Injuries associated with impact acceleration forces are a major source of loss in both military and civilian transportation. The testing of impact protective devices under operational conditions is primarily done using anthropomorphic manikins such as the Hybrid III. As part of its Impact Injury Prevention program, the Naval Biodynamics Laboratory is studying human volunteer and Hybrid III head-neck responses to whole-body acceleration. These data are being used to develop validated models, using Hybrid III responses, for predicting human head-neck responses at the full range of operational g-levels. For the directions, key linear and angular acceleration variables from selected sets of human experiments were fit using least-squares polynomial splines. The spline parameters are functions of the latency and amplitude of the peaks of the acceleration variables and are well-predicted from the initial head position and the sled acceleration profile. Similar functional forms were imposed on selected sets of Hybrid III data yielding equally good results. These common and consistent statistical models for human and Hybrid III data form the basis of a statistical scaling procedure between human and Hybrid III response for the -X direction. The results demonstrate an analytical approach for extrapolating human head/neck kinematics to levels and types of impact exposure where injury could occur. Currently, these results are being extended to include the +Y (lateral) and +Z (vertical) vector directions.