Two cases of driver death caused by airbag rupture

OBJECTIVE

This article reports two accidents caused by defective Takata airbags ruptured, which led to the deaths of the drivers. This is the first public report on the deaths caused by Takata airbags in China.

METHODS

Determine the relationship between the driver death and airbag rupture through autopsy indings and vehicle inspection.

RESULTS

Due to defects in the design of Takata's inflator, moist air was permitted to slowly enter the inflator, resulting the PSAN slowly degraded physically. The damaged propellant burned more rapidly than intended and overpressurized the inflator's steel housing, causing fragmentation and flying debris at high speed, killing or injuring vehicle occupants.

CONCLUSIONS

To date, there are still tens of millions of defective Takata airbags that have not been recalled for repair, posing safety risks. This article suggests taking preventive measures to avoid the occurrence of similar accidents.

Injuries, death and vehicle airbag deployment

Airbags are impact-activated safety devices which deploy from the interior of vehicles to protect occupants from trauma during crashes. Although airbags effectively reduce the risk of death and injury, this it is not without issues. For example, high-impact unbelted rigid-barrier testing in the USA led to the adoption of powerful, large airbags that were associated with numerous airbag-related deaths and injuries. In contrast, European designs were tested and certified in conjunction with the use of three-point restraint systems, meaning that the airbags could be smaller with reduced ‘punch-out’ power. An overview is provided of the mechanism of action of airbags and the associated non-lethal and lethal injuries that may be sustained by vehicle occupants.

Adapting load limiter deployment for frontal crash diversity

Objective: Current European restraint systems may not realize their full protection potential in real-world frontal crashes because they are highly optimized for specific conditions. This research sought to quantify the potential benefit of adapting seat belt load limit thresholds to a wider range of occupant and crash characteristics.Methods: Numerical simulations using Hybrid III dummies were conducted to determine how varying load limiter thresholds could affect occupant kinematics and injury outcome in frontal impacts. Occupant-compartment models were developed with a restraint system consisting of a frontal airbag and a 3-point belt with retractor, buckle pretensioner, and load limiting at the shoulder. Load limiting threshold was varied in 5 frontal impact scenarios, covering as wide a range of real frontal crash conditions as possible. The simulated thoracic injury risks were converted into injury probability values using Abbreviated Injury Scale (AIS) 2+ age-dependent thoracic risk curves. These values were then applied to a British real-world frontal impact sample to determine the injury reduction potential of optimized load limiting, taking into account occupant seating position, impact scenario, occupant size, and occupant age and assuming that an appropriate adaptive system was fitted to all cars.Results: In low-severity impacts, a low load limit provided the best chest protection, without increasing risk to other body regions, for both the 50th and 95th percentile dummies in both front seating positions. In high-severity impacts, the low limit was not recommended because it allowed the driver dummy to move into close proximity with the vehicle interior, although there appeared to be some benefit of lower load limiting for the 50th percentile front passenger dummy, due to the increased ride down space in that seating position. Adapting the load limit showed no injury reduction potential for 5th percentile drivers. Utilizing the best load limit threshold in real-world crashes could reduce the number of occupants with AIS 2+ chest injuries from belt loading from 377 to 251 (a 33% reduction), correspondingly reducing the number of occupants with AIS 2+ chest injuries (from all sources) in the whole frontal impact population from 496 to 370. This is a reduction in injury rate from 6.4% to 4.8%.Conclusions: The concept of an adaptive load limiter shows most promise in low-speed frontal crashes where it could lower the AIS 2+ chest injury risk for most front seat occupants, except the smallest of drivers. Generally, adaptive limiters show less potential effectiveness with increased crash severities. Overall, an intelligent adjustment of load limiting threshold could result in a reduction of at least a third of front seat occupants with AIS 2+ chest injuries associated with restraining loads and an overall reduction in AIS 2+ chest injury rate in frontal crashes from 6.4% to 4.8.

Factors associated with chest injuries to front seat occupants in frontal impacts

Objective: Frontal impact chest protection in European cars has been highlighted as an area where possible improvements could be made. The chest is particularly vulnerable in older occupants whose numbers are forecast to increase significantly in the coming decades. This study aimed to provide some direction to areas for possible improvements in frontal crash chest protection.Methods: Real-world crash injury data were interrogated, focusing on cars with current restraint components. The research examined belted front seat occupants in frontal impacts where airbags, pretensioners, and load limiters were present.Results: The chest was the most often injured body region at Abbreviated Injury Scale (AIS) 2+, 3+, and 4+ injury levels. The rate of AIS 2+ and AIS 3+ chest injuries was highest among elderly occupants and lowest among young occupants, and elderly occupants sustained proportionally more severe chest injuries in low/moderate-speed impacts compared to young and middle-aged occupants. However, it should be noted that rates of AIS 2 chest injury were also significantly higher for middle-aged occupants compared to the young. The front passenger seat was shown to be more often associated with significant chest injury than the driver seat. The higher proportion of elderly female occupants was postulated as a reason for this. Skeletal injury was the most frequent type of AIS 2+ chest injury, and the rate of injury for elderly occupants with such injuries was higher than that for young and middle-aged occupants. With the increase in the number of rib fractures, the risk of pulmonary complications and organ injuries tended to increase. The major cause of chest injury was identified as restraining loads transmitted to the chest via the seat belt. The absence of intrusion in the majority of cases suggests an opportunity for the restraint system to better manage the crash pulse, not only for elderly occupants but for those who are middle-aged as well.Conclusions: This study shows the necessity for safety interventions, through new vehicle crashworthiness systems, to improve chest protection, especially for middle-aged and elderly car occupants. Deployment of appropriate injury risk criteria, use of an appropriate dummy thorax, development of a low-energy restraint test, and the development of more adaptive restraints have been discussed as possible solutions to the problem.

