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Past rollover condition testing reported by the author utilized experimental seat belts, a rigid seat and a sitting pelvis Hybrid III mannequin or volunteer to observe dynamic vertical excursion. Other testing in a rollover condition utilized a rigid mannequin molded from a Hybrid III, sitting in a production vehicle restraint system. Application of rigid device in the test allows for simplification of the problem under study, yet limitations in the interpretation of the results. A third test program was conducted combining the rigid device of prior testing into one test, thereby allowing further scientific inference as to the affect of the seat belt restraint system in rollover conditions. Results show that an important factor in the extent of occupant vertical excursion is the kinematics and compliance of the occupant.

A series of controlled experimental programs were conducted for the purpose of improving the motor vehicle rollover protection system. Test results reported in this paper have been previously presented in SAE Paper No.980213 [1]. Experiments tested lap belt restraints utilizing a variety of lap belt geometric and webbing slack conditions. Tests utilized in the series include dynamic and static tests and the use of test mannequins and human volunteers. In the first test program, utilizing a rigid seat, human volunteers were subjected to minus 1.0 Gz acceleration and a 95th percentile Hybrid III mannequin was subjected to minus 5.0 Gz acceleration for a variety of lap belt conditions. A second program utilized a rigid mannequin in production vehicle seats for the purpose of measuring and comparing seat belt system effective slack. Finally, the rigid mannequin from the second test and the rigid seat and lap belts from the first test were brought together and tested.

Outriggers are devices that arrest vehicle rollover during handling test maneuvers to protect the test vehicle and/or test driver. Validity of data in these tests has been questioned because the effect outriggers have on vehicle dynamics is not well understood. This research quantifies changes in handling characteristics with outriggers attached to a test vehicle. Three outrigger systems of different masses were developed and tested through various limit and sub-limit handling maneuvers. Analysis of the data generated during testing indicates improvements necessary for future outrigger designs leading to better understanding of vehicle dynamics and potentially reduced injuries from rollovers.

Tire marks left by the vehicle prior to impact, rollover, or other event, are important forensic evidence reconstruction of motor vehicle accidents. Often these tire marks have some curvature that is measured and used to calculate the speed of vehicles prior to the event. This calculation is based on the coefficient of friction of the tire/road interface and the radius of curvature of the vehicle center of gravity (c.g.) path. There is controversy about the validity of this approach. To explore this theory, a test vehicle was driven through a series of maneuvers that produced yaw marks for direct comparison of actual vehicle velocity to the velocity calculated by the critical speed formula. Test results show the critical speed formula is inaccurate for most circumstances and does not correctly describe vehicle limit performance behavior.

A controlled experimental program was conducted to determine the response of humans and a human surrogate with experimental lap belt restraints in -Gz acceleration environments. In the program, lap belt anchorage position (belt angle) and belt tension/slack were varied. Human volunteers were subjected to a static -1.0 Gz acceleration for each restraint configuration. A 95th percentile male Hybrid Ill dummy was subjected to a nominal 4.25 m/s (9.5 mph), -5 Gz impact while restrained by each restraint configuration. For the -Gz acceleration, significant changes in occupant head excursion were observed with varied lap belt configurations. In general, less pre-crash belt slack and higher lap belt angles produced significant reductions in occupant vertical excursions. This research provides data for use in evaluating or developing occupant survivability systems for rollover crash environments.

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.

A variable deceleration rate approach to rollover crash reconstruction was proposed in 2009 by Rose and Beauchamp. A detailed description of Rose and Beauchamp's method was outlined in 2010. The method used a Linearly Variable Deceleration Rate (LVDR) as a function of roll distance. Improvements in responses as a function of time was demonstrated by Rose and Beauchamp using test data from two 208 dolly rollover tests; however, they noted that additional validation work using steering-induced rollover tests would be desirable. This paper provides additional validation of the LVDR model using the steer-induced rollover test data reported in 2011 by Stevens et al. The Over-The-Ground Speed (OGS) and recorded roll rate results from the five steer-induced rollover tests reported by Stevens' in 2011 were compared to reconstructed speed and roll rates as a function of time using the 2010 Rose and Beauchamp LVDR method.