The service life of durable pavement markings was evaluated over a period of nearly 4 years. The evaluation included 85 study sites in 19 states at which a total of 362 longitudinal pavement marking lines (edgelines, centerlines, and lane lines) were installed. Marking materials included epoxy, flat and profiled polyester, flat and profiled poly (methyl methacrylate), flat and profiled thermoplastic, and profiled preformed tape; glass beads; and standard and snow-plowable raised retroreflective pavement markers. One site with conventional paint markings and three sites with waterborne paint markings were included for comparison. The service life of marking materials and roadway types was modeled as a function of time and cumulative traffic passages. Regression modeling identified large variations in the shape of the relationship for identical materials and types of lines between different sites within a given state and required that modeling be done separately for each pavement marking line at each study site. Variations in service life can be attributed to roadway type, region of the country where the markings were installed (e.g., weather conditions, manufacturers of marking materials and glass beads, and individual state highway agencies), marking specifications, contractors installing the markings, quality control at the time of installation, and winter maintenance snow removal policies.