A 29-year-old Saanich woman remains in hospital in critical condition after the vehicle she was travelling in struck a tree early Sunday morning.

Police say the vehicle left the road and hit a tree near the 900-block of Burnside Road West around 2 a.m.

Both the driver and the passenger were still in the vehicle when emergency crews arrived.

The driver, a 29-year-old man, was treated in hospital and was later released.

Investigators are working to determine if speed or impairment were factors.