Descriptive Title: Proportion of households living within 150 meters of a designated truck route
Geographic Unit of Analysis: Streets and residential lots
|Truck route exposure (2011)|
|Neighborhood||% of households living within 150 meters of designated truck routes||# of truck route signs|
|Financial District/South Beach||89%||1|
|Golden Gate Park||0%||0|
|South of Market||97%||0|
|West of Twin Peaks||17%||2|
Epidemiological studies have consistently found that areas with high truck volumes and traffic densities have disproportionate community environmental health hazards due to increased amounts of diesel exhaust, fine-particle pollution, traffic-related noise, and preventable traffic-related injuries. Public policy and planning decisions, including the designation of truck routes, and project design help to shape local and regional traffic patterns and subsequent traffic-related health consequences. Air pollution associated with diesel trucks and proximity to heavily trafficked roadways contributes to cancer, respiratory disease including asthma, impaired lung development and function, heart disease, and increased child medical visits.a Traffic-related noise triggers community annoyance and sleep disturbanceb and is associated with hypertension and heart disease.c High traffic volumes, speeds, and heavier vehicles also contribute to an increased risk of injury and death from vehicle collisions.d Areas with truck route signage can help truck drivers, particularly those less familiar with local areas, stay on designated routes and off of local, residential streets (except as necessary).
The San Francisco truck route network consists of freight routes, freeways and arterials, as well as local roads for direct delivery. The routes provide access to most of eastern San Francisco along Highways 280 and 101, as well as along the city’s main arterials. As San Francisco is a relatively dense urban environment, these roads tend to have high proportions of households, jobs and/or services located nearby. The proportion of households within 150 meters of a truck route table (above) illustrates larger proportions of households in the Downtown/Civic Center, South of Market, and Financial District neighborhoods are located proximate to truck routes. These are also neighborhoods with high levels of commercial/business activity. However, other neighborhoods located along key freeway entry points into the city or proximate to freight centers also have relatively higher proportions of residents living near truck routes, including Mission Bay, the Mission, and Western Addition.
Using ESRIs ArcMap 10.0 software, a buffer of 150 meters was created around San Francisco’s freight route network, which is composed of freight routes, arterials and freeways (see data sources). Using the Spatial Join tool, estimated household counts were summed and joined to the entire buffered freight route network, citywide, based on whether or not the households fell inside the network buffer. To calculate total household counts per planning neighborhood, the buffered freight route was intersected with the neighborhood polygon to create a separate secondary freight networks for each San Francisco’s 37 neighborhoods. Using the same method as for citywide calculations, household counts were summed by each planning neighborhood based on a spatial join. The number of truck route signs per neighborhood was calculated by performing a join based on spatial location to the planning neighborhood.
This indicator reflects the location of truck routes in San Francisco and the proportion of households within 150 meters of those routes. This indicator does not capture the variation in levels of truck and other traffic along those different routes which ultimately impacts on the health effects of living near those routes related to air and noise pollution as well as traffic safety hazards. This indicator also does not incorporate other factors that determine the magnitude of health impacts – including traffic speeds, time of day, truck size or age.
For example, freight or truck routes are potentially significant sources of air pollution emissions. According to the CA Air Resources Board: "Emissions are not the same as exposure. While air pollutant emissions information can serve as an indicator of local air pollution, it is the exposure to emissions that influences health effects. Exposure is the amount of pollution that someone actually breathes or otherwise ingests at different locations. Exposure varies with the distance from the source of pollution, how the emissions are released into the air and dispersed by the wind, and in what locations a person spends their time doing various activities. Exposure to air pollutants can also occur from indoor sources such as cooking, cleaning, and smoking... The importance of the exposure to health risk depends on the combination of multiple air pollutants, the relative toxicity of the pollutants, and many other factors."e For more information, visit: http://www.arb.ca.gov/ch/chapis1/chapis1.htm.
San Francisco Freight Traffic Route data was received from the San Francisco Municipal Transportation Agency (SFMTA), September 2009. Key major and secondary arterials (created by the SFMTA) are based on the San Francisco General Plan Transportation Element Vehicular Street Map, adopted in 1995.
Truck route signage data obtained from the San Francisco Department of Public Works, 2009.
Residential population was obtained from Census 2010.
Map prepared by City and County of San Francisco, Department of Public Health, Environmental Health Section using ArcGIS 10.0 software, 2012.
Table data is presented by planning neighborhood. While planning neighborhoods are larger geographic areas than census tracts, census tracts do not always lie completely within a planning neighborhood. SFDPH used ArcGIS software and a dasymetric mapping technique to attribute Census block group data to residential lots. We then assigned residential lots to planning neighborhoods to calculate Census population totals within the neighborhoods.
Detailed information regarding census data, geographic units of analysis, their definitions, and their boundaries can be found at the following links:
Air Quality and Land Use Handbook: A Community Health Perspective. Sacramento, CA: California Air Resources Board; April 2005. Available at: http://www.arb.ca.gov/ch/handbook.pdf. Accessed May 27, 2009.
Seto EYW, Holt A, Rivard T, Bhatia R. 2007. Spatial distribution of Traffic Induced Noise Exposures in a US city: an Analytic Tool for Assessing the Health Impacts of Urban Planning Decisions. International Journal of Health Geography. 6(24). Available at: http://www.ij-healthgeographics.com/content/6/1/24. Accessed November 17, 2008.
Miedema HME, Vos H. 1998. Exposure Response for Transportation. J Acoust Soc Am. 1998;104:3432–3445.
Ewing R. Raimi M, Patrick S, Frank L, Kreutzer R. Understanding the Relationship Between Public Health and the Built Environment: A Report Prepared for the LEED-ND Core Committee. 2006:33–68. Available at: http://www.activeliving.org/files/LEED_ND_report.pdf. Accessed December 21, 2008.
"CHAPIS Emissions Maps." CHAPIS Emissions Maps. California Environmental Protection Agency Air Resources Board, 22 May 2008. Web. 06 Apr. 2012. http://www.arb.ca.gov/ch/chapis1/chapis1.htm.