関連ワード:  is an a road a dual carriageway    is a highway a dual carriageway    is a trunk road a dual carriageway    is a ring road a dual carriageway    is a b road a dual carriageway    is finchley road a dual carriageway    is a 3 lane road a dual carriageway    is the coast road a dual carriageway    is a dual carriageway the same as an a road    what is classed as a dual carriageway