Environmental Characteristics of Smart Growth Neighborhoods
An Exploratory Case Study
Sprawling land development, characterized by low-density, single-use subdivisions at and beyond the fringe of metropolitan regions, is known to cause a range of environmental problems, from consumption of farmland and open space, to polluted water runoff, to energy waste and air pollution from high rates of automobile dependence. Environmental organizations and "smart growth" developers believe that these problems can be ameliorated by encouraging growth in a different way, with walkable, compact neighborhoods integrated with or closer to jobs, shopping, and community amenities. This new exploratory study conducted for the Natural Resources Defense Council, in cooperation with the United States Environmental Protection Agency, suggests that the environmental benefits of smart growth are real and can be measured.
Previous research has also suggested that well-located "smart" or "new urbanist" communities can produce environmental benefits, but past studies have been based on plans and models. Our new exploratory study, conducted on the Metro Square neighborhood in Sacramento, California, is one of the first to examine a fully completed and occupied development. While few firm or general conclusions can be drawn from the study because of its preliminary, limited nature, the indications are encouraging. Moreover, they suggest that additional, more sophisticated research on additional sites could prove fruitful in confirming that successful new neighborhoods can be designed and located to perform more efficiently than conventional suburban developments on several environmental indicators, including land consumption, water use and pollution, and energy use and air pollution from residents' travel patterns.
Metro Square is a development of 46 single-family, detached homes built in 1998. Its "smart" features include its location one mile from Sacramento's city center, its compact lots situated around common green space, and its conventional grid-pattern streets. Compared to two conventional suburban developments with the same number of single-family homes, Metro Square consumes only roughly one-quarter as much land and, unlike the case with the suburban developments, no agricultural land was converted in its construction. Photographs and site plans of Metro Square and the two suburban developments in the study are provided in Appendix A.
Despite the use of alleys and wide sidewalks in Metro Square, the development contains less paved surface per household and per capita than the conventional developments, reducing surface water runoff. Its more compact lots also reduce the need for pesticides and fertilizers, as well as water for irrigation during Sacramento's dry summers.
Unlike the situation in the conventional developments, Metro Square has many neighborhood amenities within walking distance, including a convenience store, a supermarket, a school, a park, and public transit service. It also features connected streets, bicycle network markings, crosswalks and other traffic controls at intersections, traffic calming measures, and shade trees along its sidewalks, all of which make it more inviting to pedestrians and bicyclists than conventional developments.
While the exploratory study's analysis of residents' travel behavior was not sufficiently detailed to reach firm conclusions, the preliminary evidence suggests that the location and features of Metro Square may well make a difference in reducing driving and attendant motor vehicle pollution. Survey results indicate that Metro Square residents may be over four times as likely as residents in conventional Sacramento developments to accomplish daily tasks by walking and may take only half as many driving trips, driving a total of between only 50 and 60 percent as many miles. This translates into fuel and energy saved, as well as fewer emissions of greenhouse gases and unhealthy air pollutants.
NRDC and Criterion hope to explore these issues further in future studies on additional sites.
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Kaid Benfield's Blog
Kaid Benfield writes about development, community and the environment on Switchboard.
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