Possible Lessons here:

• Don't "take your lane." If you keep getting clipped, and punched in the face, you're obviously not safer this way.
• Next time, beat the crap out of the guy. He threw the first punch, so you would be defending yourself.
• Why did you stop to talk to the jerk? You knew he was a road-rager. He was in a car, even if he got in front of you & stopped, you wouldn't have to stop.
• Wasn't there any "physical evidence" from him punching you in the face? Next time, get physical evidence by making the police get off their butts and writing a report. Then, you've got his plates and physical evidence. If they won't do it, go to an emergency room or call an ambulance and get it documented. Leave it bleeding. Next step, call the lawyer & put the hurt on him.

Even if you have video, it has to show everything to be admissible as evidence. The lawyers will "create reasonable doubt" So here's what you do: Whup his butt for him, then leave. You have no license plate and it usually takes the cops a good while to show up. If the cops do show up, it will be obvious he pulled over to start the altercation with you. It isn't like you could stop him and make him get out of his car...

Lesson: Next time, fight. If you don't get away Scot free, you'll at least share the misery with the jerk.