John King and Claus Salger say thousands of Victorians are wrongly fined for speeding each year caught by fixed cameras that are poorly installed, calibrated and maintained.
But they say the millions of dollars in revenue at stake mean police are using every legal mechanism available to deny them secret information that will help uncover a public scandal.
At Heidelberg Magistrates' Court yesterday, Mr King applied for a subpoena against Victoria Police to obtain a number of speed camera technical documents that, he says, will help him challenge a 2007 fine.
He told the court he successfully challenged a speeding fine in his previous case after he and Mr Salger, who acts as his technical expert, gained access to technical manuals through Freedom Of Information rules.
Barrister Robert Taylor, for the police, argued the subpoenaed documents would not help Mr King's defence. He said Mr King had not set out to prove his fine was wrong, but that fixed speed cameras were generally unreliable.
The decision on the application will be announced on February 24.
In 2007, Mr King and Mr Salger each won battles to overturn mobile speed camera fines. By comparing police photos with images in a technical manual, Mr Salger worked out that his 22-year-old Nissan Patrol had apparently accelerated faster than the space shuttle.
He was allegedly caught driving at 66km/h in a 60km/h zone at the corner of Gardenia St and Doncaster Rd, North Balwyn.
"History shows us that these fixed cameras are notoriously unreliable," Mr King said.
Outside court yesterday, the pair said they were battling on behalf of all Victorian drivers.