Traffic came to a standstill following a major crash on the Mitchell Freeway on New Years Eve.
The crash, which involved a motorcycle and a car, happened about 7pm on Sunday evening, and quickly closed all four lanes just after the Karrinyup Road exit.
Motorists parked their vehicles as the Main Roads WA incident response team, St John Ambulance and WA Police attended.
A Main Roads WA spokeswoman said the incident had forced the complete closure of the Mitchell Freeway northbound, and advised motorists to avoid the area.
Main Roads said they were unable to give a time when the freeway would be re-opened.
It is unclear at this stage if anyone was injured in the incident.
In order to clear traffic WA Police directed motorists across the four lanes to reverse and execute a U-turn manoeuvre, and exit at the Reid Highway off-ramp.
#MitchellFwy CLOSED northbound at #KarrinyupRd, Innaloo - Crash #perthtraffic
— Main Roads WA (@Perth_Traffic) December 31, 2017