Road speed limits in the United Kingdom are used to define the maximum legal speed (which may be variable) for vehicles using public roads in the UK.
Speed limits are one of the measures available to attempt to control traffic speeds, reduce negative environmental effects of traffic, increase fuel use efficiency and satisfy local community wishes. The speed limit in each location is indicated on a nearby traffic sign or by the presence of street lighting. Signs show speed limits in miles per hour (mph) or the national speed limit (NSL) sign may be used.
The national speed limit is 70 mph (112 km/h) on motorways and dual carriageways, 60 mph (97 km/h) on single carriageways and generally ( in Wales) in areas with street lighting (built-up area). These limits may be changed by road signs and apply to cars, motorcycles, car-derived vans up to 2 tonnes maximum laden weight (MLW), and to motorhomes or motor caravans not more than maximum unladen weight. Other classes of vehicles are subject to lower limits on some roads.
Enforcement of UK road speed limits was traditionally achieved using police 'speed traps' set up and operated by the police who now increasingly use speed guns, automated in-vehicle systems and automated roadside traffic cameras. Some vehicle categories have various lower maximum limits enforced by speed limiters.
Ever since they have been introduced, speed limits have been controversial. They are both opposed or supported by various sources; including motoring advocacy groups, anti-motoring groups and others who either consider them to be irrelevant, set too low or set too high.
Current regulations
National speed limits
Default maximum speed limits apply to all roads where no specific lower numeric speed limit is already in force. The default speed limit is known as the national speed limit (NSL). The NSLs vary by road type and for vehicle types.
+National speed limits by vehicle type and road typeBuilt-up area (Wales)Built-up area (England, Scotland, and Northern Ireland)Single carriagewayDual carriagewayMotorwayCars and motorcycles (including car-derived vans up to 2 tonnes max laden weight)60 mph (96 km/h)70 mph (112 km/h)Vehicles towing caravans or trailersinc cars, motorcycles, goods vehicles up to 7.5 tonnes MLW60 mph (96 km/h)60 mph (96 km/h)Vans, buses, coaches, minibuses up to Goods vehicles up to 7.5 tonnes MLW70 mph (112 km/h)Goods vehicles over 7.5 tonnes MLW (in England and Wales)60 mph (96 km/h)Goods vehicles over 7.5 tonnes MLW (in Scotland and Northern Ireland)
In Northern Ireland only, vehicles displaying L-plates (for learner drivers) or R-plates (for newly qualified drivers) may not exceed , regardless of whether the driver is required to display them. This restriction does not apply to goods vehicles, buses and coaches displaying L-plates while driving on a motorway, or to motorcycles of Class A2 or A displaying R-plates.
Speed limiters Some classes of vehicles are required to have speed limiters which enforce a maximum speed by physical means. New vehicles should be fitted with limiters as follows: Buses and coaches, including minibuses: HGVs: Mopeds:
The law also stipulates retrofitting of limiters to older buses and HGVs, mostly at the above speeds, with two minor variations allowing "70 mph" (technically, 112 km/h) for some older buses, and "60 mph" (96.5 km/h) for a limited selection of HGVs between 7.5 and 12 tonnes. Some older mopeds may be restricted instead to either 30 mph or 50 km/h (31 mph), although the accuracy and reliability of the restriction methods used is variable.
Some other vehicles, especially light commercial or service vehicles, may be voluntarily fitted with limiters by their owners (either private businesspeople or company fleets), generally set to various speeds between and 70 mph (112 km/h), though some mostly-citybound service and delivery vehicles may be limited to or less. Likewise, some heavy goods vehicle operators choose to limit to or for fuel saving. In all cases, a warning sticker must be displayed on the rear of the vehicle.
Signs
20 mph speed limits and zones The Department for Transport encourages the use of either ' speed limits' or ' speed limit zones' in urban situations where vulnerable road users are at particular risk.
In 1998 the TRL reported that signed speed limits only reduced traffic speeds by about and delivered no discernible reduction in crash numbers but that zones achieved average speed reductions of with child pedestrian crash reductions of 70% and child cyclist crash reductions of 48%. The report noted that the cost of wide area traffic calming was prohibitive.
20 mph speed limits speed limits are based on signage alone and are used where 85th percentile speeds are already below .
A report published in 2010 by the Department for Transport regarding Portsmouth City Council's speed limit on of the city's of roads found a small reduction in traffic speed and a small 8% increase in the number of serious crashes – neither of which were statistically significant – and a 21% reduction in the number of crashes. There was a 6% increase in the numbers killed or seriously injured (KSI) – also not statistically significant due to the small numbers involved – and a 22% reduction in the total number of road casualties.
20mph zones
In places where speeds are desired but where excessive speeds (85th percentile speed of or above) occur, zones are recommended. These have to use traffic calming measures to reduce speeds to below .
