'Smart' Traffic Signals Save Dumb Drivers

Aug. 31, 2007 — Even the most cautious drivers make mistakes. But a new, "smart" traffic signal could help motorists make better decisions and avoid collisions, especially at intersections that lack lights or signs altogether.

The smart signal, in development at the Technion-Israel Institute of Technology, is part of a bigger transportation infrastructure being designed to incorporate computers and automated systems to improve traffic flow and safety. Such a system could work to not only alert individual drivers, but also to prevent accidents and track violations.

The alert system consists of two standard surveillance cameras, each mounted on a pole at an intersection. One camera faces the main road and the other faces the secondary road. As traffic approaches, the cameras record and send video to a computer at ground level.

Image processing software discerns moving cars from the background and determines how fast the vehicles are traveling. The software automatically projects the cars' trajectories and, based on their speed and direction, calculates the likelihood of a collision.

If it identifies a risk, red lights on a stop or yield sign will flash.

"What makes this system innovative is the fact that it flashes only when needed," said Yotam Abramson, team leader for the Smart Junction project. According to Abramson, other systems attempting to produce such a warning either flashed continuously or frequently enough that drivers got accustomed to seeing the lights and began to ignore them.

But why put such a high-tech system at an intersection that lacks traffic signals? Why not just put up some traffic signals?

According to Abramson, traffic signals alone don't reduce the number of accidents at intersections. Statistics show that the chance of an accident in a signalized intersection is no lower than in a non-signalized one.

Also, said Abramson, traffic signals delay traffic on major roads. In fact, with traffic lights at all intersections, it takes a person five to 10 times as much time to travel from point A to point B.

"Most of this time will be wasted on standing in front of a redundant red signal, where no traffic exists on the other road," he said.

The list is long of the kinds of things a highway planner could do with that information, said Phillip Tarnoff, director of the Center for Advanced Transportation Technology at the University of Maryland.

"If we knew more about when cars were getting closer to an intersection, we could do a much better job of timing signals," he said.

But despite the safety benefits of such a system, municipalities might shy away from it because of the unavoidable cost of installing and maintaining the system, said Tarnoff.

"Even though it's a good idea, I think it's unlikely that something like this would receive wide spread acceptance in the U.S. and even elsewhere in the world," said Tarnoff.

Right now, Abramson and his team are currently evaluating the smart signal at a four-way urban intersection in Tel Aviv by measuring the number of "almost accidents" with and without the device.

Eventually, the alert could detect pedestrians at a crosswalk and even be used to generate an alert inside the vehicle. That way if the driver doesn't brake, the car just might.

Related Links:

The Smart Junction Project

The Center for Advanced Transportation Technology

Technology Review

Popular Mechanics