A dozen bus drivers in Australia stand accused by speed cameras of speeding while on the job, but their cases actually demonstrate a significant error rate with the speed cameras used.

One driver was accused of driving a bus at 87 km/h on a flat stretch, yet the maximum speed of this vehicle -- downhill -- is 82 km/h.

Another camera ticketed the driver of a bus filled with 75 passengers for driving 74km/h uphill.

The Rail, Bus and Tram Union conducted its own test and determined the maximum possible speed on the incline in question was 56 km/h without passengers.

Union official Peter Jenkins told the Manly Daily, "Do you pay the $313 for the speeding ticket or pay $500-$600 to fight it. The demerit points could take away his driver's licence and his income. The drivers are pretty cheesed off about it."

The Roads and Traffic Authority will not review any motorist citations issued by this camera which produces $1 million in yearly revenue.

One driver said it was impossible to go faster because the gears automatically changed down, usually to second. The RTBU has contested all 13 fines and the RTA has agreed to review the cases. "How could you be going at that speed [74km/h] when the automatic transmission is dropping back to second?"