Why do all EVs make the same quiet hovering sound when they drive ?
In: Engineering
Because they’re required by law to make ~~that~~ a sound at low speeds for pedestrian safety.
It’s literally a sound played through a speaker.
People have gotten very used to listening out for the sound of a vehicle approaching. Although the motors of an EV do make noise, it’s not a lot of noise. For safety, external speakers play the hovering noise at low speeds so that there’s *something* for people to listen for, but isn’t an obnoxious back-up beep or horn. The futuristic hover-whoosh sound is just what manufacturers have settled on as something that sounds scifi and modern and appropriate for an electric vehicle.
My got an icecream truck sound also beside the hovering sound. It get very annoying stuck in a congestion, the hovering sound becomes background noise pretty quickly.
EVs are required by Federal regulation to “make noise” at lower speeds because totally silent vehicles would lead to pedestrian unawareness. Many pedestrians — especially those with visual disabilities — rely (consciously or unconsciously) on sound to be aware of nearby, slow-moving vehicles on streets.
To maintain this awareness, fully-electric vehices usually [emit artficial noise](https://www.usatoday.com/story/money/cars/2024/09/06/electric-car-sound-inspirations/74908203007/) — which is probably what you’re identifying as the “hovering sound” — at speeds below 25 mph to comply with regulations.
At higher speeds, tire-on-pavement sounds and wind sounds serve that need. I believe the regulation only requires the artficial sounds at low speeds.
Teslas before 2021 don’t make that sound. They are pretty much silent at low speeds other than tires. Now federal law requires that they make a sound. And the NHTSA also requires it be the whirring sound you hear. This is so that blind people know what sound to listen for in identifying an EV nearby.
A little of it is tire noise and motor noise. Most of it is piped through a speaker so pedestrians can hear an EV coming in a parking lot or at crosswalks. Early hybrids and EVs were hitting pedestrians because they made so little noise people were walking out in front of them.
Favourite fun fact: When Dominoes got EV cars for delivery, they picked a model where they could themselves design the “sound” of the engine. So they made it:
Dominos………………………….Dominos…………….Dominos…..
speeding up:
Dominos-Dominos-Dominos-Dominos….
Full speed:
DOMINOSDOMINOSDOMINOSDOMINOSDOMINOSDOMINOSDOMINOS!
I was curious what the regulation actually says. Here it is: [https://www.regulations.gov/document/NHTSA-2016-0125-0001](https://www.regulations.gov/document/NHTSA-2016-0125-0001)
Great [New Yorker](https://www.newyorker.com/magazine/2022/08/08/what-should-a-nine-thousand-pound-electric-vehicle-sound-like) article about the design of these sounds.
Does it sound like an alien? My neighbor a few doors down had a Tesla and I always thought it was a spaceship lol
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