Primary road

Roads in the United Kingdom form a network of varied quality and capacity. Road distances are shown in miles or yards and UK speed limits are indicated in miles per hour (mph) or by the use of the national speed limit (NSL) symbol. Some vehicle categories have various lower maximum limits enforced by speed limiters. Enforcement of UK road speed limits increasingly uses speed guns, automated in-vehicle systems and automated roadside traffic cameras. A unified numbering system is in place for Great Britain, whilst in Northern Ireland, there is no available explanation for the allocation of road numbers.

The earliest specifically engineered roads were built during the British Iron Age. The road network was expanded during the Roman occupation. Some of these survive and others were lost. New roads were added in the Middle Ages and from the 17th century onwards. Whilst control has been transferred from local to central bodies and back again, current management and development of the road network is shared between local authorities, the devolved administrations of Scotland, Wales and Northern Ireland and Highways England. Certain aspects of the legal framework remain under the competence of the United Kingdom parliament.

Although some roads have much older origins, the network was subject to major development from the 1950s to the mid-1990s. From then, construction of roads has become increasingly controversial with direct action campaigns by environmentalists in opposition.

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