The attack happened on Aug. 19 after a collision on Duckworth Street near Highway 400.
Following that crash, police say, a man got out of his vehicle and assaulted the other driver involved in the collision.
The suspect then fled the area in what is believed to have been a gold-coloured Dodge Journey, added the Barrie force.
The driver of the second vehicle, an 86-year-old man, was assessed at the scene and treated for his injuries, say police.
The driver being sought by police is a man, possibly in his 40s, with a medium build and brown hair.
He was wearing a black T-shirt, a red-and-grey hat, black pants and black-and-white Converse shoes.
