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A decade ago, James, et.al. published a detailed study of the available NASS data on severe rear impacts, with findings that “… stiffened or rigid seat backs will not substantially mitigate severe and fatal injuries in rear impacts.” No field accident study has since been advanced which refutes this finding. Advocates of rigidized seat backs often point to specific cases of severe rear impacts in which MAIS 4+ injuries are associated with seat back deformation, coupled with arguments supporting stiffer seatback designs. These arguments are generally based upon laboratory experiments with dummies in normal seating positions. Recent field accident data shows that generally, in collisions where the majority of societal harm is created, yielding seats continue to provide benefits, including those associated with whiplash associated disorders (WAD).

The BSAN crash pulse model has been shown to provide useful information for restraint sensing evaluation and for structural force-displacement studies in flat fixed rigid barrier (FFRB) crashes. This paper demonstrates a procedure by which the model may be extended for use with central and offset vehicle to vehicle (VTV) crashes through appropriate combinations of vehicle parameters.

The original Malibu II study, conducted by Bahling et al, found that neck compression loading in rollover crashes is caused by the occupant moving toward the ground and therefore, roof crush was not causally related to the loading. Some have disputed this finding claiming that the occupant does not “dive toward the roof,” but rather, the roof “moves in” toward the occupant, and that roof deformation is the primary cause of cervical spine injuries in rollover crashes. The original study included a detailed analysis of film and force transducer data for 10 Potentially Injurious Impacts (PII's). This paper presents an independent analysis of these 10 PII's and one additional PII. This analysis uses the film and transducer data to evaluate the timing of roof deformation and neck loading, the magnitude of roof deformation at the time of peak neck load, and the motion of the vehicle and occupants in the inertial reference system.

Understanding of events within the history of a crash, and estimation of the severity of occupant interior collisions depend upon an accurate assessment of crash duration. Since this time duration is not measured independently in most crash test reports, it must usually be inferred from interpretations of acceleration data or from displacement data in high-speed film analysis. The significant physical effects related to the crash pulse are often essential in reconstruction analyses wherein the estimation of occupant interior “second collision” or airbag sensing issues are at issue. A simple relation is presented and examined which allows approximation of the approach phase and separation phase kinematics, including restitution and pulse width. Building upon previous work, this relation allows straightforward interpretation of test data from related publicly available test reports.

Heavier, larger pickups and SUVs are bound to encounter lighter, smaller passenger vehicles in many future accidents. As the fleet has evolved to include more and more SUVs, their frontal structures are often indistinguishable from pickup fronts. Improvements in geometric compatibility features are crucial to further injury prevention progress in side impact. In corner crashes where modern bullet passenger car (PC) bumpers make appropriate geometrical overlap with target PC rocker panels, concentrated loads sometimes disrupt foam and plastic bumper corners, creating aggressive edges. In situations where sliding occurs along the structural interface, these sharp edges may slice through doors, panels and pillars. End treatments for such bumper beams should be designed to reduce this aggressive potential.

To date, several lateral impact studies (Bolte et al., 2000, 2003, Marth, 2002 and Compigne et al., 2004) have been performed on the shoulder to determine the response characteristics and injury threshold of the shoulder complex. Our understanding of the biomechanical response and injury tolerance of the shoulder would be improved if the results of these tests were combined. From a larger data base shoulder injury tolerance criteria can be developed as well as corridors for side impact dummies. Data from the study by Marth (2002, 12 tests) was combined with data from the previous studies. Twenty-two low speed tests (4.5 ± 0.7 m/s) and 9 high speed tests (6.7 ± 0.7 m/s) were selected from the combined data for developing corridors. Shoulder force, deflection and T1y acceleration corridors were developed using a minimization of cumulative variance technique.

Traumatic rupture of the aorta (TRA) is a leading cause of death in high velocity blunt trauma, particularly motor vehicle accidents. However, little is understood about the mechanisms of TRA and thus, the opportunities to prevent TRA in the motor vehicle environment are compromised. The objective of this study was to determine the relationship between impact response and TRA through analyses of data from cadaver tests that successfully produced TRA in lateral impacts. Seventeen Heidelberg-style side impact sled tests were conducted using unembalmed human cadavers. Three sled speeds were used: 6.7, 9.0, and 10.5 m/s. Three barrier configurations were used: rigid flat wall, rigid wall with a 152-mm offset toward the pelvis, and a flat wall with padding of varying stiffness. Multiple load and acceleration measurements were made on the barrier and cadaver. Potential injury parameters were evaluated and their relative predictive abilities were examined.

