Road routes in New South Wales assist drivers navigating roads in urban, rural, and scenic areas of the state. Today all numbered routes in the state are allocated a letter (M, A, B or D) in addition to a one- or -two digit number, with 'M' routes denoting motorways, 'A' routes denoting routes of national significance, 'B' routes denoting routes of state significance, and 'D' for Detour routes of a major motorway. The route system includes the officially designated highways, urban and intercity motorways and arterial roads, and important cross-state roads that have not been declared highways.