I use to ride in the mountains of So Calif, and in the summer time those rattle snakes would come out to the edge of the road to warm up. Going up the mountain I would just give them a wide berth, coming down I was going to fast to swerve so I would just run them over at 40mph or so. I don't think snakes liked that, but I don't think it killed them, I never went back to check.