the year the volume:-; will exceed the stated average of 6,000 to 8,000 vehicles per day.
Recognition of these relationships is most important if the warrants are to be properly interpreted. A sill;nal installation cannot be con
157

sidered justified under the minimum vehicular volume warrant unless

the volumes are recorded on or adjusted to a day reasonably repre-

sentative of the average condition under which the signal is to be

operated.

,#'

On urban streets, traffic during the highest 8 hours of the average

day is a somewhat more variable percentage of the 24-hour volume

than is found on important rural highways. The range of one-half

to two-thirds of the total 24-hour volume will nevertheless include a

large proportion of the city traffic patterns for average weekdays,

which is the time when signals will be of most use. Applied to the

urban area warrant stated above, this means that the minimum total

vehicular volume entering city intersections must ordinarily be from

9,000 to 12,000 vehicles on an average day, of which total approxi-

mately one-fourth must be side-street traffic, before signal installation

on the basis of this particular warrant would be justified.

From studies made at isolated signalized intersections, principally

in cities, it appears that the peak hour will often be as much as 50

percent higher than the average of the 8 highest hours during the day.

Selection of the 8-hour volume warrant period (not necessarily 8 con-

secutive hours) is based on the knowledge that heavy traffic flows of

shorter duration in effect include only morning and evening rush-hour

traffic at many locations, which might be better handled by traffic-

actuated equipment or by officer control. It is also obvious that a

count of 8 hours provides a more reliable measure of need than do

shorter period counts.

Regardless of the general warrant stated above, traffic signals should

not, if avoidable, be installed' at a street or highway intersection near

a railroad grade crossing. Traffic signals too close to railroad grade

crossings are likely to be misinterpreted by some drivers as governing

the periods when it is safe t,o cross the railroad tracks. If the grade

crossing is also protected by standard train-approach signals) there

may be considerable confusion between the two types of signal appa-

ratus so close together.

If, however, the minimum vehicle volume warrant is satisfied at an

intersection within 200 feet of a railroad grade crossing and if, with-

out signals, traffic is likely to be retarded and vehicles forced to stop

on the tracks, a signal installation may be warranted. This type of

installation is regarded as exceptional, and extreme care should be

taken in all matters relating to the lay-out, design, and operation to

avoid the possibility of forcing vehieular traffic to stop on the crossing.

To accomplish this, there should normally be an auxiliary control sig-

nal at the railroad crossing to stop traffic approaching the intersection

from the railroad side when the intersection signal shows a Stop indi-

cation and when trains are approaching and crossing the highway.

If standard train-approach signals are employed at the crossing, their

Hi8

operation should be positively coordinated with the intersection signal to prevent any possibility of forcing vehicular traffic to stop on the tracks when a train is approaching.
Similarly, coordination of the crossing and intersection signals may be required for traffic moving away from the intersection SD as to avoid undue blocking of traffic movement parallel with the railroad whilp trains are approaching or are on the crossing.
When for a period of two or more consecutive hours the total Yf'hicular volume entering an intersection having fixed-time signals installed under this warrant falls below 50 percent of the minimum volumes stated above for urban and rural intersections, flashing operation shall be substituted for fixed-time operation for the duration of such periods of reduced volume.
In many of the medium and smaller size communities, a change to flashing operation will frequently be vvarranted by 8 or 9 p. m. on an ordinary evening. The impracticability of changing the method of operation many times during the day is recognized and therefore it i:recommended that flashing operation be limited to not more than three periods in 24-hours.
Interruption of Continuous Traffic
Vehicles on through streets or highways tend, if uncontrolled, to travel through minor street intersections at speeds that make it difficult and hazardous for vehicles and pedestrians from the side street to cross or enter the principal traffic stream, despite laws that require such vehicles on the highway to yield the right-of-way to cross traffic under certain conditions. Where cross traffic suffers undue delay or hazard because of this condition, a signal installation may correct the condition. If several intersections in the same vicinity are similarly affected, a speed-controlling, progressive signal system may be a suitable remedy. However, if such a system is installed, it is generally undesirable to have signalized intersections more than 1,200 feet apart.
Minimum warrants for interruption of continuous traffic are as follows:
In Urban Areas: 1. At an intersection on an important street, the vehicle volume along that principal street must average at least 750 vehicles per hour for any 8 hours of an average day; and
2. The combined vehicle and pedestrian volume from the side street or streets must average at least 75 units per hour for the same 8 hours; and
3. The average vchiele speed must exceed 20 miles per hour on the principal street approaches to the intersection.
1M!

In R ural Areas:
1. At an intersection on an important highway, the vehiele volume along that principal highway must average at least ;jOO nhieles per hour for a'f'iy 8 hours of an average day; and
2. The combined vehicle and pedestrian volume from the side high_ way or highways must average at least 50 units per hour for the same 8 hours; and
3. The average vehicle speed mm;t exeeed 35 miles per hour on the principal highway approaches to the intersection.
I n addition to the above-described conditions warranting signal installation, there are similar instances where traffic signals can provide a genuine service over a somewhat shorter period of time. Industrial plants, resorts, stadiums, and other places where large volumes of traffic are found 011 regular and reasonably frequent occasions are examples. For this special purpose, there are presented below a series of additional warrants for the interruption of continuous traffic, anyone of which may justify signal installation:
I n Urban Areas:
I. Vehicular volume on the major thoroughfare past an estahlishment of the type mentioned above exceeds 800 cars per hour at the approximate time of major movement of traffic to and from the establishment, and traffic to or from the establishment roadway during the same period of time meets one of the folhl\\"ing warrants: (a) A minimum of 300 cars per hour, or (b) A minimum of 200 pedestrians crossing per hour, or (c) A minimum of 200 cars and 100 pedestrians crossing per hour.
2. Left turns into or from the establishment roadway exceed 30 percent of the 800 cars per hour past the establishment.
:'l. Four lanes of traffic moving past the establishment exceed an average speed of 40 miles per hour during major movement of traffic"
4. A sharp vertical or horizontal ('UlOVe or view obstruction exists near the entrance or exit of the establishment, one or a combination of which creates a serious accident hazard.
I fI R ural Areas:
\Varrants for establishments located in rural areas are 50 percent of the foregoing traffic volumes for major thoroughfare and establishment entrance or exit.
'Vhen for a period of two or more consecutive hours the vehiele volume on the principal thoroughfare or the combined vehicle and pedestrian volume from the side street or highway falls below ,')0 pereent
1m

of the minimum volume stated above for urban and rural intersections, flashing operation shall be substituted for fixed-time operation for the duration of such periods of reduced volume.
Minimum Pedestrian Volume
Provi::;ion for safe and convenient crossing of roadway::; by pedestrians de::;erve::; greater attention than it ha::; heretofore received. Nearly two-thirds of all persons killed in city traffic accident::; and nearly half the person::; killed in all traffic accidents in rural and urban areas combined are pedestrians. The criteria for installation of fixed-time signals on the basis of pedestrian volume are as follows:
In Urban Areas: 1. Pedestrian volume cro::;sing the major street must average at least 250' persons per hour for any 8 hours of an average day; and 2. Vehicular traffic entering from the major street must average at least GOO vehieles per hour for the same 8 hours; and 3. The average vehicle speed must exceed 15 miles per hour on the approaches to the interseetion.
In Rural Areas: 1. Pedestrian volume crossing the major highway must average at least 125 persons per hour for any 8 hours of an average day; and 2. Vehicular traffic entering from the major highway must average at least 300 vehieles per hour for the same 8 hours; and 3. The average vehicle speed mu::;t exceed 30 miles per hour on the approaches to the inter::;ection. When for two or more consecutive hour::; the vehicular and pedes-
trian traffie volume drop::; to 50 percent or Ie::;::; of the warrant value::; stated above, the signal shall not be operated as a fixed-time signal.
Traffic control signals may be warranted for pedestrian benefit in certain case::; where vehicular volume is somewhat less than the warrant values but where vehicular speeds frequently exceed the warrants stated. Such a condition may create a serious traffic hazard. At intersections where a pedestrian and vehicle conflict is the predominating factor in determining the need for signal con!,!"ol, special pedestrian signal::; may be ju::;tified.
Conditions at certain noninterseetion location::; may be improved by the installation and operation of a traffic control signal for the benefit of pedestrian::;, especially if large numbers of pede::;trian::; must cross roadways at irregular intervals. Such locations are in the vicinity of schools, large meeting places, and parks. Generally such signals should either be of the pedestrian-actuated type or should be operated manually only during periods when they are needed.
Studies of pedestrian and vehicular movements are essential to determine whether pedestrian conditions justify the installation and op-
IG1

eration of a traffic control signal. The pedestrian study should deter. mine the number of pedestrians crossing each roadway in each direction separately. Persons going to or from a streetcar loading Point acroSs one or more ;g;lOving traffic lanes should be counted. Pedestrian counts should cover at least those hours when it is believed that pedestrian volume crossing the major street may warrant traffic control operation.
To supplement pedestrian and vehicle counts at a given intersection, it is frequently desirable to make studies at other signalized intersections in the same area to determine the degree of driver and pedestrian observance of the signal indications. This should include a record of the percentage of pedestrians crossing on the red indication, the percentage of drivers going through on the yellow or red indication, and especially those making unauthorized turns on the yellow or red indication. If the observance record is poor, it is likely that the value of a signal otherwise justified under this warrant will not materialize without the introduction of other measures designed to secure improved observance.
Coordinated Movement
A fixed-time signal may be warranted as a part of a coordinated signal system if a maj ority of the signalized intersections composing the system comply with one or more of the established warrants and if the proposed signal installation is necessary to maintain compact group movement or desired group speed. Coordinated control sometimes necessitates traffic signal installations at intersections where they would not otherwise be warranted, for effective regulation of speed and for maintenance of proper grouping of vehiclps. By keeping the.vehicles in a coordinated system in compact groups and effectively regulating their speed, less delay and greater convenience and safety are accorded both vehicles and pedestrians entering the coordinated roadway at intervening unsignalized intersections.
In general, additional signals for coordinated movement are not warranted if the distance between signalized intersections is already less than 1,200 feet. If there is a choice between intersections to be protected by signals to be installed under this warrant, there should be a careful analysis to determine which intersection most nearly justifies the signal installation under other warrants.
Since signal installations at intersections within 200 feet of a railroad grade crossing are to be avoided, it may be preferable to space signals in a coordinated system somewhat more than 1,200 feet apart in the vicinity of grade crossings. If a signal is needed near the crossing to maintain progression, extreme care should be used in selecting its location, design, and plan of operation so as to preclude the possi-
162

bility of forcing vehicles to "top on the tracks under heavy traffic conditions.
In designing coordinated "ignal systems, the que"tion of desirability of installing ""pacing "ignals" to maintain vehicle group~ng" will frequently arise. In studying the situation, vehicular volume counts as heretofore described should be made at all intersections where the data may be needed. These should be supplemented by observations of "peeds of vehicle" and the amounts and kinds of delay encountered in moving along the highway.
Accident Hazard
If none of the warrants except the accident-hazard warrant described below is fulfilled, the initial presumption "hould be againHt signalization. ,The installation of a traffic control signal because of a
0;' spectacular much-publicized accident, or because of a small num-
ber of accidents, is strongly condemned. The full accident record of the location should be carefully investigated before any installations are made under this warrant. Such study and experience may show at once that the hazard existing cannot be corrected by a device less restrictive than a signal. In general, however, a fixed-time signal may be considered warranted only where:
1. Adequate trial of less restrictive remedies with satisfactory observance and enforcement has failed to reduce the accident frequency; and
2. Five or more reported accidents of types susceptible of correction by a traffic control signal have occurred within a 12month period, each accident involving personal injury 01'_ property damage to an apparent extent of fi5'O'r more; and .
3. There exists a volume of vehicular and pedestrian traffic not less than 50 percent of the requirements specified in the minimum vehicular volume warrant, the interruption of continuous traffic warrant, or the minimum pedestrian volume warrant.
Any fixed-time signal installed because of accident hazard should be operated on the shortest cyele length that will adequately serve traffic' approaching during the heaviest traffic hour.
Thorough analysis of accident experience in advance of making installation under this ,varrant is important. Accident history can usually be obtained from police accident records or from accident reports made by vehicle operators involved. 'ithout a careful analysis of such records it is impossible to determine upon the most suitable remedial measures.
The following four step" are very helpful in determining what should be done:
1. Analyze summarized statistics of all recorded accidents at the intersection.
163

2. Analyze physical characteristics at and near the intersection. 3. Analyze traffic flow characteristics. 4. Analyze the collision diagram. A review of these data '~ill frequently reveal a number of significant facts. For example, types of accidents have a very important bearing on the appropriateness of signalization. A traffic control signal, when obeyed by drivers and pedestrians, can be expected to eliminate '01' reduce materially the number and seriousness of the following types of accidents:

1. Those involving substantially right-angle collisions or conflicts

as occur between vehides on intersecting streets.

'

2. Those involving conflicts between straight-moving vehides and crossing pedestrians.

3. Those between straight-moving and left-turning vehides approaching from opposite directions, particularly if an independent time interval is allowed during the signal cycle for the left-turn movement.

4. Those involving excessive speed, in cases where signal coordination will restrict speed to a reasonable rate.

()n the other hand, traffic control signals cannot be expected to reduce the following types of accidents:

1. Rear-end collisionti, which often incrcatie after tiignalization.

2. Collisions between vchides proceeding in the same or opposite directions, one of which makes a turn across the path of the other, particularly if no independent signal interval iti provided for these turn movementti.

3. Accidentti involving pedestrians and turning vehicles, when both move on the same Go interval.

4. Other types of pedetitrian aeeidents, if pedestrians do not ohey the signalti.

As an alternate to intitalling traffic :-;ignals arbitrarily at intertiection locations that appear to be hazardou:-;, it iti detiirable to institute, with proper education and enforcement, remedial measures which cause le:-;ti delay and inconvenience to traffic. vVarning, Advisory Speed, and Stop :-;igns; marking of laneti or othen\"i:-;e organizing traffic movements; pedestrian and traffic island:-;; fixed street 01' highway lighting; removal of view obstruction:-;; and propel' regulation of parking are exampleti. If titudie:-; indicate that one or a comhination of these other remedial measure:-; i:-; adapted to conditions. it tihould be given a fail' trial for at least G months, and preferably for a year. Following the trial period, a restudy tihould be made, and if satisfactory results have not been achieved, :-;llch additional stepti :-;hould be taken as are indicated hy the study.

lG4

Combination of Warrants-Other Factors
Fixed-time signals may occasionally be justified where no one warrant is satisfied but two or more are satisfied to the extent of 80 percent or more of the stated values, particularly if there are present other important factors, such as:
1. A sudden change from rural eonditions, where relatively high speeds are safe, to those of an urban business district;
2. Extreme width of roadway which pedestrians must eross; 3. Predominanee of especially handicapped pedestrians, such as
small ehildren or blind, aged, or erippled adults, who need to eross the roadway; or 4. An intersection on or at the bottom of a long or steep grade. In case 4, there should generally be a traffic control signal at the top of the grade, coordinated with the signal or signals below so that a vehicle permitted to enter the descending grade will be able to proceed at the indicated speed without stopping on or at the foot of the grade. This plan greatly reduces the hazard from vehides unable to stop on slippery hills. These exceptional eases should be decided on the basis of a thorough analysis of facts-never on the basis of petitions or complaints alone. A combination of the above warrants may be used to develop a formula satisfaetory not only for determining the feasibility of installing signals at one location but also for arriving at a priority so that a proper sequenee for the installation of a number of signals may he determined. Such a formula is also helpful in identifying loeations ,Y!wre traffie signal operation is no longer necessary.
Selection of Type of Fixed-Time Control Mechanism ~Where any of the previously described warrants is satisfied and the
decision has been made to install a fixed-time signal, it is neeessary to seleet the type of fixed-time control meehanism to be used.
1. .:\onsynehronous fixed-time eontroller for isolated intersections. 2. Program type of fixed-time controller for isolated intersections. 3. Synchronous type of fixed-time controller for isolated inter-
seetions. 4. Controllers providing for coordination.
Nonsynchronous Fixed-Time Controller for Isolated Intersections
This type of eontroller is the least desirable. Its operation, and hence the resultant timing, varies with ehanges in line voltage and temperature. Controllers of this type already purehased should he shifted to relatively unimportant isolated interseetions \nlrranting signalization where:
1. There is little likelihood that the signal installation will ever be eoordinated with any other: and
165

2. The fixed lengths of cycle and intervals will be tolerable during all hours of traffic control (Stop-and-Go) operation.
Program Type of Fixed-Time Controller for Isolated Intersections
';J'
This type of controller provides for a limited number of changes in cycle length and in the proportions allotted to various Go intervals. Such controllers may be used at isolated intersections where:
1. There is little likelihood that the signal installation will he coordinated with any other;
2. There are marked variations for considerable periods in the traffic demand, as, for example, where the major traffic stream enters on different Go intervals in the morning and evening peak periods; and
3. With this program in effect, delays are not unreasonable.
Synchronous Type of Fixed-Time Controller for Isolated Intersections
This type of controller involves the use of a synchronous motor and should be used at isolated intersections where:
1. The installation is likely to be coordinated with one or more other signal installations but interconnection with a master controller is determined to be unjustified economically; and
2. The fixed length of cycle and intervals will be tolerable during all hours of traffic control operation.
This type of controller is almost always preferable at intersections for which the nonsynchronous type is suitable.
Controllers Providing for Coordination
Two types of control are available for coordination. One of these involves noninterconnected synchronous motors, the other a master controller interconnected to local controllers at each signal installation in the system. The selection should be based upon:
1. The volumes of traffic involved: 2. Variations in traffic volume during the hours of intended Stop-
and-Go control; 3. Variations between traffic volumes in the two directions on the
highways involved; and 4. An analysis of the differences of cost involved. In general, the noninterconneeted synchronous motor plan should not be used for very heavy traffic because of its limitations as to flexibility and because of the absence of assurance that the desired eoordination will continue indefinitely. If funds do not immediately permit interconnection and the use of a master controller, it is possible to install synehronous motor controllers of a type which ean later be utilized in a very flexible type of system. Under such conditions, the use of synehronous controllers of this type is recommended.
1{ii)

Signal Timing in Accordance With Traffic Requirements
As pointed out in the discussion of signal operations previously mentioned, the full value of a signal installation is realized only when it is operated in a manner consistent with the traffic requirements. The use of unduly long cycles, or improper division of cycles of reasonable length, fosters disrespect and poor observance of signal indications. Signals should not be operated manually more than is absolutely necessary, as this type of operation has frequently proved to be more inefficient than properly timed automatic control. This is particularly true of signals in a coordinated system.
One of the principal difficulties in signal timing comes from the need to accommodate two or three radically different volume patterns at various times during the period of operation. Any timing plan which is devised should be .checked against the traffic-count information colleded to be sure that the inevitable volume changes on the streets concerned will be handled in the best possible manner.
This problem can become exceedingly complex when it involves not one but a series of signalized intersections which are to be operated so as to provide for continuous movement of a platoon of vehicles. Varying block lengths often constitute a major difficulty in arriving at a satisfactory timing plan. There are many details involved in the development of efficient time-space diagrams for progressive signal systems and no attempt will be made to present a full treatment of the subje(,t in this manual. The Traffic Engineering Handbook, published by the Institute of Traffic Engineers and the National Conservation Bureau, contains a helpful discussion of the significant details of signal timing and deseribes a number of practical refinements possible in traffic sill;nal systems.
Division of Total Cycle Time
Referenee has been made to the importance of assigning Go time to the intersecting streets in aecordance with the traffic demand. There follows a description of a method that has been employed successfully:
If, during the heaviest traffic hour, the effect of turning movements, slow-moving commercial vehicles, and other factors on the time spacing between vehicles in the critical lane leaving the intersection is equal for the two heavier traffic flows at rill;ht angles, the division of the total time cycle into the two Go periods will be approximately correct if these periods are made directly proportional to the intersecting volumes of traffic per (Titical lane.
However, if, during the heaviest traffic hour, there is a considerable difference in the time spacing between vehicles in the two intersecting critical lanes because of, say, the presence of trucks and busses in one of the eritical lanes and not in the other, this fact should be taken into account. In makinll; the eycle division. the Go periods will he approx-
1m

imately coned if made proportional to the products of the crir I Iane voIurnes and t he tIme spacm. gs on the respeet1.\"e intersectIicna

streets.

g

To illus~rate, ass:u~e .that a. GO-second cyele h.as been seleded and that the tIme req1llred for vehICles to dear the Illtersection after th green sI.gnaI'IS;~) seconds on caeh street. cI'hI'S Ieaves a total of ;)0 sec_e

onds of Go time to be divided between the two streets. A,,"ume that the critical lane volumes VA and Y B on "treet" A and 13 dming the heaviest traffic hour are 400 and 2;)0 vehides, respeeti\'ely, In the first case, as"UI~e that th,e time spacing be:ween vehicles; or headway on departure, for each of the two "treets I" the same. fhl' Go time a""igned to each "treet, TA and TE, would then be approximately as follow" :

'1'11 VA - .4.-0--0- - - -- - - - - - - ~ - - - - - - - -- - - - - ~ - - - - - - - - - - - - - - - TB VB 2.50
and TA + TB = 50 "econds (total Go time) - . - - - - - - - - - - - - - -
Solving for TB in (2) and sub"tituting in (1):

']'..1

4.(){') whence 1'A = 31 "cconch

50~TA 250

From (2), TB=.50~31=19 "econch

- - (1) (2)

In the second ca"e, assume that the time spacing between \'E'hiclcs, or departure headway, 1111 and HR, i" 3 second" on "treet A and ;) seconds on Street 13. Thi" difference in headway might be cau,,('d by a sizable percentage of trucks in the nitical lane on street B. TIl(' divi"ion of the Go time would then be approximated a" follO\vs:

TA VAXH4. 400X3
TB VBXHB 250X5 Solving for TB in (2), and "ub"titllting in (3):
_. T~ = 400:><~ whence TA = 24 seconch
50-1'.4. 250 X 5 From (2), TB = 50~24 = 26 seconds.

