Nov. 2, 2006 — A network of traffic lights that decides to turn green when lots of cars are waiting can help reduce traffic jams, say researchers.
Unlike other traffic light systems that are coordinated centrally, these lights would optimize traffic flow by acting autonomously.
Seung-Bae Cools of the Vrije Universiteit Brussel in Belgium and colleagues report their findings in a paper posted on the arXiv preprint website.
Traffic management aims to optimize traffic flow, reduce traffic jams and cut the time drivers spend waiting at traffic lights.
Green lights are synchronized into 'green waves' to allow cars to flow through the main avenues of cities without facing a red light.
The idea is to make the speed of the green wave match the desired cruise speed for the street.
But if the green waves remain the same whatever the traffic condition, this can lead to traffic problems.
When traffic is heavy, cars entering a green wave will stop as there are cars ahead of them. And once a car misses the green wave it has to wait the whole duration of the red light to enter the next green wave.
Self-Organizing Traffic Lights
Most advanced traffic control management systems rely on a central computer to help optimize the flow of traffic.
But the Belgian researchers have developed a system that relies on "self-organizing traffic lights".
They say the system relies purely on "local interactions between cars and traffic lights" to generate "flexible green waves on demand".
At each traffic light, there is a counter that is set to zero each time a light turns red and then counts the number of cars that build up at the lights.
"If there are more cars approaching or waiting behind a red light, this will turn into green faster than if there are only few cars," said the researchers.
The researchers claim the system can greatly improve traffic flow and they have tested this by feeding real traffic data from a Brussels avenue into a traffic simulator.
