I think this is an issue better-resolved by separating traffic modes. Strapping noise makers on to a vehicle to make it safer is a sort of "pseudo-solution" which hops around solving the core issue.

Electric bicycles traveling that fast probably shouldn't be permitted on the same channel/road that foot-traffic uses. Though I don't live in Beijing so I can't speak to their decision (or lack of) for that.

Likewise, in the U.S. I've seen a few downtown areas try to be "green" by simply throwing some bike lanes on a 5-lane road. It's quite dangerous to ride a bike along that because of the traffic going 35-40mph. Separate that bike lane with bollards, at minimum, or build a separated "sidewalk" for e-bikes and scooters. Putting bicycles on the same road as 3,500 lb vehicles hurtling at 40mph is a joke.

One reason to like Seattle is that they actually have bike trails, not just lane separation with car traffic.

Beijing used to have a lot of such bike lanes in 1999 when I first visited (the land of the sea of bicycles) but sadly all of this has been turned into parking for cars.

I ride by bicycle all over the land of the Model S and have had no issues hearing the various EVs wandering around.

Are you speaking as a pedestrian/cyclist/driver? What kind of speeds are people driving at?

Yes. I'm talking about electric bikes, not EVs, traveling around 10-20km....on the sidewalk.

Hehe. I think that's the difference. It is usually illegal to ride on sidewalks in the US.

If it's an electric bicycle, then since it's now "motorized", simply cannot ride on the sidewalks.

In China, it seems like almost anything goes. ;)