The National Academy of Sciences: Transportation Research Board published an academic article authored by Alex Frost, Dr. Bruce Appleyard, Dr. Sherry Ryan, and Dr. Joseph Gibbons. The piece titled “Quantifying the Sustainability, Livability, and Equity Performance of Urban and Suburban Places in California,” is available here (paywall).
For years, researchers and practitioners have worked toward measuring urban form, but a gap remains in the research to quantify how urban and suburban place-types affect economic, social, and environmental outcomes at small geographic scales. To provide such analysis, the article describes the development of a place typology and sustainability performance measurement framework for 8,043 census tracts in California. Using statistical and geospatial techniques, seven major neighborhood archetypes in California were identified: urban center, urban place, compact suburban place, suburban place, rural place, employment center, and special district.
Overall, the study found there were clear trade-offs between urban and suburban living. Compared with suburbs, the households in urban places benefited from a 57.9% reduction in annual vehicle miles traveled, 37.2% lower transport-related greenhouse gas emissions per capita, and saved more than US$2,675 in annual transportation costs, while consuming less electricity (39.9%) and water per capita (63.8%). However, the cost of urban homeownership was 40% higher, despite rents being 18.5% cheaper. And although obesity and cardiovascular disease rates were 10.3% and 8.9% lower in urban places, asthma rates were 7.5% higher.
In terms of housing, from 1970 to 2015, the share of urban housing decreased from 34% to 21%, while statewide housing per capita dropped 7.5% from its peak in 1980. Despite ambitious climate action and smart growth goals, most of the recent growth in California continues to be in low-density suburban/rural areas, responsible for 80% of the state’s total household carbon emissions.
This analysis and place typology could prove useful in identifying areas with the highest potential for lowering vehicle miles traveled and other sustainability, livability, and equity goals. This is made even more significant given California’s recent move to abolish the level of service analysis for traffic impact studies. The study also illustrates the spectrum of benefits and trade-offs between infill and greenfield developments.
Special thanks to Dr. Bruce Appleyard, Dr. Sherry Ryan, Dr. Joe Gibbons at the San Diego State University’s School of Public Affairs and Department of Sociology. Alex is a senior planner with the City of San Diego Planning Department. If you want a copy of the research article, please email me at email@example.com.