A report published in 2008 estimated that following the introduction of zones in London, a reduction of casualties by 45% and KSI by 57% occurred.
20 mph default speed limit in Wales On 17 September 2023, Wales introduced a default speed limit of in built up areas. An estimated of the of road in the country was changed from a to a speed limit, with local authorities allowed to apply for exemptions to the new law. Following its introduction, only an estimated 3% of the total road network in Wales remains at , as opposed to 37% before the change. The Welsh Government said they were implementing this to reduce death and injury on the roads, as well as to reduce noise and pollution and encourage active travel. This was despite their own figures showing the measure could cost Wales £4.5 billion over a 30-year period. Spain had already enacted a similar default speed limit in 2019. Across the UK, many cities and towns already had residential areas with speed limits. Scotland were considering a similar default speed limit to Wales.
Shared space Research carried out for the Department for Transport, to provide supporting evidence for Local Transport Note 1/11 on shared space, showed that in all of the ten shared space sites that were studied, that although they all had speed limits of , that the average speeds on them was around .
Types of speed limit
Fixed speed limits
Speed limit road signs are used to inform road users where speed limits other than the applicable national speed limit apply.
Variable speed limits
Variable speed limits are used on some major traffic roads. These can be changed in response to weather, traffic levels, time of day or for other reasons with the currently applicable speed limit displayed using an electronic road sign. Signs with the speed shown in a red circle are compulsory, signs where the speed is not within a red circle are advisory and exceeding these speeds while driving safely within the applicable national speed limit is not in itself an offence. Variable speed limits were introduced on some congested major routes as an element of controlled motorway techniques to improve traffic flows for given prevailing conditions. Part-time variable speed limits may also be used outside schools.
Minimum speed limits Rarely, minimum speed limits are used, such as through the Mersey Tunnels, to maintain free flow and safe passage through otherwise hazardous or enclosed areas. Circular blue signs with white numbers indicate the start of these limits, and similar signs with a red diagonal line indicate their end. Contrary to popular belief, there is no minimum speed limit on motorways, although certain classes of slow vehicles (as well as those of any class that cannot maintain on the level whilst unladen) are prohibited on safety grounds and drivers are expected to not cause unnecessary obstruction by driving unusually slowly.
Justification According to the government, speed limits are used to help achieve appropriate traffic speeds for safety, and environmental and accessibility reasons. The Department for Transport state that "speed limits play a fundamental role" in the effective management of traffic speeds in relation to the safety of both drivers and all other road users.
Safety
The speed limit in built-up areas was introduced in 1934 in response to high casualty levels. The 70 mph (112 km/h) limit on previously unrestricted roads was introduced in 1965 following a number of serious motorway crashes in fog earlier the same year.
The Department for Transport believes that effective speed management involves many components but that speed limits play a 'fundamental role' and are 'a key source of information to road users' particularly as an indicator of the nature and risks posed by that road to both themselves and other motorised and non-motorised road users.
The Parliamentary Select Committee for Transport Safety published a report entitled 'The Ending the Scandal of Complacency' in 2007 which highlighted how casualty levels rise with increasing speed and recommended reducing speed limits on streets with high pedestrian populations and on dangerous rural roads. The report highlights that when two cars crash head-on at 60 mph (96 km/h) a driver has a 90% chance of dying which falls to 65% at . While recommending speed zones the committee noted that these zones 'should not rely on heavy-handed enforcement measures'.
In 2008 14% of collisions reported to the police had a speed-related contributory factor (either "exceeding the speed limit" or "travelling too fast for conditions") reported rising to 24% for fatal crashes and 25% of all road deaths.Department for Transport (2009), p. 41 "Fourteen per cent of accidents had a speed related contributory factor reported, either exceeding the speed limit or travelling too fast for conditions. This increased to 24% for fatal accidents, accounting for 25% of all road deaths." "Exceeding the speed limit" was reported as a contributory factor in 5% of collisions and 14% of fatal collisions. "Travelling too fast for conditions" (but within the prevailing speed limit) was recorded as one of the contributory factors in a further 8% of all collisions (and 9% of all fatal, 9% of all serious and 8% of all slight accidents),Department for Transport (2009), p. 45 "Exceeding the speed limit was reported as a contributory factor in 5% of all accidents. However, the factor became more significant with the severity of the accident. It was reported in 14% of fatal accidents and these accidents accounted for 362 fatalities, 15% of all deaths... The factor travelling too fast for conditions was a contributory factor in 8% of accidents. Again, the proportion of accidents where it was reported rose with the severity of the accident and 9% of fatal resulting in 224 fatalities, 10% of all deaths (Excluding accidents and casualties in accidents which had exceeding the speed limit reported as a contributory factor)"