Well, its not that easy. If the car made no contact with the mototorcycle only forced it off the road then the police can't do anything to the driver. If the driver made contact with the bike then it's a different story.
Don't get me wrong I think the 3 other bikers did the right thing and actually the driver got off easy with only busted windowns but as far as the law goes there is not a thing you can do to the driver in Illinois at least.
About a year ago I was in a car with my buddy (he was driving), we were going down a one way street and a car came out of the alley in front of us I mean he didn't even slow down the only thing my buddy could do is swere onto stopped cars to avoid hitting him. Guess what, when the police showed up they said we should have hit the other car but because the other car didn't make contact with ours they were not at fault. The cops actually let them drive away (we made sure they stuck around until the cops came). We couldn't believe it but my buddy ended up at fault for hitting parked cars. The cop told us we would have been better off just plowing into them there would have been no question then as to whose fault it was.