A motorcyclist has been critically injured in a collision on the Queen Elizabeth Way in Oakville, police say.
It occurred on the westbound lanes of the highway before Dorval Drive and involved a motorcycle and a light-coloured passenger van.
Police say the motorcyclist was taken to a trauma centre with life-threatening injuries.
Meanwhile, the driver of the van did not stop, police say. No further descriptions of the van have been released.
The cause of the collision is unknown.
Police say two left lanes of the highway are expected to be closed for several hours for the investigation.
This was the second collision on the highway on Tuesday. During the afternoon rush hour, five vehicles were involved in a crash on the Toronto-bound lanes near Third Line.
A driver was taken to the hospital with serious injuries.
The cause of this crash is under investigation. Police said charges were pending.