Researchers propose a fourth traffic light for autonomous vehicles

However, a group of researchers proposes that travel times and gas consumption can decrease if drivers let autonomous vehicles direct traffic using a fourth traffic light color. When the percentage of self-driving cars falls below the threshold, the traffic light returns to normal. The researchers originally proposed the concept in 2020, but that initial version relied on traffic light computers to direct the self-driving vehicles. The fourth traffic light doesn't do anything to direct the robocars. It just tells the human drivers that the traffic computer and autonomous vehicles are negotiating traffic flow and that they should follow them.