Thirty-three fresh human cadaver shoulders were harvested and bone-ligament-bone specimens of acromioclavicular joint, coracoclavicular joint and sternoclavicular joint were obtained. A test fixture and clamps specifically designed for this ligament study and a high-speed Instron machine were used. One quasi-static rate (nominally 0.1 %/sec) and two high rates (nominally, high rate 1 = 40,000 %/sec and high rate 2 = 15,000 %/sec) were used in this study. In the acromioclavicular joint tests, ligament failure was the most common failure mode. Bone fractures occurred most often at the clavicle rather than acromion. In the coracoclavicular joint tests, the majority of specimens failed at the ligament and bone fractures occurred at the coracoid. In the sternoclavicular joint tests, the specimen failed at the bone in most cases. In the acromioclavicular joint and coracoclavicular joint tests, high rate 2 tests and quasi-static tests had more bone fracture cases than high rate 1 tests.

Field experience has consistently indicated that lap-only belts and lap-shoulder belts perform well and about equally in prevention of fatalities and serious injuries in the rear seating positions. Analyses based on overall usage and injury figures from the Fatal Analysis Reporting System (FARS), double-pair analysis of FARS data, and still older data bases have shown that, in the rear outboard seating positions, injury rates are about the same for lap-only and lap-shoulder belted crash occupants. Although sparse, recently available field data from the 1988-2001 National Analysis Sampling System / Crashworthiness Data System (NASS/CDS) files confirm the finding that, when used by rear seat occupants, lap-only belts perform about equally with lap-shoulder belts as countermeasures for serious and fatal injury in severe frontal crashes.

The biomechanical response and injury tolerance of the shoulder in lateral impacts is not well understood. These data are needed to better understand human injury tolerance, validate finite element models and develop biofidelic shoulders in side impact dummies. Seventeen side impact sled tests were performed with unembalmed human cadavers. Data analyzed for this study include T1-Y acceleration, shoulder and thoracic load plate forces, upper sternum x and y accelerations, and struck side acromion x, y and z accelerations. One dimensional deflection at the shoulder level was determined from high-speed film by measuring the distance between a target on T1 and the impacted wall. Force-time response corridors were obtained for tests with 9 m/s pelvic offset, 10.5 m/s pelvic offset, 9 m/s unpadded flat wall, 6.7 m/s unpadded flat wall, 9 m/s soft padding and 9 m/s stiff padding. Maximum shoulder plate forces in unpadded 9 m/s tests (5.5 kN) were larger than in 6.7 m/s tests (3.3 kN).

The purpose of this study is to help understand the thoracic response and injury mechanisms in high-energy, limited-stroke, lateral velocity pulse impacts to the human chest wall. To impart such impacts, a linear impactor was developed which had a limited stroke and minimally decreased velocity during impact. The peak impact velocity was 5.6 ± 0.3 m/s. A series of BioSID and cadaver tests were conducted to measure biomechanical response and injury data. The conflicting effects of padding on increased deflection and decreased acceleration were demonstrated in tests with BioSID and cadavers. The results of tests conducted on six cadavers were used to test several proposed injury criteria for side impact. Linear regression was used to correlate each injury criterion to the number of rib fractures. This test methodology captured and supported a contrasting trend of increased chest deflection and decreased TTI when padding was introduced.

The reconstruction of accidental impacts to the side structure of one or more accident vehicles often incorporates estimates of the energy absorbed by laterally struck vehicle(s). Such estimates generally involve considerably more issues than does the assessment of frontal or rear impact deformation energy. The sides of vehicles are, compared to the usual striking object, relatively broad, and they contain zones of varying stiffness supported by collapsible box structures. Side stiffnesses can vary widely, depending upon impact geometry. Most side impact crash tests that can readily be used to make estimates of side stiffness have been conducted by the National Highway Traffic Safety Administration (NHTSA).

Occupant simulation models have been used to study trends or specific design changes in “typical” accident modes such as frontal, side, rear, and rollover. This paper explores the usage of the Articulated Total Body Program (ATB) as an accident reconstruction tool. The importance of model validation is discussed. Specific areas of concern such as the contact model, force-deflection data, occupant parameters, restraint system models, head/neck loadings, padding, and intrusion are discussed in the context of accident reconstruction.

