Twice, I've run over snakes where they came across my path and I didn't have time to avoid them. It's a little disconcerting to run over a snake, but both times the snake has slithered away seemingly unhurt. One time I was able to pull up on my front wheel to kind of hop over him, perhaps that helped. I think in a situation like this, I'd go for the snake to be sure to avoid getting any closer to the truck and hope for the best for the snake.