This is an excellent point, and one that I had overlooked in the
context of this discussion.

While were're on a psychological, social, and behavioral mood, let's
consider the effect of blood alcohol on driver connectivity. Alcohol is a
general nervous system depressant, and the ears are hooked to the brain
via
the nervous system...

I don't know of any evidence that suggests that alcohol would have an
influence on loudness perception, though it almost certainly would
contribute to the stupidity factor - that is, turning it up beyond reason.