THe question is could you have avoided using deadly force? Could you have stopped your bike & turned around or was the guy in the car a hit man, was he trying to run you down? Obviously you can't out run a car on a bike. Deadly force would be justified at that point. If the driver bumped you, say a bunch of college punks were trying to make you wreck, then likely no, especially if all you had to do is stop and let them go on ahead. Now if it were me in that situation, I would probably brandish the weapon to encourage them to move on. If you EVER have to pull/brandish a gun for defense, even if some punk just goes goggle eyed and runs after seeing it. You must call the cops. The first one to the phone is the good guy. You could be tromped by 20 cops if the scared little punk gets to the phone first.