A 37-year-old Markham man is facing an impaired driving charge after a two-car crash Tuesday morning on Highway 407 west of McCowan Road.
Police said the driver of an eastbound BMW rear-ended a Toyota just after 1:30 a.m.
The BMW rolled and both cars came to rest on the side of the highway.
The driver of the Toyota remains in hospital with serious but non-life-threatening injuries.
The driver of the BMW was arrested at the scene.