Self-driving cars get all the attention, but another, much simpler technology called car-to-car communications might save just as many lives. And the tech is now getting its first commercial test on the roads of Sunnyvale, California.

Car-to-car technology involves cars broadcasting their speed, bearing, and other data over a few hundred meters. This can alert onboard computers and safety systems to impending accidents, even in situations where the sensors on self-driving cars would be blind, such as rear-endings caused by sudden braking, or T-bone collisions. A related system, called car-to-infrastructure communications, could help smooth the flow of traffic and reduce congestion by having vehicles work in collaboration with modified traffic lights and specialized roadside beacons.

The U.S. Department of Transportation is interested in car-to-car technology, and it organized a large-scale test in the city of Ann Arbor, Michigan, that involved 2,800 cars equipped with radio equipment and data recorders, between 2012 and 2013.

Since then, however, the DoT has stalled on mandating the technology in future vehicles, perhaps because of the potential cost burden facing carmakers. There is also some concern about potential interference with the proposed wireless frequency, with some suggesting that existing standards, like 5G or LTE, could be used instead.

But perhaps the Sunnyvale test, which is being coordinated by Nissan and a wireless company called Savari, is a sign that regulations are on the way. One analyst contacted for the story said the rules could be announced in the fourth quarter of this year.

(Sources: EE Times, ”10 Breakthrough Technologies 2015: Car-to-Car Communication,” “The Internet of Cars Is Approaching a Crossroads”)