Scientists suggest to add white colour in traffic lights to help self-driving cars

Green denotes "go," yellow denotes "slow down," and red denotes "stop" in terms of the regulations of the road. But those fundamental traffic laws could change as artificial intelligence becomes more prevalent. 

Researchers from North Carolina State University suggest introducing a white light as a fourth colour to traffic signals so that autonomous vehicles can help manage traffic flow and inform other drivers of what is happening.

The addition of this fourth white light dramatically reduced fuel usage and increased travel time through intersections, according to a series of computer simulations conducted by the study's authors.

“This concept we’re proposing for traffic intersections, which we call a ‘white phase,’ taps into the computing power of autonomous vehicles (AVs) themselves,” said Ali Hajbabaie, corresponding author of the paper and an associate professor of civil, construction and environmental engineering at NC State, in a university release. 

“The white phase concept also incorporates a new traffic signal, so that human drivers know what they are supposed to do. Red lights will still mean stop. Green lights will still mean go. And white lights will tell human drivers to simply follow the car in front of them.”

How would 4th traffic light work?

The wireless communication capabilities of AVs and the computers in charge of traffic signals are essential to the white light concept. In general, the white light will indicate that AVs are planning their movements in order to improve the flow of traffic through the intersection.

The traffic light will simply return to the standard green-yellow-red signal pattern when a large number of human-controlled cars are approaching the intersection.

“Granting some of the traffic flow control to the AVs is a relatively new idea, called the mobile control paradigm,” Prof. Hajbabaie added. 

Authors believe it is crucial to use the white light concept at crossings since it informs human drivers of what is happening and helps them know what to do as they approach the intersection.

“And, just to be clear, the colour of the ‘white light’ doesn’t matter. What’s important is that there be a signal that is clearly identifiable by drivers.”

The team at NC State actually pioneered the "white phase" traffic intersection concept in 2020. That original concept, however, centred on using a centralised computing approach, with the computer operating the traffic light being entirely responsible for taking input from all approaching AVs, performing the necessary calculations, and ultimately directing the AVs on how they should proceed through the intersection. 

One computer had a lot of work to do.

Self-driving cars improve traffic flow

The effectiveness of the distributed computing white phase concept was evaluated by the research team using microscopic traffic simulators. 

These are extremely intricate computational simulations that mimic real-world traffic, including the actions of specific automobiles.

“The simulations tell us several things,” the study author continued. 

First, AVs enhance traffic flow even when the white phase is not present. Second, the white phase enhances traffic flow even more when AVs are present. Fuel consumption is also decreased as a result of less stop-and-go traffic. Third, the amount of AV traffic at a white-phase intersection affects how quickly traffic flows through the intersection and how efficiently fuel is consumed.