Update 2: NHTSA reached out to Ars to assure us that the V2V rule isn't dead. "The Department of Transportation and NHTSA have not made any final decision on the proposed rulemaking concerning a V2V mandate. Any reports to the contrary are mistaken. In all events, DOT hopes to use the dedicated spectrum for transportation lifesaving technologies. Safety is the Department’s number one priority," the agency told us.

Update: Ars reached out to NHTSA this morning, which told us that it has yet to make a final decision. "The vehicle-to-vehicle notice of proposed rulemaking was released in December 2016 for public feedback, and received over 460 comments. NHTSA is still reviewing and considering all comments submitted and other relevant new information to inform its next steps. An update on these actions will be provided when a decision is made as part of the Department’s ongoing regulatory review," it told us in a written statement.

The Trump administration is notoriously unfriendly to red tape; one of its earliest actions in January was aimed at slashing the number of government regulations. According to an AP report on Wednesday morning, the vehicle-to-vehicle communications (V2V) mandate is among the deceased. This may not mark the death of V2V, but if true, it's yet another nail in the coffin of the technology, which uses a dedicated band of radio spectrum for short-range alerts between vehicles.

Hopes have long been pinned on V2V as a way to cut traffic fatalities, which have been on the rise the past two years . Long before self-driving car fever took hold, the benefits of V2V were being touted as just around the corner—literally. Cars would not need line-of-sight the way human drivers do, instead communicating with each other at ranges of up to 984 feet (300m) to warn each other of unseen hazards, as Sean Gallagher discovered at CES a few years ago.

But the safety protocol's story is long and tortuous. More than a decade passed between the allocation of a dedicated band of spectrum by the Federal Communications Commission and the agreement on the 802.11p protocol in 2010. From there, several more years passed while the National Highway Traffic Safety Administration deliberated on how best to implement V2V—a draft rule wasn't released until December 2016. If implemented, car makers would have two years to start fitting V2V systems to new cars, meaning an even longer lag until enough V2V-equipped vehicles were on the roads for the tech to start really paying off.

In the meantime, technology has moved on. OEMs have been waiting for a government mandate to add V2V to their model ranges but have shown no such reticence when it comes to cellular modems. In fact, it's going to be difficult to buy a new car in 2018 that doesn't have 4G LTE—which Nexar has shown is sufficient for short-range warnings—and 5G won't be far behind. Automakers like BMW and Mercedes-Benz are on record wanting a more technology-agnostic approach to the problem, and Qualcomm recently revealed a "vehicle-to-everything" chipset for those who want to hedge their bets.

The AP's Joan Lowy cites four unnamed "auto industry officials" who told her that administration officials made the decision to kill the V2V mandate in part because of "general wariness of imposing costly mandates on industry, even though most automakers support requiring V2V." Lowy's article notes that NHTSA has not confirmed the news but that the decision was made at a higher level than the agency.