Planning for Rapid Urban Expansion

A recent article in Reuters gave a creative interpretation of the NYU Urban Expansion Program strategy for managing urban growth, saying:

Yet, as far as I know, Anjali Mahendra’s actual quote said nothing about affordable housing, transport links, sanitation, or recreational areas. In rephrasing her quote, the piece played to a bias among urban planners for comprehensive solutions that address all aspects of urban development. As a result, the article unfortunately failed to accurately describe our strategic recommendations for rapidly-growing cities, which are all about bare bones plans that can be implemented quickly.

Here is what we advise: Figure out how much your city is likely to grow, spatially, in the next 30 years. Then, figure out where you want the arterial roads and public open spaces to go in this expansion area. Plan for the arterial roads to be at least 30m wide, and around 1km apart. This will form big blocks. Buy the land for the roads now, today, as soon as possible. It will amount to about 5% of the land in the expansion area. Come up with a locally appropriate scheme for protecting the public open spaces and implement it.

To planners, particularly those with a background in architecture or design, this approach is almost laughably simplistic. How can you plan a city without zoning, landfills, or schools? What about affordable housing, hospitals, and jails? Let’s not forget public transportation networks, sewerage systems, or electrical grids.

These things are very important, but we should remember that most cities in high-income countries added them gradually over time as capacity and resources increased. 2.3 billion people will move to cities in the next 30 years. 95% of this growth in urban population is occurring in developing countries, where complexity can stymie effective planning. Strategies for managing rapid urbanization have to be more rapid than the urbanization that is occurring.

For now, the best strategy is probably triage, with planners focusing on things that 1) become dramatically more difficult and expensive if they are done later and 2) offer enormous long-term bang for the buck.

Securing the rights of way for arterial roads 30 years in advance means that the city can put these roads in place as development occurs rather than scrambling to acquire and service land after development takes place. This helps keep urban land affordable, gives continuity and certainty to developers, and saves an enormous amount of money when compared to purchasing the land closer to the time of development. Securing public open spaces lets the city protect environmentally sensitive areas, increases the value of adjacent real estate, and, again, are much cheaper to secure when the surrounding areas are still rural.

As our work in Ethiopia and Colombia shows, these two things can actually be done quite quickly, even when governments are weak and lack resources. The idea that rapidly-growing cities should try to do everything at once makes the perfect the enemy of the good, in the worst case dooming developing cities to doing nothing at all.