yes, the music. I did the same thing too.
Found some old movies from me driving bus. Loud rock music...
Not so loud that the passengers can't have a conversation, but loud enough to destroy the movie
I can't see any trouble with filming while driving, as long as you do like I do it:
Mount the camera somewhere, push "Rec" and then do what you always do: Drive.
It's not like I sit with the camera in my hand all the time.