Trunk roads in Wales

Trunk roads in Wales were 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 was increased 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 the North and Mid Wales Trunk Road Agent on behalf of the Welsh Government. As of April 2019, out of a total of 34,850 miles (56,090 km) of roads in Wales, 1,576 miles (2,536 km) are trunk roads (including 135 miles (217 km) of motorways and as of 2015 350 miles (560 km) of dual carriageway).^[1][2]

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. The North and Mid Wales Trunk Road Agent still use it to distinguish the trunk road from a non-trunk road.^[3] When a trunk road had been improved by a motorway, bypass or a similar route, it may be de-trunked. 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. With road improvements, most notably the M4 motorway, much of both the A48 and the A40 has been de-trunked^[4][5]