In this study, we introduce a refined method for assessing near-roadway emission exposure, termed emission density, focusing on NOX and PM2.5 at the census block level across the U.S. in 2020. Our findings reveal significant disparities in air pollution exposure by race, ethnicity, and socioeconomic status, as well as across different types of vehicle traffic. Specifically, people of color experience approximately twice the exposure to traffic emissions compared to White individuals, while lower-income groups face exposure levels two to four times higher than the national average. This disparity is pervasive nationwide, highlighting a substantial public health and environmental justice issue beyond urban areas.