Lessons Learned from MEPDG Development: A Confession of the JPCP MEPDG Developers

After 15 years from the initiation of the National Cooperative Highway Research Program (NCHRP) 1-37A project, the Mechanistic-Empirical Pavement Design Guide (MEPDG) developed under that study has been adopted by the American Association State Highway and Transportation Officials (AASHTO) and is in the process of adoption by many transportation agencies in the United States and abroad. Although it may take some time until the MEPDG completely replaces current empirical procedures, it is important to reflect on the lessons learned from the MEPDG development. The MEPDG was never envisioned as the “final answer” for all the pavement design problems, but rather an important milestone in the continuous improvement of the pavement design methodology. The MEPDG was supposed to reflect the state of the practice of the late 1990s. The MEPDG documentation includes volumes of appendixes that provide information for researchers, but some information that is important for future improvements of the MEPDG has never been recorded. This paper describes some of the experiences and lessons learned from the development of the MEPDG. This experience may be useful in the development of future M-E designs for jointed plain concrete pavements (JPCP).