Assuming something happened before the video:

1. The bikers were controlling the pace and there were literally hundreds of bikers directly behind the truck. Any of them could have taken the plate number and called police.

2. Much like worldstar videos where levels heads say...why don't you stop recording and call police since you have a phone there. GoPro dude could have at any time called and reported the dude and incident.

3. The SUV came to a complete stop...while the white van creeped by and there was plenty time THEN to take a plate number.

4. After the run over, you clearly see a biker chase the SUV and pull behind it reading the plate number...

5. I doubt anything happened before based off the reaction of everyone after the initial hit. The other two times he stopped after the initial hit, their strategy to cut him off and approach the vehicle collectively was as if they had to get at dude. When he hit the dummy that stopped in front of him, only the bikes behind them stopped. The ones ahead had no clue what happened and dude that got off his bike turned to walk back before dude ran over the other bikes. I can gather from that he thought the situation would be handled and it seemed that dummy wanted to slow the other cars to a standstill so all of the other bikes could pass.