A life saved at the cost of hand injury - A case of hand burn due to airbag deployment

According to the Malaysian Department of Statistics motor vehicle accidents are the third leading cause of death in Malaysia and accounts for 7.4% of premature deaths in 2016. With the invention of the airbag, the number of serious injuries and fatalities have been reduced significantly. However, there has also been a corresponding increase in the number of injuries attributable to these devices. The patient narrated in this case report sustained a mixed dermal thickness burn over the upper limb as a result of an airbag deployment. She recovered without other life threatening injuries.

Chest injuries of elderly postmortem human surrogates (PMHSs) under seat belt and airbag loading in frontal sled impacts: Comparison to matching THOR tests

OBJECTIVE

The goal of the study was to develop experimental chest loading conditions that would cause up to Abbreviated Injury Scale (AIS) 2 chest injuries in elderly occupants in moderate-speed frontal crashes. The new set of experimental data was also intended to be used in the benchmark of existing thoracic injury criteria in lower-speed collision conditions.

METHODS

Six male elderly (age >63) postmortem human subjects (PMHS) were exposed to a 35 km/h (nominal) frontal sled impact. The test fixture consisted of a rigid seat, rigid footrest, and cable seat back. Two restraint conditions (A and B) were compared. Occupants were restrained by a force-limited (2.5 kN [A] and 2 kN [B]) seat belt and a preinflated (16 kPa [A] and 11 kPa [B]; airbag). Condition B also incorporated increased seat friction. Matching sled tests were carried out with the THOR-M dummy. Infra-red telescoping rod for the assessment of chest compression (IRTRACC) readings were used to compute chest injury risk. PMHSs were exposed to a posttest injury assessment. Tests were carried out in 2 stages, using the outcome of the first one combined with a parametric study using the THUMS model to adjust the test conditions in the second. All procedures were approved by the relevant ethics board.

RESULTS

Restraint condition A resulted in an unexpected high number of rib fractures (fx; 10, 14, 15 fx). Under condition B, the adjustment of the relative airbag/occupant position combined with a lower airbag pressure and lower seat belt load limit resulted in a reduced pelvic excursion (85 vs. 110 mm), increased torso pitch and a substantially lower number of rib fractures (1, 0, 4 fx) as intended.

CONCLUSIONS

The predicted risk of rib fractures provided by the THOR dummy using the C_max and PC Score injury criteria were lower than the actual injuries observed in the PMHS tests (especially in restraint condition A). However, the THOR dummy was capable of discriminating between the 2 restraint scenarios. Similar results were obtained in the parametric study with the THUMS model.

Factors involved in the assessment of paediatric traffic injuries and deaths

Motor-vehicle collisions are the leading cause of unintentional injury and death in children in many parts of the world, including Europe, North America and Australia. The number of fatal collisions has decreased considerably in countries where safety measures such as child restraints, seat belts and air bags have been introduced, providing protection for children within vehicles, although it is recognised that there have been concomitant improvements in emergency responses and techniques, and in hospital treatments. Helmets and changes in external vehicle designs have been implemented to protect paediatric pedestrians and cyclists. However, despite the development of safety guidelines and technologies, injuries still occur. This paper provides an overview of the role of motor-vehicle collisions in paediatric morbidity and mortality to analyse the nature and aetiology of common fatal and non-fatal injuries in children that may present for forensic assessment as passengers, pedestrians or cyclists.

Corneal endothelial decompensation due to airbag injury

PURPOSE

We report a case of localized endothelial decompensation due to airbag deployment during a motor vehicle accident.

CASE REPORT

A middle-aged woman involved in a motor vehicle accident presented with diminution of vision in left eye. Initial ocular examination revealed corneal abrasion, localized central corneal edema and mild anterior chamber reaction. An anterior-segment ocular coherence tomography (AS-OCT) revealed focal paracentral corneal edema. Patient was managed with lubricating eye drops and antibiotic steroid combination. Significant endothelial cell loss compared to right eye was noted on specular examination. At one- month follow-up, visual acuity recovered to 6/6 but the pleomorphism and polymegathism persisted.

CONCLUSION

Airbag-related localized corneal endothelial decompensation is a less known occurrence. This case emphasizes on the fact that serial monitoring of endothelial counts and conservative management can prove beneficial in such scenarios.