It should be empha"ized that "uch caleulation" provide only an approximate means of determining the proper time for each "treet. Other considerations, "l1ch a" the time required for pedestrian cro"sing" and physical conditions at the intersection, also affeet signal timing. After the initial selection of a cyele length and a timing program, frequent checkbacks and "tudies of the signal in operation "hould be made to obtain the mo"t efficient timing schedule.
A" a general principle of traffic "ignal timing, no n~hicle Go intelTal "hould be les" than the time reCjllired for the \nliting group of pedestrian" to get "tart cd and to crm.;s to a point of safety unless an exChl"i\"e pede"trian internl1 is also employed. Experiment" with sig-

168

1 timing have shmvn that, insofar as vehide movements are eon-
narned, exeellcnt efficiem~y can be attained under certain off-peak ~~nditions \yith Go intervals as short as 1:) seeonds. ()r~linarily,.how-
e,'er, they .must b~ somewhat longer to gIve the pedestnan a safe oportunity for crossmg the road\vay. P When thel pet e' stnan eross. mg.tIme nms COlH'\lITent1y W'lthtlle "ehide Go period, which is the usual case, the total (;0 interval should be long enough to allmy not less than ;) seconds during which it is indicated that pl'destrians may start to (TOSS, and enough longer to permit pedestrian"! who have entered the roadmly to reach a place of safety with the additional time provided hy the vehieular clearance interval. Thus if it takes 14 seconds for most pedestrians to crm3S the roadway or reach a point of safety, and if the yehicle clearance (yellow) interval is :3' seeonds, the total Go (green) interval should be at
least :5 + 14 - 3, or Hi seeonds.
Coordination of Fixed-Time Signals
In general, all fixed-time signals within 1,200 feet of one another and controlling the same traffic should be operated in coordination. Eyen at greater distances coordination may be desirahle under certain conditions.
Great inconvenience and delay result from independent, noninterrelated operation of dosely adjacent signal installations operating on fixed-time control. 1\lost of this delay can he eliminated by carefully planned eoordination. However, under eertain a(}Yerse conditions which seriously affeet the efficiency of coordinated control, greater effieieney may he possible with traffic-aetuated eontrol, operated either independently or in eombination \yith coordinated control.
Types and Selection of Coordination
The most useful classification of traffic eontrol signal systems is based on their method of eoordination. Since the primary purpose of this coordination is to organize and faeilitate traffic flow, it is essential to understand what yehicular traffic will do under the various systems. On this basis of elassification there are four general types of coordination of fixed-time signals. These are defined as simultaneous system, alternate system, progressiYe system, and flexible progressive system.
Simultaneous System
In a simultaneous systClm all signals show the same indication to the same highway at the same time. This is one of the early types of signal systems and it has a yery limited applieation in modern traffic signal practice.
169

In its simplest form it involves the use of one controller for a series of signals. At all intersections the timing is precisely the same and indications change simu!taneously to show green at each signal fac_ ing main street traffic aria red to all side streets, and similarly through_ out the cycle. A basically simultaneous system may be made more efficient by utilizing independent controllers at critical intersections to permit some adjustment in interval timing in accordance with local intersection requirements.
Intersections less than 300 feet apart often constitute a serious coordination problem. At normal traffic speeds the time required to move from one intersection to the next is so short that a very short cycle would be required for a flexible progressive or alternate system of control. If only two such intersections are to be coordinated, the best plan is generally to operate them as a simultaneous system, giving an ample Go interval on the main street for a major portion of the traffic to clear through both intersections. If two such close intersections are encountered in a larger ;roup to be coordinated, the best plan is to select the flexible progressive system and to adjust the offsets at the two closely adjacent intersections so as to interfere the least with the continuous movement of traffic. Frequently this will result in virtually simultaneous operation of these two signal installations. Except for this limited application and perhaps other occasional exceptions, the use of the simultaneous system is not recommended.
In most applications the simultaneous system has serious operating disadvantages:
1. The simultaneous stopping of all traffic along the highway prevents continuous movement of vehicles and tends to result in high speed between stops, but low over-all speed.
2. Cycle length and interval proportioning are usually controlled by the requirements of one or two major intersections in tha system. This often creates serious inefficiencies at the remaining intersections.
3. On streets carrying numerous streetcars, there is an extremely heavy power drain at the beginning of the Go interval.
4. When the main street is completely filled with a continuous line of traffic and this traffic is stopped on a red indication, vehicles from the side street often have difficulty in turning onto or in crossing the main street.
Alternate System
In the alternate system all signals change their indications at the same time, but adjacent signals or groups of signals show opposite indications alternately along a given highway. The alternate system is usually an improvement over the simultaneous system in that throughout a series of intersections so controlled there can be, under favorablc
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conditiom" continuous movement of groups of \'ehieles at a predetermined Rpeed, thiR heing completely achieved only where the lengthR of the blocks, or of the alternating groups of blocks, are equal. The inflexibility of the alternate RyRtem lies in the fact that the main street cannot at any interRedion have more than half the cyele for 1),- Go interval without a cOlTeRponding loss of time for the Go intelTal at an adjacent intersection, Hence, for maximum efficiency of through movement the cyele must be divided into equal Go and Stop intervals, Under this condition the side streets all receive aR much Go time as the main Rtreet, \vhich iR ordinarily not conRistent with the relative requirements of traffic on the main and Ride Rtreets,
The alternate system can be operated ,,'ith a Ringle controller, but this arrangement is not recommended, Although the alternate "ystem can be used on a, street where blocks arc of equal length to control speeding and to provide equal facility of movement in either direction through the Rystem, it doeR haw limited application for the following reasonR:
I, It requires wbstantially equal Go intervals for both mainand side-Rtreet traffic, which iR likely to be inefficient at mORt of the intersections.
:2. It iR not well adapted to a Rtreet having hlock,., of unequal length,
:~, If the signals arc alternated by groupR the capacity of the roadway is materially reduced during heavy traffic since the latter part of the vehicle group will be stopped by the second signal in the group (aRsuming they are being operated in pairR! when the signal indication changeR,
1. AdjuRtments f01' changing traffic' conditionR are difficult to make.
Simple Progressive System
In the simple progreRRive Ry"tcm, a common ('yele length is used at each interRection and Go indications arc given independently in ac('ordance with a timing :ochedule deRigned to permit continuouR 01' nearly eontinuous movement of groupR of vehideR along the highway at a planned rate of speed,
Synchronous-motor-driven controllers operated by a eommon or pleetri('ally synchronized source may he employed without interconnection in the progressive system and thiR will serve RatiRfactorily until some difficulty caUReR one or more of the eontrollerR to get out of Rtep, The proper time relation between Rignal indicationR at the various loeations in the system must then he re-eRtahliRhed hy adjuRting, with the aid of a RtOP \vakh, the offRetR of those timers ,,'hich are out of Rtpp.
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If a master controller is used and connected to a circuit which runs to all signal controllers in the system, there can be a constant super~ vision of the time relation between successive signal indications, and timers can be requ4;ed to keep in step. Flashing signal operation can be obtained at any or all intersections, either by local time switch if noninterconnected or from the master controller if interconnected.
The simple progressive system is normally far more efficient than either the simultaneous or the alternate system but does not provide the full flexibility possible in a completely modern traffic signal system.
Flexible Progressive System
The flexible progressive system incorporates all the advantages of the simple progressive system and has a number of additional advantages. A common cycle length is used throughout, but Go intervals are scheduled independently to meet to the extent possible the demands of traffic for movement through the system as well as at individual intersections. Through the use of modern two- and three-dial equipment, timing adjustments to meet efficiently the widely varying needs of traffic at individual intersections and throughout the system are possible. Predetermined timing programs can be set up on the multi-dial controllers to favor rush-hour movements at appropriate periods during the day or week, midday or off-peak traffic demands, and other conditions requiring special timing schedules and cOOI'dination. Such refinements offer great advantages over the unchanging timing plans of earlier progressive signal systems. Careful measure of the demands of traffic and of the potential value of the flexibility features in the multi-dial systems should be made before acquiring control equipment for use in flexible progressive systems.
True flexibility is obtained by the interconnection of all controllers in the system with a master controller to permit not only the supervisory check of the coordination between signals but one or more of the following additional features:
1. Remote control of changes in offset relation between controllers to favor movement in one direction at certain times, such as for inbound and outbound peaks.
2. Remote control of changes in total time cycle or in interval timing, or both, to meet the varying requirements of traffic at various periods of the day.
3. Flashing signal operation at any or all intersections.
In general, a properly designed and operated flexible progressive system is the fixed-time system best adapted to the efficient movement of traffic. Its advantages include the following:
1. Continuous mOvement of entire groups of vehicles is possible with a minimum of delay and at an average speed planned for
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the system. This advantage can be realized on both the main and side streets. 2. A high degree of efficiency can be obtained by proportioning the intervals to fit the traffic requirements at each intersection. 3. Speeding is discouraged because a vehicle must make-frequent stops if it exceeds the speed for which the system is planned. 4. Differences in block lengths can be handled better than with other fixed-time systems.
Conditions Affecting Efficiency of Signal Systems
Certain conditions seriously reduce the efficiency of signal systems, even of the best flexible progressive systems. Among these are:
1. Very short street blocks (assuming signals at all intersections) especially where reasonably high speeds are possible (this particular condition does not affect the simultaneous system).
2. Narrow streets, where parking and loading interfere with free movement.
3. Traffic composed of units of widely differing speeds, such as streetcars, busses, trucks, and passenger automobiles, especiallyon narrow streets.
4. Certain types of complicated intersections, such as those requiring three or more Go intervals per cycle.
5. Heavy volumes of vehicles turning from or into the artery, especially if the block into which they turn is short or otherwise limited in capacity.
Nevertheless, some type of flexible progressive system generally gives the best results possible by fixed-time control under such street and traffic handicaps as cannot be removed or relieved.
When conditions along a given highway where it is desired to install a signal system are not particularly favorable to fixed-time flexible progressive control, consideration should be given to the possibilities offered by progressive traffic-actuated control or independent trafficactuated control.
Manual Control
At heavily traveled intersections operating under isolated control, manual operation of signals at certain times may be warranted by varying traffic requirements. The provision of apparatus to permit manual operation of signal installations in a flexible progressive system, however, is not generally rBcommended.
Experience has shown that if manual control features are available a tendency on the part of the police to operate certain intersections manually is apt to develop. This often destroys coordination at those intersections and through the system, with disadvantages generally more important than the possible improvement achieved by propor-
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:r tioning intervals manually. The presumption :,;hould be strongl
against ~anual control in coor~inat~d systems Ilnt~l the inability
automatIc control to meet the sItuatIOn at the partleular intersection is proved.
Speeds for Progressive Systems
The speed or speeds for which a flexible progres:,;ive :,;y:,;tem i:,; designed should accord reasonably with what speed studie:,; show would be the speed of vel;1icle movement if cross-traffic delays were eliminated. After drivers have become accustomed to a progressive system, it may be possible to increase the :,;peed with safety.
High speeds should be avoided, especially in bu:,;y urhan districts. Except in business districts, progressive systems along arteries are generally timed for speeds ranging from 20 to 30 miles per hour. In general, the more heavily used the artery, the narrower the roadway, the more built-up and busy the district, the shorter the blocks controlled, the more mixed the types of traffic, or the more pedestrians and cross-street traffic there are, the slower should be the design speeds.
Local authorities should be careful to avoid design speeds that will conflict with Stats laws governing speeds.
Signs Indicating Timed Speed Traffic Signal Speed signs should be erected to guide drivers operat-
ing under an a1t2rnate, simple progres:,;ive, or flexible progressive system. Where the system timing is different for various periods of the day, however, the resulting speeds may vary enough to make this posting of speed signs impractical. When such signs are used, they should be mounted on, or as near as pos:,;ible to, each :,;ignal where the timed speed changes, and at intervals of not more than two blocks throughout the system.
Coordination With Railroad Crossing Signals Traffic :,;ignals near railroad crossings shall be interconnected with
the flashing light or wigwag signals or gates at the railroad grade crossing and with all other traffic signals on the same street or intersecting street within 500 to 1,000 feet of the crossing to the extent necessary to prevent conflicts between rail and highway traffi(. The signals shall be so operated as to prohibit, to the maximum extent practicable, vehicles from entering the roadway bstween the railroad cl'Ossing and the intersection near the crossing as trains appl'Oach and travel thl'Ough the crossing area.
On the approach of a train, all signals which could permit vehicles to reach the crossing area without having another red indication before them shall, unless already showing red, go immediately to yellow and then to red. remaining red until the crossing is clear. At all other
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times, these signals should operate as standard flashing signals or a" Stop-and-Go signals, depPDding on the conditions \yarranting their installation. Rate of Flashing
When fixed-time signals are put on flashing operation, the rate of flashing shall he not less than 50 nor more than GO times per minute. The illuminated period of each flash shall be approximately equal to the nonilluminated period.
17,5

E-TRAFFIC-ACTUATED SIGNALS
Definition '~ A traffic-actuated signal is a type of traffic control signal in which
the intervals are varied in accordance with the demands of traffic as re!!;istered by the actuation of detectors or push buttons.
]. A semi-traffic-aetuated signal is a type of signal in which means are provided for traffic actuation on only some of the approaches to the interseetion.
2. A full traffic-aetuated signal is a type of signal in which means are provided for traffie actuation on all approaehes to the interseetion.
3. A speed control signal is a type of si!!;nal in whieh means are provided for traffic actuation on some or all approaches and which provides Go indications in sueh a manner that vehicle speeds on one street are limited to a preselected maximum value.
Warrants for Intersection Control
Because traffic-actuated signals at intersections do not normally delay traffic exeept when it needs to be delayed to avoid conflict with traffic on cross streets, it is not advisable to set values of minimum traffic volumes or other fixed warrants for their installation. There are, however, a number of factors that should be eonsidered and weighed before selecting and installing such signals. These factors are:
]. Vehicular volumes.-At intersections where the volume of vehicular traffic is not great enough to justify fixed-time signalization, traffic-actuated signals may be applied if other conditions are such as to indicate the need for Stop-and-Go signal control and if the cost of the installation can be justified by the conditions.
2. Cross traffic.-When the volume of traffic on a main street is so great as to restrict and jeopardize unduly the movement of vehicular cross traffic on a minor street, semi-traffic-actuated signals may be installed to provide assignment of right-of-\Yay to the cross street without seriously delaying traffic on the main street. Traffic-actuated signals are desirable at all s\lch signalized intersections, except in cases when they constitute a part of a coordinated or progressive system, thus warranting fixed-time control.
3. Peak-hour volumes.-When signal control is required at an intersection during only a small part of the day, such as during peak traffic hours, traffic-aetuated signals may be installed
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if economically justified, SUlce they will not unduly delay traffic at other times. .~. Pedestrians.-If the principal need for a traffic signal is to accommodate pedestrian traffic, traffic-actuated signals are usually desirable and may be economically justified. _ Most urban intersections with heavy pedestrian volumes also have heavy vehicular volumes and thereby warrant the usc of fixedtime signals. However, signals may be warranted at special locations, such as in the vicinity of schools, when pedestrian crossings are the primary consideration. In these special cases, traffic-actuated signals will delay vehicular movements only when the streets are in use by pedestrians. D. Accident hazard.-When a study of intersection conditions indicates that signalized control would be an effective remedy for the acddent hazard existing, but the minimum warrants established for installation of fixed-time signals are not met, a traffic-actuated signal installation may be justified.
6. Wide traffic fluctuations between streets.-When the preponderance in traffic varies from one street to another, at an intersection where one or more of the warrants for fixed-time signals is substantially fulfilled, full traffic-actuated control will usually provide the greatest efficiency in intersection operation.
7. Complicated intcrsections.-Traffic-actuated signals offer special advantages at complicated intersections with conditions substantially warranting signals, where multiple traffic phases are needed, in that they are capable of skipping phases when some of the streets are not being used. In each case, they use only the time aetually then required, thus providinll; a high degree of efficiency.
8. Unwarranted signals.-When traffic authorities are compelled to install traffic sill;nals at locations where they are needed for safe and efficient movement, traffic-actuated types should be employed. They cause a minimum of unnecessary delay and thus do not tend to break down public respect for traffic signal control.
.9. Progressive signal s,ljstems.-When the spacing or character of some intersections in a fixed-time progressive signal system is such that satisfactory progressive timing cannot be achieved, traffic-actuated control may be employed at those intersections.
10. Speed control.-If approach speeds present a particular hazard at intersections, in addition to normal intersection problems, full-actuated control employing speed control on the artery may be installed for best results.
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Warrants for Nonintersection Control
Special conditions at roadway locations other than intersections may warrant the installation of vaffic-actuated signals. Some of the factors that may justify such installations are:
1. Speed control.-Traffic-actuated signals may be used to Control speeds at the approaches to special roadway locations such as bridges, sharp curves, and entrances to towns. The; may be of especial value at school zones if speeds average higher than 35 miles per hour in rural or 25 miles per hour in urban areas.
2. One-way restricted zones.-At locations on two-way roadways where traffic can only move in one direction at a time, such as at narrow bridges and tunnels, traffic-actuated signals may be applied to assign the right-of-way and to provide clearance intervals in accord with traffic requirements.
3. M idblock pedestrian protection.-Pedestrian crossings concentrated at schools where intersections are a considerable distance apart, and at other midblock points, often justify use of pedestrian-actuated signals.
The installation of signals between intersections for the purposes indicated above should be accompanied by the erection of appropriate 8igns advising the motorist of this special application. Immediately 8ub8equent to installation, there should be a period of strict enforcement so that disrespect for signal indication8 will not develop.
Types of Traffic-Actuated Control, and Factors Governing Selection
As indicated earlier, traffic-actuated signal control" may be classified in two general categories: (1) Semi-traffic-actuated, and (2) full traffic-actuated. There are also several special types of applications for traffic-actuated equipment. The8e include: (1) coordinated control, (2) pedestrian-actuated control, (3) speed control, and (4) oneway restricted zone control. All these special applications make it essential that a thorough knowledge of the traffic and physical facts be obtained prior to selecting equipment for installation.
To aid those who have the problem of choosing the proper type of equipment for a particular job, the characteristics of the two general types of traffic-actuated control and the several special applications are presented below.
Semi-Traffic-Actuated Control
Semi-traffic-actuated control is applicable primarily to intersections of a heavy-volume or high-speed traffic artery with a relatively lightly traveled minor street. Detectors are located only on the minor street. The signal is normally green on the artery, changing to the minor street only as a result of vehicle or pedestrian actuation. In some
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types of controls the minor street green interval is of fixed duration, but in the more flexible types the duration of the minor street green interval is proportioned to the traffic demand thereon, with provision for a maximum limit beyond which the green light may not be retained on the minor street even when traffic demands thereon is heavy. IIpon the expiration of the required, or maximum, minor street interval, the Go signal will revert automatically to the artery where it must remain for at least a predetermined minimum interval. At the expiration of this minimum interval the control is again free to respond at once to minor street actuation.
Full Traffic-Actuated Control
Since semi- or part traffic-actuated control does not measure the demands of certain traffic streams, it cannot attain the efficiency of full traffie actuation. Therefore, full traffic-actuated control should be selected for intersections where failure to take into account certain traffie demands will seriously affect the efficiency of control. In full traffic-aetuated control, deteetors are installed on all approaches to the intersection and right-of-way is assigned to a street only as a result of actuation thereon. When there is no traffie on either street, the green indication will ordinarily remain upon the street to which it was hst assigned. The duration of the green interval on any street is dependent upon the traffic demand on that street, subject to a maximum time limit in the event of a continued demand and the presence of traffic on the other street. In the event of eontinued actuation, transfer of right-of-way will be made to waiting eross traffic after a predetermined maximum period, and in this ease, right-of-way will automatically be returned to the first street at the earliest opportunity without the necessity of further actuation.
Full traffic-aetuated control can be applied to more than two-phase operations. Equipment is available for three- and four-phase intersections. Operation of eontrollers at such interseetions is similar in principle to operation at two-phase intersections. Opportunity for the right-of-way is accorded to the several phases in rotation and phases for which there is no traffic demand are skipped. In three- or four-phase eontrols, provision ean be made for allowing additional noninterfering traffic flows to move during more than one phase. Thus, a three-phase eontrol may handle four or five flows. provided only three of them are eommonly interfering.
A recently developed form of full traffic-actuated controller operates upon a "VOlume-density" basis, many of its circuits being subjeet to automatic and continuous adjustment with respect to variations in volume, relative densities on the two opposing traffic phases, elapsed time between actuation and assignment of right-of-way, and other factors. As this form of control is essentially "platoon respon-
17B

