A number of youths were seen pushing a car out of the way of oncoming traffic after the driver crashed into a centre barrier between Moffat Road and State Highway 2, Bethlehem.
A police media communications spokeswoman said a member of the public reported the crash at 1.30am on Sunday.
"A whole lot of youths were seen pushing the car out of the way," she said.
The spokeswoman said one of the four people inside the car fled the scene and another received medical treatment.