Air Bag-Associated Retinal Tear

We report a case of a patient seen after a minor traffic accident, showing an ocular injury due to the air-bag, with minimal corneal edema and a retinal tear. When faced with the traumatic alterations caused by an inflated air-bag, we recommended detailed exploration of the peripheral retina.

Airbag deployment-related eye injuries

OBJECTIVE

We studied the correlation between airbag deployment and eye injuries using 2 different data sets.

METHODS

The registry of the Finnish Road Accident (FRA) Investigation Teams was analyzed to study severe head- and eyewear-related injuries. All fatal passenger car or van accidents that occurred during the years 2009-2012 (4 years) were included (n = 734). Cases in which the driver's front airbag was deployed were subjected to analysis (n = 409). To determine the proportion of minor, potentially airbag-related eye injuries, the results were compared to the data for all new eye injury patients (n = 1,151) recorded at the Emergency Clinic of the Helsinki University Eye Hospital (HUEH) during one year, from May 1, 2011, to April 30, 2012.

RESULTS

In the FRA data set, the unbelted drivers showed a significantly higher risk of death (odds ratio [OR] = 5.89, 95% confidence interval [CI], 3.33-10.9, P = 2.6E-12) or of sustaining head injuries (OR = 2.50, 95% CI, 1.59-3.97, P = 3.8E-5). Only 4 of the 1,151 HUEH patients were involved in a passenger car accident. In one of the crashes, the airbag operated, and the belted driver received 2 sutured eye lid wounds and showed conjunctival sugillation. No permanent eye injuries were recorded during the follow-up. The calculated annual airbag-related eye injury incidence was less than 1/1,000,000 people, 4/100,000 accidents, and 4/10,000 injured occupants.

CONCLUSIONS

Airbag-related eye injuries occurred very rarely in car accidents in cases where the occupant survived and the restraint system was appropriately used. Spectacle use did not appear to increase the risk of eye injury in restrained occupants.

Placental abruption and fetal intraventricular hemorrhage after airbag deployment: a case report

BACKGROUND

There has been very limited documentation of the adverse maternal and/or fetal consequences of airbag deployment in association with motor vehicle accidents.

CASE

A 20-year-old woman, gravida 1, para 0, at 31+ 4 weeks' gestation, was involved in a motor vehicle accident. The car had been hit from the passenger side at an estimated speed of 45 miles per hour. The vehicle was noted to have rolled over, along with deployment of the driver's side and passenger's airbags. Via star low transverse cesarean, the patient was delivered of a very pale-appearing, 1,890g infant with Apgars of 1 and 7 at 1 and 5 minutes of life, respectively. There was an approximate 50% abruption noted on placental evaluation, as well as a 2 x 3-cm area ofecchymosis at the uterinefundus. The neonate's immediate postdelivery hematocrit was 17%. A cranial ultrasound was notable for a grade III germinal matrix hemorrhage with progressive hydrocephalus. Serial ultrasounds showed interval increases in the amount of clots within the lateral ventricles.

CONCLUSION

Airbag deployment can be associated with placental abruption and fetal intracranial hemorrhage.

Airbag lung: an unusual case of sarcoid-like granulomatous lung disease after a rollover motor vehicle accident

Sarcoid-like granulomatous lung disease (SLGLD) is a condition associated with the formation of noncaseating, nonnecrotizing granulomas. The final by-product of airbag deployment is alkaline silicates or glass. Silicates trapped and sequestered in the lung parenchyma are a potential mediator for immune system activation and development of sarcoid-like granulomatous lung disease.

Trigeminal Nerve Injury Following Accidental Airbag Deployment and Assessment with Quantitative Sensory Testing

High velocity motor vehicle accidents are associated with an increase in mortality rates and a significant number of facial injuries. Accidental deployment of airbags and the associated release of hot gases can result in both thermal and mechanical injuries. The more commonly reported maxillofacial injuries include temporomandibular joint fractures and dislocations, dental trauma, facial nerve paralysis, and other orofacial pain complaints. The following case report describes a patient with facial trauma from the accidental deployment of an airbag resulting in complaints consistent with a neurological injury for which quantitative sensory testing was used in confirming the diagnosis.

Minimizing the injury potential of deploying airbag interactions with car occupants

Minimizing the injury potential of the interactions between deploying airbags and car occupants is the major issue with the design of airbag systems. This concern was identified in 1964 by Carl Clark when he presented the results of human volunteer and dummy testing of the "Airstop" system that was being developed for aircraft. The following is a chronological summary of the actions taken by the car manufacturers, airbag suppliers, SAE and ISO task groups, research institutes and universities, and consumer and government groups to address this issue.

