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.

Comments

Prepare for the AICP Exam

Join the thousands of students who have utilized the Planetizen AICP* Exam Preparation Class to prepare for the American Planning Association's AICP* exam.
Starting at $245
Planetizen Courses image ad

Planetizen Courses

Advance your career with subscription-based online courses tailored to the urban planning professional.
Starting at $16.95 a month
T-shirt with map of Chicago

Show your city pride

Men's Ultrasoft CityFabric© tees. Six cities available.
$23.00
Women's t-shirt with map of Los Angeles

City T-Shirts for the ladies!

Women's Supersoft CityFabric© Fashion Fit Tees. Now available in six different cities.
$24.00