A crash on Roe Highway westbound at Kenwick Link, Beckenham has caused major traffic congestion.
The right lane is blocked and traffic is moving slowly.
The roads are wet and motorists are urged to drive with caution.
Cars are also severely backed up to Cedric Street after a breakdown at Narrows Bridge southbound.
Incident response has closed the right lane.
Towing services have cleared a crash on Kwinana Freeway northbound at Anketell Road, Mandogalup but traffic remains heavy.
Lanes have been reopened but traffic is moving slowly and drivers are backed up to Mortimer Road.