Trunk road

A trunk road is a major highway with a specific legal classification in some jurisdictions, notably the United Kingdom, Sweden and formerly Ireland. Trunk roads are planned and managed at the national level, distinguishing them from non-trunk roads which are managed by local authorities. Trunk roads are important routes usually connecting two or more cities, ports, airports and other places, which is the recommended route for long-distance and freight traffic. Many trunk roads have segregated lanes in a dual carriageway, or are of motorway standard.^{[citation needed]}

The term trunk road, or trunk highway, is sometimes used more generically to refer to other categories of major highway.

In the United Kingdom, trunk roads were first defined for Great Britain in the Trunk Roads Act 1936 (1 Edw. 8. & 1 Geo. 6. c. 5). Thirty major roads were classed as trunk roads, and the Minister of Transport took direct control of them and the bridges across them. The Trunk Roads Act came into force in England and Wales on 1 April 1937, and in Scotland on 16 May 1937. This development did not extend to Northern Ireland, which has always had a separate system of highway and road traffic law.

At that time, 4,500 miles (7,200 km) of British roads were classified as trunk roads. Additional roads have been "trunked", notably in the Trunk Roads Act 1946 (9 & 10 Geo. 6. c. 30). Others, like virtually all British motorways, have entered the system as a result of new construction. As of 2004, Great Britain had 7,845 mi (12,625 km) of trunk roads, of which 2,161 mi (3,478 km) were motorways.

Since 1994, trunk roads in England have been managed by National Highways (formerly Highways England, and before that, Highways Agency), while Scotland has had responsibility for its own trunk roads since 1998; these are currently managed by Transport Scotland, created in 2006. The Welsh Government has had responsibility for trunk roads in Wales since its establishment in 1998.

England has 4,300 miles (6,900 km), Scotland has 1,982 miles (3,190 km) and Wales has 1,048 miles (1,687 km) of trunk roads, inclusive of motorways. National Highways publishes a full network map of trunk roads and motorways in England.

Most interurban trunk roads are primary routes, the category of roads recommended for long distance and freight transport. Not all primary routes are trunk roads, the difference being that maintenance of trunk roads is paid for by national government bodies rather than the local councils in whose area they lie. Primary routes are identified by their direction signs, which feature white text on a green background with route numbers in yellow. Trunk roads, like other "A" roads, can be either single- or dual-carriageway.

Historically, trunk roads were listed on maps with a "T" in brackets after their number, to distinguish them from non-trunk parts of the same road, however this suffix is no longer included on current Ordnance Survey maps, which simply distinguish between primary and non-primary "A" roads. A trunk road which has been upgraded to motorway standards may retain its original "A" number, but with an "M" in brackets to denote that motorway regulations apply on it. Long distance examples of this are the A1(M) in England, and the A74(M) in Scotland.^{[citation needed]}