On-road measurements of four pollutants (PM2.5, PM10, NO2, and O3) were continuously recorded by three U.S. EPA-certified FEM air pollution monitoring devices installed inside a vehicle traveling repeatedly on the same route in a near-road community. Spatio-temporal on-road air quality data were aggregated and compared to data collected at two fixed stations, one residence located 15 m from the frontage road adjacent to Interstate Highway I-10, and another residential site 300 m from the frontage road. The first objective of this study was to assess the suitability of using the spatio-temporal on-road air monitoring data for representing community exposures to transportation-related air pollutants (TRAPs). The second objective evaluated the feasibility of using on-road air monitors instead of near-road monitors.