Yeah, in Vietnam it's far, far different than in the States. There are basically no road rules to obey, so nearly everyone is very aware of their surroundings and would never do something like the driver in the incident you saw, where they're depending on someone else's alertness or common sense for their own fate. Honking here is not an angry gesture, and it's often not even a request for someone to move out of the way. It usually just means, "hey, I'm here." People honk before they round a corner so people know that a motorbike is about to come around the corner, and they honk when they're about to ride up close to the side of someone to warn them not to make a sudden move to the side.

It was a difficult adjustment, actually. At first I kept getting mad, almost as a reflex, when someone would blast their horn at me and then breeze past me. Now I see it as a precautionary measure, and I actually get mad when someone passes me closely and they didn't honk first.

So being here without an effective horn is kind of like trying to maneuver through a crowd without being able to say "excuse me, pardon me".