Evaluating socioeconomic and racial differences in traffic-related metrics in the United States using a GIS approach

Abstract

Previous studies have reported that lower-income and minority populations are more likely to live near major roads. This study quantifies associations between socioeconomic status, racial/ethnic variables, and traffic-related exposure metrics for the United States. Using geographic information systems (GIS), traffic-related exposure metrics were represented by road and traffic densities at the census tract level. Spearman's correlation coefficients estimated relationships between socio-demographic variables and traffic-related exposure metrics, and ANOVA was performed to test for significant differences in socio-demographic variables for census tracts with low and high traffic-related metrics. For all census tracts in the United States, %Whites, %Blacks, and %Hispanics (percent of tract population) had correlation coefficients greater than 0.38 and 0.16 with road density and traffic density, respectively. Regions and states had correlation coefficients as high as 0.78. Compared with tracts with low road and traffic densities (<25th percentile), tracts with high densities (>75th percentile) had values of %Blacks and %Hispanics that were more than twice as high, 20% greater poverty levels, and one-third fewer White residents. Census tracts that had mid-level values for road and traffic densities had the most affluent characteristics. Results suggest that racial/ethnic and socioeconomic disparities exist on national level with respect to lower-income and minority populations living near high traffic and road density areas.

A new approach for evaluating regional exposure to particulate matter emissions from motor vehicles

“…While other metrics are available for measuring equity and social disadvantage, these two metrics are chosen because federal environmental justice policies require their consideration (DOT Order 5610.2(a) and Executive Order 12898). Previous studies find that low income and minority residents are disproportionately located in areas near high volume roads or where mobile source air pollutant emissions are higher (Gunier et al, 2003;Houston et al, 2004;Rowangould, 2013;Tian et al, 2013). These studies have often relied on analytical methods that use proximity to roadways or emission inventories as proxies for exposure to mobile source emissions.…”

Disaggregating Data on Asian American and Pacific Islander Women to Provide New Insights on Potential Exposures to Hazardous Air Pollutants in California

“…The disproportionate distribution of air pollution in areas with low-income and minority populations have created concerns around environmental injustice (54)(55)(56). Several studies have identified socioeconomic and racial disparities in cancer risk from exposure to HAPs, using cancer risk estimates by U.S. EPA NATA program and socioeconomic and demographic data from U.S. Census at census tract level (57)(58)(59)(60).…”

Dispersion Modeling of Traffic-Related Air Pollutant Exposures and Health Effects among Children with Asthma in Detroit, Michigan

“…Many individuals living in high-traffic areas are nonwhite and low income (6), characteristics that are associated with susceptibility to the adverse effects of air pollution. In the United States, an estimated 40 million people live within 100 m of major roads, railways, or airports (7), and millions more commute on major roads, suggesting the importance of exposure to traffic-related air pollutants for public health.…”