Red, yellow, green … and white? Smarter vehicles could mean big changes for the traffic light

As cars and trucks become smarter and more connected, the humble lights that have controlled traffic flow for more than a century may also be on the cusp of a major transformation.

Researchers are exploring ways to use features in modern cars, such as GPS, to make traffic safer and more efficient. Ultimately, the upgrades could do away with today’s red, yellow and green lights entirely, leaving control to self-driving cars.

Henry Liu, a civil engineering professor who leads a study at the University of Michigan, said the rollout of a new traffic light system could be much closer than people realize.

“The pace of progress in artificial intelligence is very fast, and I think it’s coming,” he said.

Traffic lights haven’t changed much in the US over the years. Cleveland debuted what is considered the first “municipal traffic control system” in 1914, historian Megan Kate Nelson wrote for Smithsonian Magazine. Engineer James Hodge’s invention, powered by electricity from the city’s streetcar line, consisted of two lights: red and green, the colors long used by railroads. A police officer sitting in a booth on the sidewalk had to flip a switch to change the signal.

A few years later, Detroit police officer William Potts is credited with adding the yellow light, although as a city employee he was unable to patent it. In 1930, Nelson wrote, all major American cities and many smaller towns had at least one electric traffic light.

However, the advent of connected and automated vehicles has opened up a world of new possibilities for traffic signals.

Among those reshaping traffic flows is a team from North Carolina State University led by Ali Hajbabaie, an associate professor. Rather than abolishing the current traffic lights, Hajbabaie proposes adding a fourth light, perhaps a white light, to indicate when there are enough autonomous vehicles on the road to take charge and lead to walk.

“When we get to the intersection, we stop when it’s red and we go through when it’s green,” said Hajbabaie, whose team used model cars small enough to hold. “But when the white light is active, you just follow the vehicle in front of you. yours.”

Although Hajbabaie’s research talks about a “white phase” and possibly even white light, the specific color is not important, he said. Current lights could even suffice by, for example, adapting them to flash red and green at the same time to indicate that self-driving cars are in charge. The key would be to ensure that it is universally adopted, like the current signals.

It would be years before such an approach would be implemented, as 40% to 50% of vehicles on the road would need to be self-driving to function, Hajbabaie acknowledged.

Waymo spokesperson Sandy Karp pointed out that the self-driving car subsidiary of Google’s parent company has launched a fully autonomous ride-hailing service in Los Angeles and Austin, Texas, even without the addition of a fourth traffic light.

“While at this early stage of AV development it is good for people to think creatively about how to facilitate the safe deployment of secure AVs, policymakers and infrastructure owners should be cautious about jumping too early on AV-specific investments that may well could prove to be profitable. premature or even unnecessary,” Karp said in an email to The Associated Press.

Researchers at the University of Michigan have taken a different approach. They ran a pilot program in the Detroit suburb of Birmingham, using insights from the speed and location data of General Motors vehicles to change the timing of that city’s traffic lights. The researchers recently secured a grant from the U.S. Department of Transportation under the bipartisan infrastructure bill to test how to implement the changes in real time.

Because the Michigan study deals with driver-driven vehicles and not fully autonomous vehicles, it could be much closer to broader implementation than what Hajbabaie is aiming for.

Liu, who led the Michigan study, said that even if only 6% of the vehicles on Birmingham streets are connected to the GM system, they provide enough data to adjust traffic light timing to improve traffic flow. ease.

Birmingham’s 34 traffic lights were chosen because, like more than half of the signals across the country, they are set to a fixed timetable, without cameras or sensors monitoring traffic congestion. Liu said that while there are high-tech solutions to monitor traffic, they require cities to make complex and expensive upgrades.

“The great thing about this is you don’t have to do anything to the infrastructure,” Liu said. “The data does not come from the infrastructure. It comes from the car companies.”

Danielle Deneau, director of traffic safety at the Road Commission in Oakland County, Michigan, said initial data in Birmingham only adjusted the timing of the green light by a few seconds, but it was still enough to reduce congestion. Even bigger changes could come under the new grant-funded research, which would automate traffic lights at a yet-to-be-determined location in the province.