The OPP say a man was killed when the car he was driving collided with the rear of a tractor trailer at about 2:15 a.m. He was pronounced dead at the scene.
The westbound lanes of the QEW are closed just past Walker's Line while police reconstruction teams complete their investigation.
At the time of the crash, the OPP was on scene assisting with maintenance operations in the area.
The OPP says the Special Investigations Unit has been notified. There is no information yet about the victim.
The SIU investigates all reports involving police where there has been death, serious injury or allegations of sexual assault.