The objective of the study was to determine the head-neck biomechanics with a focus on lower neck injury metrics using different anthropomorphic test devices (dummies). Specifically, sled tests were conducted by positioning the mid- and large-size Hybrid III and Thor dummies in a custom designed frontal impact buck that consisted of a rigid seat, an adjustable head restraint, and an adjustable knee bolster. Tests were conducted at low, medium, and high change in velocities using three restraint conditions. Peak upper neck moments were more sensitive than peak upper neck forces for all dummies. Moments in the Thor dummy were more sensitive than the moments in the mid-size Hybrid III dummy at both the upper and lower necks. This study offers restraint-based data and addresses biofidelity differences between dummies, and dummies of the same family with differing size. Such data are critical in off-center and small overlap frontal crashes where airbag may not offer the most optimum protection, and for rear seat occupants wherein frontal impact airbags do not exist.