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Seas of Suburbia and How to Combat Them: A Case Study

By: Kushal Chattopadhyay

In many cases, a contemporary city of the United States can be found encircled by miles of suburbia in all directions, housing the hundreds of thousands of the metropolitan area’s commuters in single-family, separated homes. With the expansion of cities and increased suburbanism of the nation arose the externality of urban sprawl, a characteristically American phenomenon referring to these unplanned agglomerations of suburban “edge” cities and their lack of vital public transportation, entertainment, and greenspace infrastructure.

The impacts of urban sprawl in metropolitan areas are numerous, leading to widespread pollution as well as elevated levels of traffic and vehicles (longer commutes by car have been shown to have externalities of their own, negatively impacting economic mobility and inducing stress or sadness). Effective solutions must allow the city’s population to grow in a healthy and controlled manner with minimal consequences to residents or the city. An economic lens is critical to formulating these solutions for urban sprawl in order to minimize financial and environmental costs while maximizing benefits for both residents and the metropolitan area itself. The San Francisco Bay Area, one such metropolitan area, can serve as an effective case study for other regions on how to leverage a multifaceted approach to mitigate urban sprawl.


As a result of high levels of car dependence in sprawling suburbs with little access to public transportation, the externality of traffic congestion on freeways as well as lower ridership of buses and trains have had widespread impacts on commuters and cities alike. High-density condos near bus or train stations with amenities such as cafés, parks, and shops integrated into the community could prevent urban sprawl by capitalizing on existing public transportation without forcing residents to drive into the city from further away.

These housing projects, known as transit-oriented developments (TODs), benefit residents by providing affordable, convenient communities minutes away from public transportation. The Bay Area’s implementation of TODs at rapid transit stations has allowed residents to cut their overall transportation costs by nearly 25%, as evidenced by BART reports. As high costs are a primary reason for urban sprawl, by decreasing transportation costs in urban areas, residents have access to affordable housing in the city and have less of a reason to contribute to outward sprawl. These housing developments provide lasting benefits for the public transportation system as well by increasing public transportation ridership, in turn eliminating the negative externality of increased automotive traffic levels.

To preserve these TODs, it is critical that investments and regulations are incorporated to consistently adapt to the changing population. For example, if the percentage of low-income residents rises dramatically, investments to support job training and access to areas with employment opportunities are very important; similarly, if there are high levels of high-income residents, rent control and purchases of affordable nearby buildings will be able to preserve income diversity and decrease displacement. By strategically allocating funds and maintaining accessibility, TODs will be able to prevent externalities such as gentrification, polarization, and unemployment as they arise, replacing low-density, auto-oriented sprawl with thriving communities of high-density housing.


Urban growth boundaries, or UGBs, are development boundaries and rules which decelerate outward expansion. With UGBs, urban planners can prevent the externality of inferior infrastructure from unregulated growth by planning for future schools, fire stations, greenspaces, and more before neighborhoods are annexed into city limits. In addition, they protect nature outside of city limits and encourage improvement in already existing urban and suburban areas. However, they can also greatly increase house prices for renters and home buyers within the allocated residential zones, which can lower affordability.

Metropolitan areas including the Bay Area have incorporated boundaries into city and county plans through the strict consideration of greenbelt and regional park locations. However, there are many situations where cities continue to expand past boundaries when unable to invest in existing city facilities. Through a $50 million fund for affordable housing and high levels of support for boundaries in votes, the Bay Area has been successful in combating these unauthorized expansions. City governments which choose to utilize UGBs to limit urban sprawl must similarly obtain sponsorships while budgeting for new housing projects; otherwise, local activism must take action to protect green spaces by voting for measures which strengthen urban growth boundaries and against those that annex open space for further development. Although house prices rise as developable land is limited, effective developments such as TODs and high-density communities provide healthy and affordable communities within UGBs while preventing the negative externalities of what would have been urban sprawl in the absence of boundaries.


Many American cities are heavily car-oriented and are thus breeding grounds for auto-oriented urban sprawl. New urbanism, an old yet enduring urban development approach, calls for the reformation of urban neighborhoods dominated by automobiles into walkable and environmentally friendly areas with parks, bike trails, and gardens. This principle indirectly mitigates urban sprawl by making urban areas much more livable for residents, thus making the option of moving to “edge” suburbs or developing rural areas in hopes of better quality of life less attractive.

A downside to New Urbanism is that integrating new developments into existing neighborhoods requires large amounts of capital and can potentially be damaging to authentic and historic neighborhoods. Additionally, these developments only can currently exist on small scales due to the difficulty of developing in existing urban centers. Developers must acknowledge the context of the region before construction begins and capitalize on opportunities such as bare rooftops for gardens or roads for plazas and walkways to ensure the project is fruitful in promoting urban growth rather than suburban sprawl.

With over 175 million Americans living in suburban areas, it is critical that major cities and their suburbs consider walkability, affordable housing, the preservation of green spaces, and more as populations grow. By viewing externalities of population growth through an economic perspective, urban planners and residents will be able to make better decisions on which developments will allow cities to thrive with minimal sprawl.



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