§ Sir A. Meyerasked the Secretary of State for Transport what is the maximum permitted gradient on newly constructed dual carriageway roads.
§ Mr. HoramThe normal maximum gradient on new motorways is 3 per cent. (1 in 33.3), limited to 4 per cent. (1 in 25) in hilly country. On other new rural dual carriageways, 4 per cent. is normally regarded as the desirable maximum, though in hilly country steeper gradients may have to be adopted.
§ Sir A. Meyerasked the Secretary of State for Transport what is the minimum radius of curve permitted on newly constructed dual carriageway roads.
§ Sir A. Meyerasked the Secretary of State for Transport what is the minimum permitted width of grass verge and the minimum width of central reservation on newly constructed dual carriageway roads.
§ Mr. HoramThe Department's advisory manual "Layout of Roads in Rural Areas" recommends a grass verge width of 1.5 metres behind the hard shoulder and normally a 4-metres wide central reserve for new dual two- and three-lane motorways. The latter may be reduced to 2.5 metres on long bridges.
On other new rural dual carriageways, the normal grassed verge width is 2.5 metres behind the 1-metre hard strip and the central reserve 4.5 metres, which may be reduced to an absolute minimum of 1.25 metres for short lengths where valuable or historic buildings are close to the road.