Ok, this thread seems to be the best place to ask this.
I was driving home with the GF in my cage on Saturday, northbound on the 410, in the left lane. A car in front of me is doing 110. I hate riding the left lane when there is no clear need to, so I wanted to get past and move back into the middle lane, but there was another car there. So I waited until the car in front of me passed that car, and gave him a few seconds to move out of the way. He doesn't. So I high beam him. At which point, he does signal a lane change, but then, for some reason, he hits his brakes. So obviously, I do the same. It wasn't too hard, I had more than enough room, and we didn't come to a complete stop or anything. Thinking back, I think there was someone in front of him with their taillights out and they got spooked because they didn't see them.
Then, all of a sudden, we feel a knock from behind. Turns out, there was a pickup/SUV behind us that was tailgating us too. I usually am vigilant about checking my rearview and keeping enough space in front, but I'll be honest, I lapsed this time. So we felt this knock, and my GF flips out because we got hit. Luckily, we weren't stopped, I had my foot pulled in on the clutch, and I wasn't slammed on the brakes, so it just rolled us forward a bit. Calmly, I signaled, and we pulled off on the shoulder.
Before I write what happened, my question is, what is the proper procedure for handling these situations? What information should I be getting? What should I be doing? How do I ensure that all parties are held accountable?
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I stepped out, and we checked out the damage. It was just our bumpers knocking. I had light scuffs on my painted bumper, and his metal bumper was undamaged according to him. I confirmed that my GF and I were ok, and that he was too. I got his name, cell number (and called it, to make sure it was right), and his license plate. He started saying that I slammed on my brakes, and that I shouldn't have done that (almost making it seem like it's my fault). I wasn't argumentative, but I stated, that the people in front of me hit the brakes, and that I had more than enough room to stop. I said, these things happen, and thankfully, it looks like everything's ok. That I would contact him if anything changes.
We set off, and my GF starts freaking me out saying that we might feel whiplash in our neck the next morning. I was pretty shaken, just because I've never been in a multi-vehicle collision (except once on the track). I do my best to be a safe driver, and this whole thing made me evaluate what I did wrong. I know in the eyes of the law/insurance, it's not my fault, but still. Anyway, thankfully, the GF and I felt no pain the next day, and I haven't had to call the guy.