If they do exist, they would have the intelligence enough to know enough about the rules of the road to avoid getting hit.
The late Grover Krantz wanted a type specimen, and suggested that the only way to get one would be to hunt one down from the air, since the wild areas where they’re reported aren’t easy to cover on the ground, plus the critter can pretty much disarticulate a human in a few seconds.
http://en.wikipedia.org/wiki/Grover_Krantz#Bigfoot_research