A serious crash has closed WB Hwy 401 in the Whitby and Oshawa area.
OPP Sgt Kerry Schmidt says that four vehicles collided in the westbound lanes between Stephenson and Thickson Rds.
He says it appears that a transport truck rear-ended a Toyota car. Another car and a coach bus were also involved.
The back seat passenger of the Toyota was killed. The driver and other passenger sustained serious injuries.
The occupant of the other car received minor injuries.
Police are investigating the cause of the crash.
The WB lanes remain closed along that stretch.