What does it mean when a black bird flies right into your car while driving?

When a blackbird singles you out, it usually means their on the attack. Its a defence mechanism they are more that likely defending a small nets of hatching's. You are seen as a direct treat and in order for the survival of the species you have to be removed. The so called head attacking or hitting, the attacker has to be removed from the area. Their also a territorial bird so you could be in its space it defencing itself and space because it more than likely its sexual breeding area.

Have a think about where you are in the environment and does it happen on a particular time or date.