"It was done in front of my son, he's 10. He was dragged from the car while my son was yelling for him to stop," she said.
The victim said the mob member stopped his car suddenly and hit his car while trying to overtake him.
"He got out and walked up to the window and said 'what are you doing?' and spat at me through the window," the man said.
"He just lined me up and he was away. It was bang, bang, bang through the window there wasn't half a dozen words spoken before he punched me."
The man received cuts and bruises to his head.
"It's just extremely disappointing. My son was there and that's concerning."
The victim's wife said her son was "shaken up" by the ordeal.
Police said several other gang members were reported to be in the other vehicle, which left the scene.
Hamilton police are making further inquiries with the victim and ask any witnesses to contact them.