Electric vehicles are often more difficult to hear at low speeds than gasoline-powered engines. Under rules mandated by Congress and finalized by NHTSA, automakers must add sound to hybrid and electric vehicles while traveling at speeds of up to 18.6 miles per hour (30 km per hour) to help prevent collisions among pedestrians, cyclists , and the blind.
NHTSA in 2019 proposed that automakers install a number of pedestrian warning sounds that drivers can choose from in “quiet cars.”
The agency said on Tuesday that the proposal “was not adopted due to a lack of supporting data. … Removing these restrictions would allow manufacturers to make a more muted voice that only appeals to a minority of (hybrid electric car) owners.”
“At higher speeds, tire noise, wind resistance and other factors eliminate the need for a separate warning sound,” NHTSA said.
Tesla in February recalled 578,607 vehicles in the US because pedestrians may not be able to hear the required warning sound from approaching cars due to loud music or other sounds played by the “Boombox” feature.
Tesla says the “Boombox Function” allows sound to be played through external speakers while the vehicle is in motion and may obscure the required Pedestrian Warning System sound.
NHTSA projects the warning will prevent 2,400 crashes annually by 2020 and cost the auto industry an estimated $40 million a year as automakers need to add external waterproof speakers to comply. Benefits from injury reduction are estimated at 250 million to 320 million US dollars per year.
The agency estimates the likelihood of a hybrid vehicle being involved in a pedestrian accident is 19% higher than that of a traditional gasoline-powered vehicle. Last year, the number of pedestrians killed jumped 13% to 7,342, the highest number since 1981. The number of cyclists killed rose 5% to 985, the highest number since at least 1975.