Driving off the road ain't a collision if you don't collide with anything, but it's still an accident.
I agree with you, but that ain't a great word either.
I'd like to have a word that also includes did-not-cause-accident-by-luck failures, such as running a red light or failing to notice a bicyclist who slammed brakes to avoid you sideswiping them.
Best I can offer is "incident".
