The debate over the costs and benefits of urban consolidation has perhaps never been more important given the rise in the importance of sustainability principles as a basis of planning, the growth of megacities and development pressure on countrysides. Urban consolidation is typically defined as an increase in population and/or dwellings within an existing urban area, or the fullest use of an existing urban area (Lock, 1995). Intensification refers to both built form and activity.
Urban consolidation has been justified on economic, social and environmental grounds. The claimed benefits have been broadly classified by Neilson Associates (1985) as improved economic efficiency in the use of urban infrastructure, land and buildings, and reduced development costs; better utilisation of existing facilities; structural benefits through improved access to employment and services; and greater diversity in population and housing. To this list can be added the conservation of land and resources by limiting outer urban expansion; and the reduction of energy use through energy efficient buildings and less reliance on private vehicle use.