Dual carriageway

A dual carriageway (British English) or divided highway (American English) is a type of road. It is an important route that usually carries long-distance traffic. 
A dual carriageway has four lanes (2 lanes each side), and is always separated by a man-made barrier or strip of land.
Dual carriageways have no hard shoulder. A hard shoulder is an area at the side of a road where drivers can stop if there is a serious problem, a breakdown for example.