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Urban Expansion



Led by Solly Angel, the Urban Expansion initiative works with cities to make room for their inevitable expansion. The initiative has a “stakes-in-the-ground” orientation—a focus on real and tangible results in rapidly growing cities. We work with municipal officials and their colleagues at the regional and national level to make realistic long-term preparations for urban expansion.

Expansion is Inevitable
Urban expansion is inevitable. Angel found that, between 1800 and 2000, urban area per person grew at an average annual rate of 1.5% in a representative sample of 30 global cities. For example, while the population of Paris, France grew 20-fold between 1800 and 2000, the city’s built up area grew 200-fold. The rapidly growing cities of the developing world cities can expect similar trajectories. Those that embrace their expansion as inevitable can act now to make room for it.

Making Room
Making room entails four key steps. The first step involves making realistic projections, both about the amount of land that the growing urban population will require and where the physical expansion of the city is likely to take place. Second, cities must work with regional and national officials to ensure that they obtain jurisdiction over the projected area of expansion. The third and fourth steps involve basic urban planning in the area of expansion. The city will have to establish the rights of way for a network of arterial roads— roads that will one day carry public transit and private traffic as well as infrastructure such as water mains, sewers, storm drains, and telecommunications networks. Finally, the city will have to identify public open spaces large and small and work to protect them in the face of urban development.

Why Making Room Matters
Making room matters because it ensures a supply of developable land that is ample enough to keep housing affordable for the urban poor. It also matters because it allows the city to guide development rather than follow it. By leading rather than following development, cities can greatly reduce the cost of providing infrastructure and public open spaces and ensure that all urban residents have access. In short, cities that make room will be more equitable, more efficient, more livable, and more sustainable.