Research in currenly being conducted in Kentucky to evaluate the long term performance of several pavement sections. A total of 20 sites are being monitored throughout the state. Seven oh these sites are included in the long term pavement performance portion of the SHRP. Data have been collected on these sites on an annual basis since 1989. Falling Weight Deflectometer and Road Rater deflection measurements have been obtained on 25-foot intervals along the length of the 500-foot test section. Data has been obtained at various load levels to evaluate the non-linier properties of the pavement stucture. The backcalculated layer moduli indicated conciderable variability across the test section. Variability was observed in both the asphaltic concrete layer moduli and the subgrade moduli. The coeficient of variation ranged as high as 65 percent within a 500-foot section. This variability could present a problem if the testing were conducted as a tool for analysis of overlays designs. the designer would have difficulty determining the appropriate value to be used. This problem may be approached statistically, and at the same time, a degree of reliability may be determined.