Table 5

Sensitivity analyses including best predictor in each category, all summary measures.

Indicator Type
Traffic Indicator
Estimate(s), p-value(s) from multivariate model
Model R2

Base model (w/out traffic)


R2 = .74
Cumulative Density scores
Unweighted 500 m traffic density (n = 57)
β1 = 4.74*10-4 (.17)
R2 = .75
Summary Measures
Total roadway length:



50 meters (n = 57)
β1 = 1.31*10-4 (.35)
R2 = .74

100 meters (n = 57)
β1 = 1.48*10-4(.02)
R2= .76

200 meters (n = 57)
β1 = 1.42*10-5 (.56)
R2 = .74

300 meters (n = 57)
β1 = 5.54*10-6 (.57)
R2 = .74
Distance-based measures
Distance to nearest designated truck route (n = 57)
β1 = 1.80*10-5 (.62)
R2 = .74
Characteristics of nearest major road
Average daily traffic (ADT) (n = 57)
β1 = -3.04*10-6 (.25)
R2 = .74

Final model bolded; models with diesel-based terms italicized. Traffic indicators for PM2.5

Clougherty et al. Environmental Health 2008 7:17   doi:10.1186/1476-069X-7-17