A car crash has left the Kwinana Freeway southbound choked up from a crash site around Thomas Road, Casuarina, back up to the Berrigan Drive area.
"That's at least six kilometres of traffic," a Main Roads spokesman said.
"It's blocking the left and right lane, so traffic is going through the emergency lane."
The left lane has reopened and Main Roads is hoping congestion will ease soon.
Police and paramedics rushed to the scene where the crash occurred about 2.20pm, but a St John Ambulance spokesman said the patient examined, a man in his 80s, was not seriously injured.
