A 24-year-old Oshawa man sustained life-threatening injuries after a single-vehicle crash early Monday on Highway 427 in Etobicoke, leading to the temporary shutdown of a major ramp.

The incident happened around 1:40 a.m. in the northbound collector lanes near Highway 401. Authorities say the sedan veered right into a steel guardrail, then swerved across all lanes and hit the opposite barrier. The driver, who was alone in the vehicle, was taken to hospital in critical condition.

Police are still investigating the cause of the crash, and charges may be laid. The ramp from northbound Highway 427 to eastbound Highway 401 was closed for several hours before reopening at approximately 8:45 a.m.