I had similar thing happen to me. I was driving on the turnpike maybe 20 miles north of Norristown going north. The traffic was really bad, stop and go slowing down to as low as 20 and then back up to 65 - 70. I always keep myself a nice length so if I have to stop I can. I was in the passing lane and there was absolutely no where to go, this guy passes me on the right and slides into my safety zone in front of me like he he is going to get somewhere.
Of course the instant he did that was when traffic came to complete stop. I slammed the brakes on and looked in the rear view mirror because if there was truck anywhere behind the foot was coming off the brake, it was going onto the accelerator and I was going into bumper code mode.
I hit the guy that had pulled in front of me, he had a hitch and that is what I hit. Wasn't very hard and put a little round dent in the plastic on the bumper, the front of his car the one in front of him he hit was banged up pretty good but still drivable. I restrained from beating him senseless and the three of us exchanged insurance info. A couple of weeks later I get a letter in the mail asking for money and we'll keep it between us. Right in the circular filing cabinet and I never heard anything about it again.