yeah, life's a ***** like that... Some times we have to make decisions based on what we know at the time and live with it. I can make up scenarios all day long with a gotcha in them. "Oh but the bum was actually a super government ninja fighting a communist disguised as a pork chop" "the man shooting at you was actually shooting mosquitoes carrying malaria and just saved your life"So the impersonator in this scenario is driving a car that is the same make and model of the local LEO cars. He is not in uniform (obviously) so there is no way to be sure that he is a LEO. You don't know that he isn't LEO, but you don't know that they guy in the flannel is a state police officer either. If the guy in the flannel dies as a result of being hit with your car, how would you feel about that? You just killed a state police officer while he was in the course of defending himself from a man with a gun.
I learned a long time ago to make the best decision I can, based on the intel I have at the time. No regrets for doing your best, regardless of the out come.