No More Stopping at Red Lights

If you are not happy when you have to stop at a red light, hang in there. Help is coming. A group of researchers at Singapore’s Agency for Science, Technology and Research (A*STAR) have developed a driving aid that is being installed in some test cars.

City traffic can flow more freely without the inefficient stop-start interference of traffic lights. (Source: A*STAR)

The idea behind this system is similar to the token ring network topology, an efficient and fast network protocol. When a test car reaches an intersection without red lights, it crosses it in its own “safe space,” controlling its speed using adaptive cruise control.

According to Bo Yang, from the A*STAR Institute of High Performance Computing, who led the work, in the future, to help the path of the vehicles, intersections will have a communication beacon – similar to a GPS satellite – that will replace traffic lights. This instrument will collect, analyze and transmit data about the vehicles approaching the intersection, including their approaching speed and distance from the intersection and other vehicles. Each vehicle approaching the intersection will collect this data, and using a computer algorithm, each car will plot the safest course it should follow without stopping.

A smart intersection with communication beacons. (Source: A*STAR)

The algorithm uses the concept of “adaptive repulsive force,” in which a repulsion between two approaching cars is inversely proportional to the distance between each other. The stronger the repulsion force, the greater the speed adjustment the cars will make so they can pass each other safely.

“One of our most interesting findings is that the rules governing the necessary repulsion between vehicles is rather simple,” Yang said. “The result is a system that does not require much computing power at the beacon or in the vehicle itself,” he adds.

For this system to work, cars should be able to break and accelerate autonomously – activities that today are a reality in cars with smart cruise control; they don't necessarily need to be fully self-driving. At the intersection, the driver gives control of the speed to the car computer, but retains the steering control. In tests, the algorithm worked very efficiently even for very complex intersections. “In most cases, pre-emptive deceleration only slightly lowered the vehicle velocity, resulting in safe passage of each vehicle across the intersection without coming to a full stop at any point,” Yang said.

If adopted, the system would have to be phased out slowly to help older cars pass smoothly through the intersections. As more and more smart vehicles populate our streets, traffic lights could be eliminated slowly until they are no longer needed.

“Our simple algorithm only requires basic vehicle intelligence, but is also fully compatible with more intelligent vehicles that may come in the future,” Yang noted.

The result of Yang’s team work was published by ScienceDirect. An abstract can be found on their site.