Traffic lights could get a 4th color — which color is it and what it might mean for drivers

Researchers from North Carolina State University have proposed launching a new color, white, to traffic lights, specifically intended for autonomous vehicles (AVs). While red, yellow, and green have functioned as standard indicators for stop, caution, and move, the meaning of a white light is a concept focused at stabilizing traffic flow.

What is the Concept

In a 2024 research, Ali Hajbabaie, associate professor of civil, construction, and environmental engineering, mentioned that the fourth light could facilitate to improve traffic flow more smoothly with self-driving cars on the roads.

“Our earlier work introduced the idea of a fourth traffic signal called a ‘white phase,’ which taps into the computing power of autonomous vehicles (AVs) in order to expedite traffic at intersections – but we had not yet incorporated what this concept would mean for pedestrians,” Hajbabaie cited.


He said, “We’ve now expanded our computational modeling to account for foot traffic, and the results are extremely promising for both pedestrians and vehicles.”

How the White Light Works

The white light would transmit wirelessly with AVs, activating when a required number of them approach an intersection. It indicates to human drivers to follow the vehicle in front of them. If illuminated, the white light shows that a major number of autonomous vehicles are coordinating their flow to suit current traffic situations.

“Our previous research found that the more AVs there are on the road, the more efficiently the traffic moves,” Hajbabaie stated. “To be clear, this improves travel time, fuel efficiency and safety for all of the cars on the road, not just AVs.”

Benefits of the New System

Even with pedestrians present, the white light system still portrayed enhanced traffic movement. Hajbabaie cited, “If at some point in the future we see almost universal adoption of AVs, our models suggest that delays at intersections would decrease by more than 25%. More realistically, we will eventually see a lower percentage of wirelessly connected AVs on the road, but there would still be meaningful improvements in traffic time.”

Future Implementation

Although the white traffic light has only been examined in simulations, local authorities are considering pilot initiatives to evaluate its possibility in simplifying congestion.

“We are currently setting up a physical testbed that will allow us to experiment with this concept in the physical world not just in a computer model,” Hajbabaie mentioned. “However, the vehicles we are using in the testbed are small enough to hold in your hands. This will help us identify challenges in implementation without the expense and safety risk involved with using full-scale vehicles. In the meantime, we are open to working with industry and research partners to explore ways to move forward with these technologies.”

FAQs:

Q1: What is a white traffic light?
A white traffic light portrays a proposed fourth signal strategy made for autonomous vehicles. It helps coordinate movement and enhances traffic flow.

Q2: Who proposed the white light?
Researchers from North Carolina State University, led by Ali Hajbabaie, developed the system.