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Traffic lights see into the future


Scientists have developed a computer-based system to reduce the risk of crashes at intersections (Image: iStockphoto)

A traffic system that predicts whether two cars will collide could help motorists avoid crashes, especially at intersections that lack lights or signs.

The signal, in development at the Technion-Israel Institute of Technology, is part of 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 travelling.

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 give-way sign will flash.

"What makes this system innovative is the fact that it flashes only when needed," says Dr Yotam Abramson, team leader of the Smart Junction project.

Abramson says other systems attempting to produce such a warning either flash continuously or frequently enough that drivers get used to seeing the lights and begin to ignore them.

But why put such a high-tech system at an intersection without traffic signals? Why not just put up some traffic signals?


Abramson says traffic lights alone don't reduce the number of accidents at intersections.

Statistics show the chance of an accident at an intersection with signals is no lower than at one without.

Also, says 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 says.

The list is long of the kinds of things a highway planner could do with that information, says 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 says.


Despite the safety benefits of such a system, cities might shy away from it because of the unavoidable cost of installing and maintaining the system, Tarnoff says.

"Even though it's a good idea, I think it's unlikely that something like this would receive widespread acceptance in the US and even elsewhere in the world," he says.

Right now, Abramson and his team are 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 crossing and even be used to generate an alert inside the vehicle. That way if the driver does not brake, the car just might.
