You're stuck at a red light. It's taking forever. How much time until the light turns green? Ten seconds? Twenty seconds? A minute and a half? Would you be more patient if you knew exactly how long it will take?

Audi is betting yes. The German luxury carmaker said Monday that several cars in its 2017 lineup will be available with a cloud-computer-connected countdown timer for red lights, displayed on the instrument panel and heads-up display.

The service is scheduled to roll out city by city, starting this year in Las Vegas; Washington, D.C.; Seattle; Portland, Ore.; and possibly others.

The Los Angeles area will have to wait at least a year or two -- because the region is so huge, with so many governments involved, according to the countdown system's technology supplier, Traffic Technology Services.

Government agencies already collect information from traffic signals and road sensors to help manage traffic flow. Now, participating agencies will contract with companies to sift that software and predict when lights will change from red to green.

Audi will pass along that information to drivers who subscribe to its broadband data plans.

How do drivers benefit? Audi believes they will feel less stressed in heavy traffic if they know how long they'll have to wait for a green light.

"If you've got 45 seconds, you can take care of the kid in the back seat," said Anuparm Malhotra, general manager of connectivity for Audi. "It's a more relaxed form of driving."

City air, theoretically, could benefit, too. Vehicles equipped with start-stop engines, like hybrids, could be programmed to shut themselves down while they wait for the green light, saving fuel and wear and tear. That won't be immediately available on the Audis, but it could be in the future.

Such systems might also be used to time a string of green lights and recommend a speed to help the driver make them all, or integrate with mapping systems to give advance warning of traffic tie-ups and suggest alternative routes.

The countdown clock is more than a gimmick. It's an early indicator of dramatic changes in automobile transport as more connected cars hit the highways.

"Traffic engineers will do their jobs better. Vehicles and drivers will make better decisions," said Kevin Balke, research engineer at the Texas A&M Transportation Institute.

For decades, the U.S. Department of Transportation has been working with academics, transportation officials and vehicle manufacturers to use data to make highways safer, using available technologies. Those bad weather road reports you can get by tuning into 1610 on your AM radio? That's part of what's known as Intelligent Transportation Systems.

With technology at the point where it's cheap enough and pervasive enough for cars to begin communicating with each other and with traffic management systems, new applications are beginning to flood in, Balke said.

Some examples: When a cluster of vehicles hits their brakes hard around a curve, vehicles traveling behind and out of sight could be warned. Same for cars skidding on a suddenly icy road. The countdown clock could be improved to warn drivers trying to make it through a yellow light that they don't have a chance. The potential applications are countless.

"It's a huge benefit for the infrastructure and vehicles to talk to each other," Balke said.

Other car companies are likely to follow Audi's lead, according to Traffic Technology Services.

This is not the first foray into red light countdown timers for drivers. The EnLighten app for iPhones, Android devices and connected BMW vehicles has the same function, though users have given it mixed reviews.

Audi emphasized that the feature it announced Monday is not a smartphone app but is integrated into the automaker's communication system.

Drivers in the Los Angeles area may be ripe for such technology. There are 4,584 red-light intersections in the city, managed through a network called the Automated Traffic Surveillance and Control system, one of the world's most extensive.

"Los Angeles is the biggest of our deployment areas," said Kiel Ova, the chief marketing officer at the Beaverton, Ore., company.

But the region has a complex network that makes streamlining it a challenge.

"There are 114 agencies in the L.A. area and we have to work with each one," he said. "Las Vegas has a single agency."