A 37-year-old road worker has undergone surgery at Royal Perth Hospital overnight after being hit by a car in Silver Sands.
It happened just before 9.30pm on Sunday when a Toyota Camry, being driven by a 58-year-old man, crashed into the worker on Mandurah Road near Watersun Drive before ploughing into a street sweeper.
It's understood the driver and his passenger had to be cut from the wreckage.
They were also taken to Royal Perth Hospital for treatment.
The road worker remains in a serious but stable condition.
Police are investigating whether alcohol was a factor in the crash.
Investigators are urging anyone with dash-cam or mobile phone vision of this crash to upload
the vision via this link: https://wapf.au.evidence.com/axon/citizen/public/seriouscrashsilversands
Anyone with information is asked to call Crime Stoppers on 1800 333 000 or to make a report online at crimestopperswa.com.au.