Science and Tech


Google says it's using AI to optimize traffic lights, reduce emissions

A dozen cities are already using the technology, with more cities likely to be added.
A motorist waits at a traffic light while the waxing full moon rises in the distance.
Posted at 1:16 PM, Oct 17, 2023

A new project by Google is using artificial intelligence and Google Maps driving trends to optimize traffic lights with the goal of reducing greenhouse gas emissions. 

Project Green Light has been launched in 12 cities across the world. Seattle is the only U.S. city that has participated so far. The Google project is looking to add other cities to its waitlist as it unveils the technology. 

Google says that its technology helps cities model traffic patterns to make recommendations for optimizing existing traffic light plans. Google says it uses Google Maps user data from each intersection to make recommendations. 

"City engineers can implement these in as little as five minutes, using existing infrastructure. By optimizing not just one intersection, but coordinating across several adjacent intersections to create waves of green lights, cities can improve traffic flow and further reduce stop-and-go emissions," wrote Yossi Matias,Google engineering and research vice president.

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Google said its data from the 12 cities indicates a 30% reduction in stops and up to 10% reduction in greenhouse emissions at nearly 70 intersections where the technology is being used. 

"We might identify an opportunity to coordinate between intersections that are not yet synced and provide a recommendation around the timing of the traffic lights so that traffic flows more effectively along a stretch of road," Matias said. 

Google said it not only wants to expand programs within existing cities, but add more locations by next year. 

There has been research indicating that optimizing traffic signals would reduce greenhouse gases. A 2022 analysis by Inrix found that nearly 28 million metric tons of carbon dioxide are emitted by motorists at red lights in the U.S. every year.

“Idling at signals results in lost time, fuel wasted, and unnecessary greenhouse gas emissions,” said Bob Pishue, transportation analyst at INRIX.