Advisory Speed Limit - Use

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.