North Carolina State University researchers propose white traffic light signal

Researchers at North Carolina State University are investigating a potential fourth color for traffic lights: white. Unlike traditional red, yellow, and green signals, a white light would be used to facilitate the coordinated movement of autonomous vehicles.

This “white phase” would allow self-driving cars to communicate with the intersection's control system and each other, enabling them to coordinate speed and order of passage more efficiently than human drivers. For human drivers, a white light would serve as a signal to follow the vehicle directly ahead, mimicking the autonomous flow. The system would likely only activate when a sufficient number of intelligent vehicles are approaching the intersection.