[henearkr]

At least that's better than loud exhaust pipes. Loud bikes activate the fight-or-flight system in a way that klaxons do not.

Maybe that's because the loud bikes have frequencies and intonation modulation close to those of a menacing voice? (or growl)

At least in Japan, some bikers (bōsōzoku) do on purpose some kind of sounds similar to somebody arguing angrily (and snarkingly!).

But I don't want to accept neither as a solution air horns and vuvuzuelas competing for my attention and for the privilege of prematurely obliterating my cochlear hair cells.

There are other ways, let's do this. We are smarter than that, aren't we.