I kind of think car crashes could fit pretty well into my horror movie idea, Sanewashing; in which an amateur serial killer is clumsily killing people, but an overbearing sense of “normalcy” is preventing people from panicking or investigating, just viewing the deaths as tragedies rather than mysteries.

Something that could be thematic is to just have someone hear about a friend being killed, and be completely on edge; but then hear it was a car crash, and all tension releases.