Finite element analysis of occupant head injuries: parametric effects of the side curtain airbag deployment interaction with a dummy head in a side impact crash

In this study, we investigated and assessed the dependence of dummy head injury mitigation on the side curtain airbag and occupant distance under a side impact of a Dodge Neon. Full-scale finite element vehicle simulations of a Dodge Neon with a side curtain airbag were performed to simulate the side impact. Owing to the wide range of parameters, an optimal matrix of finite element calculations was generated using the design method of experiments (DOE); the DOE method was performed to independently screen the finite element results and yield the desired parametric influences as outputs. Also, analysis of variance (ANOVA) techniques were used to analyze the finite element results data. The results clearly show that the influence of moving deformable barrier (MDB) strike velocity was the strongest influence parameter on both cases for the head injury criteria (HIC36) and the peak head acceleration, followed by the initial airbag inlet temperature. Interestingly, the initial airbag inlet temperature was only a ~30% smaller influence than the MDB velocity; also, the trigger time was a ~54% smaller influence than the MDB velocity when considering the peak head accelerations. Considering the wide range in MDB velocities used in this study, results of the study present an opportunity for design optimization using the different parameters to help mitigate occupant injury. As such, the initial airbag inlet temperature, the trigger time, and the airbag pressure should be incorporated into vehicular design process when optimizing for the head injury criteria.

Bilateral chemical eye injury resulting from airbag deployment

A case report highlighting an unusual cause of a chemical injury and an explanation of the basic initial management of chemical eye injuries: relevant to all Armed Forces medical personnel.

The association between knee airbag deployment and knee-thigh-hip fracture injury risk in motor vehicle collisions: A matched cohort study

INTRODUCTION

In the U.S. alone, an estimated 30,000 knee-thigh-hip (KTH) injuries occur annually in frontal motor vehicle collisions. These fractures typically occur through occupant contact with the vehicle's knee bolster. Research has suggested that knee airbags (KABs) can mitigate the forces sustained during this contact, resulting in decreased injury risk; however, previous research has been limited by small sample sizes or by occurring in a controlled setting. The objective of the current study is to determine the effectiveness of KABs on KTH fracture risk using nationally representative, real-world data.

METHODS

Using combined data from the Crash Injury Research and Engineering Network and the National Automotive Sampling Survey, a matched cohort study was conducted among front-seat occupants of vehicles involved in a frontal collision occurring from 2000 to 2009. Occupants exposed to a KAB deployment were matched to occupants with no KAB deployment based on age ±5 years, sex, seatbelt use, vehicle seating position (i.e., driver or front passenger), car vehicle body type, collision impact, and sampling weight. A Cox proportional hazards model was used to calculate risk ratios (RRs) and associated 95% confidence intervals (95% CI) to estimate the association between KAB deployment and lower extremity fracture risk.

RESULTS

There was no association between KAB deployment and risk of lower extremity fracture (RR 0.83, 95% CI 0.52-1.31). A notable pattern in fracture risk, though not statistically significant, was observed, with a decreased risk of hip (RR 0.72, 95% CI 0.26-1.97) and thigh fracture (RR 0.81, 95% CI 0.32-2.05), and an increased risk of tibia/fibula (RR 1.23, 95% CI 0.52-2.90) and foot fracture (RR 1.96, 95% CI 0.72-5.32).

CONCLUSIONS

The results of the current study suggest that KABs are not associated with the risk of lower extremity fractures. However, given the small sample size of the current study, it is difficult to definitively say whether the observed injury pattern is representative of the true pattern.

Investigating occupant safety through simulating the interaction between side curtain airbag deployment and an out-of-position occupant

The objective of this research is to elucidate the effect of side curtain airbag deployment on occupant injuries and safety when the occupant is either in-position or out-of-position (OOP). We used side impact vehicle collision simulations with a 1996 Dodge Neon model, which was further modified to include a side curtain airbag, a seatbelt, and a 50th percentile Hybrid III dummy. The airbag used in the study was inflated using both the uniform pressure (UP) and smooth particle hydrodynamics (SPH) methods. In-position and OOP simulations were performed to assess and establish guidelines for airbag aggressivity thresholds and occupant position versus risk of injury. Three different OOP scenarios (OOP1, OOP2, OOP3) were initially setup following the work of Lund (2003), then modified such that the dummy's head was closer to the airbag, increasing the chance of injury caused by the airbag. The resultant head acceleration as a function of time for in-position and OOP simulations shows that both UP and SPH methods produce similar peak accelerations in cases where the airbag is fully inflated prior to impact. In all cases, the head peak accelerations and the head injury criteria for simulations with an airbag were significantly lower when compared with the no airbag case, which would typically indicate that the use of an airbag results in improved occupant protection during side impact. However, in the case of OOP2 and OOP3, the neck flexion forces actually increase significantly when compared with the no airbag case. This finding indicates that the HIC and neck flexion forces criterion are in conflict and that there may be a tradeoff in terms of occupant injury/safety with a side curtain airbag that is strongly correlated to the occupant position. Consequently, this study shows that safety devices result in a significant effect on occupant injury/safety when the occupant is in OOP conditions. Moreover, in some cases, simulation results show that the side curtain airbag may not make the occupant safer. This study requires further investigation of the vehicle-specific airbag and its interaction with an occupant in various OOP conditions.

