On Wednesday, Audi announced that the traffic lights in Washington, DC, can now communicate with the company's cars. The nation's capital joins Las Vegas, Nevada; Dallas and Houston, Texas; the California cities of Palo Alto and Arcadia; Denver, Colorado; and Portland, Oregon, as locations where Audi vehicles equipped with the company's Connect Prime service will be able to tell drivers how long they have to wait for that red light to turn green.

The feature is called Traffic Light Information, and we first explored it when it was rolled out to Las Vegas in 2016. Briefly, Audi has been working with Traffic Technology Services to connect municipalities' traffic management systems with vehicles via 4G LTE. If an equipped vehicle is waiting at a red light, the car's instrument cluster will let the driver know how long it will be before the light changes.

"This initiative represents the kind of innovation that is critical for us to advance the traffic safety goals of Vision Zero," said DC Mayor Muriel Bowser. "We look forward to building on this and similar partnerships as we continue to build a safer, stronger, and smarter DC." More than 600 DC intersections will communicate with Traffic Light Information, adding to roughly 1,000 intersections in the seven other cities that are also covered.

It won't work on every Audi, but the feature is available on the A4 and A4 Allroad (MY17-19), A5 (MY18-19), A6 (MY19), A7 (MY19), A8 (MY19), Q5 (MY18-19), and Q7 (MY17-19), as long as the vehicle is also signed up for Connect Prime.

"Audi continues to be an industry leader in connectivity and mobility solutions,” said Scott Keogh, president of Audi of America. “Not only do V2I [vehicle-to-infrastructure] technologies like Traffic Light Information help to reduce driver stress, they are also essential infrastructure developments as we continue toward an automated future."

Is DSRC dead in the water?

That Audi has chosen to use cellular modems and not Dedicated Short Range Communications (DSRC) radio to implement V2I should serve as yet another wake-up call to advocates for vehicle-to-vehicle (V2V) and V2I systems.

Even though the protocols for using 802.11p for V2V and V2I have been finalized for almost two decades, I'm unaware of any new vehicle that comes equipped with DSRC, and local governments are not hurrying to upgrade their traffic infrastructure to allow it to communicate via this method. Indeed, at CES this January, Aptiv told me it had to install its own DSRC equipment onto the traffic signals along the routes it was using to demo self-driving vehicles.

On the other hand, most traffic infrastructure will already be connected via a network to some form of traffic management center; an approach like the one taken by Audi and Traffic Technology Services seems like a much faster and cheaper way of achieving the goal of reducing congestion and improving safety.