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Engineering teams at the University of Michigan and North Carolina State University have been studying traffic patterns. Both anticipate traffic flows to look much different than today – and a lot sooner than later. The U.S. has been using the “red, yellow, green” traffic light system since the 1930s. Now, with autonomous vehicles (AVs) entering the landscape, experts think it’s time to consider how traffic signals work. Some are even predicting that they’ll be eliminated.

Ali Hajbabaie is an associate professor of engineering at North Carolina State University. He recently told ABC News that as self-driving cars integrate with typical ICE and driver-controlled EVs, a fourth traffic light color would be helpful. His team used model cars to simulate traffic patterns if AVs were on the scene. A fourth traffic light color – perhaps white, he says – could signal to drivers to simply follow the AV in front of them.

This might seem confusing at first. However, the university’s simulation is meant to decrease the time spent sitting at a stop light unnecessarily. A white light would indicate that AVs are controlling the flow of traffic. This could eliminate machine and driver errors in making decisions about whether to stop or go.

A black traffic light signal shows all three light colors red, yellow, and green against light blue background
Rawf8 via iStock

Hajbabaie admitted that AVs would need to make up at least 40% of the vehicle mix in order for a fourth traffic light color to be justifiable. While experts agree that AVs are incoming, there is no doubt that a 40% mix is years away. What’s more, a Waymo spokesperson told the Associated Press that making country-wide changes to traffic equipment might ultimately be a waste of resources.

“While it is good at this early stage of AV development that people are thinking creatively about how to facilitate the safe deployment of safe AVs, policymakers and infrastructure owners should be careful about jumping too soon on AV-specific investments that may turn out to be premature or even unnecessary,” she said in an email.

The team at the University of Michigan is going another route. It looked at traffic and vehicle data compiled through GM. Through their analysis, the team was able to alter traffic light timing in a Detroit suburb. This reduced traffic congestion in the area. Through this pilot program, they earned a U.S. Department of Transportation grant to look into making traffic light changes in real time.

Overall, U.S. transportation continues to grapple with many issues. Distracted drivers, high new vehicle prices, costly individual ownership, and competition creeping in from China, to name a few. Before we look to AVs, we might focus on public transit and look for U.S. automakers to catch up with China’s cheap, efficient EVs.