Who is responable if a car in front of you hits an object chair on the freeway and the object chair flys back and hits you causing major damage to your car?
Assuming that the other diver hit the object accidentally, you cannot impute the damage to your car to the other guy for hitting road debris, just like you cannot blame another driver for kicking up a stone that cracks your windshield. Those are not acts of negligence. That is what collision and comprehensive insurance is for. (Usually, the former covers damage from striking objects, and the latter covers damage from striking animals.)