Countless cities are struggling to rein in development that is pushing their peripheries further and further from the city center. By 2030, many medium-sized cities in the global south are projected to double or triple in population, and much of this growth is happening in haphazard ways, leading to sprawling and scattered neighborhoods poorly served by core city services.
Urbanization can lead to many benefits for people and economies, but uncontrolled expansion often results in environmental, economic and social degradation. “We should care about urban expansion if we want the new areas to be productive, to be integrated into the metropolitan economy; if we want them to be inclusive, so that people can afford the housing there; and if we want [them] to be environmentally sustainable,” says Shlomo (Solly) Angel, a professor of city planning at the New York University Stern Urbanization Project and head of the Marron Institute’s Urban Expansion Program, speaking to WRI Ross Center as part of the Cities Research Seminar Series.
Angel advocates for a “making room” approach, in which cities analyze where population growth and development will likely occur and preemptively acquire land that can be used for public infrastructure and services later. The idea is to prepare for expansion before development makes it physically impossible, prohibitively costly or ethically unjust. Retroactively building infrastructure for already developed communities can cost three to nine times as much as if the city had made room in the first place, while also disrupting or displacing existing communities.
Angel says that road infrastructure is an especially important element in preparing for urban expansion. “These expansion areas need to be connected to the metropolitan economy in order for the city to be productive,” he says. An arterial road grid helps organize development so that new growth is structured within a predetermined framework. The initial result may be sprawling development, but strategies like infill development can help densify expansion areas as time goes on.
Cities can wait to invest in public infrastructure in these areas until there’s a need for it, but Angel suggests assessing growth patterns, designing the grid and acquiring land beforehand, even if there’s a chance that population growth and development don’t occur as expected.
Angel has tested out the making room approach in a number of cities with different systems of land governance. “In Colombia, all we had to do to acquire the land for the arterial roads is to put liens on property titles. In Ethiopia, we’ve had to survey the roads and move settlers to the edge of the road by giving them 99-year leases on the properties that they will occupy,” Angel says.
In some countries, like Colombia, Ecuador and Colombia, the government can legally requisition a portion of private lands for public use. “When you convert land from rural to urban use [in these countries], 40 percent of that land has to be in public use,” Angel says. “This is the easiest and best way to secure adequate lands for urban expansion.”
Alex Rogala is a former editor of TheCityFix and currently a master’s student in urban planning at the Harvard Graduate School of Design.