Driving is one of the many things in life that we all take as set in stone, and part of that is traffic lights, there are three colors, green, yellow and red and their meaning is crystal clear for anyone that has ever occupied the road in the past 100 years, but the arrival of autonomous vehicles may be challenging the status quo in more ways than we expected, and one of these ways is to change the color of the lights.
While the original three colors would still be kept and likely function just as they do now, researchers at North Carolina State University have found that a fourth traffic light color could be added as a way to help drivers of autonomous vehicle drivers handle intersections efficiently. They have called this the “white phase” and it would, in theory, enable autonomous vehicles to talk to each other and the traffic light at the intersection while notifying other drivers that autonomous vehicles are taking control of the traffic temporarily.
How would the white phase work with the current traffic light system
In theory, when the “white phase” is activated, drivers would be able to follow the vehicle in front of them, which in this case would be and autonomous vehicle and allow them to set the flow of traffic as they can communicate with other cars on the road, but this idea will take a minute to get used to and will likely cause some confusion.
Dr. Hajbabaie, associate professor of civil engineering at NC State and a co-author of the study explains that it would in fact be simple. “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.” And if there are no autonomous vehicles at the intersection, the white light would not activate and the three light system would be obeyed.
Despite the confusion that would arise initially, this new way of steering traffic should, in theory, improve the traffic flow, cut down on fuel consumption and increase the speed at which drivers go through intersections. Since many areas of the country have an excess of cars on the road, solving some of these issues would help citizens encounter less traffic jams and traverse cities a lot faster and with less accidents.
While this study would need to be performed under real life conditions to be effective, the researchers got quite far by using computer simulations of these advanced traffic models. Thanks to them they figured out that:
- Delays dropped by 70% when 30% of autonomous vehicles were present.
- Traffic flowed smoothly at intersections when 70% of autonomous vehicles were present, reducing delays by 99%.
- Traffic delays were considerably reduced even with a 10% autonomous vehicle presence.
- Without stop-and-go, fuel being burned declines too, making the “white phase” a greater move towards a greener environment as well.
Considering the desire for a greener environment, these results are quite good, and while North Carolina is the first state to accept a proposal like this, it is likely that testing it in areas where there are more autonomous vehicles would be more useful. Florida, Texas, and California are prime testing ground for these researchers as the amount of autonomous vehicles is a lot higher than in North Carolina and the testing phase could be performed around industrial areas and ports.
To see the full conclusions, you can check the full study: R. Niroumand, L. Hajibabai, and A. Hajbabaie, White Phase Intersection Control Through Distributed Coordination: A Mobile Controller Paradigm in a Mixed Traffic Stream, in IEEE Transactions on Intelligent Transportation Systems, vol. 24, no. 3, pp. 2993-3007, March 2023, doi: 10.1109/TITS.2022.3226557.