The AASHTO-supported interim Mechanistic-Empirical Pavement Design Guide (MEPDG) was published in 2008 for trial use. However, local calibration of the empirical distress models in the design guide has been an essential exercise for any transportation agency before it formally adopts the MEPDG for practical design use. Nevertheless, a universally agreed upon local calibration methodology using historical pavement performance data from field evaluation has not been available. This research focuses on permanent deformation or rutting models in MEPDG and presents a layer-by-layer longitudinal local calibration process at the DARWin-METM platform coupled with Excel Macros. Using the best input data available, many of Level 3 accuracy, the study performs local calibration for 10 reconstructed and 19 rehabilitated flexible pavement sections. Further, this thesis statistically evaluated the level-3 pre-overlay rut value for rehabilitated flexible pavements in Ontario. A comparison of the longitudinal calibration and pooled local calibration demonstrated the importance of the longitudinal calibration in the quantification of uncertainties involved in local calibration.