sive," it is capable of facilitating progressive platoon movements. This is discussed in the following section on coordinated control.
Coordinated Control
There are three principal applications of traffic-actuated equipment in coordinated operation of a series of related signalized intersections. These are characterized by the features described in the following paragraphs:
Supervisory background cycle.-In one type, a supervisory background cycle is imposed upon a series of semi-traffic-actuated controls. this being accomplished by a master timer sending out impulses over interconnecting wires to each semi-actuated controller, or by local syn('hronous motor control at each intersection.
The l:ackground cyele is set up in the same manner as for fixed-time ('ontrol, a time-space chart being worked out for the series of intersections that will give the maximum travel band through the area. The fmwtion of the supervisory cyele is to assure that the local semiactuated controllers provide at least the minimum of Go time, and in the time relation called for in the time-space chart. In addition to this minimum Go time, each semi-actuated controller adds to its artery Go interval all time not required by traffic-actuated demand on the minor street, thereby providing the widest possible travel band. One possible disadvantage is that such an extended Go interval may seriously overload a subsequent intersection at which cross-traffi(' requirements are greater.
It is also apparent that the above type of operation does not provide the speed control characteristics of a fixed-time progressive system, and hence should be used only where the consideration of moving maximum amounts of traffic with the least delay outweighs thc desirability of speed limitations.
V olvme density control.-Another form of coordinated traffic-actuated ('(mtrol is accomplished by the use of full-actuated controllers of the so-called volume-density type. This type of control operates so that no background cyele or interconnection is used. The controller is capable of responding to the natural platoon movement of traffic. The impulses from an advancing platoon of cars are received by the controller and tend to produce a foreing effeet in seetHing a Go interval for the\group of vehieles, this tendency being increased by a carryover effect impressed upon the control mechanism by the passage of the previous platoon. Increased spacing of vehicles at the end of the platoon is sensed by the eontroller and utilized to terminate the movement. It is thus possible for platoon movements to affect a series of traffic-actuated intersections of this type in such a way as to set up a pattern of progressive movement based on natural speeds and Rpacmgs.
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Special use in a flexible progressive system.-A further application of traffic actuation in the field of coordinated movement occurs in a fixed-time flexible progressive system where intersection spacing at one or more points in the system may be such that the best possible progressive timing arrangement involves considerable ~eduction or displacement in the progressive Go band. Multiple intersections in a progressive system may also cause difficulties in the time-space chart. In these instances, full traffic-actuated control may sometimes be effectively employed to bridge the gap.
Pedestrian-Actuated Control
Operation of both the semi- and full traffic-actuated controls, as well as certain types of fixed-time controls, can be accomplished by pedestrian push buttons. Such actuation may affect movements in any of the following ways:
1. Pedestrian actuations are handled on the same basis as vehicle actuations. No special signal indications are shown for pedestrians.
2. Pedestrian indications (WALK, WAIT, or equivalent) are shown in parallel with the vehicle indications. The most desirable types of such controls provide for a termination of the Walk indication sufficiently in advance of the expiration of the vehicle interval to permit persons who have left the curb to complete the crossing of the street without vehicular interference.
3. An exclusive pedestrian interval, normally justified only under conditions of low vehicle volume at high speeds and heavy pedestrian movement, is inserted in the signal cycle and during this interval all vehicle traffic is stopped.
4. In the case of pedestrian-actuated signals that normally operate in conjunction with fixed-time intersection signals and which have the pedestrian interval introduced into the cycle upon actuation of the push button, the pedestrian interval can either be taken from one of the vehicular traffic greenlight periods or be added to the cycle without decreasing either of the green periods. During flashing operation of signals at night, actuation of the push button changes the flashing signals to give a steady red Stop indication to the major traffic flow crossed by pedestrians, with or without a special Walk signal.
Equipment is also available for the protection of pedestrian cross walks at midblock locations, schools, and similar locations. With this form of control the green signal shows normally to traffic on the thoroughfare, right-of-way being accorded to the cross walk upon push-button actuation. After providing an interval for pedestrian
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movement, these signals automatically return the right-of-way to Ve-

hicular traffic, and give a predetermined and adjustable minimum in-

terval to this traffic before the pedestrian indication can again be

obtained.

';I"

Speed Control
Speed control can be applied at nonintersection locations and abo at full traffic-actuated controlled intersections.
N oninlersection speed control.~An adaptation of the traffic-actuation principle affords a means of controlling the speeds of vehides at nonintersection locations such as curves, bridges, and school zones. The component parts of the system are a speed controller, a vehicle detector, and a traffic signal. The signal indication is normaJly red or Stop. Detector actuation at a point in advance of the signal initiates the timing of a delay interval after which the signal is changed to a green or Go indication in time to permit the passage of a vehicle traveling at or below the maximum allowable speed (i. e., covering the distance between detector and signal in not less than the timed in terval). A vehicle traveling at too great a speed will arrive at the Stop line before the signal changes from Stop to Go and hence will be required to stop. Succeeding vehicles, if closely enough spaced, will extend the Go indication, but when the maximum spacing is exceeded the red indication is at once shown and speed control again becomes effective.
This type of control should always be identified with appropriate signs so that the motorist will recognize and understand the function of the signal. For the same reason, some additional enforcement may also be desirable for a period immediately after the installation is made.
Intersection speed conlrol.~At interseetion locations where speeds OIl the artery approach present a particular hazard in addition to til(' normal problems of intersection control, it may be desirable to employ full traffic-actuated control incorporating speed-control featllJ'('~ on the artery.
All signals normally show red in the absence of approaching traffic. A single vehicle approaching the intersection on the main street and (:rossing the detector will receive the green indication at the end of a vehide approach period. If the vehicle is traveling at or below the' speed designated as safe for the location, the green indieation will come on in time to allow passage through the intersection without delay. If, on the other hand, the approaching vehicle is coming too fast, it will have to slow down or stop before the green indication will be displayed.
A ear following close enough so that it crosses the detector before the green indication period for the first car expires will extend the

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given period, thuH allowing itself time to paSH the intersection. A platoon of ears can all proceed through the intersection, hy this extension feature, without interruption. The speed control inherent in this latter ease lies in the fad that the first ear of the platoon is monitored for speed as it approaches the intersection. Should a hreak _occur in the line of ears long enough so that the speed of the next ear will not be so controlled the signal will have returned to red. This ear upon crossing the detector will institute a new vehiele approaching period and thus monitor its own speed.
The vehicles approaching the signal on the main street from one direction and obtaining the green indication do not cause the same indication to be displayed toward the other direction on the main street. Signals facing in the opposite direetion on the main street remain red in order to have a speed-monitoring effect on traffic which may approach from that direction.
When the signal is not to tranHfer the right-of-way to the cross street, the main-street indication changes directly from green to red in order to give immediate speed-monitoring effect for other approaching vehicles. This is a satisfactory procedure inasmuch as had the next following ear been close enough to get into trouble it would have heen close enough to extend the green light period.
If cross traffic is waiting and traffic is moving through the interHection in one direction on the main street, a driver approaching the signal from the other direction on the main street will not receive a green indication unless there is time for him to go through the interseetion before right-of-way is transferred to the cross street. If there is not sufficient time hefore the right-of-way transfer is made, the green light will be returned to the waiting driver on the main street after the cross-street traffic has passed. On the cross street the display of the red signal is always preeeded by a yellow signal as in normal signal operation.
A clearance interval is alwayH provided for the main street when the green signal is to be given to the cross street. If there are ears on the main street between the detector and the intersection that must be stopped a yellow Hignal is displayed to them during this period. Otherwise the elearance period is all red.
A maximum period limits the time that moving traffic on either street can maintain its right-of-way against waiting cross traffic.
One-Way Restricted Zone Control
Full traffic-aetuated control equipment iH available for use at a narrow passage, such as a bridge or tunnel, which is not wide enough to allow traffie to flow in opposite directions simultaneously. This control operates essentially as a full traffic-actuated two-phase control, each approach being one phase. \yith an all-red clearance period added
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to the normal cycle. Traffic moves in one direction on one phase and in the opposite direction on the other phase. Between these movements the all-red interval provides time for clearance of such traffic as may be in the restricted area.
,'#'
Detectors and Controllers
Since the traffic-actuated signal, as its name implies, responds to vehicle or pedestrian actuations by providing Go indications for the appropriate movements, it is necessary that detector and controller equipment be designed for this service. In this respect, traffic-actuated signals differ considerably from fixed-time signals, which require no detector units and a somewhat simpler timing mechanism for their control. The design characteristics of the various types of detectors and controls that have been developed for use with traffic-actuated equipment are described below.
Types of Detectors
A wide variety of detectors can be used with traffic-actuated sIgnals. These are classified as follows:
1. Pressure-sensitive detectors. 2. Magnetic detectors. 3. Sound-sensitive detectors. 4. Light-sensitive detectors. 5. Pedestrian push-button detectors. Some of these offer special advantages for particular physical and traffic conditions, and the type of detector should therefore be selected with care. To aid in this selection, the characteristics of the several types are outlined below.
Pressure-Sensitive Detectors
Pressure-sensitive vehicle detectors are of two general types. The most common type is actuated when crossed by vehicles traveling in any direction. In the other type, used principally on narrow twoway roadways, actuation occurs only when the detector is contacted by vehicles traveling in one direction. A brief explanation of the two types follows:
N ondirectional detectors.-Detectors of the nondirectional type operate on the open-circuit principle, with electrical contact established only at the moment that vehicle wheels pass over the rubber surface.
Directional detectors.-With directional type detectors, vehicle impulses are passed into the signal controller from traffic in one dirc('tion only, impulses being rejected from traffic moving in the opposite direction. While similar in appearance to nondirectional detectors, the directional type contains two separate sets of electrical contacts, rather than one.
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Magnetic Detectors Magnetic detectors are available in two general types: (l) non-
compensated, which have a wide zone of influence; and (2) compensated, which have a sharply defined zone of influence. They are not rendered inoperative or continuously operative by parked cani or_ hy other fixed metal objects within their zone of influenee.
N oncompensated detectors.-K oneompensated magnetie detectors are mounted in or under the road\yay surface and are usually (~apahle of providing a road coverage up to about 15 feet on either side of the detector. They are not reeommended for use at locations suhject to severe and fluctuating electromagnetic influenees sueh as arc caused by streetcars and trolley busses.
Compensated detectors;-Deteetors of the compensated magnetic type involve two magnetic ~iremits and are so designed that their operation is not affected by extraneous electromagnetic influences. They are characterized by a relatively sharp definition of their zone of influence, usually extending only about 6 inches beyond each end of the detector. A further eharacteristic of the best deteetors of this type is that they are capable of a high degree of directional discrimination and can, therefore, be used to detect vehicles by lanes of travel.
Sound-Sensitive Detectors Detectors of this type consist of a hollow metal chamber with a
steel top plate and are actuated by sound waves set up in the chamber by the passage of a vehicle wheel over the top plate. These detectors are not affected by ordinary external noises not associated \\'ith the passage of wheels over their surface. They are not directional.
Light-Sensitive Detectors The passage of a vchide can be detected by the interruption of a
beam, or beams, of light between a light source and a photoelectric cell or cells. Sequential interruption of two beams of light can be utilized to provide directional detection.
Pedestrian Push-Button Detectors In addition to detectors for registering the demand of vehides ap-
proaching an intersection, it is in many instances desirable that means be provided for registering pedestrian traffic demand. Pedestrian push buttons arc used for this purpose and are properly regarded as a form of detector. In order to be suitable for traffic-actuation purposes, a push button must be designed to withstand rigorous service.
Types of Controllers Because traffic conditions are subject to wide variation, it is neces-
sary that traffic-actuated controllers have sufficient flexibility of op-
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eration to meet all normal conditions and as many others as possible.

Ready adjustments of various time intervals over wide ranges should

be possible.

,~

In traffic-actuated controls, Go signal intervals for the approaches with actuation have an initial portion, to permit standing traffic to get into motion, \vhich is followed by one or more unit extensions, the number and duration of which are determined by the traffic itself within the timing limitations pre-set on the controller. A maximu~ period protects waiting cross traffic against undue delay in the event that traffic on the other street is very heavy. Clearanee intervals are provided at the end of the Go interval.

In semi-traffic-actuated eontrol, the Go interval is normally accorded to the main street, being called to the cross street upon actuation by cross-street traffic. The cross street has an initial portion, which may be followed by an extension portion if cross-street traffic requires. The main street, not having actuation, has only one predetermined period, namely, the minimum period. At the end of this minimum period the Go indication can again be transferred to the cross street in response to actuation. The main-street minimum period should therefore be set at a value to take care of the expected normal main-street traffic.

All these portions, intervals, and periods should be readily adjustable by suitable knobs, pins, or dials which will require the use of no tools. The limits between which they should be adjustable for the various types of eontrol are presented below.

The ranges of timing adjustment shown are desirable, but in actual operation the adjustment of Go intervals within the range provided should always be made with a view toward safeguarding pedestrian movements. as well as to facilitate vehicle traffic.

Two-Movement, Semi-Traffic-Actuated Controller with Time Extension

For this type of control the interval timing should be adjustahle within the following limits:

Main-street minimum pcriod_ _

Clearance intervals

_

Cross-street initial portion_

Cross-street extension limit-

Cross-street maximum period

8eCOlld8
10-90 2-10 2-12 2-12 10-60

Two or More Movements, Full or Semi-Traffic-Actuated Controller with Time Extension
The various intervals in two-, three-, or four-phase controls, in

186

phases susceptible to extension by traffic actuation, should he ad-

justable between the following limits:

Seconds

Maximum period .

10-60

Initial portion _

2-30

Extension limiL __ .

2-30

Clearance intervaL _.

1-10

Phases not having extension by traffic actuation should have minimum green signal intervals adjustable between 10 and 90 seconds on the main streets and between 10 and 60 seconds on minor streets.

Traffic-Actuated Speed Control for Nonintersection Locations
N onintersectional speed controls such as may be used on a curve or at a school zone, narrow underpass, or other roadway hazard should have intervals adjustable between the following limits:

Vehicle approach period Extension limit. . Vehicle indicator period

. _

Seconds 1-10 1-10
3-30

Two-Movement, Full or Semi-Traffic-Actuated Controller With Speed Control

This is the type of controller used at intersections of two streets where excessive speed on one of the streets is an important factor. The various intervals should be adjustable between the following

limits:

Maximum period_ Initial portion _ All extension limits_ . All clearance intervals All vehicle approach periods.

Seconds 10-60
2-30 1-10 1-10 1-10

Two-Movement, Full Traffic-Actuated Controller With Automatic Adjustments of Periods With Respect to Traffic Volume, Relative Density, and Elapsed Time

In this type of control the various intervalH and actuations should

he adjustable between the following limits:

Minimum initial portion __

seconds_

5-60

Increase of initial portion per car. __

do _

0.1-2

N umber of cars before minimum initial por-

tion starts to increase __

cars

i)-50

Passage period_ .

seconds.

Minimum time to which extension limit can

he reduced. _

do

1-10

1~7

Waiting time to reduce extension limit to

mInImUm

--_ _

_ seconds_ - - 10-90

N umber of waiting cars to reduce extension

limit to minimulJ).

. __. ________ ___ ears

;")-40

Density of traffic into green signal (number

of cars per 10 seconds to reduce extension

limit to minimum)

.

_ cars

;")-40

Clearance intervaL Maximum period

- _. .

_ seconds _ do

_ 1-10 10-90

Carry-over effecL - - __ ___ - - - - -

_ percent

_ 10-90

Two-Phase, Full Traffic-Actuated Control for One-Way Restricted Zone
With this control the initial portions, extensions, and usual yellow clearanee intervals, as well as the maximum intervals, should be timed in accordance with the usual procedure given heretofore. In addition, the all-red clearance interval, during which traffie that has entered the restricted area during the display of the Go signal is allowed to dear, should be adjustable between the limits of 10 and 70 seconds.

Additional Flexibility for Controllers Used in Coordinated Systems
Where a series of interseetions along a main street equipped with traffic-actuated control, using aetuation on the cross streets only, are to be coordinated, the equipment may be such that the time at whieh each control can respond to a cross-street actuation is determined by a master timer, or by a local synchronous motor timer.

Provision for Manual Operation
Manual operation of traffic-actuated signals is not generally reeommended. The wide flexibility of operation they afford is usually adequate to eare for varying traffic demands. However, where traffic conditions are so variable as to make normal operation of the signals inefficient and undesirable at certain times, switches for manual operation of the controller may be provided. Such switehes should not be aceessible to police officers who are not especially trained and experienced in the direction and control of traffic at intersections.
When the control is being operated manually, actuation of the manual control push button causes the signals to change their indications to those normally displayed in the next interval. Signal display will then remain unchanged until the manual control push button is again actuated.

Installation of Traffic-Actuated Signals
The installation of signal heads, controllers, and certain other elements of traffic-actuated signals involves the same considerations as those described in Fixed Time Signal Head Locations, applicable to

188

all signals. Details of the location and installation of vehicle detectors, however, deserve special explanation because of their importance to the efficient and reliable operation of traffic-actuated signal equipment.

Distance of Vehicle Detectors From Stop Line

The proper location for vehicle detectors in relation to the Stop line depends upon the type and operating characteristics of the controller, the speed of vehicles approaching the intersection, physical characteristics of the roadway (grades, widths, parking, visibility, etc.), and special signal functions (turns on separate intervals, stopping sideroad traffic before entrance to high-speed artery, etc.). With conventional full and semi-traffic-actuated controller equipment used under average conditions-i. e., level roadway, not more than two traffie lanes in each direction, and good visibility-good results have been obtained when the distance from the Stop line to the detector is related to the speed of approaching vehicles as follows:

Speed (miles per hour):

Less than 20 _

20-30 _

30-40 ___ _ _ _ __

40-.50 __ . _

Over 50

_

Distance from stop line (feet) 110 140 170 210

When the approach to the intersection is on a grade, the distance from the Stop line should be increased about 4 percent for each 1percent down grade and decreased about 4 percent for each I-percent up grade. Where there are more than two lanes approachin?; the interseetion, and visibility is not restricted, it has often been found desirable to increase the above distances by small amounts, since higher speeds through the intersections usually can be allowed with safety. The increased distances in such cases may be as much as ]5 percent ?;reater than the average values given above. Under no eondition should detectors be located less than 40 feet from the Stop line. Where they are installed to permit left-turn movements on a separate si?;nal interval, detectors are usually placed mueh closer to the interseetion than for the control of normal traffic. 'Where a minor road interseets a high-speed route, it may be desirable to foree most ears on the side road to stop before enterin?; or erossin?; the artery. In sueh eases, the spacing of detectors should be shortened on the side street so that most ears will arrive at the Stop line on a red signal.
Bus stops, filling-stations' drives, and other special eonditions near an intersection may necessitate the installation of a second deteetor

189

very near the Stop line. Such installations would in no way interfere

with the spacing of the initial detectors of the street so affeeted.

Speed-control signals nonpally require longer spacings between de-

tectors and Stop lines, so that desired speed reductions can be achieved

gradually and stops required only in rases of abnormally high speeds,

or at intersertions when right-of-way has been assigned to the (TOss

street. For normal road\vay and traffir conditions, \vhen speed-rontrol

features are provided, the recommended distance from the Stop line

to the detertor as related to the speed of approaching vehides is as

1'ollo\vs:

Distancc frO/ll

stop til/!

