I am sure you were doing what you thought was right in the circumstances after being hit and the driver not stopping but once you have got his number, phoned the police and almost got hit why carry on the chase...
No doubt he done wrong in hitting you but maybe he did not stop as he had his family in the car and was not sure what might happen if you caught up with him.
Defending his family maybe!! If it were me I would have got out at the lights and took a photo of him and the damage on his car but certainly would not have approached close enough for him to take a swing.
Don't get me wrong, I feel for you, no one likes there car to be hit and then having the hassle of the insurance as the other party has not stopped, but maybe he felt threatened. If he was driving badly for 20 minutes what were you doing to keep up.