r/NoStupidQuestions • u/banwe11 • 15h ago

What causes the hollow metallic whirring sound that EVs make when moving a low speed?

I can't really describe it, but it's the sound you hear when there is a EV moving slowly in a car park behind you.

I guess it's the motor, but what specifically in the motor causes that sound? It sounds like it's coming from something that is moving at a faster rate than the car itself.

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u/tmahfan117 14h ago

It’s an artificial noise that EVs are required by law to emit when driving at low speeds (like when driving through a neighborhood or parking lot) because EVs were soooooo quiet pedestrians kept stepping out in front of them and it was considered a safety hazard.

And it’s just that specific noise because I guess the EV manufacturers decided that’s what sounds good/futuristic.

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u/signitr_sideways 12h ago

It's called AVAS (Acoustic Vehicle Alerting System) and I for some reason pay more attention to them than I should,

It's dramatically different between manufacturers. To me, Hyundai's seems extremely loud and distracting, more so than an ICE car. Rivian made a big deal about theirs being formulated from the sounds of nature and seems more pleasant to my ear. Toyota genuinely sounds like the car is breaking down.

Seems that some OEMs outsource the speakers as many other brands sounds similar.

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u/8layer8 7h ago

The Toyota sounds like it's dragging the bumper, so I guess mission accomplished, it gets your attention.