after slamming into the sign, which was already a mess, yeah he had some part lodged in his car. I don't remember it if hindered his car's movement or not when I was listening this morning.
On that note, yes some people tend to stop in the middle of the street even for fender-benders. "oh we touched! we should stop in the middle of the road." Not all the time but frequently enough that we have these kind of traffic situations where they couldn't / didn't make it to the shoulder and everyone else can't stop in time to miss them.