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The Federal Motor Vehicle Safety Standard 571.201 discusses occupant protection with interior impacts of vehicles. Recent rule making by the National Highway Traffic Safety Administration (NHTSA) has identified padding for potential injury reduction in vehicles. Head injury mitigation with padding on vehicular roll bars was evaluated. After market 2 to 2.5 cm thick padding and metal air gap padding reduced the head injury criterion (HIC) and angular acceleration compared to the stock foam roll bar padding. Studies were conducted with free falling Hybrid 50% male head form drops on the fore head and side of the head. Compared to the stock roll bar material, a nearly 90% reduction in HIC was observed at speeds up to 5.4 m/s. A concomitant 83% reduction in angular acceleration was also observed with the metal air gap padding. A 2 to 2.5 cm thick Simpson roll bar padding produced a 70 to 75% reduction in HIC and a 59 to 73% reduction in angular acceleration.

Contemporary production emergency locking seatbelt retractors (ELRs) have been proven very effective in the crash environment for which they have been primarily designed and most adequately tested, that is, in the full frontal crash mode. However, researchers have documented spool out during offset, angled, override, underride, and rollover crashes where seatbelt retractors are subject to acceleration pulses in varying directions, including the vertical plane. Occupant motions during these real world accident modes may also impart loads into the belts and belt hardware (webbing and buckle assemblies) that may not be immediately apparent in the frontal barrier test mode. Numerous laboratory studies have demonstrated that the inertial sensor can be held in the neutral position when an overriding opposing force is applied to the retractor, resulting in webbing spool out. Various ELR designs include ball and cage sensors, pendulum, and disk systems.

Accident reconstruction analysis of both pre- and post-impact vehicle trajectory wherein an involved vehicle has collided with or traversed a roadside curb often leaves the analyst with uncertainty associated with the speed loss and accelerations attributable to these impacts. A review of available published data reveals very few studies considering the energy dissipated and transferred to the vehicle's occupants. This paper quantifies the changes in vehicle velocity (delta-v) for various vehicles traversing a typical roadside curb at various approach angles and impact speeds. Vehicle accelerations are recorded in the vertical, longitudinal, and lateral directions. Resulting three-point belted driver movements are observed via an interior mounted video camera and general occupant motions are described. Curb impacts were conducted with four different passenger vehicles ranging in size from a small compact car to a large full-size sport utility vehicle.