Speed (miles per hour) :

(.feel)

20-30.

HlO

30-40.

220

40-50.

2G;j

50-GO

:32;)

Over GO

:350

These values Hhould also be inneased or decreased, as explained

previously, to arcord with roadway grades, visibility, and special traffie

ronditions. vVhere speed control is applied at an interHection, the

above values should be used in locating deteetors on the artery awl

those previously given for standing traffic-actuated control should be

used in lorating the detectors on the side road.

Detectors for \lse with t\vo-movemcnt. full traffic-actuated eOll-

trollers with automatic adjustment of periods with respect to traffic

volume, relative density, and elapsed time should be located farther

from the Stop line than would \w the case with other types of traffic-

actuated (ontrol. This enables the control to recognize the presene('

of platoons of ears and in general to get the complete data on traffic'

conditions neeessary to regulate its refinements of control. For nor-

mal roadway and traffic ronditions, the recommended distance from

t he Stop line to the detector ai' related to the speed of approaching

\'('hie1es is as fo11O\\'s:

INstance frolll

stop linc

Spepd (mil('s per hO~lr) :

(feet)

20-30

240

:30-40

270

40-50

:320

Over 50

:3/;)

For special roadway conditions these values may be changed a" recommended for other types of installations discussed above. 'Where t he greatest coordination effeet is desired between a i'erie" of inter-

\ \10

I
sections, the detector spacings on the street on which through moyement is desired should be increased about 20 percent.
Location of Vehicle Detectors From Center Line
Pressure-sensitive and sound-sensitive detectors should be placed transversely in the roadway so that all vehicles approaching the intersection cross them with one or more wheels. No vehicle moving away from the intersection should normally cross the detector. When physical conditions are such that more than an occasional car leaving the intersection crosses the detector, a directional detector should be installed so that this traffic will not actuate the controller unnecessarily.
The end of the pressure-sensitive detector nearest the center line of the road should usually be placed about 3 feet therefrom. If the approach side of the road requires more than one detector to cover it satisfactorily, the detectors should be spaced so that the end of the rubber surface of one will be 4 feet from the next. This will insure that no car can pass between the detectors without causing an actuation.
In the case of pressure-sensitive detectors, consideration must be given to parked vehicles. In areas where curb parking is allowed, detectors should never be located so that a properly parked car can stand with a wheel on the detector. On one-way streets, the entire roadway should be given detector coverage, except as spaces may be necessary from each curb for parking.
The compensated type of magnetic detector should be buried in the road with the end nearest the center line approximately 4 feet therefrom. If additional compensated magnetic detectors are required to cover the distance to the curb, they should be spaced so that their ends will be about 4 feet apart. The compensated magnetic detector has a rather sharp cut-off and, in general, a vehicle must pass either over it or within 6 inches of its end to cam,e an actuation.
The noncompensated type of magnetic detector does not have as sharp a cut-off as the compensated type. Its zone of influence is not so clearly defined. It should, therefore, be located under the path traveled by the right wheels of a car traveling in the center of the lane to be covered. A noncompensated magnetic detector can usually be adjusted to cover about 25 feet of roadway. In special cases noncompensated magnetic detectors may be located in or on the shoulder of the roadway.
Light-sensitive detectors, employing photoelectric cells and light beams across the roadway, are normally used only at special locations such as bridges and tunnels. They must be mounted so as to deteet the approach of vehicles by having the light beam interrupted by the passing cars. The beams may he in either a vertical or horizontal plane, but if mounted in the open, consideration must be given to
Hll

Hnow and ice conditions if the beam iH uHed in a vertical plane. Parked carH would seriously handicap their use in many places.
Installation of Pedestrian Detectors Pedestrian detectors or 'push buttons are available for mountinl!; on
either wood or steel poles. They should be conveniently located near each end of eross walkH used by pedestrians at the roadway location
controlled by the signal. The detector should be 3Y2 to 4 feet above
the sidewalk and in view of persons usinll; the cross walks. Penmmenttype sill;ns should be mounted just above the detectors, explaininl!; their purpose and use.
When pedestrian detectors are provided for special purposes, such at; at school crossingH, and are to be used only by authorized persons, lock s\yitches should be installed so that the detectors can be operated only by persons with keys. Such detectors are not intended for the use of the general public and the supplemental signs are not necessary.
Installation of Streetcar Detectors \Vhen streetearH operate on streets where traffic-actuated sil!;nal
equipment is installed, it is necessary to provide special devices to detect the approach of the streetcars. This distance of detectors from the Stop line is usually determined in the same manner as that for vehide detectors. However, when streetcar stops or other conditions make it necessary, the spacing between the streetcar detectors and the Stop line may be shortened, or a second detector may be provided on each approach to the sill;nal.
Operation and Adjustment of Traffic-Actuated Signals ,\s with all types of signals, it is necessary that appropriate ()quip-
ment be installed to meet the normal traffic requirements of a givpn roadway location. Assuming the availability of the proper equipment, it is still necessary to adjust and operate the equipment as nearly in accordance with the needs of vehicular and pedestrian traffic as is possible.
Continuous Operation Traffic-actuated signals of all types should be operated at all times
as Stop-and-Go devices except: 1. As a caution signal (flashing yellow) when interconneeted ,,-ith other signals and/or remotely controlled for emergency vchides such as fire trucks; or 2. As a caution signal, or as a combination caution and Stop signal (flashing yellow on certain approaches and flashing red on others) when failure of controller, wiring, or signal lamps prevents normal operation.
192

~inee (raffie-actuated signals, properly timed, eause a mllllmum of unneeessary delays, there is no justifieation for changing them to flashing operation during light traffic periods. Right-of-way is normally denied approaching motorists only when intersecting streets are m use by others or when safe approaeh speeds are exeeeded.
Time Intervals and Adjustments
In order to obtain the greatest efficiency from traffie-aetuated equipment, the correet setting for the various time intervals must be determined. This often requires some trial and experimentation after the installation has been made. The following explanation is intended as a guide for those not thoroughly aequainted with the general prineiples and terminology associated with the operation of traffic-actuated equipment.
In general, it will be desirable for a person not familiar with sueh time intervals and adjustments to seeure the advice of an experienced representative of the company that manufactures the equipment or of some other well-informed person, until the desired settings and adjustments are well understood. It should be added that these settings and adjustments sound more eomplicated than they are found to be with experienee.
The minimum Go signal interval on a street having traffie-actuated control with time extension includes an initial portion followed by a unit extension. If there is a line of ears crossing the detector after the initial portion has expired, eaeh ear erossing the detector will eaneel the unexpired remainder of the previous unit extension and initiate a new unit extension. Thus ten car8 sueeessively extending the Go period will no( nece8sarily cause the Go signal to remain on that street for ten times as long as one ear would. The Go 8ignal will be transferred to the cross street, if there is waiting traffie thereon. following the expiration of the last unit extension.
From the foregoing explanation it ean be seen that the unit extension represents the time spacing between cars approaching the green light in excess of whieh it is desired that the right-of-way be yielded to wai ting eross traffic.
Sinee traffie-actuated equipment eontrols permit considerable flexibility in the selection of the Go period, extreme care must be used to safeguard pedestrian movements by provision of a minimum length of Go interval which will accommodate the slower pedestrians.
The various settings and adjustments necessary for operation of traffic-actuated eontrols are as follows:
Initial portion.-Thc initial portion should be adjusted to a time which, added to a unit extension, will permit a solid line of cars between the detector and the Stop line to rlear the intersection.
193

Unit extension.-The unit extension should be set so that a car which has actuated the detector, if it is traveling at a speed normal for the street, will clear the intersection before losing the right-of-way .
.LvIaximum period.-Tbe maximum period is brought into play only when continuous traffic prevails and cross traffic waits. The point to be considered in setting it is that, when traffic becomes very heavy on both streets, the signal operates, in effect, as a fixed-time signal, and the maximum period determines the proportion of time to be allotted to each street.
Clearance interval.-The elearance interval is set at a value that will permit moving traffic to come safely to a halt when a Stop signal is displayed.
Vehicle approach interval (speed control oj the nonintersectional type).This interval should be set at such a value that a car moving at a speed considered safe for the location will receive the Go signal in time to permit continuing at that rate of speed. Cars approaching at a greater speed will be forced to reduce their speed before proceeding.
Vehicle approach interval and unit extension (speed control with intersectional control).-The vehicle approach interval and the unit extension should be set in accordance with the foregoing suggestions. The maximum period on the main street should be set in accordance with the suggestions previously given for adjustment of the maximum period. Cross-traffic periods (not speed monitoring) should 1)(' adjusted as in any traffic-actuated control with time extension.
Interval adj1lstments for volume-density controllers.-The minimum initial portion should be set at a value that will permit a few cars to pass through the intersection before its expiration. A larger number of vehicles will need more time than this minimum initial portion and 8ince the detectors are far enough away from the intersection so that a large number of vehicles can be between the detector and the inter8ection, provision must be made for lengthening the initial portion. The number of cars that can pass the detector before the minimum initial portion starts to increase should be the number that can move into the intersection during the minimum initial portion. Each car above this number will cause additional time to be added to the minimum initial portion. The amount of time added by each car is called "increase of initial portion per car" and should be set at such a value that, under heavy traffic conditions, waiting cars will clear the intersection before the expiration of the minimum initial portion plus thc increase thereof. Streetcar and bus actuations are sometimes weighted 80 as to affect the controller in the same manner as would several passenger automobiles.
The passage time 8hould be set at a value that will permit a ('ar crossing the detector on the green indication to elear the intersection
194

before the expiration of that green indication if the vehicle is moving at a reasonable speed. This can be set long, because if traffie conditions are such that this long period should not be granted, a shorter period determined by requirements of traffic will automatically be substituted therefor.
In this type of control the timing is responsive to several traffic conditions, including the following:
1. Number of cars waiting on cross street.
2. Time that cross traffic has been \Yaiting.
3. Time spacing of vehicles on street with Go signal.
As the number of cars waiting at the red indication increases, the duration of the unit extension on the street having the Go signal is simultaneously decteased, thus requiring denser traffic in order to hold the Go signal thereon. As the numher of cars waiting at the red light increases, the extendible portion on the other street is reduced until the low limit sct on the controller is reached. The time to which tlw extendihle portion can he reduced, as well as the number of cars waiting against the red light required to cause such reduction. call be adjusted independently for each street. Thu." the control ('Ollstantly balances the numher of cars waiting 011 the Stop signal against the density of the traffic moving into the Go signal in allocating the rightof-way. A platoon of cars erossing the detector on the main street can reduce the extendible portion of the Go interval on the noss street so markedly that it \\'ill secure preferential treatment and pa"s through the interseetion without delay.
The controller also keeps traek of the time "pacing het\n~ell ('an; approaching the Go signal and if ('ro"s traffic is waiting gives the rio signal to the other street "'hen some preseleeted amount of straggling occurs. If the pattern of approaching traffie gives an average spacing between cars of 1 second, the unit extension time on that street i" automatically set slightly in execs" of 1 second. When the main bod~' of the platoon of ears has passed and ears begin to approach at intervals considerably greater than 1 second (in other words, to straggle), the right-of-way will be transferred to the cross street, if traffic is \vai ting there. If the average time "pacing of cars approaching the Go signal is 2 or 3 seconds, the control \\ill automatically set thp unit extension at slightly greater than 2 or 3 s('('.onds, again operating to transfer the right-of-way when straggling oeems if there is waiting eross traffic. This effect is adjustahle on two dials. One of these sets the minimum time to which the extension limit can be redueed by the rate of traffic flow, and the other sets the rate of traffie flO'v \\hich will reduce the extension period to the set low level. Lntil the low level j" reached, the more frequent the approaching traffic on the Go signal, the shorter the extendible' portion for that indication will be'come.

The features described above work together to recognize both the approach and clearance of a platoon of vehicles and to operate the signals so as to facilitate these movements.
Intervals for one-way restiicted zone controls.-The timing of the initial portion, the unit extension, and yellow clearance interval is the same for a one-way restricted zone signal control as in any trafficactuated signal having extendible portions. The all-red clearance interval should be set at a value that will permit a car which has crossed the detector to elear the restricted area before the Go signal is given in the opposite direction.
Interval Sequence
Traffic-actuated intersection controllers should provide time intervals for any desired combination of signal indications. The sequence of intervals for each traffic phase should be fixed so that the various intervals will always appear in order when the signal indications on that phase are changed.
Equipment for standard traffic-actuated control (speed control excluded) at intersections should provide any of the standard color sequences. Sequences are limited by the number of intervals available in the controller and the wiring of the controller to the signal heads, so that they are fixed except as they can be changed hy rewiring or, of course, by the replacement of the controller.
Interval sequence for traffic-actuated speed control signals can he varied for the application. Typical sequences provide for a normal red indication which changes to green, yellow, or flashing yellow after termination of a vehicle approach period. After the expiration of an extension period, or periods, the signal indication automatically returns to red.
Speed control with traffic actuation at a two-movement intersection causes the signal to operate as a modified three-phase signal. Two of the phases correspond to the two approaches of the speed-controlled street and these may, of course, operate in unison. The third phase handles the cross street.
Controllers actuated by pedestrian detectors may provide distinct pedestrian intervals, with WALK and WAIT indications, as a part' of the signal sequence, or they may simply provide a green indication for the street being used by the pedestrian in the same manner as would actuation by an automobile of a vehicle detector on that street.
Rotation of Phases
The rotation of intervals with traffic actuation is determined by demands of vehicles and pedestrians. With simple two-phase operation, the various color sequences are provided in fixed order as the controller responds to the actuation on the two streets. While the se-
196

quence of intervals is always the same, the duration of intervals is governed by traffic demands.
With three- or four-phase operation, intervals for each phase will be initiated only when the demand exists, and the duration of intervals is governed by traffic demand. If there is no demand for one -of the phases, that phase is omitted in the rotation of phases.
1m

F-SPECIAL PEDESTRIAN SIGNALS
Definition Special pedestrian signal~are highway traffic signals erected for the
exclusive purpose of directing the pedestrian to take some slwcifi(. adion.
Warrants
Special pedestrian signals should be installed in conjunction ,,'j til traffic signals already meeting one or more of the minimum warrantii previously set forth in the sections on fixed-time or traffic-aetuated signals, under the following conditions:
1. When pedestrians and vehicles move during the same phaiie and the pedestrian volume crossing the major street averages at least .500 persons per hour for any 8 hours of an average day; or
2. When a separate phase is provided for pedestrian movement in all directions (as at a T intersection or traffic cirde). all vehicles being stopped; or
:3. 'Vhen heavy vehieular turning movements require a separa Ie pedestrian indication for the protection and convenien(~e of the pedestrian desiring to cross the street; or
4. 'Vhen pedestrian movement on one side of an intersection iii permissible while through vehicular traffic is stopped to protect a turning movement on the other side of the intersedioll; or
5. When a separate phase is made available for pedestrians in til(' operating cycle of a traffic-actuated signal; or
6. When a traffic signal is installed solely for the benefit of pedeiitrians, as at a fadory entrance or a school crossing, even though the volume in warrant Xo. 1, above, is not equalled or exceeded.
Special pedestrian signals should not ordinarily be installed at school crossings where schoolboy patrols can be used effectively or where students can be directed to cross at 10('ations already controlled by signals or police officers. However, they may be warranted at an intersection used as a school <Tossing under the following condition:
'Vhen minimum vehicular volume entering an urban interseetion from all directions averages 600 or more vehides per hour for the opening and dosing hours of school, and minimum pedestrian volume crossing the urban major street averages lOa or more person,.; per hour during the opening and closing periods of the school. The rural warrant is fiO percent of the foregoing urban volumes.
Other conditions, anyone of which may warrant special pedestrian signals at a midblock school crossing. are as follows:
198

r
I. Whpn intcniections adja('pnt to t he school are more than 1,OOll feet apart: 01'
2. 'When two lanes 01' more of traffie in an urban area are moving at average speeds of 25 m. p. h. or greater, during the opening and (Iosing periods of sehool, and students are required til eross these lanes; or
:). \Vhen two lanes or more of traffic in a rural area are moving at average speeds of 35 m. p. h. or greater, during the opening and closing periods of school, and concentrations of students are required to cross these lanes; or
4. \Vhen a sharp vertical or horizontal curve or a view obstnH'tion, or a combination of these, exists adjacent to the school crossing, and creates a serious hazard.
In connection with signals installed for school crossings, it should be understood that the signal is not the only remedy nor is it necessarily the bes('solution to the perplexing problem of traffic confliets between vehieles and school children. Brief periods during which the hazards are unusually high may often be better handled by officer eontrol. In some circumstanees, the pupils' respect for traffic signal indieations may be so low as to make the installation of a signal a contributory faetor in increasing rather than decreasing accidents. The obedienee response to officer eontrol is usually less uncertain. (;omplete facts should be obtained and studied by eompetent traffic engineering authorities before deeisions are made on special school signal installations.
Type of Control
The control of pedestrian signal indications may be accomplished with the timing mechanism normally employed with traffic signals, in whieh case the pedestrian phase or indication is given at a predetermined point during each cyele; or the control may be such as to permit the usc of a push button to introduee the pedestrian phase or indication in aecordance with the needs of pedestrian traffic.
As a general rule, the installation of signals at midbloek loeations adjacent to schools is to be avoided. However, when sueh signals are required by some unusual eondition. the traffic-aetuated type of control should be employed.
General Design Requirements
Special pedestrian signals should meet with three important eonditions:
1. They should he located directly in the line of vision of eaeh ('rossing of pedestrians in pither direetion.
ID9

,

2. The ~ignal indications ~hould attraet the attention of and he

dearly readable or under~tandable to the pedestrian hoth day

!

and night and at all di~tanee~ from 10 to 150 feet.

3. The signal indications must be such that they will not JJe mis-

taken as vehiele indications by motori~ts.

The two type~ of design described below for pede~trian control sig-

nal~ are approved a~ standard:

1. Two seetions of the standard traffic signal face, one len,.; of

which contains the word WALK, the other lens of whieh con-

tain~ the word WAIT. (Sec fig. 32 for details of the WALK

lens developed by the Institutc of Traffic Engineers. The

de~ign of a typical 'VAIl' lens having a dark orange gla,.;s is

also shown in figure 32. There i,.; no generally accepted pat-

tern for this lens a~ .v./ et.),

,

2. A rcctangular box-type~ignal in which the words 'VALl...: and

nOI\'T WALK arc are properly Hl'umi.nated .

.~ W ALK signal shall always be accompamed by a WAIT Of DO:\''1'

WALK indication. Particular care should be given to the de~ign and

construetion of the neon type of pedestrian signal so that in case of

an electrical or mcchanieal failure of the word DOK'T, the \\'ord

WALK \\ill al~o remain dark.

I,en~cs should carry letters at least 3 in<:he~ high ~o designed and

spa('ed as to give a maximum of legibility. Figure 33 shows a WALK

and WAIT in,.;tallation that has proved to be effective. In order to

avoid pmisible confusion to vehicle driver~, letters should appear il-

luminated on a black background.

Special pede~trian ~ignals are not a~ yet in extensive use and e:qwri-

mentation with their design details, subj('cj to the conditions ~tat ed

above, i~ desirahle.

Meaning of Indications
Jndications in special pede~trian signals should have the meaning~ a~cribed to them in this ~ection and no other meaning. These meanings are in accord with those set forth in Act 854, Uniform Act Rcgulating Tra.tTic on Highways.
WALK.-While the WALI\. lens or indication is illuminated, pcdestrians facing such ~ignal may proceed across the roadway in the direction of this signal and shall be given the right-of-way hy the driver~ hf all vehicles.
WAIT or DON'T W ALK.-While the WAIT or DO~'T WALK lens or indication i~ illuminated, no pedestrian shall start to cro~~ the roadway in the direction of sueh signal, but any pedestrian who ha~ partially completed his crossing on the WALK signal shall proeeed to a ~idewalk or safety island, if one is provided, while the WAIT or DOX'T WALl"': signal is showing.

