Experimental composite pavements were constructed at MnROAD in Minnesota and the University of California Pavement Research Center at Davis, where the pavements were instrumented and monitored under climate and heavy traffic loadings. A composite pavement consisting of HMA over jointed plain concrete also was constructed in the field by the Illinois Tollway north of Chicago. At the Tollway, extensive field surveys were performed on 64 sections of the two types of composite pavements. This project also evaluated, improved, and further validated applicable structural, climatic, material, and performance prediction models, and design algorithms that are included in the AASHTO MEPDG and DARWin-ME, CalME, NCHRP 1-41 reflection cracking, NCHRP 9-30A rutting, and the Lattice bonding model. The current DARWin-ME overlay design procedure for HMA/PCC and a special R21 version of the Mechanistic-Empirical Pavement Design Guide (MEPDG [v.