This report presents the results of a qualitative study of driver perception of quality of service (QOS) on urban arterial streets. The purpose of the study was to identify the factors that are important to drivers of personal automobiles (non-commercial) regarding the quality of their driving experience. The study used an in-vehicle, on-the-road methodology in which drivers drove their own vehicles and talked out loud about the driving experience. This method provided the opportunity for drivers to respond to events as they occurred during the drive and to express their reactions to actual roadway elements and circumstances. Participants also completed a written survey after the drive about the relative importance of roadway, operational, and environmental conditions on urban arterials.