The University of Virginia Center for Applied Biomechanics conducted a parametric modeling study of seat performance in rear impact for the Insurance Institute for Highway Safety using OpenVT seat geometry, foam, and structure characteristics spanning real seats. Simulations compared BioRID and EvaRID dummy responses across multiple crash pulses. Some kinematic measures correlated between dummies, while most kinetic measures did not. EvaRID showed greater sensitivity to seatback foam stiffness and pre-crash braking effects than BioRID, with pre-pretensioner reducing several outcome measures.