Highway 401's westbound collector lanes have reopened following a fatal crash between three vehicles.

The crash occurred near Bayview Avenue at about 4:50 a.m. when the driver of a BMW X3 SUV collided with a Chevrolet Impala taxi in the westbound collector lanes, Ontario Provincial Police said in a statement Monday.

A Mercedes-Benz SL63 AMG was also involved, and the driver lost control and stuck a cement barrier. On Monday afternoon, police said the sequence of events remained unclear.

The Markham man driving the Mercedes, 22-year-old Alvin Gu, was pronounced dead at the scene, while a female passenger suffered non-life-threatening injuries and was transported to hospital by paramedics.

The occupants of the BMW and taxicab were not injured, OPP said.

The westbound collector lanes were closed for several hours after the crash, as debris was removed and police examined the scene.

OPP's Traffic Support Unit is still investigating the details of the collision. Police ask any witnesses to call the Toronto OPP detachment at 416-985-4981.