Some dogs are a bit protective of their cars. On the way home yesterday this happened to me.
The Blue Heeler was hanging out of the passenger window of a big old truck. The truck was lifted and had big wheels on it so the dog was a little above my head. There was another cyclist in the intersection before I got there, and he had scooted as far forward as he safely could, past the white stop lines at the traffic lights. I waited behind the raving loony dog and didn't take off until the truck was gone.
Reminded me of when I went overseas and my brother looked after Bender for a while. He had Bender in the car and was driving down to visit my folks. The police pulled him over, and the cop leaned in to the window to be confronted by a barking Bender. Apparently the cop was quite scared of him!
We don't often have car issues with Bender. We go through fast food drive throughs and he has no problem with those people sticking their arms close to his car. I just don't think Bender liked this particular officer of the law.