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Which Major City Was the First to Sync Its Traffic Lights?

Last Modified Date: February 11, 2024

Traffic lights are an essential safety system for pedestrians and motorists alike. With that being said, however, they are also a source of frustration for commuters, especially poorly timed signals that cause significant delays and congestion. Syncing traffic signals to a traffic control system can make a big difference. In 2013, Los Angeles became the first city to do so, establishing 4,398 signals in the city's Automated Traffic Surveillance and Control System. So how does this system work, and what are its benefits?

Synchronized traffic signals are designed to give more “green time” to a street that has higher amounts of traffic on it than others. The city’s traffic control center calculates when a group of vehicles moving at a certain speed will reach a given intersection. The traffic signal is timed to turn green as those vehicles reach the intersection.

In 2013, Los Angeles became the first city to sync its traffic signals – all 4,398 of them – to a traffic control system.

Besides relieving congestion, synchronized traffic signals can help reduce carbon emissions from idling cars, shorten travel times, and increase traffic speed. They can help ease the flow of traffic, especially in heavily congested areas and during special events like parties or concerts. Synchronized traffic signals can also be controlled by emergency services and law enforcement vehicles to allow them to move about the city more efficiently.

Stuck in traffic:

According to officials, LA's traffic signal synchronization reduces carbon emissions by one million metric tons a year.

In 2018, it was reported that New York City, San Francisco, Atlanta, Miami, and Los Angeles (despite the synchronized traffic lights) were the worst U.S. cities for traffic congestion.