Carlos Barria/Reuters

The next generation of traffic signal technologies aim to take the guesswork out of intersections.

There's plenty of "smart" traffic light innovation going around these days. But if you're perpetually stuck in traffic, the smartest light is surely the one that turns green right when you get there. Traffic Light Assist, a product German automaker Audi showcased at the Consumer Electronics Show in Las Vegas earlier this month, comes with the promise that hitting the green light, every time, could one day be a reality.

Combining data from a city’s traffic signal infrastructure and the car itself, Traffic Light Assist shows the driver a countdown clock to green as well as what speed to drive at to make the next green light, all in a dashboard display. Audi claims that by making traffic flow more efficiently, TLA can help cut down on carbon emissions as well. 

Traffic Light Assist tells the driver what speed to drive to hit the next green light. (Image courtesy of Audi
A countdown timer for the next green light. (Image courtesy of Audi

The system is currently being tested on the streets of Berlin and Ingolstadt in Germany, and Verona, Italy. Audi spokesman Brad Stertz says the company would also like to see TLA tested in U.S. cities where congestion is a big problem, like Los Angeles and New York.

And therein lies the complication. For technologies like TLA to work at any sort of scale, cities—lots of 'em—will have to make traffic signal data readable for individual cars.

Both L.A. and New York have recently begun upgrades to their traffic light infrastructure. For example, each of L.A.’s 4,400 traffic signals can now be monitored and controlled remotely, while New York’s congestion management system can respond to traffic issues in real time through networked traffic signals. Neither city, however, is currently considering technology that allows direct communication between traffic signals and private vehicles.

That’s not to say cities aren’t interested.

In Topeka, Kansas, where "smart" traffic lights can adjust signal timing based on traffic, technologies like TLA might be able to help address complaints about the lights being unpredictable. "Even though we can show improved operation statistically through reduced travel times and overall vehicle delay, [drivers] perceive this unpredictable signal operation in a negative manner,” writes Doug Whitacre, Topeka’s Public Works Director, in an email. For drivers, a signal prediction system could theoretically help eliminate frustration due to unpredictable lights, and probably some gratuitous honking as well.

Whitacre says while Topeka is interested in Audi's idea, implementing vehicle-to-infrastructure communication won’t be considered until costs become reasonable, and standards and hardware specifications are locked down and widely accepted. There also has to be proof that a significant percentage of cars on the city's roads are already outfitted with the technology.

It’s hard to say just how many automakers are already developing systems like Audi’s TLA, but a new mobile app called Green Driver wants to offer signal prediction to drivers regardless of which car they use. Green Driver, which also uses data from the city’s traffic management system, is already operating in Portland and Eugene, Oregon. The company is beta testing the product in cities across Utah and Texas, and has approached Los Angeles about doing trials there.

Allowing communication between traffic signals and individual cars could very well make drivers' lives easier and help alleviate congestion. But at the same time, cities could be compromising the safety of everyone who uses the roads. For example, drivers using signal prediction systems could be encouraged to speed to make lights or to pay less attention to actual road conditions, potentially threatening pedestrians, cyclists, and other drivers.

Top image: Vehicles stopped at a red light in downtown Shanghai. (Carlos Barria/Reuters

About the Author

Jenny Xie
Jenny Xie

Jenny Xie is a fellow at CityLab. 

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