200

PAl NT MUST EXTEND OVER THIS EDGE TO FRONT OF LENS
NOTE: THE LENS SHALL BE KOPP OR CORNIN(,
GLASS 8-3;ll"DIAMETER CLEAR WITH THE WORD"WALK"RAISED ON THE INNER SURFACE. OR APPROVED EQUAL THEREOF.
THE LENS SHALL BE GIVEN ONE COAT OF BLACl\ OPAQUE ENAMEL OF A TH ICKNESS SUFFICI~NT TO TOTALLY OBSCURE LIGHT OF IOO-WATT LAMP PLACED BEH IND IT. THE ENAMEL SHALL BE FREE FROM ALL PIN HOLES. THE ENAMEL IS TO BE Ap PLIED ON THE INSIDE SURFACE OF THE LENS IN SUCH A MANNER THAT WHEN THE LENS IS IN USE. THE WORD" WALK" SHALL BE THE ILLUMINATED PORTION OF THE LENS. THE ENAMEL SHALL BE BAKED OR FI RED INTO THE GLASS. THE ENAMEL SHALL BE HARD AND DURABLE AND SHALL NOT PEEL OR FLAKE OFF WHEN SUBJECTED TO THE HEAT OF A SIGNAL LAMP WHEN THE LENS IS IN USE OR WHEN THE LENS IS WASHED.
THE WORD"WALK"SHALL BE REPRODUCED ON THE LENS IN CONFORMANCE WITH THE DIMENSIONS AND SHAPE SHOWN ON THIS DRAWING.

---:::::=1=::::::::::------

ORAMi< GlASS

OI/ANG GLASS
Figure 32.-(ABOVE) WALK lens design, Institute of Traffic Engineers. (BELOW) A typical WAIT lens design.
Location Special pedefit rian fiignab fihould he mounted on eorner pOfitfi \",ith
the hottom of the fiignal not 100\'er than 7 feet nor more than 10 feet ahove the fiide\n1lk leyel and fi() that there ifi a signal in the line of vifiion of each ('l'osfiing of pedefitrianfi in any direction. These signals may he mounted fieparately OJ' \\'ith the traffic control signals.
Signalfi infitalled at midhlo('k fi('hool crossings shall follow the usual lo('ation standanlfi ex('ept that pOfit-mounted signals fihall he located lEi feet in advanc'e of the marked (TOfifi walk and on the right-hand fiide of the street. ;\ Stop line shall also he provided.
Operation Most of the general requirement;; relating to the operation of high-
"-ay traffi(' fiigna Is appl:v to the operation of special pedestrian signals
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.'t.
figure 33.-WALK-WAIT signal installation.
as well. It may sometimes be that the need for a separate pedestrian phase will diminish considerably before vehicular volumes drop to a point where flashing operation would be employed. In such cases, it may be desirable to add the time normally allotted to the pedestrian phase to the main-street green interval during this interim period. Phases and Intervals
The length in seconds of phases and intervals provided for special pedestrian signals is normally determined by those allotted to vehicular traffic in the operation of fixed-time or vehicle-actuated traffic signals. When the average walking time required for the pedestrian to cross the roadway is greater than the time necessary for vehicular traffic to clear, however, the former should govern the length of the pedestrian WALK interval, and the vehicular interval should be adjusted accordingly. Since the pedestrian, as well as the vehicle, requires a clearance interval, the period during which it is not possible to start and complete a crossing at the normal walking speed should always be recognized by an appropriate signal indication. Such indication should be given to pedestrian sufficiently in advance of the transfer of vehicle right-of-way to prevent pedestrians from being stranded in the middle of the street.
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G-OTHER SPECIAL TRAFFIC SIGNALS
Types of Special Traffic Signals
Special traffic signals include: 1. Flashing beacons and signals. 2. Lane-direction traffic signals. 3. Traffic si!!;nals at drawbridges.
Flashing Beacons and Signals
Definition and Application
Flashing beacon.-A flashing beacon is a section of a standard traffic signal head or a similar type device having a yellow or red lens in each face, which is illuminated by rapid intermittent flashes.
Flashing signal.~A flashing signal is a standard highway traffic signal in which the yellow or red lens in each face is illuminated by rapid intermittent flashes.
Flashing beacons and signals perform a very useful function at locations where traffic or physical conditions do not justify a conventional type of Stop-and-Go installation. At other special points of hazard, experience has indicated that the flashing beacon or signal is the only device sufficiently conspicuous to identify the hazard to the motorist.
Warrants
The warrants presented herein for flashing beacons and flashing signals differ, since the latter are merely a utilization of an existing traffic signal installation.
Flashing yellow beacon.-The installation of a flashing yellow beacon may be warranted as an advance warning device at an intersection or other location under one or more of the following conditions:
1. Physical obstruction existing in the roadway. 2. Important intersection hidden by an obstruction or sharp curve
in the highway. 3. Proximity of a fire station. 4. Sudden change from rural conditions, where relatively high
speeds are safe, to those of an urban district where speed must be reduced. Flashing red and yellow beacon.-The installation of a flashing beacon at an intersection ,vith yellow flashing on the main street and red flashing on the side street or streets may be warranted by one or more of the following conditions: 1. Instead of or in conjunction with Stop and Advisory Speed si!!;ns at intersections where sight distance is extremely limited or where other conditions make it especially desirable to emphasize the need for stopping on one street and for proceeding with caution on the other. This type of installation is especial-
203

ly effective at interseetions where approach speeds are in excess of that warranted by conditions, and drivers are not adequately impressed with the need for stopping or redueing speed by the use of stan~rd or oversize Stop signs, by StqP sill;l1s and Advance vVarning signs, or by Advisory Speed signs. 2. Minimum vehicular volume entering an urban intersection from all direetions averages 300 vehicles per hour for at least 2 consecutive hours, of which vehicular traffic entering the intersection from the minor street or streets averages at least 30 vehicles pel' hour for the same hours. \Varrants for rmal areas are ;30 percent of the above urban volumes. 3. Two or more reported a('cidents in a 12-month period of types susceptible of eorrection by cautioning and stopping of traffic. 4. Intersection on or at the bottom of a long or steep grade where excessive speed may prevail. Flashin(J Ted and yellow si(Jnal.-A combination flashing yellow (Caution) and flashing red (Stop) signal is warranted as part of a signal installation not continuously operated on a Stop-and-Go basis if the volume of traffic falls below the minimums lI;iven in sections pertaining to Minimum Vehicle Volume and ylinimum Pedestrian \'olume. When signals normally operated as Stop-and-Go signals are Pllt on flashing operation in accordance with the abm'e, the (~olor indications given to the several streets should be baspd on thp following ('011siderations: 1. If one of the streets involved is a through street, it should be given a flashing yell 0\\' (Caution) indication and the other approaches should 1)(' gi,'en a flashin!!; red (Stop) indication. 2, If the safp approa('h speed on one street differs from the safe approach speed on the other street or streets, the street having the higher safe approach speed should he !!;inm the flashin!!; yellow (Caution) indication and other approaches should hI' givpn a flashing red (Stop) indication. :3, If the safe approaeh speed on any street in urban areas is below 8 miles pel' hour, that street, regardless of other considerations, should be ginm the flashing red (Stop) indication, The correspondin!!; safe approaeh speed \'olume for rural areas is 12 miles per hour, Other approaches should 1w !!;iven the flashing yellow (Caution) indication,

1 I I

Types of Control
Types of control llsed with flashing signal" or ht~aeons are as follows: 1. The motor flashing switeh, usually installed in the housin!!; of the flashing beacon, is used solely to provide intermittent illumination of the beacon lenses.

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2. Where flashing operation of the conventional fixed-time or traffic-actuated signal is desired, the control is provided by an electrical mechanism supplementary to the signal timer. This operates in a manner similar to the motor flashing switch to provide intermittent illumination of the signal lenses. -
Design Flashing beacon and signal units and their mountings shall follow
the general design specifications of standard traffic signals, which include the following essentials:
1. Each signal unit lens shall have a visible diameter of 8 inches. 2. The illuminating clement, lens, reflector, and visor shall each
be of such design as to render the lens, when illuminated, clearly visible to traffic facing the signal at all distances from 10 to 300 feet under all atmospheric conditions, except dense fog, both day and night. 3. The color of the lens shall be red for Stop and yellow for Caution. All flashing contacts should be equipped with filters for suppression of radio interference.
Location The particular purpose of a flashing beacon should largely govern
its location with respect to the roadway and the hazard or other condition warranting the beacon. If located at the roadside, flashing beacons as measured from the bottom of the signal head should be at least 8 feet above the pavement. If suspended over the roadway, they should not be more than 15~ feet nor less than 14~ feet above the pavement. In no case should they be mounted on pedestals in the roadway unless the pedestal is within the confines of a traffic or pedestrian island.
Operation The illuminating element in a flashing yellow (Caution) or flashing
red (Stop) beacon or signal shall be flashed continuously at a rate of not less than .50 nor more than 60 times pel' minute. The illuminated period of each flash shall be approximately equal to the nonilluminated period.
Flashing beacons should generally be operated continuously throughout the 24-hour period.
Flashing signals also should generally be operated continuously throughout the 24-hour period, except when conditions warrant their being changed to standard Stop-and-Go operation. In every case, the change from Stop-and-Go to flashing operation should be made during or immediately following the main-street green interval.
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Lane-Direction Traffic Signals
Definition and Application
Lane-direction or off-centelil'traffic signals are traffic signals used to I
control the direction of traffic movement by individual lanes of a streel or high\vay. These installations are distinguished by signal units OVer each lane of the roadway, and supplementary signs are often lised to explain their significance.
Warrants Lane-direction traffic signals may be warranted when:
1. Vehicular traffic flow in one direction on a two-way strept. highway, bridge, or tunnel, having three lanes or more, exceeds the reasonable capacity of the lane or lanes normally used for traffic moving in that direction and, at the same lim~. traffic flow from the opposite direction does not require thl' number of lanes which it is generally allocated.
2. Traffic movement at toll-booth areas and single-lane 1unnels requires reversal in direction of traffie flow for efficient Ojwralion.
;). Traffic movement in one direction at an entrance or exit of a parking lot at an industrial plant, stadium, or similar location greatly exceeds the capacity of the traffic lanes allocated for handling balanced traffic flow.
-to Heavy traffic flow is slowed down and congested on a long uphill grade of a three-lane roadway because of slow-moving commercial vehicles traveling up the hill, thereby warranting the use of two lanes for uphill and one lane for downhill movement.
;). Temporary road conditions reduee the number of lanes normally available to handle traffic movement, even though it is extremely unbalanced at various periods of the day.
Types of Control
The type of control provided for lane-direction signals should he such as to permit automatic or manual operation of the signals. The control mechanism should permit the illumination of the red lenses in both directions in the same lane for those lanes where the traffic flow is subject to being revised. The possibility of an erroneous inclication of green in both directions in the same lane should be avoided by wiring the green signal so that it can be illuminated only when the red signal shows in the opposite direction. ?\ormally, no more than a two-lens signal, having red and green lenses, is required for each direction of traffic, since the signals are not often placed at intersections.
20G

Design
Traffic signal heads used for controlling the direetion of moyement by lanes :shall haye two faces. Each face controlling a lane subject to reyer:sing traffic flow :shall contain standard red and green len:se:s and otherwi:se shall follmy the general design :spccification:s of traffic control signals. In lanes not subject to reyersing traffic flow signal face:s shall haye a :single lens, red or green, \yhieheyer i:s appropriate for the location. :\Iountings :shall permit the signals to be suspended oyer lanes on cables or fixed :supports.
Location
A traffic :signal head ,yith a face for each direction of traffic to be controlled shall he located oyer the center of eaeh lane of the roadway at the beginning and end of the lane-controlled :section. If the area to be controlled is more than 1,000 feet in length, or if the \'Crtical or horizontal alinement is curyed, intermediate :signal heads shall be placed oyer each lane at frequent enough interyaI8 so that motori:st:s will at all time:s be able to see at least 1\n) :signals along the roadway and have a definite indication of the lane:s specifically reseryed for their use. At the terminal and intermediate signal installation points on the lane-controlled :section, signal heads aboye the yarious lanes :shall be located in a transYerse :straight line at right angles ,,'ith the roadway alinement.
Operation
All traffic :signals u:sed to control traffic movement by lane:s shall he coordinated and wired to a ma:ster control \yhich will operate :so as to permit all two-Ien:s signal faces for each direetion in any of the reyer:sing lanes to ehange from red to green or from green to red, except that the showing of green in both direetion:s over the same lane :shall be guarded against by electrical interlock. It :shall also be po:ssible to :shmy a red indication in both directions in any of the lanes subject to reversing traffic flow. Thi:s latter feature permits the establi:shment of a neutral area or :safety zone during light traffic periods or during an emergency traffie :situation.
The :sy:stem :shall operate either manually or automatically through the use of a time dock.
Traffic Signals at Drawbridges
Application
Signa18 installed at drawbridge:s to control vehicular traffic are a speeial application of highway traffie signals.
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Warrants Traffic signals should always be used in conjunction with gates and
the other types of protection commonly employed at drawbridges.
,'#'
Design The traffic signal heads and mountings shall follow the standard
design specifications of traffic signals. Drawbridge signals may be supplemented with bells which operate with the red signal indication to provide additional warning to drivers.
Location Traffic signals shall be located at both ends of the movable span.
To assure positive visibility, two signal heads should be mounted on each approach to the movable span, one on the right and the other on the left side of the roadway. They should ordinarily be not less than .50 feet nor more than ]00 feet from the end of the movable span.
Operation Traffic signals at drawbridges shall be interconnected with the draw-
bridge gates and, if feasible, with other signals on the same street or highway within 500 feet of the bridge. Not less than 1.5 seconds before the gates are closed, the signal shall change from green to yellow to red. While the gates are closed and the draw is open, the signals shall show a continuous red indication. After the draw is dosed and the gates opened, the indication shall change to a steady green and remain so until the next bridge opening.
If the drawbridge is close to a railroad grade crossing and there is a possibility that traffic may be stopped on the railroad crossing as a result of the bridge opening, a supplementary traffic signal may be required at an intersection on the approaches near the grade crossing. In this event, extreme care should be used in planning the signal layout and operation so as to avoid the creation of confusion and hazard to motorists, either at the drawbridge or at the grade crossing. :\'ormally, such installations should be interconnected to provide coor<lination in signal indications under a given set of conditions.
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H-TRAIN-APPROACH SIGNALS AND GATES
Railroad Grade-Crossing Protection Signs are inadequate protection at railroad crossing" where highway
traffic is heavy, train movements are frequent, or visibility is seriously obstructed. At sueh erossings there should be installed train-approach signals to indicate the approach and passage of trains, or gates which will extend into or across the roadway to prevent vehicles from entering upon the crossing while trains are approaching and occupying the crossing. The following sections deal only with signals and gates of the automatic type.
Train-Approach Signals
Classification and Definitions Train-approach signals are elassified as flashing-light or wigwag
signals. A flashing-light signal is an electrically or mechanically operated
signal in which indication of the approach of a train is given by two horizontal red lights flashing alternately at predetermined intervals, producing the equivalent of a signal given by a watchman swinging a red lantern.
A wigwag signal is similar to the flashing-light signal except that the indication of the approach of a train is given by a swinging disk and a red light enclosed in the disk.
Warrants Train-approach signals shall be installed at railroad-highway grade
crossings to warn highway traffic of any approaching train where the volume of traffic of both the railroad and the highway warrants, or where physical obstructions to clear vision exist on highway approaches. Such signals shall be used for no other purpose.
Types of Control Flashing-light and wigwag signals may be controlled manually, or
automatically through track circuits arranged so that the flashinglight signals will operate until the rear of the train reaches or clears the crossing and so that the signals will operate upon the approach of trains from either direction on the tracks for which protection is provided.
Design Flashin{/-l1:ght signals.-The following provisions relate to the de:-;ign
of flashing-light signals: ]. Signal lights shall shine in both directions along the highway and be mounted horizontally. The distance between centers of lights shall he 30 inches. Lamps shall preferably be not
20!1

less than 7 feet nor mol'(' than \) feet abon' the surfacc~ of thp highway. 2. Lenses or rOU!Hlels shall be a minimum of 8:~s inches in cliarnetel', and shall be in accor~ance with Signal SectionSpeci{icotion 69 of the Association of American Hailroads. 3. The Hailroad Crossbuek sign and the signal shall be mOllnted on the same post.
IVigwa(J signals.-The following provisions relate to the dpsign of wigwag signals:
1. A wigwag signal shall consist of a disk 20 inches in dianw\c,r, in the renter of \yhich a lamp \yith red lens or roundel IS provided for night indication.
') The disk shall be supported by a pivoted rod and the !pngth of stroke of the s\yinging light in the disk measured horizontally between extreme positions shall he 30 inches.
3. Lenses or roundels shall be a minimum of ;) inches in cIiamctc>r.
and shall be in accordance with S1:gnal Section 1m Spec~{icatioli
of the Assoriation of American Hailroads. L The Hailroad Crossbuek sign ancI the signal shall be mounted
on the same post.
Location
\Vhichever type is used, one signal shall be plac'ed on each sidp of the track.
The location of signals for railroad-highway grade-crossing pro\ection should be determined after inspection and study at the site. [n addition to providing for adequate clearances, consideration should be given to the type of pan,ment, angle of crossing, and visibility \0 drivers approaching the nossing.
Installation Flashing-light and wigwag signals shall he installed in accordan('p
with the standards as preserihed in Railroad Highway Grade Crossill,!l Protection, Bulletin :\0. 3 (or subsequent issue), Assoriation of Ameri('an Railroads, Joint Committee on Grade Crossing Protection.
Operation
Automatic signal de\ices used to indicate the approarh of trains shall so indicate for not less than 20 seconds before the arrival of the fastest train operated over the crossing,
Local conditions may require a longer operating time, but too long an operation by slo\\' trains is undesirable. 'Fniform time control for all train speeds is the most desirahle arrangement and at crossings \yhere there is considerable difference bet\yeen high and low train speeds and whem travel on the high\\'ay is heavy, provision for a tyP('
2LO

of circuit control that will insure equal or approximately equal timing should be considered.
Lights in the flashing-light type of signal shall flash alternately. The number of flashes of each light per minute shall be 30 minimum. 45 maximum. Lights shall each burn the same length of time. Total burning time of both lamps shall be practically the entire operating time.
Each flashing-light unit shall provide an indication having a beam candlepmver of uniform intensity at any angle up to 10 degrees on either side of the axis, and the range at any point in the 20-degree angle under bright sunlight e(lllditions, with the sun at or near the zenith, shall not be less than 1,500 feet when a lO-watt lamp rated at 1,000 hours is burned at rated voltage.
'With the wigwag type of signal, movement of the "winging disk from one extreme to the other and baek eonstitutes a eyele. The number of eyeles per minute shall be 30 minimum, 4;") maximum.
The signal light of thc wigwag signal, when the disk is suspended vertically, shall have a range, at night, of 1/>00 feet through a total angle of not Ie"s than 30 degrees when a 10-watt lamp rated at 1,000 hours is burned at rated voltage.
Maintenance Signals shall be kept \vell painted and in a good "tate of effieieney.
The "urfaees of lermes on signal lamps shall be kept free from such deposits a" soot or other materials, since these will seriously affect their efficiency.
Railroad-Highway Grade-Crossing Automatic Gates
Application Automatic gates, where installed, shall be provided as an adjunct
to the Association of American llailroads' recommended automatic crossing signals of the flashing-light or wigwag type described above. When indicating the approach of a train they shall present toward the highway in both direetions the appearanee of a horizontal arm carrying three red lights and extending over the traveled roadway a sufficient distanee to ('over the lane or lanes used by traffic approaehing the crossing.
Warrants Automatic gates and signals of the type des('ribed herein shall be
installed at railroad-highway grade crossings to warn highway traffic of any approaching train where the volume of traffie of both the railroad and the highway warrants, or where physical ob"tructions to clear vision exist on highway approaehes. These devices shall be used for no other purpose.
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Types of Control
.\utomatie gatC::i may he ('Olltrolled manually, or automati('ally t Ill'ough traeK eireuits. The gates shall reaeh the full horizontal position before the arrival of t<tle fastest train operated over the (Tossing and shall remain dmnl until the rear of the train has deared HlP ('I'Osslng, and the~' shall operate upon tlw approaeh of trains from eit her direction on the traeKs for \\'hieh protp('fion is provided.
Design The gate ann!' and housing!' ('ontallllllg the arm-operating nw<'1l-
anism!' shall be mounted 011 the post !'upporting the crossing signals and Railroad ('rossbueK sign.
The bottom of the gate arms, when in the horizontal or lowered positioll, shall he not less than ;) feet nor more than 4 feet above the crown of the roadway and, when not indicating the approach of a train, shall neither obstruct nor interfere with highway traffic.
The mechanisms shall be so designed that if the arms, while heing raised or lowered, striKe or foul an objeet, they will readily stop and, on removal of the obstruction, shall assume the position corresponding with the control apparatus.
Each gate arm extending over the highway shall have three red lights shining in hoth direetions along the highway. The light nearest the tip shall hum steadily and the other two lights shall flash alternately.
The gate arm::; shall be painted on both ::;ide::; with In-inch altemate diagonal ::;tripes of white and blaCK.
Lenses or roundels shall be in accordanee with 8i(Jnal Section .specification 6.9 of thp Association of American Hailroads.
Location The location of automatic crossing gates for railroad-highway grade-
nossing protection shall hp determined after inspection and study at the site. In addition to providing for adequate dearances, consideration shall be giv(~11 to the type of pavement, angle of (Tossing, and ,'iew when approaching the crossing.
Installation Automatic: gates shall be installed in accordance with the standanb
prescribed in Railroad Hi(Jhway Grade Crossin(J Protection, Bulletin :':0. 3 (or subsequent issue), Association of American Railroads, .Joint Committee on (:rade Crossing Protection.
Operation Circuits for the operation of automati(' gates shall he so arranged
that the gate::; will start to assume the horizontal positioll between ;) and ,) se('onds after the waming signals start to operate. Gates shall
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reach a full horizontal posltlOn before the arrival of the fastest train operated oyer the crossing and shall remain down until til(' rpar of the train has cleared thp (Tossing.
Cniform time control for all train speeds is the most desirable arrangpment, and at erossings \yhere therp is a ('onsidprable dif'fen'!l\'(' between high and Imy train speeds and \yhere tnwPl on the high\yay is heavy, proyision for a type of circuit ('ontrol that \yill insure equal or approximately equal timing in the operation of automati( gale!' should be consideJ'(~d. Maintenance
Automatie gates shall be kept well painted and in a good state oj efficiency. The surfaees of lenses OIl signal lights on the gatp arms shaJJ be kept free from such deposits as soot or other materials. since these will seriously affect their efficim}(~.
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Part IV
ISLANDS
A-INTRODUCTION Function of Islands
The term "island" is applied to eertain areas within the roadway from whieh vehieular traffic is diverted by pavement markings or other warning deviees, or excluded by physical eonstruction. Such islands are designed to segregate pedestrians and vehicles or otherwise to eontrol streams of traffic in order to minimize eonfliets, expedite traffic flow, or increase safety. For the purposes of this manual, an island ineludes not only the restrieted area, but also all end protection or other approaeh-end treatment.
Although rotary islands (traffie cireles) admittedly are devices for traffic control they are rather to be regarded as basic elements of highway design. The following discussion is confined to traffic control islands that are or can be located in relatively restricted roadway or intersection areas.
For similar reasons, the treatment of divisional islands here applies primarily to urban and suburban installations, where intersections are frequent and the islands are correspondingly discontinuous, rather than to extended median strips in open country.
Certain features of island design, however, such as approach-end treatment and illumination, are to be regarded as generally applicable to all islands, including those of the rotary and divisional types.
The right of a pedestrian to occupy a pedestrian island in safety is eommonly protected by law. Uniform A.ct Regulating Traffic on Highways, Act No. 854, Article I, Section 17, for example, defines a "safety zone" and prohibits motor vehicles from entering a safety zone at any time, regardless of whether or not the physical construction would permit such entry.
General Engineering Requirements As islands are placed in areas which would otherwise be available
for vehicular traffic, they should be installed only after careful engineering study to determine their necessity and value. Islands should be so designed and placed as not to create additional traffic hazards. They should be plainly visible to oneoming vehicle operators, both by
2]5

