New in Virginia: Variable speed limits

Virginia recently introduced a novel concept to its highway system: the variable speed limit. On a fifteen-mile stretch of northbound I-95, the state has installed a total of forty-eight brand new electronic speed limit signs which can change the speed limit of the highway in real time. These new signs offer significant improvements for both traffic and safety conditions.

highway traffic

Cutting out reaction time

Surprisingly, a lower speed limit can lead to a higher overall rate of travel when traffic is congested. Traffic jams are caused not only by the sheer volume of cars, but also by the reaction times of individual drivers. It takes the average driver 1.5 seconds to react to a new situation. Every time a car has to start or stop, it takes each driver, all the way down the line, another 1.5 seconds.

If cars are moving steadily, even if they are moving slowly, there will be less time spent reacting. Highways will be able to handle far more vehicles without a traffic jam developing.

That’s where the variable speed limit comes in. As traffic volume increases, the electronic speed limit signs slowly lower the maximum speed. This allows drivers to approach congestion gradually, rather than coming upon it at speed and braking sharply. Ultimately, designers hope that the system will increase the safety and efficiency of highways all over the Commonwealth.

female driver

How does the system work?

The variable speed limit system is a sophisticated network. Radar detectors along I-95 collect data on traffic volume and speed. That information is analyzed by a program that adjusts speed limits to account for traffic patterns, minimizing congestion. The system also senses when traffic conditions are lightening, and quickly brings the speed limit back up. This allows normal traffic patterns to resume.

Avoiding deadly crashes

The variable speed limit system also has enormous safety benefits. On the highway, vehicles traveling 70 or 80 miles per hour may suddenly and without warning come upon a line of stopped traffic. This leads to some of the deadliest and most catastrophic crashes on the road.

deadly crash , paramedics pulling out person in flipped car on the road

The variable speed limit system gives drivers multiple miles in which to gradually reduce their speed, and provides increased warnings of traffic conditions.

In addition to the speed limit signs themselves, each new area of signage is equipped with flashing beacons to draw drivers’ attention and provide additional warnings of an impending need to brake. There are also new message boards installed near the beginning of the section, to allow VDOT to directly communicate traffic conditions and other important information to drivers.

Click here to see a video about the new variable speed system, and get more information about how the system works. None of us like to sit in traffic, and no one wants to be a victim of a terrible highway crash. Variable speed limits are helping to make the roads safer and more efficient for every driver.

If you or someone you love has been involved in a highway crash, call the car accident attorneys of Allen & Allen for a free consultation, at 866-388-1307.