A WA Police spokesman said at 4.50am the silver Suzuki Swift exited the Kwinana Freeway south at Paganoni Road.
‘It appears the vehicle left the road and rolled down the embankment back towards the southbound lanes of the freeway,’ he said.
‘The front female passenger, a 25-year-old woman from Meadow Springs, was ejected from the vehicle and was found pinned under the front of the car.’
A motorist stopped and helped the driver lift the car off her.
The RAC Rescue Helicopter flew her to Royal Perth Hospital.
Major Crash Investigators need anyone with information about the crash, or who saw the vehicle involved before the crash, to call Crime Stoppers on 1800 333 000.