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The factors that influence airbag-induced upper-extremity injuries sustained by drivers were investigated in this study. Seven unembalmed human cadavers were used in nineteen direct-forearm-interaction static deployments. A single horizontal-tear-seam airbag module and two different inflators were used. Spacing between the instrumented forearm and the airbag module was varied from 10 cm to direct contact in some tests. Forearm-bone instrumentation included triaxial accelerometry, crack detection gages, and film targets. Internal airbag pressure was also measured. The observed injuries were largely transverse, oblique, and wedge fractures of the ulna or radius, or both, similar to those reported in field investigations. Tears of the elbow joint capsule were also found, both with and without fracture of the forearm.

Injuries to the thorax and abdomen comprise a significant percentage of all occupant injuries in motor vehicle accidents. While the percentage of internal chest injuries is reduced for restrained front-seat occupants in frontal crashes, serious skeletal chest injuries and abdominal injuries can still result from interaction with steering wheels and restraint systems. This paper describes the design and performance of prototype components for the chest, abdomen, spine, and shoulders of the Hybrid III dummy that are under development to improve the capability of the Hybrid III frontal crash dummy with regard to restraint-system interaction and injury-sensing capability.

In recent investigations of airbag deployments, drivers h v c reported abrasions to the face, neck, and forearms due to deploying airbags, A study of the airbag design and deployments parameters affecting the incidence and severity of abrasions caused by driver-side airbags has led to the development of a laboratory test procedure to evaluate the potential of an airbag design m cause skin injury This report describes the procedure, which is based an static deployments of airbags into a cylindrical lest fixture. The target area is covered with a material that responds to abrasion-producing events in a manner related to human skin tolerance. Test results show excellent correlation with abrasion injuries produced by airbag deployments into the skin of human volunteers.

Late model passenger cars and light trucks incorporate occupant protection systems with airbags and knee restraints. Knee restraints have been designed principally to meet the unbelted portions of FMVSS 208 that require femur load limits of 10-kN to be met in barrier crashes up to 30 mph, +/- 30 degrees utilizing the 50% male Anthropomorphic Test Device (ATD). In addition, knee restraints provide additional lower-torso restraint for belt-restrained occupants in higher-severity crashes. An analysis of frontal crashes in the University of Michigan Crash Injury Research and Engineering Network (UM CIREN) database was performed to determine the influence of vehicle, crash and occupant parameters on knee, thigh, and hip injuries. The data sample consists of drivers and right front passengers involved in frontal crashes who sustained significant injuries (Abbreviated Injury Scale [AIS] ≥ 3 or two or more AIS ≥ 2) to any body region.

Although driver-side airbag systems provide protection against serious head and chest injuries in frontal impacts, injuries produced by the airbag itself have also been reported. Most of these injuries are relatively minor, and consist primarily of skin abrasions and burns. Previous investigations have addressed the mechanisms of airbag-induced skin abrasion. In the current research, laboratory studies related to the potential for thermal burns due to high-temperature airbag exhaust gas were conducted. A laboratory apparatus was constructed to produce a 10-mm-diameter jet of hot air that was directed onto the leg skin of human volunteers in time-controlled pulses. Skin burns were produced in 70 of 183 exposures conducted using air temperatures ranging from 350 to 550°C, air velocities from 50 to 90 m/s, and exposure durations from 50 to 300 ms.

In a review of 540 crashes in which the steering-wheel airbag deployed, 38% of the drivers sustained some level of upper extremity injury. The majority of these were AIS-1 injuries including abrasions, contusions and small lacerations. In 18 crashes the drivers sustained AIS-2 or-3 level upper extremity injuries, including fractures of the radius and/or ulna, or of the metacarpal bones, all related to airbag deployments. It was determined that six drivers sustained the fracture(s) directly from the deploying airbag or the airbag module cover. The remaining 12 drivers had fractures from the extremity being flung into interior vehicle structures, usually the instrument panel. Most drivers were taller than 170 cm and, of the 18 drivers, 10 were males.

A method has been developed to identify and document the locations of rib fractures from two-dimensional CT images obtained from occupants of crashes investigated in the Crash Injury Research Engineering Network (CIREN). The location of each rib fracture includes the vertical location by rib number (1 through 12), the lateral location by side of the thorax (inboard and outboard), and the circumferential location by five 36-degree segments relative to the sternum and spine. The latter include anterior, anterior-lateral, lateral, posterior-lateral, and posterior regions. 3D reconstructed images of the whole ribcage created from the 2D CT images using Voxar software are used to help identify fractures and their rib number. A geometric method for consistently locating each fracture circumferentially is described.

