The heart of an urban area, usually located at the meeting point of the city’s transport systems, containing a high percentage of shops and offices. High accessibility leads to high land values, and therefore intensive land use. Consequently, development is often upwards. Within the CBD, specialist areas, such as a jewellery quarter, benefit from external economies. Vertical land-use zoning is also common, so that retail outlets may be on the ground floor, with commercial users above them and residential users higher up. See Chang (2007) Urb. Plan. & Dev. 133, 2 on measuring and assessing the economic activities of CBDs. The CBD is under threat from traffic restrictions, and out-of-town developments, such as superstores. ‘Arguments on the future [of the CBD] range from a speculated centre-less form to one of centrality’ (Wong (2004) Land Use Policy 21).

Methods of delimiting the CBD include the central business height index, recording the percentage of floor space given over to CBD functions, charting high level pedestrian flows, and surveying pavement chewing gum.