First major city in the world to synchronize all its traffic lights.

Los Angeles is the first major city in the world to synchronize all its traffic lights. Nearly 4,400 lights across 469 miles receive real-time updates about traffic flow to make second-by-second adjustments. The system limits congestion by up to 16% while also dramatically reducing idling time.

The system uses magnetic sensors in the road that measure the flow of traffic, hundreds of cameras and a centralized computer system that makes constant adjustments to keep cars moving as smoothly as possible.

The magnetic sensors in the road at every intersection send real-time updates about the traffic flow through fiber-optic cables to a bunker beneath downtown Los Angeles, where Edward Yu runs the network. The computer system, which runs software the city itself developed, analyzes the data and automatically makes second-by-second adjustments, adapting to changing conditions and using a trove of past data to predict where traffic could snarl, all without human involvement.