Your point makes sense.
But I find the idea intrusive.
I think it unsettling that a person be subject to something that he/she may or may not be able to figure out where it comes from.
There are a lot of sounds that are innately like that, not that they sound like they’re inside your head they just don’t triangulate well with the human ear. Most electronic phone rings, and almost every squeaky cardio machine at the gym I go to (once a week or so I play “is that my machine?” varying my rhythm to see if it synchs). I’d certainly be annoyed with any company that beamed their advertising at me like this and would probably make a point of not patronizing them, it’s just not an invasion.
A product that allows you to inform the idiot in the car ahead of you that the light has changed, or the idiot behind you that he is driving too close.
If you can combine some sort of laser distance reading system, a "voice of God" translator, and this Holosonic deal, then you could have some fun messing with bad drivers!