South Korea's top two automakers say the next big step forward in autonomous vehicle technology is getting the car and the road to talk to each other.  

Hyundai Motor and its sister firm Kia Motors say it is working with the city of Hwaseong in Gyeonggi province to conduct tests of a system called V2X, which stands for "vehicle to everything."

The aim is for vehicles to exchange real-time information with the road, signal lights, other cars and even pedestrians. 

The car makers say such information is a critical addition to the data gathered by onboard cameras, radars and sensors in making autonomous navigation safe.