A case of severe airbag related ocular alkali injury

While airbags have saved many lives and are clearly beneficial overall, sodium hydroxide (NaOH) powder produced by the inflation reaction can cause significant alkali ocular injury if not irrigated promptly. Here we report a case of severe airbag related ocular alkali injury as a way to bring attention to the need for prompt ocular irrigation following motor vehicle accidents (MVA) with airbag deployment. A 47-year-old man was involved in a MVA with airbag deployment in a rural setting. Attention was paid to several other life-threatening traumatic injuries, however, ocular irrigation was not performed until some 6-7 hours after the MVA. Over the course of 6 months, airbag related alkali injury caused severe limbal ischemia, conjunctivalization of the cornea, corneal epithelial defects, cicatricial scarring, haze, and corneal/limbal vascularization despite amniotic membrane graft. Awareness of the importance of ocular irrigation following airbag deployment must be raised both in the ophthalmology and emergency medicine communities.

Door velocity and occupant distance affect lateral thoracic injury mitigation with side airbag

The relationship between thoracic injury risk and parameters of door velocity and occupant distance was delineated in blunt lateral impact with side airbag deployment. A sled impact model was exercised with the validated MADYMO fiftieth percentile facet occupant model and a generalized finite element torso side airbag. Impact velocity was incremented from 4.0 to 9.0m/s; occupant-airbag distance (at time of airbag activation) was incremented from 2.0 to 24.0 cm; simulations without airbag were also examined. Using compression, deflection rate, and the Viscous Criterion, airbag performance was characterized with respect to occupant injury risk at three points of interest: occupant distance of most protection, distance of greatest injury risk, and the newly defined critical distance. The occupant distance which demonstrated the most airbag protection, i.e., lowest injury risk, increased with increasing impact velocity. Greatest injury risk resulted when the occupant was nearest the airbag regardless of impact velocity. The critical distance was defined as the farthest distance at which airbag deployment exacerbated injury risk. This critical distance only varied considering chest compression, between 3 and 10 cm from the airbag, but did not vary when the Viscous Criterion was evaluated. At impact velocities less than or equal to 6m/s, the most protective occupant location was within 2 cm of the critical distance at which the airbag became harmful. Therefore, injury mitigation with torso airbag may be more difficult to achieve at lower ΔV.

Determination of pre-impact occupant postures and analysis of consequences on injury outcome--part II: biomechanical study

This paper considers pre-impact vehicle maneuvers and analyzes the resulting driver motion from their comfort seating position. Part I of this work consisted of analyzing the driver behavior during a simulated crash in a car driving simulator. The configuration of the virtual accident led to an unavoidable frontal crash with a truck. The typical response to this type of emergency event was to brace rearward into the seat and to straighten the arms against the steering wheel, or, to swerve to attempt to avoid the impacting vehicle. In a turn crossover maneuvers, the forearm is directly positioned on the airbag module at time of crash. This position represents a potential injurious situation and is investigated in this Part II. Static airbag-deployment tests were realized in collaboration with Zodiac using conventional airbag (sewn cushion, pyrotechnical system and open event) and a Hybrid III 50th Male Dummy seated with the left arm positioned in the path of the deploying airbag. These experiments were numerically reproduced with Madymo and the ellipsoid Hybrid III dummy model. The dummy arm interaction with airbag was correlated with experiments. Then, a numerical simulation of a frontal collision at 56 km/h was realized. The results of the computational runs put forward injurious situations when the driver's arm was in front of the steering wheel. Indeed, in this case, the arm could hit the head under airbag deployment and induced serious neck bending and violent head launching. To mitigate head and neck trauma in this out-of-position situation, an airbag prototype (bonded cushion, two pure helium cold gas generators allowing mono- or multi-stage inflating, patented silicone membrane) was proposed by Zodiac. The results of static airbag-deployment tests with conventional and prototype airbags showed a significant reduction of the maximum linear head acceleration and neck bending with airbag prototype when a dual stage inflating was ignited, due to a reduced 'flinging' of the arm.

Are airbags a dangerous safety measure? A meta-analysis of the effects of frontal airbags on driver fatalities

A meta-analysis has been conducted of the effectiveness of frontal airbags in reducing driver fatalities, and some potential moderator variables for airbag effectiveness have been investigated. The results confirm the assumption that airbags reduce accident fatalities among belted drivers, but the results are too heterogeneous for drawing conclusions about the size of the overall effect. No support has been found for the hypothesis that airbags increase overall fatality risk, as has been found in the study by Meyer and Finney (Meyer, M., Finney, T., 2005. Who wants Airbags? Chance, 18 (19) 3-16). The results do not seem to be affected by publication bias, and no indications of confounding effects of vehicle characteristics or impact velocity have been found. In frontal collisions belted driver fatalities were found to be reduced by about 22% when all types of airbags are regarded together. The revision of the test criteria for airbags in the USA in 1997 has improved airbag effectiveness. For unbelted drivers airbags are neither effective nor counterproductive, but may increase fatality risk in single vehicle accidents. The results show that there is a lack of knowledge about the effects of airbags in accidents that are not frontal collisions.

