Unless it's really slopping editing, there's no way Annie was the first one to hit the person in the road. The way they showed it, she went "bump" over something that was already there. If she hit a person standing up she would have seen that, drunk or not. So, either he was passed out in the middle of the road, or someone else hit him first.
I have two theories: One is, the new guy hit him and then felt guilty and came back to the scene. Second theory is, and this is based on the fib new guy told about his father trashing the cabana, is suppose new guy really does frequently have to clean up "messes" of his famous father? Maybe his father hit the guy in the road and called his son to go "clean it up." When he got there, maybe he saw Annie driving over him and decided not to do anything, waiting to see how things play out. He may even have been the one to call 911.
Anyway, I don't know that I'll stick around to find out if I'm right. This isn't going to be a must-see show for me.