Synchronized Lights Make Traffic Worse

Lights synchronized to ease jams might be making matters worse. Rush-hour traffic might flow better if lights were set at random.

Ideally, traffic lights are set so that each changes to green just as a typical vehicle approaches from the previous set of lights... But above a certain density of traffic -- typical of daytime flow in many cities -- the choice of delay time stopped making any difference to flow.. In such traffic, lights turning green failed to clear the queue that had developed in front of them."

Thanks to Congress on New Urbanism

Full Story: Phased traffic lights fazed by heavy traffic.

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