,

day and by night, and accordingly should be of a color contrasting

with the street surface. They should be illuminated, signed, and

marked as herein recommended,..,.depending on their design and the

traffic conditions.

'

In the determination of type and size of structure or device, Con-

sideration should be given to maintenance as well as construction cost.

Esthetics should be given full consideration but should not be permit-

ted to decrease the usefulness of the island.

Classification
I lands may be clas ed functionally and physically as follows: 1. Pedestrian islands: (a) Loading islands. (b) Refuge islands. 2. Traffic islands: (a) Divisional islands. (b) Channelizing islands.
These several types of islands are illustrated in figures 34 and 35. Pedestrian islands include all areas in roadways set aside exclusively for persons on foot. Traffic islands include all areas created for the separation and directing of vehicular traffic. The basic functions of

figure 34.-A raised loading island with no protection other than pavement markings. No turns are permitted at this intersection.
the two groups are different, and they are accordingly treated separately herein. However, an island may serve as both a pedestrian island and a traffic island.
Standardi.zation Islands are not adaptable to detailed standardization, inasmuch as
they cover areas of widely varying sizes and shapes and require adapta-
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Figure 35.-A raised loading island in business district. Also serves as a protection for left turn movement.
tion in each case to the roadway and traffic characteristics. This is particularly true with respect to end protection, approach-end treatment, and illumination. This manual sets forth certain basic requirements, based upon present knowledge, which should be considered in the location, design, and construction of islands, certain minimum dimensions that should be observed, and advantages and disadvantages of certain types and designs. Although further study and experimentation is under way in various communities, and should be encouraged, it is recommended that present-needed installations be designed in accordance with the approved practices described in this manual.
Additional information on island design is contained in the following publications of the American Association of State Highway Officials: A Policy on Highway Types (Geometric), A Policy on Intersections at Grade, A Policy on Rota1"y Intersections, and A Policy on Grade Separations for Intersecting Highways.
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B-LOADING ISLANDS
Legal Authority
Loading islands, being in the roadway, can be established only on the authority of the local or State highway authorities. A model of legal authority for the establishment of loading iRlands (safety zones) is presented in the Model Traffic Ordinance (sec. 51). No other legal authority is involved.
Functions The main function of loading islands is to afford protection to street-
car riders at loading, discharge, and transfer points, and to riders of busses and trolley busses using such islands. They also expedite traffic by permitting other vehicles to continue in motion while the puhlic vehicles are stopped for loading.
Warrants Loading islands are warranted and should be established at street-
car stops under any of the following conditions: 1. Where both vehicular and pedestrian traffic are heavy. 2. Where the speed of vehicular traffic along the roadway is relatively high. 3. Where accident experience indicates the need.
Loading islands may be used by husses and trolley busses as well as by streetcars. The chief advantage of this is that it concentrates all of the mass-transportation vehicles in one traffic lane and leaves the other lanes free for vehicles not required to stop frequently. Disadvantages are that bus passengers, having to cross traffic lanes, are deprived of the greater safety of loading at the curb, and that these free-wheeled vehicles which might do their loading at the curb may, while using the loading islands, delay streetcars unable to reach the islands.
When a separate loading place is used by busses or trolley busses, it should be located at the curb and well away from the loading island, to avoid congestion in the traffic lane beside the island.
Location Loading islands at street intersections should be extended to the
cross walk, unless this is not feasible because of switches, streetcar turning movements, or similar conditions. They shall not, however, be continued within the cross walk (fig. 34). Loading islands should in general be located at intersections, but a midblock island may be warranted in a long city block.
In no case shall a loading island he established unless there is at least one adequate traffic lane between the curb and the island.
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Where it is intended to permit automobiles and trucks to pass on the left of islands, such islands, to serve transit vehicles (streetcars or busses) moving in opposite directions, should not be located laterally opposite each other.
Access
Access to loading islands adjacent to intersections and of sufficient length to accommodate four or more transit vt'lhicles should be safeguarded by a marked cross walk from the near sidewalk in addition to the cross walk at the intersection. lVIidblock loading islands should have at least one marked cross walk from the near sidewalk or across the entire roadway, depending upon conditions.
Elements of Design
Loading islands shall be of a permanent type, and shall be designed to afford the necessary protection to streetcar riders or other pedestrians and at the same time create as little hazard as possible to passing vehicles.
Loading islands will ordinarily have four distinct parts: (1) The area intended to be occupied by pedestrians, (2) a physical barrier at the approach end to prevent motor vehicles from entering the pedestrian area, (3) devices at the approach end to warn vehicle operators of the presence of the island and to direct them into a suitable path or paths past it, and (4) illuminating devices adequate to make all parts of the island clearly visible at night. They may in addition require side protection.
Designation of Area The pedestrian areas of loading islands are in practice specifically
designated either by platforms or by some other means. Platforms.-Platforms raised above the pavement level to approxi-
mately the height of the adjacent curbs and with adequate safeguards afford the best protection to pedestrians.
The platforms are usually permanent structures of concrete or other sturdy materials, with the surface properly sloped for drainage. In some instances, for economy or convenience, they are made of wood. In all cases they should be built substantially and of proper height, and the outside edges should be faced smoothly.
Other means.-Other means of designation in use include rows of fixed posts connected by chains or rails, mushroom buttons, pavement markings, or various combinations of these or other devices.
Platfonns are the most satisfactory means of designation. providing the greatest actual protection and the greatest sense of security to pedestrians. Posts and chains or rails are next in order of effectiveness. Islands designated by simple pavement markings, with or with-
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-''IJ
out mushroom buttons or portable stanchions but without other protection, are dangerous and not recommended except in some business districts where speeds are ordinarily low.
Dimensions Length and width.-A loading island should be of sufficient length
to provide adequate access to entrances for the full number of streetcars or other public tmnsportation vehicles likely to stop at the island at one time in recurring peak traffic.
Loading islands shall be at least 4 feet wide. Where the number of transit vehicles and passengers normally using the island requires, the width should be greater and sufficient to enable riders to reach the desired vehicle entrances without undue crowding or delay.
Because of the differences in widths of streetcars, no standard distance from the rail can be specified. Platforms should be built to accommodate the narrowest car. If any cars are operated which will overhang the edge of the island, warning to this effect should be given by plainly visible line markings on the surface of the island indicating a safe clearance distance.
Height.-The platform height of a loading island shall be from 5 to 7 inches, except where transit vehicles require a lesser height for clearance, and in general shall conform to local standards of curb height for sidewalks.
Where additional thickness of roadway pavement surfacing is anticipated due allowance should be made for it.
End Protection Loading islands outside of congested business districts and wherever
feasible within business districts shall, at the end toward approaching traffic, have adequate physical protection in the form of a buffer to withstand the impact of a colliding vehicle. This buffer may be a concrete block, a series of solid posts or pipes, or other massive structure (fig. 36).
A concrete block is an effective buffer. It should be sloped or rounded to deflect a colliding vehicle not meeting it head-on, and should be so constructed and marked as to be highly visible. It should be of an attention-arresting color, usually in sharp contrast with the color of the pavement. In addition, effective illumination, reflectors, indented facets, or other high-visibility treatment is recommended. Care must be exercised in the design of concrete buffers to assure adequate clearances for all types of streetcars in present or prospective use in the community.
Where vertical posts are used, three or more should be set to form a deflecting arc. These may be connected with horizontal members
220

and should be provided with a sheet-steel facing to deflect a vehicle hitting them at an angle.
figure 36.-A concrete loading island with end protection provided by a concrete buffer, six-inch red reflectors and concrete painted with black and white stripes. The white stripe reflectorized, this panel warns drivers of approaching vehicles
of the island's presence.
Approach-End Treatment The approach end of a loading island, whether or not protected by
a buffer, shall be carefully designed to provide a maximum degree of warning of the presence of the island and, where necessary, definite indication of the proper vehicle path or paths to be followed.
Various types and forms of such treatment have been used and deemed satisfactory. Experimentation on other forms and on modifications of present forms is developing new possibilities and should be continued. The following devices, which vary greatly in details, are in present use:
1. Pavement markings, with or without mushroom buttons. 2. Signs. 3. Reflecting devices. 4. Flashing yellow beacons. 5. Contrasting pavement colors and textures. 6. Jiggle bars. 7. A vertical element sloping up to the island nose. 8. Various combinations of 1 to 7. A development of the sloping vertical element is the prow. Prows installed to date, with lengths varying from 10 to 40 feet and with wide variations in shape, indicate the need for further study to determine their relative merits and the mo t effective design. Whatever the form or forms of approach-end treatment and end protection, their adequate night illumination is vital.
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Side Protection
Side protection of loading islands is warranted only where unusually hazardous conditions indicate its need, as where crowds of waiting passengers would otherwise ove1flow the island, particularly where a platform is not provided. Such protection should be provided by a line of fixed or firmly secured posts, not less than 3 feet high and set not more than 8 feet apart, connected by chains or rails. The purpose of this is not only to keep motor vehicles off the island but also to keep streetcar and bus riders within the island and discourage crossing between island and sidewalk at other than designated points.
In addition to a chain or rail connection of posts for side protection it is desirable to place a substantial sheet of metal along the line of posts, on the side of vehicular traffic, to prevent vehicle wheels from striking the posts, to divert such traffic away from the loading island, and to serve as a splash plate. Such a plate should be of adequate height to serve the intended purpose. Splash plates are particularly advantageous at islands without a raised platform, but also are used in some cities in conjunction with platforms. Where space permits, some form of solid wall may be employed.
When posts without a splash plate are used on raised platforms they should be set back somewhat from the platform edge to lessen the likelihood of being hit by motor vehicles.
Where a cross walk leads to a loading island, any side-protection posts should leave an opening the full width of the cross walk.
Illumination and Reflectorization All loading islands, including their approach-end treatment, shall be
provided with: 1. General illumination of the entire area, including adjacent vehicular-traffic lanes, or as much of the area as is required for safe operation; 2. Intensified illumination and reflectorization to show clearly the outlines of buffers or other structures, collision with which would seriously damage motor vehicles or imperil pedestrians.
Loading islands shall not be installed unless they can be adequately illuminated. It is desirable to have two independent sources of light in case of failure of one.
The effectiveness of approach-end treatment of islands depends greatly upon illumination and reflectorization. There are numerous possible ways of providing these, and the successful devices and combinations of devices suggested herein should not preclude further research and experimentation.
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Direction of Flow Whenever loading islands are established in roadway areas, the
local traffic authority shall specify, in each case, whether vehicles may pass on both sides of the island or are restricted to pass only on the right. The rule at each island, or in each locality, should be deter= mined after careful analysis, taking into account width of roadway, volume of motor traffic, and volume and character of transit services. A uniform rule, however, along anyone street or in one area, where conditions are substantially similar, will be more readily understood and observed.
The requirement that automobiles and trucks shall pass to the right of the loading island may virtually eliminate one traffic lane. In locations where the traffic of transit vehicles stopping alongside loading islands is light and other traffic is fairly heavy, it is usually desirable to permit the general traffic to pass on either side of the island. Allowing other than transit vehicles to pass to the left of the islands, however, may seriously delay streetcars and busses in reaching the islands, with consequent loss of time to passengers and derangement of transit schedules.
Signs Standard signs indicating the permitted directions of flow shall be
placed at the approach end of every loading island that is in the line of traffic flow. When vehicles are required to pass to the right of the island a regulatory Keep Right sign shall be used. When passing is permitted on either side a Double Arrow warning sign shall be used.
Such signs shall be adequately reflectorized or illuminated. They should normally be mounted at a height of 2y:z feet above the pavement to the lowest point of the sign. A duplicate sign, placed with its lower edge at least 7 feet above the pavement, is recommended as a means of giving advance information to approaching traffic.
Standard parking prohibition signs shall be placed along the curb of the sidewalk adjacent to all loading islands to prohibit parking opposite the entire length of the island and for such distances beyond the ends thereof as are necessary to expedite the flow of traffic.
Markings
The approach-end treatment of a loading island shall include pavement markings.
The ends of all loading islands toward approaching traffic shall be marked. The latter applies particularly to buffers and lighting standards. Markings are also very effective when placed on the curbs of islands in or adjacent to the line of approaching vehicular traffic. If curb or pavement markings are used in other nearby locations to in-
223

dieate parking prohibitions, such indications should also be used opposite loading islands.
The use of a eontrasting eolor, reflectorized paint, or other speeial treatment is recomI)J.Cnded to indicate clearly the presenee of the island in whieh ease additional curb markings are generally unneees_ sary.
Summary Specifications for Loading Islands
Designation of Area.-Platform preferable; other means include fixed posts or mushroom buttons or combinations of these, with or without pavement markings.
Dimensions.: Length.-Sufficient to accommodate adequate number of streetcars or busses. Width.-Four feet minimum, wider where needed to prevent overcrowding.
End protection.-Use of buffer is mandatory outside of congested business districts, desirable in sueh districts.
Approach-end treatment.-Adequate to warn of presence of island and indicate proper vehicle path or paths.
Side protection.-Posts, posts and chains, plates, ete., as conditions require.
Illumination.-General illumination of entire area; intensified illumination and reflectorization of buffers or other structures.
Signs.-Standard Keep Right sign or Double Arrow sign as required.
Markings.-Standard approach pavement markings; standard markings on buffer or curbs.
224

C-REFUGE ISLANDS
Legal Authority The models of legal authority applicable to loading islands (safety
zones) cited are equally applicable to refuge islands, and 110 other legal authority is involved.

Functions
The main function of refuge islands is to provide a place of safety for pedestrians caught within the roadway on cross walks by changing signals or by oncoming traffic at unsignalized intersections. In congested areas they also expedite vehicular traffic by permitting vehides to proceed without waiting for pedestrians to cross the entire roadway.

Warrants

Where anyone or a combination of the following conditions indicate the need, one or more refuge islands shall be installed:

1. High accident frequency. 2. Dense pedestrian traffic. 3. Dense vehicular traffic.

4. High-speed vehicular traffic. 5. Wide roadway. G. Complex intersection.

Refuge islands are warranted and shall be used in urban areas 011 exceptionally wide roadways or in large or irregularly shaped intersections where there is a considerable amount of pedestrian traffic and where heavy volumes of vehicular traffic: make it difficult and dangerous for pedestrians to cross (fig. 37). No refuge island shall be placed where it will leave less than two lanes available for traffic between it and the adjacent curb or another island. So placing a refuge island as to confine right-turning movements to a single lane, however, may be desirable if there is not a heavy turning movement.
Refuge islands should not be located in roadways carrying fastmoving vehicles unless they can be so placed, usually in the eenter of the roadway between the opposing streams of traffic, as not to create hazards to the vehicles. At any other point on such roadways where there is any considerable pedestrian movement across the roadway pedestrians should be protected by other means, such as a pedestrianactuated traffic signal or a pedestrian underpass or overpass.
In urban areas, however, where the vehicular traffic is relatively slow-moving, particularly in intersections without traffic signal control, pedestrians ill any considerable number should not be required

to find their way through more than four lanes of two-way traffic without the refuge of a center island, or through more than three lanes in one direction without an intermediate island. Such islands may also be desirable at signalized intersections to reduce the dearance

periods and expedite traffic.

