This paper presents results of an ongoing research program to develop and validate data sets for computer models which accurately predict the head-neck kinematics and dynamics of existing dummies in crash environments. The mathematical model utilized for this research is the Armstrong Aerospace Medical Research Laboratory (AAMRL) Articulated Total Body (ATB) Model. The goal of this investigation was to review, validate, and compare ATB data sets of the Hybrid III manikin head-neck system. The data sets were based upon experimental data from the AAMRL, Prasad, and Deng, and model parameters and data sets proposed by the AAMRL, Deng, Seemann, and Wismans. Simulations of the Amended Part 572 Head-Neck Pendulum Compliance Test, of the Code of Federal Regulations, were performed to validate these data sets. The predicted model responses were compared to compliance test specifications and published experimental data from the Transportation Research Center of Ohio. The information generated by this study should help in the understanding of the head-neck biomechanics of existing manikins and in future manikin development.