A proposed macroscopic methodology for measuring the level of service (LOS) of toll plazas has been developed using delay as the measure of effectiveness (MOE). On the basis of field research and data analyses, the 85th percentile of the cumulative individual vehicular delay was found to be the most comprehensive measure for evaluating the LOS at a toll plaza. Other MOEs were examined but found to be less flexible with different plaza configurations and lane payment types. More than 55,000 individual vehicular records from three mainline toll plazas in Orlando, Florida, representing eight different plaza configurations with varied percentages of electronic toll collection (ETC) usage were used to validate the methodology. TPSIM, a toll plaza simulation model, was used to produce an additional 49 scenarios representing the three plazas with varied percentages of ETC usage and 21 additional plaza configurations. Service time was examined to determine the level at which a driver begins to feel discomfort and inconvenience at a toll plaza. An LOS hierarchy was established based on the conclusions of this analysis, feedback from professionals, and reference to the Highway Capacity Manual (HCM) 2000. The 85th delay percentile graphs from each of the plaza analysis results for LOS values were also observed to be similar.