[PetitPrince]

It's been a while since I've been to Vietnam but most of the traffic is composed of motorcycle and not cars, so honking is indeed a signal of presence that's needed compared to just having the noise of a single car that's behind you.

(crossing the street is also kind of surreal as it's more like going through a school of fish; the trick is to walk at a steady pace to maximize your position predictability)