Motorists can expect peak-hour delays on two major road arteries in the Perth metropolitan area.
There has been a crash on Kwinana Freeway northbound just before the Thomas Road off-ramp in Bertram.
It is not known how many lanes are closed but traffic is heavy on approach and snakes back beyond Mortimer Road.
Tow trucks are onsite.
There has also been a crash on Roe Highway northbound near Kalamunda Road in High Wycombe.
Various lanes have been affected and while police are on the scene, traffic is slow.