Got to love Californicator petty Fascist thinking. Need a law for everything — throw the book at ’em. If it causes an accident, then look twice at it, but treating any unrestrained dog like a DUI is frankly insane.
I may add that some dogs do NOT deal with car rides well, and having them ride in a crate or wear a harness would make things a lot worse. Think shaky/vomity/messy mutt.