- Indicator Description
- Related Strategies
- Transportation and Health Connection
- About the Data
- Moving Forward
- References
Proximity to major roadways estimates the percentage of people who live within 200 meters, or approximately 650 feet, of a high traffic roadway that carries over 125,000 vehicles per day. Data on the location of roads and traffic levels come from the 2011 National Transportation Atlas Database; data on population come from the 2010 Census.
- Clean freight
- Complete Streets
- Expand bicycle and pedestrian infrastructure
- Health impact assessment (HIA)
- Health performance metrics
- Improve vehicles and fuels
- Integrate health and transportation planning
Transportation and Health Connection
According to CDC, more than 11 million people in the United States live within 150 meters (or approximately 500 feet) from a major highway (Boehmer et al., 2013). The vehicle traffic on these roadways is a major source of noise and air pollutants, such as particulate matter, nitrogen oxides, carbon monoxide, and ozone, which are known health hazards (U.S. EPA, 2010a, b, 2009, 2008). Specifically, exposure to traffic-related pollution is linked to asthma and other respiratory symptoms, development of childhood asthma, and cardiovascular disease and death (National Heart, Lung, and Blood Institute National Asthma Education and Prevention Program, 2007; Health Effects Institute, 2010). For example, one study estimated that 8% of childhood asthma cases in Los Angeles County, California, could be partly attributed to living close to a major road (Perez et al., 2012). Living near a major road also has been associated with decreased lung function in adults with asthma (Balmes et al., 2009). Increasing the distance from the road to more than 150 meters, or approximately 500 feet, might decrease concentrations of some air pollutants by at least 50% (Karner et al., 2010). Also, research has demonstrated that traffic noise at normal urban levels can also lead to stress and sleep disturbances, both of which can lead to a higher risk for type 2 diabetes (Sørensen et al, 2013).
To calculate the indicator, a geospatial analysis is used to identify every census block in the United States that is within 200 meters of a roadway that has average annual daily traffic (AADT) of at least 125,000 vehicles per day.. For census blocks that are only partially intersected by the 200-meter buffer, the proportion of the block’s area within the buffer is used to estimate the population of block that would be within the buffer. The population within the 200-meter buffer is summed for each MSA and state and compared with the total population of the MSA or state, respectively. The resulting indicator reports the percent of each MSA and state population living within 200 meters of a high traffic (more than 125,000 vehicles per day) roadway.
This indicator may help inform how future roadways are designed and influence future land use development and land use policies affecting the environment near roadways. Shifting land use patterns and investing in strategies that increase air quality might lead to improved health outcomes. One Los Angeles County-based study estimated that a 20% reduction in regional air pollution and a 3.6% decrease in population living near major roadways would result in 5,900 fewer cases of asthma caused by near-roadway pollution exposure (Perez et al., 2012). Transportation officials can also use the information from this indicator to consider air pollution mitigation strategies, including using vegetative buffers or sound walls to dilute traffic emission concentrations in the near roadway environment (U.S. EPA, 2015; Baldauf et al., 2008).
Baldauf R, Thoma E, Khlystov A. Impacts of noise barriers on near-road air quality. Atmospheric Environment 2008;42:7502-07. http://www.sciencedirect.com/science/article/pii/S1352231008005311.
Balmes JR, Earnest G, Katz PP, Yelin EH, Eisner MD, Chen H, Trupin L, Lurmann F, Blanc PD. Exposure to traffic: Lung function and health status in adults with asthma. Journal of Allergy and Clinical Immunology 2009;123:626-31. http://www.jacionline.org/article/S0091-6749%2808%2902360-9/abstract.
Boehmer TK, Foster SL, Henry JR, Woghiren-Akinnifesi EL, Yip FY. Residential Proximity to Major Highways – United States, 2010. Morbidity and Mortality Weekly Report (MMWR) 2013:62(03):46-50.
Health Effects Institute. Traffic-Related Air Pollution: A Critical Review of the Literature on Emissions, Exposure, and Health Effects; 2010. http://pubs.healtheffects.org/getfile.php?u=552. *
Karner AA, Eisinger DS, Niemeier DA. Near-roadway air quality: synthesizing the findings from real-word data. Environmental Science and Technology 2010;15:5334-44. http://pubs.acs.org/doi/abs/10.1021/es100008x. *
National Heart, Lung, and Blood Institute National Asthma Education and Prevention Program. Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma; 2007. http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdf. *,†
Perez L, Lurmann F, Wilson J, Pastor M, Brandt S.J, Kunzli N, McConnell, R. Near-roadway pollution and childhood asthma: implications for developing “win-win” compact urban development and clean vehicle strategies. Environmental Health Perspectives 2012;120:1619-26. http://www.ncbi.nlm.nih.gov/pubmed/23008270. *,†
Sørensen M, Andersen ZJ, Nordsborg RB, Becker T, Tjønneland A, Overvad K, Raaschou-Nielsen O. Long-Term Exposure to Road Traffic Noise and Incident Diabetes: A Cohort Study. Environ Health Perspectives 2013;121:217–222.
U.S. Environmental Protection Agency. Integrated Science Assessment for oxides of nitrogen—health criteria; 2008. http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=194645.
U.S. Environmental Protection Agency. Integrated Science Assessment (ISA) for particulate matter; 2009. http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=216546.
U.S. Environmental Protection Agency. Integrated Science Assessment (ISA) for carbon monoxide (CO); 2010b. http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=218686.
U.S. Environmental Protection Agency. Near Roadway Air Pollution and Health; 2015. http://www.epa.gov/otaq/nearroadway.htm.
* Indicates research that supports policies analyzed
† Indicates research that supports equity or vulnerable populations studied