Top automakers including Volkswagen, Honda (HMC), Ford (F) and BMW (BMWYY) are experimenting with technology that allows cars and traffic lights to communicate and work together to ease congestion, cut emissions and increase safety.

Volkswagen (VLKAF) teamed up with Siemens (SIEGY) earlier in October to test a smart light system in its German hometown of Wolfsburg.

The companies have set up a section of road with 10 traffic signal systems that transmit information about their light phases.

The idea is that the system will be able to tell the driver (or a self-driving car in the future) when to expect a wave of green lights. The goal is to eventually make the system work with a range of cars and brands.

“BMW have a counter, which counts down 5 – 4 – 3 – 2 – 1 second to green, while Mercedes says ‘if you drive between 32 and 52 kilometers per hour, you’ll get green,'” said Franz Schober from Siemens’ Connected Mobility Systems team.

Volkswagen will start equipping cars with the technology next year.

The network uses WiFi technology and sensors to produce position data than is more accurate than GPS, the location system used in smartphones.

The system will help cars avoid unnecessary stopping and starting, reducing the amount of gasses they emit. Cars produce more emissions when idling than when in motion.

The technology could also help improve safety by transmitting information about traffic conditions directly to the driver.

Volkswagen and Siemens are using sensors to detect pedestrians and cyclists at two of the crossroads in Wolfsburg.

“[The sensors] process that information, and then the traffic controller can send a message to everyone that there is a cyclist on the left,” Schober said.

Other carmakers are working on similar technology.

Earlier in October, Honda showed off its “smart intersection” technology in a town in Ohio.

The Japanese company mounted four cameras in each corner of an intersection, creating a 360 bird’s-eye-view of cars and pedestrians moving around. That data was then sent to connected cars and decoded by their on-board computers.

When necessary, the system provides visual and audible alerts to the driver.

Ford is going even further. The company unveiled technology earlier this month that allows cars to communicate with each other when going through a crossroads. Drivers are advised to change their speed if necessary to avoid collisions.

The company said it took inspiration from how pedestrians move around in a crowd to avoid those crossing their path, adding it envisions the technology to make traffic lights obsolete in the future.