Since 1994, Texas has had the highest number of fatal crashes involving large trucks in the United States, and this number increased by 82% from 2009 to 2012. Due to the size and weight of large trucks, their crashes usually are very destructive. Although large trucks have a significant impact on traffic safety in Texas, very little analysis has been conducted of the risk factors associated with crashes involving large trucks, especially the roadway-related risk factors. In this paper, the results of a collision-diagram-based analysis are presented for selected areas in Texas where frequent crashes of large trucks occur. First, historical data related to large truck crashes from 2011 through 2015 were extracted and entered into ArcGIS to identify areas within a 0.5-mi radius of where large truck crashes occur frequently, which were named hot spots. Then, based on the results of the identified hot spots, we identified hot areas, that is, areas with clusters of hot spots. Police reports of all of the crashes that occurred in the selected hot areas were then reviewed, and collision diagrams were developed. By analyzing all of the collision diagrams that were developed, five roadway-related risk factors were identified, and potential effective countermeasures were proposed to prevent or mitigate crashes involving large trucks.