Road lengths in Great Britain statistics: Notes and definitions
Updated 20 February 2025
Applies to England, Scotland and Wales
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These notes and definitions relate to the road lengths statistics published on the Department for Transport website. For further information on these statistics please email [email protected].
Road length estimates are produced using information from Ordnance Survey鈥檚 MasterMap Highways Network, local authorities, the Scottish Government, the Welsh Government and National Highways (formerly Highways England). The majority of the data relate to a single time point of April of the year in question.
Types of road
Major roads 聽
Includes motorways and all 鈥楢鈥� roads. These roads usually have high traffic flows and are often the main arteries to major destinations.
Motorways
Motorways (built under the enabling legislation of the Special Roads Act 1949, now consolidated in the Highways Acts of 1959 and 1980). Includes major roads of regional and urban strategic importance, often used for long distance travel. They are usually 3 or more lanes in each direction and generally have the maximum speed limit of 70 miles per hour.
鈥楢鈥� roads
These can be centrally or locally managed roads. They are often described as the 鈥榤ain鈥� roads and tend to have heavy traffic flows, though generally not as high as motorways.
Trunk roads (designated by the Trunk Roads Acts 1936 and 1946)
Most motorways and many of the long distance rural 鈥楢鈥� roads are trunk roads. The responsibility for their maintenance lies with the Secretary of State and they are centrally managed by National Highways (formerly Highways England) in England, the Welsh Government and the Scottish Government (National Through Routes). For the purposes of this publication all trunk roads are referred to as 鈥渃entrally managed roads.鈥�
Non-trunk roads
These are roads for which local highway authorities are responsible and are referred to as 鈥渓ocally managed roads鈥� throughout the publication. Non-trunk roads are either classified or unclassified, the former being of 2 types, principal and non-principal. The classified principal roads are class 鈥楢鈥� roads, plus a small amount of local authority motorway, and are of regional and urban strategic importance. The non-principal roads are those which distribute traffic to urban and regional localities. The non-principal classified roads are sub-divided into 鈥楤鈥� and 鈥楥鈥� classes. Unclassified roads are those in the least important categories, such as local distributor and access roads.
Minor roads
These are 鈥楤鈥� and 鈥楥鈥� classified roads and unclassified (鈥楿鈥�) roads (all of which are maintained by the local authorities), as referred to above. Class III (later 鈥楥鈥�) roads were created in April 1946. 鈥楤鈥� roads in urban areas can have relatively high traffic flows but are not regarded as being as significant as 鈥楢鈥� roads, though in some cases may have similarly high flows.
鈥楤鈥� roads are useful distributor roads often between towns or villages and in rural areas often have markedly low traffic flows compared with their 鈥楢鈥� road counterparts. 鈥楥鈥� roads are regarded as of lesser importance than either 鈥楤鈥� or 鈥楢鈥� roads, and generally have only one carriageway of 2 lanes and carry less traffic. They can have low traffic flows in rural areas. Unclassified roads include residential roads both in urban and rural situations and rural lanes, the latter again normally having very low traffic flows. Most unclassified roads will have only 2 lanes, and in rural areas may only have 1 lane with 鈥減assing bays鈥� at intervals to allow for 2-way traffic flow.
Urban roads
These are major and minor roads that sit within a built-up area, with a population of more than 10,000 people in England and Wales or more than 3,000 in Scotland.
Rural roads
These are major and minor roads that sit outside urban areas (these urban areas have a population of more than 10,000 people in England and Wales or more than 3,000 in Scotland).
Private roads
For the purpose of this publication, private roads are considered to be road not maintained at public expense. For major roads, private roads (usually toll roads, tunnels and bridges) are included in the road length figures as they are accessible to the general public. For minor roads, private roads are not included in the road length figures as they are not usually accessible to the general public.
聽Types of road in Great Britain
The diagram below shows the road types that make up major and minor roads. Trunk roads are always major roads and are referred to in these statistics as centrally managed motorways and centrally managed 鈥楢鈥� roads. Locally managed roads can be major roads, referred to as locally managed motorways and locally managed 鈥楢鈥� roads, or they can be minor roads, referred to as 鈥楤鈥� roads, 鈥楥鈥� roads and 鈥楿鈥� roads.
Diagram 2: A diagram presenting the road types in Great Britain and their management
