Does urban sprawl inhibit upward mobility?

By Robbie Webber
A study by Reid Ewing, Shima Hamidi, et al. published in the journal Landscape and Urban Planning lends more support to the idea that sprawl can be a deterrent to upward mobility, making it difficult for low-income residents to improve their economic circumstances. Compact metro areas showed better results than those that are more spread out. The authors also note that upward mobility tends to be higher in Europe than in the U.S., and they theorize that besides differing approaches to education and social programs, the compactness of European cities may contribute to better opportunities.
Building on the work of the Equality of Opportunity Project at Harvard, which last year showed that longer commutes equated with less upward mobility, the more recent study looked at the compactness of the commuting zones instead of the length of the commute.

“[C]ommute times to work is not a valid proxy for urban sprawl. Indeed, some of the most compact metropolitan areas have some of the longest commute times, by virtue of their size and heavy use of transit (which typically involves longer travel times than automobiles).”

Instead, they used a recently released compactness/sprawl index developed by co-authors Ewing and Hamidi. The index has four distinct dimensions: development density, land use mix, population and employment centering, and street connectivity.
The most direct effect of sprawl is that jobs become less accessible. Sprawling urban areas are by definition more spread out. They often have poor transit service, and many jobs that have moved to the suburbs are simply not accessible without a car. An information mismatch can also hinder landing a job. People who are living far from job centers are generally less knowledgeable about potential openings than individuals who live closer to job centers.
Although the authors acknowledge some weaknesses in their research and suggest that more study is needed to tease out whether compactness of neighborhoods, individual municipalities, or metropolitan areas is most important, the relationship between compactness and better upward mobility results is clear. CityLab obtained some of the data on specific cities to create tables showing the 10 metros with highest and lowest sprawl indices and their corresponding mobility indices. Likewise, they also created tables with the metros with the highest and lowest mobility indices to show their sprawl indices. (It should be noted that New York was not included in the data.)
The authors conclude that transportation agencies, planners, and other decision makers should consider urban form when they seek to improve opportunities for low-income residents and evaluate how investments in transportation overcome the shortcomings of existing land use patterns.
Robbie Webber is a Senior Associate at SSTI.