A 25-year-old man is in hospital with serious injuries after being struck by a vehicle on a busy stretch of Highway 401 in Toronto.

Ontario Provincial Police Sgt. Kerry Schmidt said the man was struck in the westbound collector lanes of the highway near Don Mills Road Saturday evening.

"The driver of a white SUV was travelling along Highway 401 westbound when he noticed an issue with his vehicle. He stopped on the right shoulder, which was actually the bullnose between the 401 westbound and the on-ramp from the 404 southbound," Schmidt said.

"While he was outside his vehicle, another vehicle came through and struck the rear of that vehicle, cutting through that bullnose, possibly in an attempt to get around slower traffic and not realizing there was a stopped vehicle in that area."

The young man was taken to hospital with serious, but non-life-threatening injuries.

The driver of the second vehicle has been charged with careless driving causing bodily harm, OPP said.

Three right collector lanes of the highway were blocked for several hours because of the incident, but have since reopened.