Ontario Provincial Police said a Mercedes-Benz and Honda Civic collided in the eastbound lanes of Highway 407, east of Highway 403, at about 11:20 p.m.

Witnesses told police the Mercedes was travelling at a high speed when the collision occurred. The Mercedes then rolled and struck a steel guardrail.

OPP said the Mercedes’ male driver was rushed to hospital in critical condition, and the male driver of the Honda was treated for non-life-threatening injuries.

Speed and alcohol are being investigated as possible factors, OPP said.