Administration
Responsibility for the road network differs between trunk and non trunk routes. Trunk roads, which are the most important roads, are administered by the Highways Agency in England, Transport Scotland in Scotland and the Department of Economy and Transport in Wales. England's 6,500 miles (10,461 km) of trunk roads account for 33% of all road travel and 50% of lorry travel. Scotland has 2,174 miles (3,499 km) (about 7% of the total roads in Scotland), accounting for 35% of all road journeys and over 50% of lorry movements. Wales has 1,000 miles (1,600 km) of trunk roads. In London, Transport for London is responsible for all trunk roads and other major roads, which are part of the Transport for London Road Network. All other roads are the responsibility of the relevant County Council or unitary authority. In Northern Ireland, the Roads Service Northern Ireland is responsible for all 5,592 miles (8,999 km) roads. The pan-British total is 24,559 km.
Whilst generally they are trunk roads, several motorways are the responsibility of local authorities, for example the M275.
During design, planning, maintenance and construction, metric is used. As a result (and anticipating that the roadsigns themselves will one day be changed to display in metric units) recently-erected signs are increasingly being placed at metric intervals but display an imperial unit as required by the current road-signage rules. For example, a 110 yd marker might actually be placed at the 100 m distance. Since 2008, location marker posts have appeared on motorways and major A roads in England, situated generally at intervals of 500 metres (though the dimension is not given). These repeat the information given on the co-sited surveyors' marker post which, since the 1960s have reported distances on such roads in kilometres from a datum - usually the start of the road, or the planned start-point of the road.
Read more about this topic: Roads In The United Kingdom