The purpose of this study was to assess, by use of computer simulations, the effectiveness of motorcycle helmets in reducing head and neck injuries in motorcyclist impacts. The computer model used was the MVMA Two-Dimensional Crash Victim Simulator. The study investigated a wide variety of impact conditions in order to establish a broad overall view of the effectiveness of helmets. It was found that helmet use invariably reduces dynamic responses which have a role in producing head injury and, in addition, almost always reduces the severity of neck response as well. For no configuration or condition does the helmet greatly increase the likelihood of neck injury. Thus, these simulations of a wide spectrum of motorcyclist impacts provide further evidence that helmet use significantly reduces the likelihood and severity of both head and neck injuries. This study was supported by the Insurance Institute for Highway Safety.

A series of 16 sled impact tests was conducted at the Highway Safety Research Institute sled facility to evaluate the effectiveness of restraint devices and systems currently being used to transport school-bus and wheelchair-seated handicapped children. A sled impact pulse of 20 m.p.h. and 16 G's was used for all tests. Eight tests involved wheelchairs in forward-facing and side-facing orientations for head-on and 33-degree oblique impacts. Another eight tests involved forward-facing bus seats for head-on and 33-degree oblique impacts. The results generally point out the ineffectiveness of many currently used devices and systems for protecting the child in a bus collision. In six of the eight bus seat tests the dummy's head struck the back of the bus seat in front. This was primarily because of a lack of upper-torso restraint.

The objectives of this study are to quantify the biomechanical properties of the human neck which govern head and neck dynamic response and to establish the mechanisms responsible for primary aspects of response. Computer simulations with the MVMA 2-D and VOM 3-D occupant dynamics models were performed using head and neck sled input response data from human subjects at the Naval Biodynamics Laboratory for input and comparison. Predicted dynamic response data and preliminary values for biomechanical parameters in a three-dimensional head/neck model capable of accurately simulating response for −X, +Y, and −X+Y sled acceleration vectors are presented. The established analytical model should accurately predict head and neck responses in simulations of real-world automobile crashes where direct head impact is not involved. Additionally, the model can be used to assist in development of a design plan for the neck of advanced anthropomorphic test dummies.

Pregnant occupants pose a particular challenge to safety engineers because of their different anthropometry and the additional “occupant within the occupant.” A detailed study of the anthropometry and seated posture of twentytwo pregnant drivers over the course of their pregnancies was conducted. Subjects were tested in an adjustable seating buck that could be configured to different vehicle package geometries with varying belt anchorage locations. Each subject was tested four times over the course of her pregnancy to examine changes in seat positioning, seated anthropometry, and positioning of the lap and shoulder belts with gestational age. Data collected include preferred seating positions of pregnant drivers, proximity of the pregnant occupant to the steering wheel and airbag module, contours of the subjects’ torsos and abdomens relative to seat-belt centerline contours, and subject perceptions of their seated posture and proximity to vehicle components.

A new prototype pregnant abdomen for the Hybrid III small-female ATD is being developed and has been evaluated in a series of component and whole-dummy tests. The new abdomen uses a fluid-filled silicone-rubber bladder to represent the human uterus at 30-weeks gestation, and incorporates anthropometry based on measurements of pregnant women in an automotive driving posture. The response of the new pregnant abdomen to rigid-bar, belt, and close-proximity airbag loading closely matches the human cadaver response, which is thought to be representative to the response of the pregnant abdomen. In the current prototype, known as MAMA-2B (Maternal Anthropomorphic Measurement Apparatus, version 2B), the risk of adverse fetal outcome is determined by measuring the peak anterior pressure within the fluid-filled bladder.

The biomechanical behavior of 4-point seat belt systems was investigated through MADYMO modeling, dummy tests and post mortem human subject tests. This study was conducted to assess the effect of 4-point seat belts on the risk of thoracic injury in frontal impacts, to evaluate the ability to prevent submarining under the lap belt using 4-point seat belts, and to examine whether 4-point belts may induce injuries not typically observed with 3-point seat belts. The performance of two types of 4-point seat belts was compared with that of a pretensioned, load-limited, 3-point seat belt. A 3-point belt with an extra shoulder belt that “crisscrossed” the chest (X4) appeared to add constraint to the torso and increased chest deflection and injury risk. Harness style shoulder belts (V4) loaded the body in a different biomechanical manner than 3-point and X4 belts.

The initial positioning of anthropomorphic test devices (ATDs) can influence the outcomes of crash tests. Current procedures for positioning ATDs in rear seats are not based on systematic studies of passenger postures. This paper compares the postures of three side-impact ATDs to the postures of 24 men and women in three vehicle rear seats and 16 laboratory conditions. When positioned using current procedures, the locations of the ES-2 and SID-HIII ATD heads are generally rearward of those observed with similar-size passengers. The SID-IIs head locations matched the expected locations of heads of passengers of similar size more closely. As the seat back angle was increased, people reclined less than the ATDs. Based on these findings, a new ATD positioning procedure for rear seats was developed. The primary objective of the new procedure is to place the ATD head in the location that is most likely for people of similar size.

