The of CBR equation is empirical approach, and the recent methods of design is deterministic. A probabilistic approach-a reliability analysis, providing more reliable design at potentially lower costs, can be developed from the recent design procedure if the reliability of the CBR curve is known. This research was done to determine the reliability of the current CBR-based flexible pavement-design model by using existing data from accelerated traffic tests. The reliability of the design model was found to be about 60 percent, neglecting the effects of conservative estimates of the design parameters. For the future research is suggested that include the difference between the performance of the accelerated traffic test sections and the long term performance of actual in-service pavement, and the effect of conservative estimates values for material strength, traffic load, and traffic intensity.