Western australian speed dating
In New South Wales and Victoria, speed limit was 50 miles per hour This was subsequently reduced to 60 miles per hour (97 km/h) in late 1973.
South Australia introduced an absolute speed limit of 60 mph in 1974.
As part of metrication in 1974, speed limits and speed advisories were converted into kilometres per hour, rounded to the nearest 10 km/h, leading to small discrepancies in speed limits.
Outside of built up areas, a prima facie speed limit applied.
Tolerance, especially in light of the fact that earlier Australian Design Rules specified that vehicle speedometers may have up to 10% leeway in accuracy.
This was updated in 2006 to require that the "speed indicated shall not be less than the true speed of the vehicle." Detection measures used are radar, LIDAR, fixed and mobile speed cameras (using various detection technologies), Vascar, pacing and aircraft.
However, many existing roads, especially subarterial roads in urban areas, have had 60 km/h limits posted on them.
Queensland's Manual of Uniform Traffic Control Devices (Speed Controls) states that 60 km/h is the general minimum speed limit for traffic-carrying roads.