How to choose the urban pattern that can best serve your city
Intensify the density of existing built-up areas through infill development and setting growth limits, which would need to be moved outwards at regular intervals to prevent land shortages. Intensifying density implies regenerating brownfields and replacing existing buildings with new ones that accommodate more people. Consolidating built-up areas needs regulations to preserve no-development zones and to control a trend towards the decline of density (of both people and buildings).8 This approach may be adequate for cities with strong enforcement capabilities and where population growth is relatively stable. A successful example is Portland’s Urban Growth Boundary in the United States. Extend the city at the fringes of the built-up area. Cities growing faster than 1-2 per cent per year need to ensure there is enough land to accommodate people and this could be at least twice the size of the existing land area.9 A city extension would border the existing footprint, and its infrastructure and transport systems would be fully integrated with it. The extended area may include urban services whose capacity has been calculated to also serve residents living in deprived districts in the existing city. Planning an extension requires vision and commitment. New York’s Manhattan Commissioners’ Plan of 1811 in the United States is one far-sighted extension plan. Multiply nodes by building satellite towns that might be associated with existing urban masses. Although they would be physically separated and at least partially independent administratively, economically and socially, satellite towns would be coordinated with the central city to capitalize on synergies and economies of scale. Satellite towns differ from suburbs in that they have their own sources of employment and services, which would also prevent them from becoming dormitories. This option is suitable for fast-growing, large cities. The Comprehensive Plan of Shanghai 1999– 2020 in China features nine satellites towns that absorb people who migrate from rural areas. 27