A woman is dead and three other people are seriously injured after a truck jackknifed and its trailers smashed into their car south of Perth.
The accident happened near the intersection of South Western Highway and Hall Road near Waroona, about 110 kilometres south of the city, about 4:00pm on Thursday.
Police says the truck crossed onto the wrong side of the road and its two trailers collided with the car, killing a 32-year-old woman who was in the front passenger seat.
Two rescue helicopters were sent to the scene, and one person was airlifted to Royal Perth Hospital.
Two others were taken to hospital by ambulance.
Police said the injured people were two men aged 43 and 17, and a 18-year-old woman.
The 45-year-old driver of the truck was not injured.
Major Crash officers are investigating the accident.
The South Western Highway was closed in both directions after the crash as emergency services investigated and cleaned up.
Man killed on Perth freeway
Earlier, a man died in hospital after being hit by a truck on Perth's Kwinana Freeway, with the accident causing severe traffic disruption as the road was closed for three hours.
Emergency services were called to the scene between Armadale Road and Gibbs Road in Atwell, in Perth's southern suburbs, about 10.30am.
The man is believed to have been struck after getting out of his parked vehicle and walking into the oncoming path of the concrete truck.
