Two studies used HSIS data to create truck crash models. The Oak Ridge study developed models to relate truck crash involvement rates for three roadway types and for various geometric and traffic variables. The Grants for Research Fellowships Program (GRF) study developed truck crash models for Interstates and two-lane rural roads as a function of relevant geometric features. In the Oak Ridge study, Poisson regression models were derived for three roadway types: rural Interstates, urban insterstates, and rural two-lane undivided arterials. Overall, Average Annual Daily Traffic (AADT) per lane and horizontal curvature were significant for all three roadway types. Vertical grade was significant only for rural Interstates. Shoulder width was significant for urban Interstates and rural two-lane undivided arterials. The GRF study found that trucks are more involved than other vehicles in four crash types (run-off-road, overturning, sideswipe, and single vehicle). Variables found to be significantly related to truck crash involvement rates on Interstates included AADT, truck volume, horizontal alignment, and vertical alignment. On rural two-lane roads, variables significantly related to truck crash rates included AADT, truck volume, shoulder width, and horizontal alignment.