We lived in Reno, Nevada, USA for many many years.  There, other than an actual auto wreck, the absolutely worst thing was to run over a skunk, or an already squished skunk, which is even harder to see.  They're black, you know, with that white stripe, and not all that visible during dark hours.   The effects are hideous, immediate, and almost permanent.  There was a local story about a truck driver who ran over one many years ago, but nothing immediately happened, so he sighed with relief and drove on.  Unfortunately, it was thrown up onto his engine, where it fried.  Then things happened.