Figure 37.-A raised refuge island.
Location Refuge islands shall normally be centered on the median line of the
roadway. On roadways with streetcar tracks, and two or more lanes of maving traffic on each side of them, refuge islands should be provided on each side of the tracks.
The parts of refuge islands used by pedestrians should be in line with the cross walks.
Elements of Design Refuge islands normally have the same four distinct parts as load-
ing islands: (1) the area intended to be occupied by pedestrian, (2) a physical barrier at the approach end to prevent motor vehicles from entering the pedestrian area, (3) devices at the approach end to warn vehicle operators of the presence of the island and to direct them into a suitable path or paths past it, and (4) illuminating devices adequate to make all parts of the island clearly visible at night.
Designation of Area Refuge islands are in practice designated by platform , markings, or
mushroom buttons (figs. 37, 38 & 39). Raised platforms for part of the width of the cross walk are preferable as they afford pedestrians a greater sense of security. Part of the area, however, should be kept at pavement level to facilitate use by baby carriages, wheel chairs, and crippled or aged persons.
Whatever the form of designation, the requirements for end protection and approach-end treatment stated in section on End Protection and Approach-End Treatment apply.
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Figure 38.-Combination channelizing and refuge islands. The center islands extend into but not entirely across the cross walks.
Figure 39.-Combination divisional, channelizing, and refuge islands with desirable tapered shape, and overhead illumination.
Continuous Median Strip In roadways requiring median islands at each intersection, con idera-
tion should be given to the alternative of a continuous median strip between intersections. Such a strip will obviate the expense of buffers and other approach-end protection at each intersection, minimize weaving between intersections, and afford other advantages of a divided highway. Disadvantages are that it will bar vehicles on one side of the street from direct access to alleys, filling stations and other business facilities, and residences on the other side.
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Figure 40.-Channe/izing islands and pavement markings at a complicated inter. section. The raised islands also serve as refuge islands.
Dimensions
Length and wid/h.-Refuge islands shall be at least 4 feet and preferably at least 6 feet wide. The usable length along the roadway, including the part at pavement level for baby carriages, wheel chairs, and infirm persons, shall not be less than 5 feet nor less than the width of the cross walk.
Local conditions will determine ,,"hether the part of the island at street level is to be adjacent to the intersection, at the center of the cross walk, or elsewhere. In any event the entire area used by pedestrians should be so designed as to be protected against any encroachment by motor vehicles, including those making left turns.
H eight.-The platform height of refuge islands shall be from 5 to 7 inches, and in general shall conform to local standards of curb height for sidewalks.
Where additional thickness of roadway pavement surfacing is anticipated due allowance should be made for it.
End Protection
In areas where vehicle speeds are relatively high, a refuge island should have adequate physical protection at the end toward approaching traffic in the form of a buffer to withstand the impact of a colliding vehicle. This buffer may be a concrete block, a series of solid po ts or pipes, or other massive structure.
Even in business districts, where speeds may be high after business hours, some form of buffer at the approach end of a refuge island is desirable.
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Approach-End Treatment The approach end of a refuge island, whether or not protected by a
buffer, shall be carefully designed to provide a maximum degree of warning of the presence of the island and, where necessary, a definite indication of the proper vehicle path or paths to be followed.
Side Protection When part of the refuge island is kept at pavement level, a mush-
room button or more substantial protection should be provided at any corner which might otherwise be encroached upon by turning vehicles.
Illumination and Reftectorization All refuge islands, including their approach-end treatment, shall be
provided with: 1. General illumination of the entire area, including adjacent vehicular-traffic lanes, or as much of the area as is required for safe operation; 2. Intensified illumination and reflectorization to show clearly the outlines of buffers or other structures, collision with which might seriously damage motor vehicles or imperil pedestrians.
Refuge islands shall not be installed unless they can be adequately illuminated. It is desirable to have two independent sources of light in case of failure of one.
Signs On every refuge island that is in the line of traffic, standard regula-
tory or warning signs for loading islands shall be placed at the end toward approaching traffic.
Markings The approach-end treatment of a refuge island in the line of traffic
flow shall include pavement markings. The ends of all refuge islands toward approaching traffic shall be
marked. The latter applies particularly to buffers and lighting standards. Markings are also very effective when placed on the curbs of islands in or adjacent to the line of approaching vehicle traffic. If curb or pavement markings are used in other nearby locations to indicate parking prohibitions, such indications should also be used opposite refuge islands.
The use of a contrasting color, reflectorized paint, or other special treatment is recommended to indicate clearly the presence of the island, in which case additional curb markings are generally unnecessary.
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Summary Specifications for Refuge Islands
Designation of area.-Platform preferable; other means include fixed posts, mn.'lhroom buttons, pavement markings, or combinations of these.
Dimensions: Length.-Cross-walk width, with 5 feet minimum. Width.-Four feet minimum; preferably 6 feet.
End protection.-l:se buffer where speeds are relatively high; desirable in all areas.
Approach-end treatment.-Adequate to warn of presence of i;;land and indicate proper vehicle path or paths.
Side protection.-Mushroom buttons or curb, a;; needed to prevent vehiele encroachment.
Illumination.-General illumination of entire area; inten;;itied illumination and reftectorization of buffer;; or other ;;truetures.
Signs.-Standard Keep Hight sign or Double Arrow Hign as required.
Markings.-Stalldard approach pavement markings; standard markings Oil buffer or curbs.
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D-DIVISIONAL ISLANDS Legal Authority
Divisional islands are elements of street and highway design and accordingly no special authority is required for their installation...:. Functions
Divisional traffic islands are placed longitudinally in roadways to serve any of the following purposes:
1. Along the center line of a roadway of four or more lanes, to separate the streams of traffic flowing in opposite directions. See fig. 41.
2. Other than along the center line, in a roadway of six or more lanes, where it is desired to separate the slow-moving local traffic serving the abutting property from the faster through traffic in the center of the roadway.
3. In a roadway of any width, to guide traffic away from a fixed obstruction, such as a bridge support or pedestrian-island buffer.
4. In a roadway at any point where traffic is regularly stopped for toll or inspection purposes.
In some cases they are placed in a roadway of two lanes to prevent vehicles going ir~ the same direction from passing one another at hazardous points, such as narrow bridges, viaducts, underpasses, or dangerous curves. Curved divisional islands are sometimes placed partly around a rotary island to separate the streams of traffic from different entering highways.
Figure 41.-A paved median in. a suburban area. The width of the second island is reduced by combined acceleration and deceleration lanes provided for vehicles
making left turns to and from the divided street.
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Warrants

Anyone or a ('ombination of the following eonditions may illdi(~ate HlP desirability of installing one or more divisional islandH:

I. High accident frequeJ:rcy. :2. Dense vehicular traffic.
:3. High-Hpeed vehieular traffi(.

-t. vVide roadway. ;"). PhyHicul obstnH'tjon In
roadway.

DiviHional iHlandH shall be placed in ne\\" major thoroughfan's of four
or more lanes to separate traffic moving in opposite dire(,tion,;. Anv streetear tracks in Huch ]WW conHtruction ,;hall lw within UI(' divi,;ion~l i,;land.

This discussion is intended to apply primarily to urban areas wll(']"('

intersections are frequent, rather than to open country when' ('()Iltinuous median strips are a' matter of highway design.

As highway surfaees have been improved and speeds of automobiles

have riseu, the hazards of passing have vaHtly inereased. While 1hi,; ('(mdition ha,; been met to some extent by widening the roadway to three, four, and even more laneH, the hazard ,;till n~main,; ';0 long a,; there j,; a (~ommon surfaee in the eenter of the highway which i,; a('('essible to traffic moving in oppo,;ite direction,;. The only adequate

means of eliminating sueh hazard i,; the provi,;ion of a median st rip

to ,;eparate oppo,;ing traffic ,;treams. These strips may bp of any \I"idt h

from a narrow curbing to a broad landseapPd area. :Yledian strips, preferably rai,;ed, arp tllPrdore abo n~('ommell(kd

for existing roadways where the width permits. Their u,;e to a \'oid

('o,;tly (md proteetion and approaeh-end tnmtment of refuge island", at a ,;ucce,;sion of intersections i,; sugge,;ted in ,;e(,tion on Contillll(,u.s

::.\/fedian Strip. It i,; reeognizecl that narrow median ,;trip,; do not prm'ide adequate

protection for left-turning movements and for ('ro,;s traffie whieh mU,s1

wait at the island. Ordinaril,\' thiH can be accompliHhed only by widelling the island.
Designation of temporary islallClH by ,;andlmg,;, ,;tanehions, mark-

ing,;, or other means may be desirable to teHt a propoHed lay-out undN

aetual traffic flow.

Elements of Design
Divisional islands normally ha\"(' three distinct parts: (1) the are:1 from which motor vehicles are intended to be excluded, (:2) an area at the approaeh end eontaining devices to warn vehicle operators (If the presenee of the island and to indi('ate a suitable path or paths paHl it, and (3) reflecting or illuminating de\iceH adequate to make the island safe and effective at night.
l~nless the island serves also as a refuge island, only Hufficient end protection is required to prevent damage to vehicles, to ,;igns or markers. and to the island itself. To afford thiH tllP island should contraHt

in color with the adjacent pavement, and be so designed and located that the proper course of travel is obvious, easy to follow, and unquestionably continuous.
When divisional islands are used to prevent overtaking and Qassing at hazardous points they should be long enough and so designed as not to introduce a surprise element. A divisional island should not begin on a sharp curve or at the top of or just over a hillcrest. Designation of Area
In most cases divisional islands are designated by curbs outlining the area, with suitable filler of pavement, turf, or shrubs, depending upon the width, location, and other conditions (fig. 41).
Raised curbs are not essential where encroachment on the island is not dangerous to motorists, pedestrians, or property. In this case, islands may be designated by pavement markings, stanchions, mushroom buttons, or combinations of these. Sharply contrasting flush sections 15 to 36 inches ,yjde have also been used. Large islands, usually in park areas, .may be constructed without curbs, depending instead upon the contrast between the pavement and the island surface or vegetative cover, 01' upon delineation by guard posts or mounded earth.
figure 42.-Separate 'anes for 'eft turns. The roadway is illuminated and traffic signa's contra' movements at the intersection.
At the approach end, divisional islands sometimes are designed to rise gradually from about the pavement level to the height of the curb
233

or mounded center of the normal full-width section. On the other hand, an approach-end treatment, or the island itself, may consist entirely of jiggle bars.
At some locations it mlly be neeessary to plaee a pedestrian barrier on and along a divisional island to prevent indiseriminate pedestrian crossing of the roadways. The pedestrian barrier usually eonsists of some form of woven-wire or picket fence at least 3 feet high, lQ(~ated eentrally between the island curbs for a full block length, or for a distance of several hundred feet each side of a pedestrian overpass or underpass. Pedestrian barriers so located materially increase the visibility of the divisional island to motorists, and give it a greater overall effectiveness as a traffic separator.
Dimensions
While the dimensions and shapes of traffic islands eannot be standardized in detail, eertain basic principles whieh are particularly applicable to divisional islands should be observed.
W idth.-The width of a divisional island depends on numerous elements, ineluding available right-of-way, traffic-lane requirements, and the extent to which the island is given added protective functions at intersections.
Fixed divisional islands in new construetion shall be at least 4 feet wide. This standard, however, should not preclude placing narrower islands in existing roadways where total width is restricted. A single raised and rounded eurb has proved effective in some cases.
Where right-of-way is available or obtainable at reasonable cost for a divisional island substantially wider than 4 feet, several points should be taken into account in determining the appropriate width, particularly adjustment to adjoining traffic lanes and protection at cross streets:
1. Adjustment to adjoining traffic lanes.--This is a paramount l'Onsideration. As a general rule divisional islands should not be placed where they will confine any part of the roadway on either side to less than two free-flowing lanes. The width of these through traffic lanes will be governed hy the volume, type, and speed of traffic and by conditions at the locality, somewhat greater widths being necessary for higher speed eonditions. For any section of street or highway it is desirable to provide pavements of uniform width. However, variation in width usually is necessary on small-radius curves at intersections and on ramp conneetions.
In very exceptional cases where a divisional island is desirable even though there is not sufficient spaee for two lanes of moving traffic on each side of the island, it may be designed for a single lane on the less important side, but this lane should be wide enough to enable other
234

vehicles to proceed slowly past a disabled vehicle, and the restricted width should be limited to sections of relatively short length.
In new construction consideration should be given to the possible need for future narrowing of the divisional island to provide additional traffic lanes.
2. Protection at cross streets.-At cross street it is desirable that divisional islands be of ufficient width to provide protection for vehicles crossing, making left turns, or making U-turn . For cross traffic an island width slightly greater than the length of a vehicle is necessary for protection of the vehicle "'hen it is stopped bet\\'een the through lanes approximately at right angles to the divided street. Divisional island widths of about 20 feet will protect a passenger car or light truck, but widths of 30 to 50 feet are necessary to protect busses and commercial vehicles crossing approximately at right angles. Greater widths may be necessary, depending upon the minimum turning radii of the vehicles involved, to provide protection for vehicles making left turns to or from the cross road and those making U-turns on the divided streets so that these movements can be made bet\\"een the proper lanes and with minimum interference with other traffic. An analysis of minimum design for these conditions is to be found in A Policy on Highway Types (Geometric) of the American Association of State Highway Officials (pages 24 to 53). As shO\\"n therein, island widths of about 20 to 25 feet should be provided for protection of passenger vehicles and 30 to 50 feet for commercial vehicles.
Figure 43.-At this channelized Y intersection, with irregular-shaped islands, traffic signals regulate the principal crossing movement.
235

Curbs outlining areas used by pedestrians should be 5 to 7 inches high, with faces nearly vertical. At eross walks, or where there is heavy pedestrian traffic, the lower figure is preferable, due to the danger of pedestrians accidentally stepping off the curb. Sueh curbs effectively prevent encroachment by most vehicles under ordinary circumstances.
Where pedestrian protection is not involved, islands should be outlined by low, sloping curbs, with the incline not steeper than 45 degrees, so that in emergencies vehicles can mount them without difficulty. Curbs with flat faces are usually found to be more economical in construction than those with rounded faces, and are better adapted for high-visibility treatment. Heights of sloping curbs vary widely depending upon the slope design, but heights of 4 to 8 inches are common.
A curb higher than 6 inches should not be used on the end of an island where the width is less than about 6 feet, to prevent damage to the under parts of a vehicle straddling the island.
Barrier curbs intended to confine vehicles to the pavement or to individual lanes should be at least 9 inches high, with a batter of about 1 inch. Such curbs are sometimes favored for narrow divisional islands. It should be recognized, however, that curbs nearly vertical, particularly barrier curbs, reduce the effective width of pavement for vehicle operation, as drivers do not operate close to them. That objection has been partly met in some cases by double curbs, in which a lower step 7 or 8 inches high is sunnounted by an additional step set back 5 or 6 inches.
Night visibility of island curbs is important, and construction with white concrete, white stone chips, incorporated reflectors, or reflective facets is recommended.
Approach-End Treatment
Approach-end treatment as here described applies to the beginning of a divisional island, not to each successive part of an island resulting from breaks at or between intersections.
The approach ends of all divisional islands shall be carefully designed to provide for approaching traffic, a maximum degree of warning of the presence of the island and, where necessary, a definite indication of the proper path or paths to be followed.
Application of this rule, identical with that laid down for loading islands, will require somewhat different treatment. Unless the island serves also as a pedestrian island there will be no need for a buffer or prow to prevent a motor vehicle from mounting the island. On the other hand, particularly at points where vehicle speeds are high, advance warning of the presence of a divisional island and guidance as to the path or paths vehicles should follow is as important as at pe-
237

destrian islands, and additional indications are needed at the island proper.

As stated in section on Approach-End Treatment, the following de-

vices are in use:

,'#'

1. Pavement markings, with or without mushroom buttons.

2. Signs.

3. Reflecting devices.

4. Flashing yellow beacons.

5. Contrasting pavemlmt colors and textures.

(j. .Jiggle bars.

7. A vertical element sloping up to the island nose.

8. Various combinations of 1 to 7.

In addition, the approach end of the island may be tapered or otherwise shaped to guide vehicles into the proper roadway or roadways.

In advance of the curbed island nose, pavement markings or other devices may be placed to outline or fill up the roadway area normally unused by vehicles following a path to dear the island.

Island approach ends should be provided with a form of highvisibility indication to be effective both in daytime and at night. This may be done through the construction of white concrete curbs, by a curb surface coating of light-colored stone chips, paint, or othm

reflective material, by construction with indented faeets to refleet light from headlamps, by incorporation of reflector buttons or other reflective materials, or by other suitable means. Signs loeated near the ends of the islands and illuminated or suitably reflectorized may be used alone or in eonjunction with other treatment. Also, floodlights or other special units for area illumination, or flashing beacons with yellow lenses might be used. To the extent practicable some highvisibility treatment should be eontinued along the island.

Low-level reflector buttons rather qui('kly become ineffeetive, because of dirt, unless frequently cleaned.

At the beginning of a divisional island constituting a median strip the island nose should be offset to the left, as faeed by approaehing traffic, the right curb of the island forming a diverging taper to defle(t traffic toward the right. Where a divisional island is introduced between two lanes of traffic moving in the same direction, similar offsets may be used on each side of the nose to direct traffic into the separate roadways. In both cases the curbed nose should be semicircular, preferably about 3 feet in diameter, the curbs widening beyond to the full width of the island. At cross-road openings in divisional islands the island nose may be made semicircular or of a tapered and rounded shape for left-turning movements, consistent with the island width.

238

Illumination and Reflectorization A high intensity of well-directed street lighting is highly desirable
at the approach ends of divisional islands to show dearly the locations of the islands and the proper lanes for vehicles to travel. Where facilities for such lighting are not available, the deficiency should be overcome as fully as possible by such means or combinations as are suggested in section on Approach-End Treatment.
Signs A curbed divisional island in the line of traffic flow shall be pro-
tected at the approach end by the appropriate reflectorized or illuminated sign or marker. Where the curb-to-curb width is sufficient, 3 feet or more, a regulatory Keep Right sign as described in section on Keep Right Sign shall be used. On narrower islands the reflectorized hazard marker described in section on Hazard Markers shall be used. To reduec the likelihood of being struck, such signs or markers may be set back about 10 feet from the end of the island.
Markings The approach end of a divisional island in the line of traffic flow
should be designed, signed, and marked to indieate its presence and also to outline the proper vehicle paths. Where necessary the approaehes to sueh islands shall be marked in the manner provided for refuge islands in section on Markings.
Summary Specifications for Divisional Islands
Designation of area.-Vertieal or sloping curbs and filler, mushroom buttons, pavement markings, contrasting materials or island cover, or combinations according to conditions.
Dimensions: Width.-Four feet minimum in new construction; 20 feet or upward desirable. Other dimensions.-Depend on eonditions.
Approach-end treatment.-Ad(~quate to warn of presence of island and indicate proper vehicle path or paths.
IHumination.-Effective reflect orizati 011 or illumination of approach-end treatment.
Signs.-Standard Keep Hight sill;n or refledorized hazard marker.
Markings.-Where necm,sary, standard approach pavement markings.
239

E~CHANNELIZING ISLANDS
Legal Authority
Channelizing islands are-elements of street and highway design and accordingly no special authority is required for their installation.
Functions Channelizing islands are used at intersections to guide motor ve-
hicles into orderly courses. They prevent or reduce undesirable weaving and maneuvering by keeping the vehicles in clearly defined paths. They provide convenient space for necessary signs. They may protect turning vehicles from through traffic moving at higher speeds. They may establish the desired angles for the crossing of vehicle paths. They may permit streams of traffic moving in the same general direction to converge at very small angles, minimizing possible eonflicts. Their field of use is discussed in greater detail on pages 51 and 52 of A Policy on Intersections at Grade, issued by the American Assoeiation of State Highway Offieials.

Warrants

Anyone or a combination of the following conditions may indicate the desirability of installing one or more islands to channelize or segre-

gate vehicles: 1. High accident frequency. 2. Dense vehicular traffic. 3. High-speed vehieular traffie. 4. Complex intersection.

D. Wide roadway. 6. Difficulty in providing ade-
quate control by standard signs and markings.

Specific warrants eannot be stated. Eaeh location ealls for speeial study. Channelizing islands are warranted and desirable in existing squares, plazas, and other broad expanses of pavement where with-

out them there is a eonsiderable amount of traffic moving in various directions without desirable orderliness. They are warranted at many intersections where traffic signals, involving greater costs of installation and operation, would otherwise be called for under one or more of the signal warrants described in sections on signals. At other intersections where traffie eontrol signals are warranted, the construction of islands may increase the effieiency of the signals.

Proper ehannelization is desirable at many intersections. A few islands earefully designed and plaeed to direct the preponderant eur-

rents of traffic, however, are far better than a larger number of small islands which create too many channels, confuse vehicle operators, and result in new points of eonflict.

Elements of Design
Channelizing islands normally have three distinet parts: (l) the area from which motor vehicles are intended to be exeluded, (2) an

240

area at the approach end containing devices to warn vehicle operators

of the presence of the island and to indicate a suitable path or paths

past it, and (3) illuminating devices adequate to make the island safe

and effective at night.

.

Unless the island serves also as a refuge island, only suffi~ient end

protection is required to prevent damage to vehicles, to signs or mark-

ers, and to the island itself. To afford this the island should contrast

in color with the surface of the adjacent pavement, and be 0 designed

and located that the proper course of travel is obvious, easy to follow,

and unquestionably continuous.

The provision, location, and design of channelizing islands at im-

portant grade intersections, particularly irregular intersections, merit

careful study. Designation of temporary islands by sandbags, stan-

cruons, markings, or other means may be desirable to test a lay-out

under actual traffic flow.

In new construction at inter ectiolls, where traffic signals or lights

are likely to be utilized as a second stage development, the initial

channelization should be patterned to fit the ultimate plan with a

minimum of change. It is of considerable assistance to provide con-

duits or cables initially under the pavements for future use.

Designation of Area
In most cases channelizing i 'lands are designated by curbs outlining the area, with suitable filler of pavement, turf, or shrubs, depending upon the width, location, and other conditions.

Figure 44.-Separation to permit the addition of central islands was an important factor in the channelization of this intersection. High-visibility curbs were used
and an overhead traffic signal regulates the principal crossing movement.
241

Figure 45.-1his channelized 1 intersection has stop control for crossing movements.
Raised curbs are not essential where encroachment on the island is not dangerous to motorists, pedestrians, or property. Islands of this nature may be designated by pavement markings, stanchions, mushroom buttons, or combinations of these. Flush pavement sections 15 to 36 inches wide of sharply contrasting color have also been u ed. Large channelizing islands, usually in rural areas, may be constructed without curbs, depending instead upon the contrast between the pavement and the island surface or vegetative cover, or upon delineation by guard posts or mounded earth.
Dimensions No fixed rules can be laid down as to dimensions of channelizi ng
islands. They should not be so small as to be inconspicuous to operators of approaching vehicles.
Curbed channelizing islands in new construction shall be at least ..], feet ","ide. Ho\\"ever, this should not preclude placing narrower islands in existing road\mys ,,here width is re tricted. They should be of proper width to establish correct lane widths. Given in table 3 are pavement \\idths for separate turning lane as recommended by the American Association of State Highway Officials in A Policy on Intersections at Grade (page 94) and A Policy on Grade Separations Jor Tntersecting Highways (page 63).
242

Figure 46.-Channelizing islands of various sizes and shapes are used at the terminals of highway grade separation ramps.

