Police have unveiled four new fixed speed camera locations as fresh figures show the first one on the Mitchell Freeway has detected 60 hoons and 12,000 speeding motorists since December.
Motorists speeding over the 100km/h limit on the Kwinana Freeway at Como and Success, Roe Highway in Willetton and the Mitchell Freeway in Stirling will be the focus of the cameras.
Police hope to start using the cameras at Como and Willetton next month and pencilled in the Stirling camera for August and the Success trap for September.
The locations were chosen on road safety recommendations from the WA Government's chief speed enforcement adviser, Max Cameron, who suggested 24 of the devices be set up on Perth's main roads.
Insp. Mark Ridley said Professor Cameron had ranked Perth's roads and then police did a more detailed analysis to determine the exact places on those roads that had the most crashes.
The cameras will not be installed permanently.
An undisclosed number of WA's 23 Vitronic dual-lens mobile roadside cameras would be rotated through the sites similar to what happened with red light cameras.
The first fixed speed camera site, near the Karrinyup Road exit next to the northbound lanes, was chosen because of four fatal crashes and two serious accidents there between 2006 and 2010.
Police have caught thousands of speeding drivers over a total of 17 weeks since the camera was set up in December.
"Sixty of those charged have been reckless drivers who put their own lives and the lives of others at risk by driving at more than 45km/h over the limit," Insp. Ridley said.
But he said the fixed speed camera on the Mitchell Freeway had led to a drop in the number of speeding motorists.
"When the camera was first installed, we were catching about six hoons a week and now we're down to one or two," Insp. Ridley said.
"Infringements have also dropped from about 1100 a week to under 600, so it's obviously showing a good reduction in speeders past that site.
"We're hoping the same reductions will happen at the other sites."
Signs warning drivers about the fixed cameras will be positioned near the devices and the locations of the boxes will be published on the police website.
A sign already installed at the Como site was exposed this week when the storms ripped away the black plastic covering it.
Police said the camera boxes would be put in places where they would not endanger motorists, such as behind freeway barriers.