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
AICP CTP Storefont Display

The first online AICP* CTP exam prep class

Are you ready to take the AICP* Certified Transportation Planner exam?
Priced at $245 for May exam!

Stay thirsty, urbanists

These sturdy water bottles are eco-friendly and perfect for urbanists on the go.
$19.00
Red necktie with map of Boston

Tie one on to celebrate your city

Choose from over 20 styles of neckties imprinted with detailed city or transit maps.
$44.95