Occupant Dynamics is the study of how a vehicle occupant moves during a collision. It includes a kinematic description of the movement of the human body over a specific time period, including position, velocity, acceleration, and rotation. Occupant Dynamics also includes the analysis of forces and torques that cause these occupant movements. Occupant kinematics and dynamics are typically analyzed with respect to the vehicle interior geometry and restraint systems, such as seats, seat belts and airbags. Occupant dynamic assessments are a precursor and complement to biomechanical analyses.