We are sure you all devotedly abide by the speed restrictions in place on our roads. However, some of you may find yourself in the position that you receive a fixed penalty, or are being taken to court, for going too fast on a road where the speed limit was not clear.

You therefore need to know what the law says about speed limit signs. Thankfully, the law is comprehensive on this subject. Unfortunately, this means the law is also ridiculously complex, so we will try to keep it simple.

Speed limits must be clearly recognisable for the obvious reason that you cannot stay within the limit if you do not know what it is.

Speed limit signs must comply with the measurement requirements laid down by law, to ensure that they are clearly readable by road users. If these legal requirements are not met, the speed limit is unenforceable and therefore any speeding ticket or prosecution for speeding should be dropped.

Speed limit signs at the beginning of the restriction must generally be illuminated during the hours of darkness and all the repeater signs should then be illuminated or be reflective.

Generally, changes in speed limits must be identified by the use of a large speed limit sign on each side of the carriageway (subject to exceptions regarding roads turning onto and off the road that the speed restriction applies to).

On 30mph roads with street lighting, large 30mph speed limit signs on each side of the carriageway will be sufficient if they are as close as practicable to the first street lamp. On 30mph roads without street lighting, there must be a large 30mph speed limit sign placed on each side of the carriageway at the beginning of the restriction with small repeater signs at regular intervals along the route.

On 40mph roads, 50mph roads and 60mph dual carriageways, large speed limit signs must be placed at the beginning of the restriction on each side of the carriageway with small repeater signs at regular intervals along the carriageway.

On 60mph single carriageways and 70mph dual carriageways without street lighting, large national speed limit signs (a black diagonal strip against a white background) must be placed on each side of the carriageway at the beginning of the restriction but repeater signs are not required.

On 60mph single carriageways and 70mph dual carriageways that have street lighting large national speed limit signs (a black diagonal strip against a white background) must be placed on each side of the carriageway at the beginning of the restriction, but they must also have small repeater signs at regular intervals.

Amazingly, there are numerous roads throughout the country where the speed limits are unclear because the above laws are not complied with. For example, in March 2008 Simon Grills successfully had a prosecution dropped by Essex Police for speeding past the most lucrative camera in England, the M11 Southbound camera near Woodford. Why? The light on the large 50mph speed limit sign was broken therefore motorists at night could not see the change in speed limit. The only way these errors will be corrected is if conscientious riders and drivers challenge tickets and prosecutions.

Robert Ward is a solicitor with roadtrafficlawdirect.com. He has worked in law for over 8 years and specialises in defending motorists.

Jeremy Scott is the founder of roatrafficlawdirect.com. He has been a solicitor for almost twenty years, defending both individuals and companies in relation to road traffic law.

For further information please telephone 0808 160 5016.