Sensitivity of the WorldSID 50th and ES-2re Thoraces to Loading Configuration

An ideal injury criterion should be predictive of the risk of injury across the range of loading conditions where it may be applied. The injury risk curve associated with this criterion should be applicable to all loading conditions. With respect to side impact, the injury risk curve should apply to pure lateral or oblique loading by rigid and padded walls, as well as airbags. Trosseille et al. (2009) reported that the number of fractured ribs was higher in pure lateral impact than in forward oblique interaction with an airbag. A good dummy criterion should be able to account for this difference. To evaluate various injury criteria with the WorldSID 50 th and ES-2re dummies, the dummies were exposed to the same airbag loadings as the PMHS. The criteria measured in the dummy tests were paired with the rib fractures from the PMHS tests. Regarding the effect of configuration, results of sled tests with the 50 th percentile WorldSID (Petitjean, 2009) and ES-2re (Kuppa, 2003) have been paired with injuries found in the PMHS tested in the same conditions. The relationships obtained were compared with the relationships established in the same way for the subjects loaded in the airbag tests. Comparing the lateral and oblique lateral loading conditions, both the WorldSID and the ES-2re exhibited differences in peak lateral deflection of their ribs that were consistent with the different number of rib fractures for PMHS subjected to these loading conditions. For each dummy, the risk of rib fractures could be assessed from one injury risk curve, regardless of the loading angle. Furthermore, the same injury risk curve can be used to assess the risk of rib fractures from sled tests and airbag loading. However, because the WorldSID deflection measurements differed in the rigid and padded sled tests, it is recommended that the dummy's sensitivity to padding be further assessed prior to adopting injury risk curves for WorldSID. Rib deflections of the ES- 2re were not sensitive to padding. Finally, VC should not be considered as a valid criterion to assess the risk of rib fractures.

Biomechanical and injury response to posterolateral loading from torso side airbags

This study characterized thoracoabdominal response to posterolateral loading from a seat-mounted side airbag. Seven unembalmed post-mortem human subjects were exposed to ten airbag deployments. Subjects were positioned such that the deploying airbag first contacted the posterolateral thorax between T6 and L1 while stationary (n = 3 x 2 aspects) or while subjected to left lateral sled impact at ΔV = 6.7 m/s (n = 4). Chestband contours were analyzed to quantify deformation direction in the thoracic x-y plane (zero degrees indicating anterior and 180° indicating posterior), magnitude, rate, and viscous response. Skeletal injuries were consistent with posterolateral contact; visceral injuries consisted of renal (n = 1) or splenic (n = 3) lacerations. Deformation direction was transient during sled impact, progressing from 122 ± 5° at deformation onset to 90° following maximum deflection. Angles from stationary subjects progressed from 141 ± 9° to 120°. Peak normalized deflections, peak rates, and VCmax ranges were 0.075 - 0.171, 3.7 - 12.7 m/s, and 0.3 - 0.6 m/s with stationary airbag, respectively; ranges were 0.167 - 0.297, 7.4 - 18.3 m/s, and 0.7 - 3.0 m/s with airbag sled impact, respectively. Peak deflections were measured at angles between 99° - 135° and 98° - 125° for stationary and dynamic conditions, respectively. Because of deflection angle transience and localized injury response, both posterolateral and lateral injury metrics may be required for this boundary condition. Contrasted with flat rigid or anterolateral loading, biomechanical response to side airbag interaction may be augmented by peak normalized deflection or VCmax at 130°.

Thoracic injury metrics with side air bag: stationary and dynamic occupants

OBJECTIVE

Injury risk from side air bag deployment has been assessed using stationary out-of-position occupant test protocols. However, stationary conditions may not always represent real-world environments. Therefore, the objective of the present study was to evaluate the effects of torso side air bag deployment on close-proximity occupants, comparing a stationary test protocol with dynamic sled conditions.

METHODS

Chest compression and viscous metrics were quantified from sled tests utilizing postmortem human specimens (PMHS) and computational simulations with 3 boundary conditions: rigid wall, ideal air bag interaction, and close-proximity air bag deployment. PMHS metrics were quantified from chestband contour reconstructions. The parametric effect of DeltaV on close-proximity occupants was examined with the computational model.

RESULTS

PMHS injuries suggested that close-proximity occupants may sustain visceral trauma, which was not observed in occupants subjected to rigid wall or ideal air bag boundary conditions. Peak injury metrics were also elevated with close-proximity occupants relative to other boundary conditions. The computational model indicated decreasing influence of air bag on compression metrics with increasing DeltaV. Air bag influence on viscous metric was greatest with close-proximity occupants at DeltaV = 7.0 m/s, at which the response magnitude was greater than linear summation of metrics resulting from rigid impact and stationary close-proximity interaction.

CONCLUSIONS

These results suggest that stationary close-proximity occupants may not represent the only scenario of side air bag deployment harmful to the thoraco-abdominal region. The sensitivity of the viscous metric and implications for visceral trauma are also discussed.

Air bag-mediated fatal craniocervical trauma: a case report

This case report describes a four-year-old girl (102 cm, 17 kg) who sustained fatal craniocerebral injuries as a result of an inflating automobile air bag. The car struck the lid of the sewer system, which was 15 cm above the ground level, at a low speed, and both the driver and passenger air bags inflated. Despite the fact that air bag usage has lessened both the possibility and severity of occupant injuries in frontal collisions, case reports of serious injuries and even deaths especially in children due to air bag deployment, particularly during low speed impacts, highlight the need for changes in both system design and possibly the threshold speed of air bag deployment.

