More modern trucks use white noise instead of a beep anyway, it's both much easier to tell direction from a broad spectrum sound, and significantly less annoying at the same time.
I've never heard of a truck using white noise instead of a beep, but that might just be working as intended. Here's a video of what it sounds like: https://www.youtube.com/watch?v=6rwJ5NCf1Vw
I think I may have heard that noise, and just not known what it was. It could easily be mistaken for some sort of mechanical bit of the truck (slipping belt, various bits and bobs going around in the engine).
That's interesting. After watching the video I realized that yes the white noise style of backup sound is fairly common on trucks here in the US but never thought about why. Actually, now that I think about it the local garbage trucks use it. You definitely know where the sound is coming from, and it's loud and it gets your attention.
For the last several years I've been living in Mexico, after living in Seattle for many years, and I'm still struck by how much quieter it is here. Playing of loud music is actually far more common here, especially at night, and jake braking is a thing too but none of it's annoying. There's no noise ordinances that I know of. Even still the noise level is generally far lower than even a quiet day back in the States. Right now it's Sunday afternoon and man it feels like a quiet Sunday afternoon. No complaints.
I'm not sure about that. I used to live in an apartment building in front of a cement factory where trucks would back up all day long. They mostly had that white-noise thing instead of the beeping. Yet, I could still hear them from the 11th floor through double-paned windows, even though my building was in front of the trucks as they were backing up.
