New software alleviates traffic.

• Position: Transportation

The same in-road detectors that control traffic lights and monitor traffic could soon respond quicker to traffic jams, thanks to software developed by Benjamin Coifman, assistant professor of electrical engineering and civil and environmental engineering, Ohio State University, Columbus. In tests, the software helped California road crews discover traffic jams three times faster than before, allowing them to clear accidents and restore traffic flow before many other drivers would be delayed. This technology also could provide drivers with the information they need to plan efficient routes, and even improve future road design.

Many drivers probably have noticed the buried devices, called loop detectors, at intersections. A square outline cut into the pavement marks the spot where road crews have inserted a loop of wire. When a car stops over the loop, a signal travels to a control box at the side of the road, which tells the traffic light to change. Although the loop detectors are barely more than metal detectors, they collect enough information to indicate the general flow of traffic, Coifman explains. So, he set out to use the detectors to pinpoint traffic congestion and accurately measure vehicles' travel time.

With the software, a small amount of roadside hardware, and a single PC, a city could improve traffic monitoring significantly without compromising drivers' experience of the road, Coifman concludes. That's important, he argues, because good traffic management can't be obtrusive. "If transportation engineers are doing their job well, you don't even realize they've improved travel conditions."

Coifman wrote computer algorithms that can capture a vehicle's length as it...