Table 3.-Pavement w)dths for seporate turning lanes, passenger and truck types of traffic.!

Hadius

One-way one-lane operation

Turning speed

Does not perini t passing of tailed
vehicle

Permits passing of stalled yehiele

Two-lane operation, either onc-
way or two-way

Passenger Truck Passenger Truck Passenger Truck

car

car

car

---------1----1----- --- ----- ----1-----1---

50

reel _

75

_

100

_

?n. p. h. 20 24 27

Peet
14. 13 J3

Peet 17 15 14

Feel 19 18
17

Feet 28 25 24

Peet 26 25 25

Peet 32 29
27

150 200 300
400
500

_ _

_

_

.

_

32 37
43
47 51

J3

J4

13

14

12

14

12

14

12

14

16

22

16

22

16

21

15

20

15

20

24

26

24

26

24

26

24

26

23

2li

1 As recommended by the American Association of State Highway Officials.

The character and purpose of an island should determine its height. Those. 'erving also as pedestrian islands should be 5 to 7 inches high. Islands on which there are signals, monuments, or the like, and those

243

intended as a positive bar to vehicular traffic, obviously require curbs of suitable height. Small islands on which there are no objects susceptible to injury may be low or flush with the pavement to minimize possible damage to vehicles mounting them.
,'#'
Curbs The specifications and recommendations for curbs bounding di-
visional islands are equally applicable for curbs of channelizing islands.
Approach-End Treatment The approach ends of all channelizing islands shall be earefully de-
signed to provide for approaching traffic a maximum degree 6f warning of the presence of the island and, where necessary, a definite indication of the proper path or paths to be followed.
The detailed information regarding approach-end treatment of divisional islands is equally applicable to that of channelizing islands. To the extent practicable some high-visibility treatment should be continued around the island.
Low-level reflector buttons rather quickly become ineffective, because of dirt, unless frequently cleaned.
Illumination and Reflectorization A high intensity of well-directed street lighting is very desirable at
the approach end of channelizing islands and at intersections containing such islands, to show dearly their locations and the proper lanes for vehicles to travel. Where facilities for such lighting are not available, the deficiency should be overcome as fully as possible by such means or combinations as are suggested in section on ApproaehEnd Treatment.
Signs Channelizing islands in the lines of traffic streams shall be protected
at the approach ends by appropriate reflectorized or illuminated signs. As conditions require, a regulatory Keep Right sign, or a Destination sign shall be used.
Channelizing islands forming separate turning lanes, i. e., those islands lying to the right or left of pavements for through-traffic streams, likewise should be protected by one or more destination signs at the approach or turn-off end. The assembly on the island may consist of a destination sign with messages for both the through streams and the turning movements or, where the latter have been provided for in advance of the island, only for the through streams. Where site conditions permit, a destination sign should be provided in advance of the turn-off lane formed by the islands, and if necessary the same message repeated in the assembly on the island.
244

Markings Channelizing; islands in the line of traffic streams, and the approaches
to such islands, shall be marked in the manner provided for refuge islands, not only to indicate the presence of the island but also to outline the proper vehicle paths.
Summary Specifications for Channelizing Islands
Designation of area.-Vertical or sloping curbs and filler; mushroom buttons, pavement markings, contrasting materials or island cover, or combinations accordinl?; to conditions.
Dimensions: Width.-Four feet minimum in new construction. Other dimensions.-Depend on conditions.
Approach-End treatment.-Adequate to warn of presence of island and indicate proper vehiele path or paths.
Illumination.-Effective illumination of approach-end treatment.
Signs.-Standard Keep Right sign or Destination sign. Markings.-Standard approach pavement markings.
245

Appendix A GLOSSARY OF TRAFFIC SIGNAL TERMS

Signals

Traffic Signal-Any power-operated traffic control device, except a Hign, b~' which traffic is warned or is directed to take Home specific action.

Traffic Control Signal-A traffic signal which, through its indieations, alternatel\"

direets traffie to stop and permits it to proeeed.

..

Fixed-Time Signal-A type of traffie eontrol signal whieh directs traffic to stop and permits it to proceed in aeeordanee with a predetermined time schedule.
Traffic-Actuated Signal-A type of traffie eontrol signal in which the intervals are varied in aeeordanee with the demalHiH of traffic as registered b\" the actuation of deteetors or push buttons.

1. Semi-traffic-actuated signal--A type of traffic-actuated Hignal in whieh
means are provided for traffie aetuation on one or more but not all appl'OlwheH to the interseetion.

2. Full traffic-actuated signal-A type of traffic-actuated signal in which means are provided for traffic actuation on all aproaches to the interseetion.
:3. Speed control signal-A type of traffic eontrol signal in which means are provided for traffic actuation on some or all approaches and whieh provides Go indieations in sueh a manner that vehiele speeds on one street are limited to a preselected maximum value. Stop Signal-A flaHhing red signal having the Harne function aH a Stop Hign. Caution Signal-A flashing yellow signal having the same general function aH a warning sign. Flashing beacon-A section of a standard traffic signal head, or a similar type de-

vice, having a yellow or red lenH in each faee, which is illuminated by rapid intermittent flashes.
Signal Head-An assembly containing one or more signal faees whieh may be deHignated aceordingly as one-way, two-way, three-way, four-way, or multi-way.
Signal Face-That part of a Hignal head provided for controlling traffic in a single direetion.
Signal Indication-The illumination of a traffic signal lens or of a c,ombination of several lenses at the same time.
Optical Unit-An assembly of refleetor, reeeptacle, redireeting cover glass, and door, with the neeessary supporting parts, to be used with a light source for providing a single signal indication.
Redirecting Cover Glass, or Lens-That part of the optieal unit which redirects
the light coming from the reflector. It iH commonly referred to as a lens or roundel. Signal Support-The physieal means whereby a signal head is supported in a
particular loeation. Signal Installation-All of the equipment and materials involved in the Hignal
control of traffie at one interseetion.

Controllers

Controller-A complete eleetrical mechanism for controlling the operation of traffie control signals, induding the timer and all necessary auxiliar~' apparatus mounted in a eabinet.
Auxiliary Manual Controller-A separate and distinct manual eontroller at-

tached to an automatie eontroller by means of which the traffic control signals

may be operated by hand when the automatic timer is disconnected.

FixedcTime Controller-An automatie eontroller for supervising the operation of

traffic eontrol signals in aeeordanee with a predetermined fixed-time eyele and

division thereof.

.'

Synchronous Motor Controller-A eontroller operated by a motor that will mallltain a eonstant speed governed by the frequency of the power supply eireuit.

246

Inductian Alotor Controller-A controller operated by a motor having variable
speed dependent upon the line voltage of the power supply circuit. Synchronous Supervisory Mechanism-An auxiliary synchronous motor applied
to an induction motor-driven traffie controller to cause such controller to keep in
step with the eonstant frequeney of the power supply eireuit. Master Cantroller-A synchronous motor-driven controller, or an induetion motor-
driven eontroller provided with a synehronous supervisory meehanism, designed
to supervise the operation of all interconneeted controllers so as to maintain definite time relationships of all sueh eontrollers in the signal system and to operate the remote signal shutdown, flashing; indieations, total time (~ycle change, and other features of operation.
Secondary Controller-An automatie eontroller for operating the traffie eontrol signals at an intersection under the supervision of a master controller.
Local Controller-A controller for operating traffie eontrol signals at an inter-
section (or two or three proximate interseetions) whieh may be isolated or ineluded
in a signal system. Traffic-Actuated Controller-An eleetrieal meehanism for supervising the opera-
tion of traffie signals in accordanee with the varying demands of traffie as regis-
tered with the controller by detectors or push buttons. Traffic-Actuated Speed Control-A type of traffie-actuated eontrol designed to
provide signal indieations that have the etTeet of limiting the speed of approaehing
vehicles. 1. Intersection Speed Control-A type of traffie-aetuated speed control in
which speed control features are eombined with or are superimposed upon full
traffie-actuated control at interseetions. 2. Nonintersection Speed Control-A type of traffie-aetuated speed eontrol
designed solely for limiting the speed of approaehing vehicles at road loea-
tions other than intersections. Timer-The automatic timing meehanism in a eontroller, ineluding all dials for
adjusting or setting intervals and offsets, switching and flashing meehanism, signal cireuit eontaets, motors, gears, and eamshaft, and also, in the master controller,
the total time eyele control and resynehronization or reset meehanisms. Double Dial Timer-An automatie timer equipped with two timing dials me-
ehanieally or electrieally intereonneeted so that it is possible to set up and remotely
seleet anyone of three timing programs of all intervals and offset. Triple Dial Timer-An automatie timer equipped with three timing dials mc-
ehanieally or electrically intereonnected so that it is possible to set up and remotely seleet anyone of three timing programs of all intervals and offset.

Detectors

Detector for Traffic A ctuation (general definition)-A device by which vehicles, streetcars, trolley busses, or pedestrians are enabled to register their presence with

a traffic-aetuated controller.

Pressllre-Sensitive Vehicle Detector-A deteetor installed in the roadway, capable

of being actuated by the pressure of a vehiele passing over its surfaee.

111agnetic Vehicle Detector-A deteetor installed in or near the roadway, eapable

of being actuated by the magnetic or electrical disturbanr:e eaused by thc passage

of a vehicle.

Sound-Sensitive Vehicle Detector-A deteetor installed in or near the roadway.

eapable of being actuated as a result of sound ereated by a passing vehicle.

.

Light-Sensitive Vehicle Detector-A deteetor installed in or near the roadway,

eapable of being aetuated as a result of a vehiele interrupting a projected light

beam. Streetcar Detector-A detector installed on or near a trolley wire or rail, capable
of being operated by the passage of a trolley wheel or shot~. Nondirectional Detector-A detector capable of being aetuated by vehieles pro-

eeeding in either direetion. Directional Detector-A deteetor eapable of being actuated only by vehieles pro-
ceeding in one direetion. Pedestrian Detector-A deteetor, usually of the push-button t~'pe, installed near
the roadwa~', capable of being operated b~' hand.

Signal Operations
Time Cycle-The number of seconds required for one complete revolution of the timing dial or complete sequence of signal indications.
Color Sequence-A predetermined eonseeutive order of appearanee of signal eolor indieations during sueeessive intervals within a total time cycle.

247

Traffic Phasc (Traffic M ovement)-A part of the time cycle allocated to any t ffi movement receiving the right-of-way or to any combination of traffic mover:;a ~

receiving the right-of-way simultaneously during one or more intervals.

en

VeMcular Phase (Veh~cular 1\;[ovement)-A traffic phase allocated to vehicul

traffic.

'"

ar

Pedestrian Phase (Pedestrian M ovement)-A traffic phase allocated exclUsively t

pedestrian traffic.

.0

. I.nter.val-Any one of the several divisions of the time eycle during which signal mdlcatlOns do not change.

Clearance Interval-The time of display of the signal indication following th

right-of-way interval (generally yellow).

e

. In.terval Sequence-The order of appearance of signal indications during successive mtervals of a evcle.

t Initial Portion-The first part of the green interval which is timed-out or se
m'ately controlled by a traffie-aetuated controller before the extendible portion the interval takes effect.

Extendible Portion-The part of the green interval following the initial portion Un.it Extension-The min.imum time, during the. exte~dible portion, for whi~h

the nght-of-way must remam on any traffic phase followmg an actuation on that phase, but subject to the extension limit.

Extension Limit-The maximum time for which actuations on any traffic phase

may retain the right-of-way after actuation on another traffic phase. .~finirnurn Period-In semi-traffic-actuated control, the shortest time for which

the right-of-way shall be given to the approaches not having detectors.

P,fanual Operation-The operation of an automatic controller mechanism by means of a hand-operated switch.

Flashing Feature-A relay or other device installed in a controller which when

energized from a remote point or by an automatic time switch discontinues normal

signal operation and causes the flashing of any predetermined combination of sig-

nallights.

Ernergency Feature-A relay or other device installed in a controller which when

energized from a remote point discontinues the normal signal operation and dis-

plays special signal indications for the movement of high-speed fire apparatus, etc.

System Operatian
Signal Systern-Two or more signal installations operating in coordination. Simultaneous Systern-A signal system in which all signals along a given street always give the same indication at the same time. Alternate Systern-A signal system in which alternate signals, or groups of signals, give opposite indications to a given street at the same time. Sirnple Progressive System-A signal system in which the various signal faces controlling a given street give Go indications in accordance with a time sehedule to permit (as nearly as possible) continuous operation of groups of vehicles along the street at a planned rate of speed, which may vary in different parts of the system. Flexible Progressive System-A signal system in which the intervals at any sig!lal may be independently adjusted to the traffic requirements at the intersection, and in which the Go indications at separate signals may be started independently at the instant that will give the maximum efficiency. Through Band-The time in seconds elapsed between the passing of the first and the last possible vehicle in a group of vehicles moving in accordance with the designed speed of a progressive signal system. In-Tirne Operation-A specified timing relationship of the Go indication between (,ontrollers in a system of traffic eontrol signals in aecordanee with a predetermined timing diagram. Offset-In a signal system, the interval in seconds between a certain instant arbitrarily used as a time reference base (recurring each cycle) and the start of the Go indication at a given signal in that system. Single Offset-An adjustment mechanism for setting up the timing arrangement of the start of the Go indication. Double Offset-An adjustment mechanism providing for the setting up of two timing arrangements of the start of the Go indication, either of which may be selected manually or by means of an electric time switch. Triple Offset-An adjustment meehanism providing for the setting up of three timing arrangements of the start of the Go indication, anyone of which ma~' be selected manually or by means of an electric time switch.

Offset Dial-A calibrated dial on an automatic timer equipped with adjustment

devices by means of which it is possible to set any desired offset of the beginning

of the Go signal indication.

Interval Dial-A dial on an automatic timer, calibrated in 1 percent steps, and

equipped with adjusting devices by means of which it is possible to divide the total

time cycle into the required number of intervals and set up the offs.l)t and interlock.

A utomatic Reset-A mechanism applied to a traffic signal controller by means of

which the timing of the beginning of the Go indication is checked automaticallv

once each total time cycle.

'.

Out-oj-Step-That condition of a traffic control signal installation belonging to

a signal system when its operation does not possess the intended relationship to

the system.

Recoordination-Restoration of the intended interrelationship of operation of

signals in a signal system.

Power Failure Feature-A relay mechanism which operates upon restoration of

power after a failure, causing traffic control signals to operate as flashing signals

or illuminating a power failure indicator until the controller is restored manually

to normal in-time operation.

Power Failure Indicator-A pilot lamp mounted on or in the controller cabinet

which, when illuminated, indicates that power has failed and that the controller

requires manual recoordination.

Remote Cycle Change-A mechanism applied to the timer of the master controller

to make possible, by means of manual operation or by means of an automatic time

switch, a change in the total time cycle in operation at all local controllers inter-

connected within a signal system.

Remote Signal Shutdown Relay-A relay installed in a local controller which when

energized from a remote point causes signal operation to be discontinued and the

signal lights turned off.

Remote Flashing Relay-A relay installed in a local controller which when ener-

gized from a remote point causes normal signal operation to be discontinued and

specified signal lights to be operated in a flashing manner.

General and Accessory Equipment
Cabinet-A dustproof and weatherproof enclosure for housing the controller and associated equipment.
Panel-An insulated board within the controller cabinet upon which are mounted all fuse receptaeles, terminals, relays, hand or clc(,trically operated switches, and other equipment.
Field Terminals-Devices mounted on the panel for (,(mneeting all wires entering the controller cabinet.
Signal Contacts-A mechanism arranged to energize or de-energize signal light circuits during a specified signal color interval.
Signal Shut-down Switch-A switeh in a traffic signal controller which may be operated by hand to discontinue the operation of traffic control signals.
Radio Interference Eliminator-A combination of choke coils and/or condensers applied to signal light eireuits to suppress or minimize interference with radio reception.
Automatic Clock Switch-A device for automatic control of the operation of traffic control signals in any manner prescribed by a predetermined time schedule.
Relay Jack-A clip or reeeptacles generally installed on the panel into which the prongs of a jack mounted relay may be fitted.
Jack Jfounted Relay-A relay equipped with a prong sub-base which may be removed or replaced without disturbing an,' wiring.

249

ILLUSTRATED INDEX FOR SIGNS & MARKERS
REGULATORY SIGNS

R-1A Page 15
R-2 Page 19

R-1B Page 15

R-lC Page 16

SPEED LIMIT
60
5 5 TRUCKS
UNDER 10000 L8S
5 0 10000 TO
16000 LBS
4 5 OVER
16000 LBs

SPEED LIMIT
50
5 0 TRUCKS
UNDER 10000 LBS
5 0 10000 TO
16000 LBS
4 5 OVER
16000 LBS

OM

R-3

NIGHT

Page 20

Page 21

SPEED ZONE AHEAD
R-6 & R-7 Page 22

NO
RIGHT TURN
R-8 Page 22

NO RIGHI TURN
R-9 Page 22

NO
LEFT TURN
R-10 Page 22

NO lEfT TURN
R-l1 Page 22

[T!~JN
R-12
Page 22

~ TURN
R-13 Page 22

~TURNS R-14 Page 22

~ TURNS
R-15 Page 22

NO PASSING

WHEN

YELLOW LINE

IS RIGHT OF

CENTERLINE

R-18 Page 27

KEEP RIGHT
EXCEPT TO PASS
R-19 Page 27

NO
PASSING
R-16 Page 26
KEEP
R-I-G+HT
R-20 Page 28

END NO
PASSING
ZONE
R-17 Page 27
DO NOT ENTER
R-21 Page 28

CONE WAY~
R-22 Page 30

TWO WAY
TRAFFIC
AHEAD

R-23 Page 30

NO
PARKING
ANY TIME
R-24 Page 32

NO
PARKING 8 AM. TO 4 P.M.
R-25 Page 32

NO ANGLE
PARKING
R-26 Page 32

NO
TOPPING
OR
STANDING
R-27 Page 32

ONE HOUR
PARlIRG FROR9A! T01P!
R-28
Page 32

NO
PARIIRG BUS STOP
R-29 Poge 32

NO PARlIRG
KERE TO (ORm
R-30
Page 32

NO
pml~G
LOAOIRG lORE
R-31 Page 32

NO PARKING
ON PAVEMENT
R-32 Page 33

CROSS ON
GREEN LIGHT ONLY
R-33
Page 33

USE
CROSS
WALK

ROAD
CLOSED

R-34

Page 33

R-35

Page 34

STOP
fOR
SCHOOL BUS
LOADING UNLOADING
R-36
Page 34

SIGNALS SET FOR
25 M.P.H.
R-37 Page 34

LOAD
LIMIT
TONS
R-38 Page 35

WARNING SIGNS

W-4A Page 44

W-5 Page 45

W-25 Page 59
Page 61
W-28 Page 62

W-38 Page 68

W-39 Page 68

~.II ","
W-40 Page 68

Page 70

GUIDE SIGNS
Major Routes and Intersections

M-2 Page 70

M-3 Page 70

GEORGIA US
23
M-4 Page 70

~ M-5 Page 70

[Brn[H]~~

M-6 Page 71

M-6S Page 71

M-7 Page 71

M-B Page 71

M9 Page 71

GUIDE SIGNS
Secondary Routes and Intersections

IJUNCTIONI
M-1A Page 89

C-CAMAK 151
M-10A Poge 77

M-6A Page 74

M-6AS Page 74

lHJ
M-7A Page 74

(3J
M-8A Page 74

~
M-9A Page 74

lENDS]
M-12A Page 75

GEORGIA US
23
M-4 Page 70

~ M-5 Page 70

INFORMATION SIGNS

GEORGIA
STATE LINE
I-I Poge 78

ATLANTA
CITY LIMIT
1-2 Page 78

FULTON COUNTY
1-3 Page 78

I I ABERDEEN
1-4 Page 78

STATE

HIGHWAY

RIGHT OF WAY

FOR f'EIlM'Ts S<:E srAT~H'~~~~~~~A~~(Il'" sr4TE HIG~WAt DEPAllr..fHrOF"GEORG'4
1-5 Page 79

SCHOOL SIGNS

NO PARKING
SCHOOL HOURS
5-6 Page 94

@
5 C H 0 0
L
5-7 Page 94

~
5 C H 0 0
L
5-8 Poge 94