Indicator ST.1.c Average vehicle miles traveled by San Francisco residents per day

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ST.1.c Average vehicle miles traveled by San Francisco residents per day
ST.1.c Average vehicle miles traveled by San Francisco residents per day

Data Source

Top Chart:  VMT per capita obtained from Bay Area Metropolitan Transportation Commission (2007). 

Bottom Chart:  Metropolitan Transportation Commission (MTC) travel forecasts, based on Projections '98 (1990), Projections 2000 (1998), and Projections 2003 (2000, 2007, 2015, 2025 and 2030). Accessed online on July 18, 2006: http://www.mtc.ca.gov/maps_and_data/datamart/stats/vmt.htm

Chart/graph created by City and County of San Francisco, Department of Public Health, Environmental Health Section.

Explanation and Limitations

Any vehicle, whether a car carrying one passenger or a bus carrying many passengers, traveling one mile generates a "vehicle mile," a common measure of transportation demand on freeways and roads.

Vehicle miles traveled per capita (top chart) is the average daily number of vehicle miles traveled by San Francisco residents traveling within the Bay Area, divided by the number of residents living in San Francisco for that year. The numbers presented include all intra-regional (i.e., between Bay Area counties) and intra-zonal (i.e., travel starting and ending within each of the Bay Area neighborhoods or zones) travel by San Francisco residents. It excludes all commercial/truck travel and all inter-regional travel (i.e., between the Bay Area and neighboring counties). This measure includes "production-zone" travel (i.e., travel generated by residents of a particular county or region), but does not include "attraction-zone" travel (i.e., travel generated by non-residents commuting to work, shop, or play into a particular county or region).

Average weekday daily vehicle miles traveled (bottom chart) is the total number of vehicle miles traveled by residents and non-residents in San Francisco and the Bay Area on an average weekday.

Compared to other counties in the Bay Area, San Francisco has a relatively low vehicle miles traveled per resident and overall. In part, this is due to the comparatively wider availability and use of public transportation. It is also impacted by the availability of local jobs for San Francisco residents. VMT is notably impacted by regional planning decisions regarding the locations of jobs and housing, including the types of jobs created and their salary levels and housing cost. VMT is further impacted by transportation planning decisions, including whether employment centers and neighborhoods are served by public transit, bike routes, or have pedestrian amenities. Notably, while San Francisco residents have relatively low VMT compared to surrounding counties, a recent Metropolitan Transportation Commission report analyzing travel in the San Francisco Bay Area found that across all Bay Area counties, people who commute to downtown San Francisco “…have traditionally had the longest average trip lengths, at 15.5 miles in 2006. This is projected to increase to 17.2 miles by the year 2035.”

This indicator does not currently display neighborhood, socio-economic or racial/ethnic differences in vehicle miles traveled per resident. Additionally, this measure does not take into account traveling time. For example, while the vehicle miles travelled per capita may be low for public transportation users compared to people who drive alone, people taking public transportation may still spend a significant percentage of time waiting for public transportation to arrive, making appropriate transfers, and riding in transit.

Why is this a Community Health Indicator?

Land use and transportation planning defines the distances people travel to access jobs, schools, good, services, and recreation.  As distances between destinations increase so do the miles driven in motor vehicles, along with the associated hazards from air and water pollutants, noise, and vehicle collisions.

Air pollution from automobile emissions costs the nation’s health 50-70 million days with restricted levels of activity, 20,000 to 46,000 cases of chronic respiratory illness, and 40,000 premature deaths.  Health effects associated with short-term exposure to fine particulate matter (air pollutants) include: increased hospital admission and ER visits for cardiovascular and respiratory diseases, non-fatal heart attacks, premature death in people with heart and lung disease, and lung function changes especially in children and people with lung diseases such as asthma.a In California, transportation contributes approximately 50% of greenhouse gas emissions – and is a large and growing share of greenhouse gas emissions nationally.b  Climate change in turn threatens to have global and catastrophic effects on health through: increased frequency, intensity and length of heat waves, floods, droughts, windstorms and wildfire, leading to increased mortality, illness and mental health impacts; increased exposures to ground-level ozone and aeroallergens, exacerbating cardiovascular and pulmonary illness; and shifts towards warmer temperatures, leading to increased risk of food- and waterborne infectious diseases.c

Nationally, for people aged 4 to 34, traffic injuries are the single greatest cause of disability and death.  Approximately 40,000 people die in motor vehicle collisions each year.d  Driving longer distances and spending more time on the road increases the risk of being killed or injured in a traffic collision.e

Driving takes time away from other positive activities for physical and mental health, such as exercise, community involvement or time with family. The average U.S. resident spends 443 hours in a car each year. This represents time that could otherwise be spent in productive or leisure activity. Driving time independently predicts obesity risk. A study on the driving habits of over 10,000 Atlanta residents found that each additional hour spent in the car was associated with a 6% increase in the likelihood of being obese.f

  1. U.S. Environmental Protection Agency. 2001. Vehicle travel: Recent trends and environmental impacts. Our Built and Natural Environments: A Technical Review of the Interactions Between Land Use, Transportation, and Environmental Quality. Chapter 4. U.S. Environmental Protection Agency. Available at http://www.epa.gov/smartgrowth/pdf/built_chapter3.pdf.

  2. California Air Resources Board.  2009. 50 Things You Can Do.  California Air Resources Quality Board.  Available at: http://www.arb.ca.gov/html/brochure/50things.htm.

  3. Environmental Defense Fund, National Association of City and County Health Officers, George Mason University. 2007. Are We Ready?  Preparing for the Public Health Challenges of Climate Change.  Available at: http://www.edf.org/documents/7846_AreWeReady_April2008.pdf.

  4. Subramanian R. 2006.  Motor Vehicle Traffic Crashes as a Leading Cause of Death in the United States, 2003.  NHTSA Traffic Safety Facts Research Note. Available at: http://www-nrd.nhtsa.dot.gov/pdf/nrd-30/NCSA/RNotes/2006/810568.pdf.

  5. Lourens PF, Vissers JA, Jessurun M. 1999. Annual mileage, driving violations, and accident involvement in relation to drivers' sex, age, and level of education. Accident Analysis & Prevention. 31(5):593-7.

  6. Frank LD, Andresen MA, Schmid TL. Obesity relationships with community design, physical activity, and time spent in cars. Am J Prev Med. 2004;27(2):87-96.