(See Smashing)
Dream dictionary: Collide dream meanings
…(Bang | Collide | Hit | Impact | Knocking) To bang one’s head against a rock or a wall in a dream means suffering from failing to perform one’s night prayers, (arb. ‘Isha)…
It can be a warning against possible car accidents in the future. Perhaps your mind is telling you to be careful. It might be a good time to slow down a bit, and face your fears and doubts. Do you have control over your life? Do you feel guilty about something? It also indicates that your opinions, lifestyle or ambitions collide with those of another person. When one of your acquaintances dies in a car accident, it means that you need to check or retrieve your relationship with that acquaintance in real life. If you dream of a plane crash, it may mean that the objectives you set for yourself are too high. Or it may be, that you yourself, do not really believe that you are capable of achieving them.