Georgia DOT: ramp meters in metro Atlanta [2008]

Ramp Meter
Myths and Realities
Myth: The green means that there is an upcoming "space" on the highway into which I can move.
Reality: The green light does not mean that there is a space into which you can move. You should proceed with extreme caution when entering the freeway at all times.
Myth: Ramp meters do not benefit me because they increase my overall commute time by making me wait to get on the freeway.
Reality: Ramp meters benefit everyone. The meters help to provide consistent travel speeds, help prevent merging accidents and reduce fuel consumption. You may have to wait on the ramp for a little while, but everyone's ride on the freeway should be smoother and faster. This process should decrease your overall commute time.
Myth: Ramp meters do not do a lot of good.
Reality: Ramp meters are one of the most costeffective ways to ease freeway congestion. Tests done in other cities, with the same demographics as Atlanta, show that ramp meters reduce merging accidents, reduce recurring congestion and allow more vehicles on the freeway. These are benefits to all motorists and to Atlanta.
Ramp meters provide a smooth transition for vehicles merging from the ramps to the freeway, making travel safer for everyone on the ramp and the freeways.

Office of Communications One Georgia Center
600 West Peachtree Street, N.W. Atlanta, GA 30308

Ramp Meters in Metro Atlanta

How does it work?
Ramp Meters are traffic signal devices located on entrance ramps to the interstate. They regulate the frequency of vehicles entering the flow of traffic on a freeway.
Ramp Meters are one of the tools in the toolbox to help mitigate traffic congestion. By pacing the entry of vehicles onto the freeway usually at 3 to 4 second intervals the merging vehicles are less likely to slow the freeway traffic. The meters help to split up the continuous flow of traffic from entrance ramps; allow vehicles to merge with freeway traffic more smoothly; make travel safer; and enable the freeway to accommodate more vehicles during peak hour travel.

The Georgia Department of Transportation www.dot.ga.gov

Ramp Meters in Atlanta are necessary due to the increasing congestion in the metropolitan area. Georgia DOT's 2004-2006 accident data shows approximately 95 percent of Atlanta's traffic accidents on I-75, I-85, I-20 and I-285 occurred at entrance ramps. These accidents were, in some way, related to merging onto the freeway.
In Summer 2008, Georgia DOT added, in phases by corridor, 166 new ramp meters on all major interstates throughout metro Atlanta.
Hours of operation are at the onset of peak commuter times and when traffic volumes dictate. When traffic builds to a certain level, the meters will turn on to regulate the flow of traffic onto the freeway.
Benefits of Ramp Metering:
Reduces hours of vehicle travel
Decrease fuel consumption
Maintains consistent traffic flow on the interstate
Allows more cars to use the freeway
Increases freeway speeds
Reduces some vehicle emissions
Reduces rear-end and side swipe accidents accidents associated with merging

Questions and Answers
Q. How will I know the ramp is being metered?
A. There are signs at the beginning of the ramps which indicate whether or not the ramps are metered. There will be a flashing yellow warning light when the meters are running.
Q. Do ramp meters also have the same amount of time between each cycle?
A. No. Special under-pavement detectors located on the ramps and on the main freeway feed traffic information into the meter controllers. This process allows the metering rate to be adjusted depending on the volume of cars on the ramp and on the freeway.
Q. Will the ramp meters cause traffic to back up onto the surface streets?
A. Yes, due to the difference in ramp lengths and traffic volumes, some delays may occur on the ramps and surface streets near the interstate. However the goal is for the time to be made up on the interstate. Also, The ramp meters are built with under-pavement detectors at the top of the ramps to sense when traffic is building up toward a surface street intersection. The metering rate will be adjusted automatically to accommodate the vehicles waiting to enter the freeway. Cameras also are used to visually monitor the traffic flow.
Q. Is Georgia the first state to use ramp meters?
A. Over 20 states have successfully have successfully used ramp meters, some for more than 20 years.
Q. Will these ramp meters operate all the time?
A. Ramp meters are designed to work at the onset of peak commute times and when traffic volumes dictate. When the traffic flow on the freeway drops below a certain level, the ramp meters will be turned off.
Q. What happens if I run the red light on the ramp?
A. The meters are intended to help you. The system only will work with the cooperation of drivers. Running a red light on a ramp carries the same penalties as running any traffic signal in Georgia.
Q. How do I merge with traffic once I get the green light?
A. The same way you always do, yielding to any vehicle close enough to be of immediate danger.
Q. What happens if the freeway becomes clogged because of an accident?
A. If there is too much congestion of the freeway, the ramp meters will be turned off and vehicles will be allowed to enter the freeway on their own.

How do Ramp Meters Work?
Ramp meters work similarly to traffic signals with a red and green light. All vehicles must stop when the light is red.
When the signal turns green, the vehicle at the front of the line on the ramp may cautiously move onto the freeway. Only one vehicle is allowed onto the freeway at each green light signal.
Sensors are located at the top of each ramp to monitor back-ups that may occur on the ramps. If there are too many cars on the ramp, sensors alert the signal which then allow more cars onto the freeway. Operators at Georgia DOT's Transportation Management Center also will monitor the meters through cameras and will make necessary adjustments.
On two lane ramps, the meters will allow one car to merge at a time.