The Development of a Method for Determining Effective Slack in Motor Vehicle Restraint Systems for Rollover Protection

Effective slack associated with seat belt systems for rollover protection is studied for the purpose of improving or anticipating improvements to a motor vehicle rollover protection system. A test method and test devices were constructed to study and develop objective understandings of the effects of motor vehicle seat and seat belt characteristics on effective slack. The test devices and test method were proved in two separate motor vehicles with differing seat belt systems. Results demonstrated that effective slack as a conceptual equivalent to a seat belt webbing length could be repeatable and objectively determined for the systems tested. Determining a seat belt system's effective slack is useful for the purpose of comparing experimental restraints and experimental restraint testing to motor vehicle restraint design and performance.