Speed limits in Australia

Common limits

Australian states and territories use two "default" speed limits. These apply automatically in the absence of 'posted' speed restriction signage. The two default speed limits are:

Common speed zones below the default built up area 50 km/h limit are:

Common speed zones above the default limits are:

The "END" speed limit sign is increasingly used throughout Australia to signal the end of a posted speed restriction, or built-up area "default" speed-limit leading to the jurisdiction's "rural" default speed limit. It contains the word "END" and a number in a black circle beneath this, representing the ceasing speed-limit. It is typically used where, according to AS1742.4 the road beyond has certain hazards such as hidden driveways, poor camber, soft edges and other hazards where the road authority feels a posted speed limit sign might be too dangerous or otherwise unwarranted. It is intended therefore to invoke particular caution. This sign is used as a direct replacement for the slash-through speed derestriction signs common in Europe and elsewhere.

Speed limits are enforced in almost all areas of the country except for some areas of the Northern Territory. Tolerance ranges from 3% to 10% in most states but only 3 km/h in Victoria, an issue that has caused much controversy in that state, especially in light of the fact that previous 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.

Default speed limits by state and territory

Despite introduction of model national road rules by the states in 1999, Western Australia and the Northern Territory retain different default speed limits. The table below indicates the default speed limits along with typical school zone limits and the highest zone in each locality.

In the external territories, and in some special cases (such as Lord Howe Island, NSW), the speed limits may differ significantly from those found across the rest of the nation.

Historical limits

Historically, Australia operated a simple speed limit system of urban and rural default limits, denoted in miles per hour. With the onset 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. Signage changed from a North American-style black and white textual sign to a design based on metric signage in use in New Zealand with black number in red annulus (or circle) on white, itself a derivative of the European standard number in red circle design.

Urban limits

The urban default, which prior to the 1930s was 30 miles per hour (48 km/h), applied to any "built up area", usually defined by the presence of street lighting. This limit was progressively increased to 35 miles per hour (56 km/h) over the next 30 years by each of the states and territories, with New South Wales being the last to change in May 1964.

With the onset of metrication the default urban limits of 35 miles per hour (56 km/h) were converted to 60 km/h, an increase of 3.7 kilometres per hour (2.3 mph).

In the late 1990s and early 2000s, the 60 km/h urban default limit was progressively lowered to 50 kilometres per hour (31 mph) nationally for reasons of road, and especially pedestrian, safety. 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. The Northern Territory has retained the 60 km/h limit; however, 50 km/h is also a common speed limit (particularly in residential areas).

Rural limits

Outside of built up areas, a prima facie speed limit applied. In New South Wales and Victoria, the prima facie speed limit was 50 miles per hour (80 km/h in New South Wales after metrication). In the 1970s however, most state prima facie speed limits were gradually replaced by absolute limits. An absolute speed limit of 70 miles per hour (113 km/h) was introduced to Victoria in 1971, as a trial. 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.

With the onset of metrication in 1974 the rural defaults of 60 miles per hour (97 km/h) and 65 miles per hour (105 km/h) became 100 kilometres per hour (62 mph) and 110 kilometres per hour (68 mph) respectively. The prima facie 50 mph limit in New South Wales became a prima facie limit of 80 km/h.

New South Wales introduced an absolute speed limit of 100 km/h in 1979, replacing the prima facie limit of 80 km/h. The Northern Territory introduced an absolute speed limit of 110 km/h in 2007, along with 130 kilometres per hour (81 mph) zones on the Territory's four major highways.

NT open speed limits

In the Northern Territory, from September 2015 a 336 km stretch of Stuart Highway between Barrow Creek and Alice Springs had speed limits removed for a 12-month trial. The Northern Territory had no blanket speed limits outside major towns until January 2007 when a general rural speed limit of 110 km/h (68 mph) was introduced although four major highways had higher 130 km/h (81 mph) zones. Speed limit advocates note that the per-capita fatality rate in 2006 was the highest in the OECD and twice the Australian average. In 2009, the opposition Country Liberal Party unsuccessfully sought the removal of the 130 km/h limits on three out of the four highways where it applied, arguing that total fatalities in the Northern Territory had increased significantly during the first two years of the speed limit. In argument against the motion, the government provided more detailed statistics than normally published, these statistics showed a reduction in fatalities along the highways where 130 km/h limits were introduced. In 2011 the opposition argued for a return to "open speed limits" . For the 2012 election the Country Liberals' transport policy promised an evidence based approach. After winning, de-restriction of Stuart Highway was proposed; a planned 12-month de-restriction was initiated on 1 February, 2014. The trial on 200 km of Stuart Highway was expanded later in the year to another 72 km, and continued indefinitely in January 2015 during a review of the initial results since "in the first 11 months, there were no recorded fatalities.". 130 km/h (81 mph) speed limits will be reimposed on 20 November, 2016 due to the electoral loss of the Country Liberal Party.

Derestriction signs in NSW

Often the start of rural default 'limits' or prima facie allowances were signalled by use of the speed derestriction sign, catalogued R4-2 in AS1742.4. (2009 edition has dropped from reference the R4-2 speed derestriction). The speed derestriction sign (//) had developed 'different meaning' over time at state and territory level, although its contract-meaning under "The United Nations Convention on Road Traffic, Signs & Signals" where the sign is catalogued "C,17a", is; "End of all local prohibitions imposed on moving vehicles" and has never changed. In the Northern Territory, they designated the end of speed restrictions. In Victoria and Western Australia they meant that the rural default speed limit applied, whilst in New South Wales, they indicated that the prima facie 50 miles per hour (80 km/h) limit applied.

New South Wales's prima facie 50 miles per hour or 80 km/hr limit, often signed by derestriction signs, was only enforced in cases where a driver's speed could be demonstrated to be excessive or dangerous in the context of prevailing road conditions. This was somewhat similar in principle to "reasonable and prudent" limits in other jurisdictions. This led to the widespread but misleading belief that no limit applied, and that derestriction signs indicated an "unlimited" limit. This belief, coupled with repeated studies showing 85th percentile speeds in excess of 120 km/h on major routes, comparatively high road tolls, difficulty in prosecuting speeding offences, and the variance in meaning of the derestriction sign across states, led New South Wales to harmonise its rural default limit to 100 kilometres per hour (62 mph) in 1978. The use of derestriction signs in New South Wales was officially discouraged, and on state controlled routes, 100 km/h signs were progressively used instead.