Just looks like road rage to me. Obviously the beginning of the confrontation was cut out, and since the driver is the owner of the video, I am guessing he was doing something illegal in that portion of the video (that was omitted).
Whoever started it, they obviously go back-and-forth for a while, and we start (the video) in the middle of the altercation.
From the video, I can see the driver tailgating the biker, and trying to pass on the left. You can also see the biker brake-check him, but it may be hard to tell since the brake lights are a little washed out, and the relative speeds still show that the car should have had time to stop.
The biker will clearly argue that the other guy was tailgating.
But yeah, the look on the driver's face when he exits to check his bumper is priceless.
*Edit*
On second viewing, it's hard to tell what is going on in the beginning before the crash. It can either be that the driver sped up to duck to the left of the biker, or the biker slowed down to brake-check him. I can't tell because his lights are modified and washed out in the video.
Either way, that biker needed to be put down. Even if the driver started it, brake-checking a car is just stupid.
