On June 25, 1980, a stuntwoman was seriously injured during filming of an action sequence for the motion picture Cannonball Run, when her car was struck by a van that made the wrong move. Seat belts were removed from her vehicle prior to the accident, and part of the subsequent investigation examined whether or not seat belts would have mitigated her severe injuries.
Exponent's biomechanical engineers performed a detailed analysis to determine potential mitigation of injury of the occupant if seat belts had been used. Our engineers used Articulated Total Body (ATB) modelling software to simulate occupant motion. This whole-body, gross-motion simulator model was originally developed by Calspan Corporation, under the sponsorship of the U.S. Air Force Medical Research Laboratories at Wright-Patterson Air Force Base. The model has been validated by comparing the simulation results with numerous sled and barrier tests utilizing instrumented dummies. The program is used in a range of motion injury analyses, such as simulation of forklift accidents, investigation of helmet effectiveness, and determination of the motions of vehicle occupants with seat belts.
In this investigation, simulations were performed for both unbelted and belted occupants. Unbelted, the simulated occupant’s head impacted the windshield and chest impacted the steering wheel—correlating very well with actual injury data obtained from medical records. When the simulation included a three-point seat belt, it was shown that the belt would have prevented contact between the occupant and the car interior. By comparing injury tolerance limits, it was found that no equivalent, alternate injury would result from the use of a restraint system.