A 19-year-old man was flown to hospital after a car hit a tree north-east of Adelaide.
Emergency services were called to Yettie Road at Williamstown, 50 kilometres north-east of Adelaide, after reports a car hit a tree just after 5pm on Thursday.
A 19 year old Williamstown woman who was in the car was airlifted to hospital in a critical condition.
The driver, a 49 year old man also from Williamstown, was taken to hospital with serious injuries.