Here in the UK, I’ve only ever heard electric vehicles make that high-pitched robotic hum at low speeds. However, it seems there was a proposal in the US for car owners to be able to set their own noise.
That turned out not to be a great idea for those who are blind or partially-sighted. It would also lead to a cacophony of noise for regularly-sighted people, to be honest…
Back in 2019, NHTSA introduced a proposed rule-making that would have allowed drivers to “select the sound they prefer from the set of sounds installed in the vehicle.” The idea was an amendment to a previous rule requiring EVs to make fake sounds at low speeds to prevent injuring pedestrians, especially people who are blind or visually impaired. But after soliciting feedback from the industry and consumer groups, the agency says it is scrapping the proposed rule.
Source: EV owners won’t be able to pick their own low-speed noise after NHTSA scraps proposal - The Verge
“The great majority of the comments on the [notice of proposed rule-making], including those submitted by advocacy organizations for the blind and by 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,” a spokesperson for NHTSA said. “Most of those comments favored more uniformity, rather than less, in the number and types of alert sounds allowed.”
Currently, most EVs emit the same robotic hum when operating at low speeds. And NHTSA says that’s fine, just so long as it doesn’t add a bunch of additional sounds that owners can select. Basically, the agency says it wants to prevent a situation where you have tens of thousands of EVs on the road making all sorts of musical sounds or bird noises — or fart sounds, for that matter. (Tesla, I’m looking at you.)