New system for timing traffic lights to reduce drive time

MIT researchers have developed an improved system for timing of traffic lights that can significantly reduce drivers' average travel times.
The new system, described in the journal Transportation Science, is based on a study of traffic in Lausanne, Switzerland.
Existing software for timing traffic signals has several limitations, said Carolina Osorio, an assistant professor of civil and environmental engineering at Massachusetts Institute of Technology (MIT) and lead author of the study.
"Usually in practice, when you want to time traffic lights, traditionally it's been done in a local way," Osorio said.
"You define one intersection, or maybe a set of intersections along an arterial, and you fine-tune or optimise the traffic lights there.

"What is less done, and is more difficult to do, is when you look at a broader scale, in this case the city of Lausanne, and you want to change signal times at intersections distributed across the entire city, with the objective of trying to improve conditions across the entire city," she said.

The new system developed by Osorio and graduate student Linsen Chong can time traffic lights in large urban areas while accounting for the complex and diverse reactions of individual drivers.
Their approach uses high-resolution traffic simulators that describe, in detail, the behaviour of drivers in response to changes in travel conditions.

In detailed simulations of Lausanne's traffic, they found that the timings produced by their approach reduced the average travel time for commuters by 22 per cent, compared with timings generated by commercial traffic-light timing software.