Answer: Traffic Lights

You know that feeling you get when it seems like you’re catching every single red light in town? Thanks to traffic light synchronization, that’s a feeling people in major cities around the world are experiencing a lot less these days.

It all started in Los Angeles, California in early 2013 when the city became the first metropolis in the world to synchronize all of its traffic lights in an ambitious attempt to better manage sprawling gridlock. The system uses a vast network of magnetic sensors embedded in streets and highways along with hundreds of traffic cameras to analyze the flow of traffic.

All this information is fed into a centralized computing array that constantly crunches the numbers and adjusts the city’s nearly 4,700 traffic lights. Although only recently implemented, the city had been planning the upgrade for ages—it was originally proposed all the way back in the 1980s as part of a rehabilitation plan to prepare the city’s traffic grid for the 1984 Olympics.

Since the implementation of the city-wide system, commuting times have decreased. Now, a five-mile commute within the city limits only takes 17.2 minutes (down from 20 minutes before the implementation of the synchronized system).