Trucks make up a significant and growing portion of the traffic on freeways. The perceptions of tractor-trailer drivers regarding the quality of service on freeways are the subject of this research, with a focus on the factors that are important to this group of road users. Perceptions were determined using the standard qualitative inductive analysis approach through a focus group with professional tractor-trailer drivers. The results were compared with quality-of-service focus groups held for urban and rural freeway commuters. Freeway conditions in general were the most frequently mentioned factors and encompassed a variety of considerations. The three variables that together describe traffic conditions—travel time (or speed), traffic density (or maneuverability), and traffic flow—were all mentioned with regard to quality of service. Likely the most significant finding is that it is not traffic density that matters to these drivers; rather it is traffic flow. It appears that there is a comfortable operating range of highway speeds in which not much braking and acceleration-related gear changing are required. Other important themes included weather, attitudes toward other drivers, and road rage (i.e., aggressive driving). Participants also responded to questions about regional differences in quality of service. Safety was an issue that transcended or overlapped many other issues.