Sternal fracture due to airbag injury: case report

Although airbags reduce the overall risk of injury and death from motor vehicle accidents, the airbag may cause injuries during deployment. We present a case of apparently isolated sternal fracture caused by airbag deployment during a motor vehicle crash and we discuss the ultrasonographic diagnosis. We also examine the mechanism of injury caused by the airbag.

The effect of motor vehicle airbag deployment on tooth surfaces

Motor vehicle airbag technology is directed at the reduction of injury to drivers and passengers however a number of researchers have reported cases of injuries caused by airbags. Injuries to tooth surfaces, particularly tooth wear following the deployment of motor vehicle airbags, have never been studied. A review of the literature and clinical experience does not suggest tooth enamel abrasion to be a likely outcome following airbag deployment. This in vitro pilot study was conducted to assess the effect on tooth surfaces following the deployment of motor vehicle airbags, and in particular to attempt to reproduce the injuries claimed in a case report published in the Journal of Forensic Odonto- Stomatology in December 2007. A sample of extracted upper anterior teeth (n = 20) were analyzed using unaided visual observation, photographic and microscopic observation pre- and post- airbag deployment. Teeth were mounted on a fabricated head form (similar to those used in crash test dummies) using dental putty. The tests were performed using a modified airbag test rig with airbags deployed in 5 different positions relative to the head, with respect to distance and angulations. The result of the tests showed no changes to the teeth with unaided observation, macro photography or under the microscope. Tooth wear patterns described in the case report were not observed. Although accurate reproduction of an in vivo situation is not possible, this study has given some insight into the effects of motor vehicle airbag deployment, and suggests that significant tooth wear is an unlikely outcome from airbag deployment.

Splenic trauma as an adverse effect of torso-protecting side airbags: biomechanical and case evidence

Injury mechanisms from frontal airbags, first identified in anecdotal reports, are now well documented for pediatric, small female, and out-of-position occupants. In contrast, torso side airbags have not yet been consistently associated with specific injury risks in field assessments. To determine possible torso side airbag-related injuries, the present study identified crashes involving side airbags from reports within the CIREN, NASS, and SCI databases. Injury patterns were compared to patterns from lateral crashes in absence of side airbag. Splenic trauma (AIS 3+) was found present in five cases of torso side airbag deployment at lower impact severity (as measured by velocity change and compartment intrusion) than cases of splenic trauma without side airbag. Five additional cases were found to contain similar injury patterns but occurred with greater crash severity. To supplement case analyses, full scale sled tests were conducted with a THOR-NT dummy and cadaveric specimen. Four THOR tests with door- and seat-mounted torso side airbags confirmed that out-of-position (early inflation stage) airbag contact elevated thoracic injury metrics compared to optimal (fully inflated) contact. Out-of-position seat-mounted airbag deployment also produced AIS 3 splenic trauma in the cadaveric specimen. Due to potentially sudden or delayed onset of intraperitoneal hemorrhage and hypovolemic shock following splenic trauma, further biomechanical investigation of this anecdotal evidence is essential to identify injury mechanisms, prevention techniques, and methods for early diagnosis.

A rare case of blunt thoracoabdominal trauma with small bowel perforation from air bags

Vehicle collisions represent more than 75% of mechanism of blunt abdominal trauma. In spite of the incomparable improvement of car safety devices, recent studies pointed out that the air bags might cause injuries, specially when it is not associated with seatbelt. In fact, some studies pointed out that crash victims using air bags alone have increased injury severity, hospitalisations, thoracoabdominal procedure, and rehabilitation. Some of the most frequently injured organs reported from air bag deployment are the liver (38%), the spleen (23%) and digestive system (17%). Injury of the hollow viscera are far less common. In particular, blunt abdominal trauma resulting in small bowel perforation is an infrequent lesion. These injuries are difficult to diagnose because specific signs are poor and a delay in treatment increases mortality and morbidity of the patients. We describe a case of thoracoabdominal trauma that occurred during a head-on collision after an air bag deployment without seatbelt use.

[Damages caused by explosion of airbag]

The airbag constitutes, united to the contemporary use of the safety belts, an important and irreplaceable garrison for the safety of the motorists involved in left traffic polices. The literature has underlined and underlines the pathologies, fortunately in limited number if compared to the elevated number of the road accidents, secondary to the explosion of the sacks of the garrison, that you/they sometimes strike many districts with damages to the person permanent and serious. The elaborate one sets the accent on all these problems, observing the necessity of further studies from the auto houses, of normative community, of analytical observation of the phenomenon and the starting of epidemiological studies.

