Vehicles capable of operating silently are required by law to emit sounds at speeds up to 19 mph to alert pedestrians to the vehicle's presence. The National Highway Traffic Safety Administration was taking comments on a proposed rule that would've let automakers give drivers a choice between several different sounds, but now that idea has been left on the cutting-room floor.

NHTSA has scrapped a 2019 proposal that would let vehicles offer driver-selectable low-speed sounds. The decision, which was posted to the Federal Register on Wednesday, was dropped because of a "lack of supporting data." For the time being, drivers will remain stuck with whatever sound their vehicle makes from the factory.

The discussion about driver-selectable low-speed noises started in 2017, with a joint petition to NHTSA from the Alliance of Automobile Manufacturers and Global Automakers. The underlying idea is that no two consumers are exactly alike, and allowing for multiple selectable low-speed EV sounds would give consumers more choice and perhaps boost adoption of hybrid and electric vehicles. The proposal was then offered up to the public for comments.

"The great majority of the comments on the [Notice of Proposed Rulemaking] including those submitted by organizations and people who are blind or who have low vision, did not favor the proposal to allow [hybrid and electric vehicles] to have an unlimited number of different pedestrian alert sounds," NHTSA wrote in its final ruling. "To the contrary, most of those comments were in favor of more uniformity, rather than less."

The Alliance for Automotive Innovation, which was created in 2020 when the Alliance of Automobile Manufacturers and Global Automakers merged, said in an emailed statement that it was "disappointed" in NHTSA's decision.

NHTSA takes low-speed EV noises quite seriously. Most vehicles have a futuristic vibe to their low-speed sounds, in part because NHTSA demands that the noises not resemble anything that could be misconstrued as a natural sound. Tesla chose to initiate a voluntary recall of more than 500,000 vehicles for its Boombox function, which allowed users to play sounds or make announcements using an external speaker, because it violated federal regulations by drowning out the mandated low-speed EV noise.