What you say is true, but when I get into my car I'm not planning to go out and find a suspicious looking pedestrian to hit hoping he'll turn out to be not innocent ;)

More seriously, the one time I was involved in a pretty serious collision the sensation of heart-squeezing dread I experienced in the moments I thought someone might have been killed or even just injured and that I might have been at fault... was not pleasant. If an innocent person were hurt as a consequence of my actions I would certainly feel the guilt of it. Does the hangman feel the guilt of his noose?