The objectives of this study were to examine the response, repeatability, and injury predictive ability of the Hybrid III small-female dummy to static out-of-position (OOP) deployments using a depowered driver-side airbag. Five dummy tests were conducted in two OOP configurations by two different laboratories. The OOP configurations were nose-on-rim (NOR) and chest-on-bag (COB). Four cadaver tests were conducted using unembalmed small-female cadavers and the same airbags used in the dummy tests under similar OOP conditions. One cadaver test was designed to increase airbag loading of the face and neck (a forehead-on-rim, or FOR test). Comparison between the dummy tests of Lab 1 and of Lab 2 indicated the test conditions and results were repeatable. In the cadaver tests no skull fractures or neck injuries occurred. However, all four cadavers had multiple rib fractures.

The biomechanical behavior of a harness style 4-point seat belt system in farside impacts was investigated through dummy and post mortem human subject tests. Specifically, this study was conducted to evaluate the effect of the inboard shoulder belt portion of a 4-point seat belt on the risk of vertebral and soft-tissue neck injuries during simulated farside impacts. Two series of sled tests simulating farside impacts were completed with crash dummies of different sizes, masses and designs to determine the forces and moments on the neck associated with loading of the shoulder belt. The tests were also performed to help determine the appropriate dummy to use in further testing. The BioSID and SID-IIs reasonably simulated the expected kinematics response and appeared to be reasonable dummies to use for further testing. Analysis also showed that dummy injury measures were lower than injury assessment reference values used in development of side impact airbags.

A finite element (FE) model with knee-thigh-hip (KTH) and lower-extremity muscles has been developed to study the potential effects of muscle tension on KTH injuries due to knee bolster loadings in frontal crashes. This model was created by remeshing the MADYMO human lower-extremity FE model to account for regional differences in cortical bone thickness, trabecular bone, cortical bone with directionally dependent mechanical properties and Tsai-Wu failure criteria, and articular cartilage. The model includes 35 Hill-type muscles in each lower extremity with masses based on muscle volume. The skeletal response of the model was validated by simulating biomechanical tests without muscle tension, including cadaver skeletal segment impact tests documented in the literature as well as recent tests of seated whole cadavers that were impacted using knee-loading conditions similar to those produced in FMVSS 208 testing.

In a previous study, the authors reported on the development of a finite-element model of the midsize male pelvis and lower extremities with lower-extremity musculature that was validated using PMHS knee-impact response data. Knee-impact simulations with this model were performed using forces from four muscles in the lower extremities associated with two-foot bracing reported in the literature to provide preliminary estimates of the effects of lower-extremity muscle activation on knee-thigh-hip injury potential in frontal impacts. The current study addresses a major limitation of these preliminary simulations by using the AnyBody three-dimensional musculoskeletal model to estimate muscle forces produced in 35 muscles in each lower extremity during emergency one-foot braking.

The NASS-CDS (1998-2008) and CIREN datasets were analyzed to identify factors contributing to abdominal injury in crash environments where belt use and airbag deployment are common. In frontal impacts, the percentage of occupants sustaining abdominal injury is three times higher for unbelted compared to belted front-row adult occupants (p≺0.0001) at both AIS2+ and AIS3+ injury levels. Airbag deployment does not substantially affect the percentage of occupants who sustain abdominal injuries in frontal impacts (p=0.6171), while belt use reduces the percentage of occupants sustaining abdominal injury in both nearside and farside crashes (p≺0.0001). Right-front passengers in right-side impacts have the highest risk (1.91%) of AIS 3+ abdominal injury (p=0.03). The percentage of occupants with AIS 3+ abdominal injuries does not vary with age for frontal, nearside, or farside impacts.

Based on an analysis of the National Automotive Sampling System (NASS) database from calendar years 1995-2000, over 30,000 fractures and dislocations of the knee-thigh-hip (KTH) complex occur in frontal motor-vehicle crashes each year in the United States. This analysis also shows that the risk of hip injury is generally higher than the risks of knee and thigh injuries in frontal crashes, that hip injuries are occurring to adult occupants of all ages, and that most hip injuries occur at crash severities that are equal to, or less than, those used in FMVSS 208 and NCAP testing. Because previous biomechanical research produced mostly knee or distal femur injuries, and because knee and femur injuries were frequently documented in early crash investigation data, the femur has traditionally been viewed as the weakest part of the KTH complex.