Twice. A coyote ran in front of my car on a snowy road when I couldn't stop, and a stupid cat suddenly sprinted out in the street and stopped right in front of my tire.
Both quick clean kills at least; they died instantly.
No, but I've witnessed it or the aftermath. I saw a deer one time on the outskirts of Boulder that had been hit and had a broken leg. It kept trying to get up and run, it broke my heart. A police office was trying to keep it from getting hit again. I'm sure the poor thing had to be put down - I still feel the sadness.
I hit a deer once. She died on impact, so I didn't have to watch her suffer. My car was nearly totaled so that became an immediate distraction from the poor doe.
Both quick clean kills at least; they died instantly.