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Purpose: This study investigates NASS-CDS data on basilar skull fractures by crash type and injury source for various crash scenarios to understand the injury risks, injury mechanisms and contact sources. Methods: 1993-2008 NASS-CDS data was used to study basilar skull fractures in adult front occupants by crash type and injury source. Injury risks were determined using weighted data for occupants with known injury status in 1994+ model year vehicles. In-depth analysis was made of far-side occupants in side impacts and rear crashes using the NASS electronic cases. Results: Basilar skull fractures occur in 0.507 ± 0.059% of rollovers and 0.255 ± 0.025% of side impacts. The lowest risk is in rear impacts at 0.015 ± 0.007%. The most common contact source is the roof, side rails and header (39.0%) in rollovers, the B-pillar (25.8%) in side impacts and head restraint (55.3%) in rear crashes.

Biomechanical surrogates are used in various forms to study head impact response in automotive applications and for assessing helmet performance. Surrogate headforms include those from the National Operating Committee on Standards for Athletic Equipment (NOCSAE) and the many variants of the Hybrid III. However, the response of these surrogates to loading at the chin and how that response may affect the loads transferred from the jaw to the rest of the head are unknown. To address part of that question, the current study compares the chin impact response performance of select human surrogates to that of the cadaver. A selection of Hybrid III and NOCSAE based surrogates with fixed and articulating jaws were tested under drop mass impact conditions that were used to describe post mortem human subject (PMHS) response to impacts at the chin (Craig et al., 2008). Results were compared to the PMHS response with cumulative variance technique (Rhule et al., 2002).

Objective: A friction rollover test was conducted as part of a rollover sensing project. This study evaluates vehicle and occupant responses in the test. Methods: A flat dolly carried a Saab 9-3 sedan laterally, passenger-side leading to a release point at 42 km/h (26 mph) onto a high-friction surface. The vehicle was equipped with roll, pitch and yaw gyros near the center of gravity. Accelerometers were placed at the vehicle center tunnel, A-pillar near the roof, B-pillar near the sill, suspension sub-frame and wheels. Five off-board and two on-board cameras recorded kinematics. Hybrid III dummies were instrumented for head and chest acceleration and upper neck force and moment. Belt loads were measured. Results: The vehicle release caused the tires and then wheel rims to skid on the high-friction surface. The trip involved roll angular velocities >300 deg/s at 0.5 s and a far-side impact on the driver’s side roof at 0.94 s. The driver was inverted in the far-side, ground impact.

Role of the Seat in Rear Crash Safety addresses the historic debate over seatback stiffness, energy absorbing yielding, occupant retention and whiplash prevention; and it provides a scientific foundation for the direction GM pursued in the development and validation of future seat designs. It also describes the multi-year research study into the role of the seat in rear crash safety - first by addressing the need for occupant retention in the more severe rear crashes; and then by addressing the needs for an adequately positioned head restraint and changes in the compliance of the seatback to lower the risks of the whiplash in low-speed crashes.

In this study, U.S. accident data was analyzed to determine interior contacts and injuries for front-seated occupants in rollovers. The injury distribution for belted and unbelted, non-ejected drivers and right front passengers (RFP) was assessed for single-event accidents where the leading side of the vehicle rollover was either on the driver or passenger door. Drivers in a roll-left and RFP in roll-right rollovers were defined as near-side occupants, while drivers in roll-right and RFP in roll-left rollovers were defined as far-side occupants. Serious injuries (AIS 3+) were most common to the head and thorax for both the near and far-side occupants. However, serious spinal injuries were more frequent for the far-side occupants, where the source was most often coded as roof, windshield and interior.

A “central” theory for the biomechanics of brain injury is proposed that includes the construct that acceleration of the head, per se, is not the proximate cause of injury. Rather, rapid motion of the skull causes displacement of the hard bony structures of the head against the soft tissues of the brain, which lag in their motion due to inertia and loose coupling to the skull. Relative displacement between brain and skull produces deformation of brain tissue and stretching of bridging veins, which contribute to the tissue-level causes of brain injury. The first step in an accurate interpretation of brain injury risk in dummies involves the measurement of the three-dimensional components of translational and rotational acceleration of the head.

Injury and disability associated with head (brain), neck (spinal cord) and facial injury account for 61.7% of the total societal Harm in the most recent estimate of motor-vehicle related crash injuries. This paper discusses the need for accurate information on translational and rotational acceleration of the head as the first step in critiquing the Head Injury Criterion (HIC) and other injury predictive methods, and developing a fuller understanding of brain and spinal cord injury mechanisms. A measurement system has been developed using linear accelerometers to accurately determine the 3D translational and rotational acceleration of the Hybrid III dummy head. Our concept has been to use the conventional triaxial accelerometer in the dummy's head to assess translational acceleration, and three rows of in-line linear accelerometers and a least squares analysis to compute statistical best-fits for the rotational acceleration about three orthogonal axes.

Current finite element models of head impact involve a geometrically simplified fluid-filled shell composed of homogeneous, linear and (visco) elastic materials as the primary surrogate of the human skull and brain. The numerical procedure, which solves the mechanical response to impact, requires and presumes continuity of stress and displacement between elements, a defined boundary condition simulating the neck attachment and a known forcing function. Our critical review of the models discussed, primarily, the technical aspects of the approximations made to simulate the head and the limitations of the proposed analytical tools in predicting the response of biological tissue. The following critical features were identified as major factors which compromised the accuracy and objectivity of the models: - The brain was approximated by a fluid contained in an elastic or rigid shell with no provision for relative motion between the shell and fluid.