Urban Sprawl

The authors begin with an overview of the causes and consequences of urban sprawl in the twentieth century, focusing in particular on lower transportation costs and self-sorting of the population. By sprawl, we will mean the tendency toward lower city densities as city footprints expand. They next focus on four issues that raise clear efficiency and equity concerns: unproductive congestion on roads, high levels of metropolitan car pollution, the loss of open space amenities, and unequal provision of public goods and services across sprawling metropolitan suburbs that give rise to residential segregation and pockets of poverty. Finally, they consider the trade-offs inherent in some policies commonly proposed to address urban sprawl. Throughout, a main theme of the discussion is that a full analysis of sprawl is made difficult by the lack of a usefully integrated economic model of urban economies. Along these lines, the authors conclude with some thoughts on possible future research agendas.