Six injured in spate of crashes

Six people - including three teenagers - have been seriously injured during a grim 24 hours on WA roads.

A 19-year-old learner driver has critical head injuries after a car rollover in Mundijong on Monday night.

The Yanchep woman lost control of her Holden Commodore on Tonkin Street about 11.25pm before crossing to the wrong side of the road and hitting a tree.

She had to be cut from the mangled vehicle and was airlifted to Royal Perth Hospital.

The woman was in a critical but stable condition last night.

Her passengers, a 17-year-old girl, an 18-year-old woman and a 21-year-old man, were also seriously injured. They are in a stable condition.

Major crash officers are investigating if speed was a factor in the crash.

Yesterday, a 55-year-old man was critically injured when his motorcycle hit a tree in Secret Harbour before dawn.

Almost six hours later, firefighters had to free a trapped 62-year-old man after a head-on crash near Australind.

The Leschenault resident was travelling north along Old Coast Road when his Mazda CX-5 and a Mitsubishi Triton utility collided about 11.45am.

The man was flown to RPH.

The other driver, 48, had minor injuries.

A 25-year-old man who was directing traffic away from the crash site was also taken to hospital after he was struck by a car. His injuries were not believed to be serious.