The Ontario Provincial Police say the eastbound express lanes on Highway 401 at Hurontario Street have reopened after a four-vehicle collision on Tuesday.
OPP Sgt. Kerry Schmidt said the crash involved a transport truck and three cars.
The OPP said a disabled vehicle on the right shoulder was struck by a transport truck causing a chain reaction crash.
The transport truck driver was charged with careless driving, police said.
Two people were taken to hospital with potentially serious injuries, Schmidt said.
Motorists were able to get by on the highway going east through the collector lanes, however, traffic was slow in the area all morning.