Trunk roads in Wales

Trunk roads in Wales were first created in the Trunk Roads Act of 1936 when the UK Ministry of Transport took direct control over 30 of the principal roads in Great Britain from English, Welsh and Scottish local authorities. The number of Trunk Roads were expanded from 30 to 101 in the Trunk Roads Act of 1946. These roads formed what the Act called "the national system of routes for through traffic". Since Welsh devolution the Trunk Road system in Wales has been managed by the South Wales Trunk Road Agent and North & Mid Wales Trunk Road Agent on behalf of the Welsh Government. As of April 2015, out of a total of 34,495 miles (55,514 km) of roads in Wales, 1,576 miles (2,536 km) are Trunk Roads (including 133 miles (214 km) of motorways and 350 miles (560 km) of dual carriageway).

Historically, trunk roads have been listed on maps with a "(T)" 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. However the North and Mid Wales Trunk Road Agent still use it to distinguish the trunk road from a non-trunk road. It is possible for roads to be "de-trunked" for example, when a road had been improved by a motorway, bypass or a similar route. When a road is de-trunked signposts are often replaced, and sometimes route numbers are changed, making the original road harder to follow. The London—Fishguard Trunk Road in 1936 only included the A48 and the A40, however with road improvements most notably the M4 motorway, the A48 in south Wales and A40 in England have largely been de-trunked.

The 1936 Act came into force in Wales on 1 April 1937 and created 30 Trunk Roads in Great Britain, with 5 roads either completely or partially within Wales. The Act excluded roads in the County of London and Northern Ireland. The 1946 Act came into force in Wales on 1 April 1946 and produced a further 71 with 11 either completely or partially within Wales. This Act included roads within the County of London, but still excluded the City of London.

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