If we're that close, then the motorist would be out of his car. In that case, he is either has a firearm, in which case I might have a problem (but why would he shoot me when he could have just run me over and claimed it was an "accident"?) or he doesn't have a firearm, in which case I likely have the advantage of superior training, experience, speed and strength. While I have had motorists pull over to chat, few have ever wanted to come to blows. I think something about being 6'2" 190 lbs and obviously fit discourages people from becoming physical, which is nice since waiting around to give a statement to the police ruins a ride.