Not sure exactly what this behavior means other than he was possibly wanting to stand his ground. He might have been cold and decided to get on the asphalt for warmth and did not want to give away his warm seat.

If he flew full force at the car and was still able to get up and walk away, he probably just dazed himself. Many times, small birds will fly into glass not seeing the glass or thinking there is another bird in the reflection. If they do not kill themselves immediately, they just knock themselves out or daze themselves. Then, they fly off.

The bird could have been severely injured and chose to get out of the way for safety in order to die, but most likely if he was able to navigate the shrub at a high rate of speed, he is okay. Thanks for caring, stopping and making sure that he was okay and not just left lying in the road in the event he had been severely injuring. The Regal Swan