Opposition party officials in Australia used their version of the freedom of information act to secure information about mobile speed cameras. These documents showed that "mobile cameras gave divergent readings in tests when they were moved to different locations or different times of the day" and that the mobile cameras had as much as a 3 km/h deviation from the results indicated on handheld radar guns. Three km/h just happens to be the only tolerance level afforded to motorists. The net result is a lot of people got tickets who probably either weren't speeding at all, or their speedometer was off by 1 or 2 percent.

Opposition transport spokesman Terry Mulder said the figures showed discrepancies of up to 3 km/h between mobile speed cameras and the hand-held radar guns.

"On more occasions than not, the three-kilometre difference between the hand-held radar gun and the mobile speed camera works against the motorist," Mr Mulder said.

"If you have a 40 km/h speed zone, and a 50 km/h speed zone, and you've got a 3 km/h tolerance, well then quite clearly you can find motorists getting booked when they shouldn't be getting booked."