TRAFFIC is banked up along Great Eastern Highway in Mundaring after a truck carrying a load of sand rolled over near Chipper Street.
The westbound lane of the highway is closed and Main Roads WA is warning motorists to avoid the area.
Mundaring Police said motorists could expect lengthy delays.
Officer in charge Jeff Taylor said the truck driver was assisting police with their inquiries.
“No one was hurt thankfully,” he said.
“Traffic was a nightmare after the rollover but I am pleased to say we got things going quickly.
“We currently have the lights flashing amber at the intersection of Great Eastern Highway and Stoneville Road and we are diverting traffic.”