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Wednesday, February 5, 2014

Ramp Meters: Unappreciated or just misunderstood?

A look at a Phoenix-area ramp meter in action. There’s no delicate way to put this, so we’re just going to come right out and say it – we feel that ramp meters are underappreciated.

These signals control the flow of traffic entering a freeway, thereby helping to ease congestion. By managing queues of vehicles, ramp meters provide for safer merging of vehicles and mitigate potential collisions

Yet, it’s not uncommon to see drivers totally ignore a ramp meter and drive right through its red light.

Maybe ramp meters are just misunderstood…

If that’s the case, hopefully this post will clear things up and give commuters a new respect for these signals. Today, we’re sharing with you a series of frequently asked questions (and answers) all about ramp meters.  

Q) When traffic is light, couldn’t you just keep the lights green? It seems silly to have to stop when I’m the only car.
A) Having a continuous green light, even when there is no traffic on the ramp, could create a potential safety issue.  For example, if a group of three or four motorists see a green light on the ramp meter, they will assume they do not need to stop. But, as soon as the first car reaches the detection, the meter will kick into action and a red light will show. Now the cars are traveling at speed and once one car attempts to stop for the red light, it could set up the possibility for a crash. That’s why our ramp meters “rest in red,” and not in green.

Is there any evidence to indicate these meters have actually improved freeway safety?
There are many studies available online to support the benefit of ramp meters. Basically, ramp meters help to increase freeway speeds, decrease travel times and reduce delays. Ramp meters have also been shown to increase freeway capacity and reduce crashes (specifically rear-end collisions).  This explanation is given in the U.S. Department of Transportation’s Federal Highway Administration Ramp Management and Control Handbook: “The manner in which safety is improved depends on the type of ramp management strategy selected. Ramp metering improves safety by breaking up platoons of vehicles entering the freeway, thereby allowing more orderly and safe interactions between merging vehicles and freeway mainline vehicles.”

What should I do when I pull toward the ramp meter and the light turns green before I have a chance to stop? Am I allowed to proceed without stopping?
Ramp meters should be followed like any other traffic signal. If you reach the light when it turns green, you can proceed without stopping if it is safe to do so.  But always be prepared to stop when ramp meters are active and remember that only one car can go per green light.

Some of these new ramp meters have what appear to be cameras above them. Are they photo radar cameras?
ADOT doesn’t have cameras at our ADOT ramp meter locations. What you may be seeing is the receiver for wireless detection.

Why can’t I just ignore the ramp meter’s red light? I see other motorists do it regularly.
It is illegal to run a red light on a ramp meter, just as it is against the law to run any red light. Ramp meters are to be followed just like any other traffic signal. Drivers who fail to obey the ramp meter signal can be cited (the violation falls under Arizona State Statutes 28-645 and 28-644). Ticket fines vary from county to county, but can typically range $140-180 and include points against your driving record.
Posted by Angela DeWelles   |  Labels:  Intelligent-Transportation-System, Ramp-Meters
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