[An unusual case of fatal airbag injury]

We report an unusual case of fatal airbag injury. A woman in her forties was driving a light car when it was involved in an accident. When the car was found, the left front wheel had dropped into the gutter, the front bumper was dented and the airbag had deployed. Forensic autopsy revealed that the right subclavian artery and the left vertebral artery were ruptured and 1,570 ml and 360 ml of blood with clots were observed in the left and the right thoracic cavity, respectively. It was considered that the unusual collision produced by deployment of the airbag had caused these ruptures and massive hemorrhaging. Although an airbag is an effective tool for ensuring the safety of a driver and the passengers, it may injure and occasionally kill the occupants if they do not remain in the appropriate and restrained seating position.

Differences in the effectiveness of frontal air bags by body size among adults involved in motor vehicle crashes

OBJECTIVE

There is concern that small stature occupants (particularly women) involved in motor vehicle crashes (MVCs) may be at risk of injury or death from frontal air bags, though evidence to substantiate this concern is lacking. We sought to assess how occupant body size (measured through height and weight) affects air bag effectiveness in mitigating the risk of serious injury, after adjusting for important crash factors.

METHODS

This was a retrospective cohort study using a national population-based cohort of adult front-seat occupants involved in MVCs as included in the National Automotive Sampling System Crashworthiness Data System database (NASS CDS) from 1995 to 2006. Drivers and front-seat passengers 15 years and older involved in MVCs involving passenger vehicles and light trucks were included in the analysis. The primary outcome was serious injury, defined as an Abbreviated Injury Scale (AIS) score >or=3 in any body region. Multivariable logistic regression models were used to test interaction terms (effect modification) between air bags, body size, and injury. The predicted probability of injury across body sizes was plotted to further illustrate potential differences.

RESULTS

Sixty-nine thousand three hundred eighty-seven adult front-seat occupants during the 12-year period were included in the analysis, of which 9333 (2.3%) were seriously injured. There was no evidence that height or weight modified air bag effectiveness among all crashes (p > .40). In primary frontal collisions, there was some evidence for effect modification by weight (p = .04) but not by height (p = .59). When assessed using air bag deployment, height was a strong effect modifier (p = .0078), but not weight (p = .43). Predicted probability figures confirmed that occupant height modifies the effect of air bag deployment, but there was no similar visual evidence for body weight.

CONCLUSIONS

In this sample, we found no consistent evidence that body size modifies the overall effectiveness of frontal air bags. However, among crashes involving air bag deployment, the effect of deployment on injury differs by occupant height, with a relative increase in the odds of serious injury among smaller occupants. In such crashes, the probability of injury with (versus without) deployment began to increase with occupant heights less than 155 cm (5'), reaching a level of statistical difference below 138 cm (4' 6'').

Airbag-induced corneal flap

PURPOSE

To describe a case of airbag-induced corneal flap in a previously normal cornea.

METHODS

Case report.

RESULTS

A 27-year-old woman presented with complete loss of vision in her left eye following a road traffic accident which involved airbag deployment. There was no previous ocular history. Examination revealed a large corneal flap of 6mm in diameter, extending to the depth of anterior stroma. This was accompanied by a traumatic optic neuropathy. One month follow-up revealed complete reattachment of the corneal flap.

CONCLUSIONS

This is the first reported case of a corneal flap induced by airbag deployment in a cornea with previously normal architecture.

Engineering with uncertainty: monitoring air bag performance

Modern engineering is complicated by an enormous number of uncertainties. Engineers know a great deal about the material world and how it works. But due to the inherent limits of testing and the complexities of the world outside the lab, engineers will never be able to fully predict how their creations will behave. One way the uncertainties of engineering can be dealt with is by actively monitoring technologies once they have left the development and production stage. This article uses an episode in the history of automobile air bags as an example of engineers who had the foresight and initiative to carefully track the technology on the road to discover problems as early as possible. Not only can monitoring help engineers identify problems that surface in the field, it can also assist them in their efforts to mobilize resources to resolve problem.

Using head-on collisions to compare risk of driver death by frontal air bag generation: a matched-pair cohort study

US air bag regulations were changed in 1997 to allow tests of unbelted male dummies in vehicles mounted and accelerated on sleds, resulting in longer crash pulses than rigid-barrier crashes. This change facilitated depowering of frontal air bags and was intended to reduce air bag-induced deaths. Controversy ensued as to whether sled-certified air bags could increase adult fatality risk. A matched-pair cohort study of two-vehicle, head-on, fatal collisions between drivers involving first-generation versus sled-certified air bags during 1998-2005 was conducted by using Fatality Analysis Reporting System data. Sled certification was ascertained from public information and a survey of automakers. Conditional Poisson regression for matched-pair cohorts was used to estimate risk ratios adjusted for age, seat belt status, vehicle type, passenger car size, and model year for driver deaths in vehicles with sled-certified air bags versus first-generation air bags. For all passenger-vehicle pairs, the adjusted risk ratio was 0.87 (95% confidence interval: 0.77, 0.98). In head-on collisions involving only passenger cars, the adjusted risk ratio was 1.04 (95% confidence interval: 0.85, 1.29). Increased fatality risk for drivers with sled-certified air bags was not observed. A borderline significant interaction between vehicle type and air bag generation suggested that sled-certified air bags may have reduced the risk of dying in head-on collisions among drivers of pickup trucks.