Impact tests were conducted on thirty-one unembalmed human cadaver heads. Impacts were delivered to the temporo-parietal region of fixed cadavers by two, different sized, flat-rigid impactors. Yield fracture force and stiffness data for this region of the head are presented. Impactor surfaces consisted of a 5 cm2 circular plate and a 52 cm2 rectangular plate. The average stiffness value observed using the circular impactor was 1800 N/mm, with an average bone-fracture-force level of 5000 N. Skull stiffness for the rectangular impactor was 4200 N/mm, and the average fracture-force level was 12,500 N.

This paper summarizes work relating to the assessment of societal benefits of side impact protection. National Crash Severity Study (NCSS) and National Accident Sampling System (NASS) accident data technigues were reviewed with respect to the reliability of output information concerning the distribution of side impact accidents by impact severity and relationships between injury and impact severity. NCSS and NASS are confounded by errors and inadequacies, primarily as a result of improper accident reconstruction based upon the CRASH computer program. Based on review of several sample cases, it is believed that the NCSS/NASS files underestimate Lower severities and overestimate higher severities in side impact, with delta-V errors probably overestimated by 25-30 percent in the case of the more serious accidents. These errors cannot be properly quantified except on a case-by-case basis. They introduce unknown biases into NCSS/NASS.

The NHTSA notices of proposed rulemaking on side impact protection have focused worldwide attention on one of the most difficult and frustrating efforts in automobile crash safety. Traditional vehicle design has evolved obvious structural contrasts between the side of the struck vehicle and the front of the striking vehicle. Protection of near-side occupants from intruding door structure is a most perplexing engineering challenge. Much useful and insightful engineering work has been done in conjunction with NHTSA's proposed rulemaking. However, there are many major engineering issues which demand further definition before reasonable side impact rulemaking test criteria can be finalized. This paper reviews recent findings which characterize the human factors, biomechanics, and occupant position envelope of the typical side impact crash victim.

An understanding of fundamental kinematic relationships among the several deforming surfaces of side-impacting bullet and target vehicle, occupant protection system and occupant is fundamental to rational design of crash injury counter-measures. Unfortunately, such understanding is not easy to achieve. Side impacts address the full range of bodily contacts and injuries in a way that challenges analysis. Each bodily area and organ requires individual consideration for adequate injury protection. This paper presents a simplified graphical analysis of occupant kinematics and injury exposure applied specifically to the NHTSA-proposed crabbed moving deformable barrier (MDB) compartment impact, as described in NHTSA's Notice of Proposed Rulemaking (NPRM) for Federal Motor Vehicle Safety Standard (FMVSS) 214, issued in January of 1988 [NHTSA 1988 (1)*]. Projections are offered regarding the potential of thoracic injury counter-measures.

Collision Safety Engineering, Inc. (CSE), has developed a test prototype system to protect occupants during lateral impacts. It is an inflatable system that offers the potential of improved protection from thoracic, abdominal and pelvic injury by moving an impact pad into the occupant early in the crash. Further, it shows promise for head and neck protection by deployment of a headbag that covers the major target areas of B-pillar, window space, and roofrail before head impact. Preliminary static and full-scale crash tests suggest the possibility of injury reduction in many real-world crashes, although much development work remains before the production viability of this concept can be established. A description of the system and its preliminary testing is preceded by an overview of side impact injury and comments on the recent NHTSA Rule Making notices dealing with side-impact injury.

Results indicate the need for a redesigned Hybrid III face capable of accurate force and acceleration measurements. New instrumentation and methods for facial fracture detection were developed, including the application of acoustic emissions. Force/ deflection information for the human cadaver head and the Hybrid III ATD were generated for the frontal, zygomatic, and maxillary regions.

Nineteen sled impact tests were conducted simulating a frontal collision exposure for an unrestrained driver. The deceleration sled buck configuration utilized the passenger compartment of a late model compact passenger vehicle, a rigid driver's seat, and a custom fabricated energy-absorbing steering column and wheel assembly. Sled impact velocities ranged from 24.1 to 42.6 km/hr. The purpose of the study was to investigate the kinematic and kinetic interaction of the driver and the energy-absorbing steering assembly and their relationship to the thoracic/abdominal injuries produced. The similarities and differences between human cadaver and anthropomorphic dummy subjects were quantified.