Advisory speed limit

A U.S. advisory speed limit sign, warning drivers of a curve ahead.

An advisory speed limit is a speed limit that is recommended by a governing body, but is not enforced. Advisory speed limits are often set in areas with many pedestrians, such as in city centres and outside schools, and on difficult stretches of roads, such as on tight corners or through roadworks. While travelling above the advisory speed limit is not an offence, liability for any accidents that occur as a result of traveling above the limit can be placed partially or entirely on the speeder.

Signposting of advisory speed limits varies from country to country; Australia makes extensive use of advisory speed limits across its highway networks while the Richtgeschwindigkeit ("reference speed") in Germany is valid for the whole Autobahn network (but can be over-ruled by minimum speeds and speed limits), while the United States and the United Kingdom only give advisory speed limits for hazards such as bends. Some have criticised advisory speed limits for being a weak method of traffic control, as drivers face little or no penalty for breaking the advisory speed limit.

Use

Use of advisory speed limits varies from country to country, but they are generally used to reduce speed along short stretches of dangerous road, such as on the tight curves of an off-ramp or on a busy shopping street. The advisory speed limit when not posted is generally the same as the mandatory speed limit in ideal conditions. In the United Kingdom, most speed limits imposed by variable-message signs are advisory, and there are no sanctions for drivers who exceed them; a notable exception being the Gatsometer-camera enforced, MIDAS and ATM variable limits on the M25, M42 and M6 motorways. Crucially, the signs imposing these limits are distinct from regular, advisory VMS displays by the inclusion of a red ring surround, effectively changing them from advance hazard warnings into standard, mandatory speed-limit signs.

As local councils require consent from the Department for Transport before changing speed limits, some use advisory speed limits on roads that the DfT refuses to officially downgrade.

The usefulness of advisory speed limits has been questioned by a number of studies: one group from the Transportation Research Board found advisory speed limits through roadworks being consistently flouted by motorists, while an investigation by Manchester Evening News found that almost all buses in Manchester city centre exceeded the local 10 miles per hour (16 km/h) advisory speed limit; some by as much as 30 miles per hour (48 km/h).

In Australia, if a person is involved in a single vehicle accident and the resulting investigation reveals that the driver was exceeding the Advisory Speed Limit displayed it can be a breach of the Insurance Cover Contract, resulting in no pay-out.

Germany

German signs (in km/h) indicating the beginning and end of an advisory speed limit.

The Richtgeschwindigkeit (German Advisory or Suggested Speed of Travel) is a legal term in Germany describing the advisory speed limit for roads without a mandatory speed limit. The Autobahn has an advisory speed limit of 130 kilometres per hour (81 mph) on non-signposted sections.

Exceeding the advised speed is neither a felony nor a misdemeanour. However, an increased liability in the case of an accident may result from driving faster than the recommended speed, due to an increased danger of operating the vehicle. For instance, travelling above the Richtgeschwindigkeit can cause insurance companies to withhold payments of claims.

In Germany, the Autobahn-Richtgeschwindigkeits-Verordnung (Directive on Reference Speed on Motorways), introduced in 1974, recommends a speed of no more than 130 km/h (81 mph) for autobahns and similar roads, whose lanes are separated by a median or which have at least two lanes per direction, provided there are no traffic signs posting a lower speed limit.

Until 31 August 2009, a different reference speed could be posted by the traffic signs number 380 and 381, according to §42 of German traffic code, as seen above. Having been used only seldom, these traffic signs have been abolished meanwhile.

Signage

Australian curve warning and speed advisory signs		British advisory speed limit sign (in mph)

The signage for advisory speed limits is not defined by the Vienna Convention on Road Signs and Signals, and is therefore not standardised internationally. The United States uses a variation on the standard speed limit sign, with a yellow background instead of a white one and the words "speed limit" omitted, and an additional panel stating the type of hazard ahead; Australia uses a similar design although regulatory speed limit signs are quite different. Germany uses a square sign with a blue background and white lettering, similar to the minimum speed limit sign, and New Zealand uses a yellow background with black lettering (similar to the Australian design without the "km/h" lettering). The United Kingdom currently uses an oblong white rectangle with black lettering stating "Max Speed". These signs are never used alone - they accompany warnings for hazards such as bends or hills. In the UK it is illegal for a "max speed" sign to be used to enforce a speed limit.

See also

• Speed limits in Montana