Improving the Chest Protection of Elderly Occupants in Frontal Crashes Using SMART Load Limiters

Ekambaram, Karthikeyan; Frampton, Richard; Bartlett, L.M.

doi:10.1080/15389588.2015.1064528

Cited by 6 publications

(11 citation statements)

References 9 publications

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“…As people age, both bone morphology and the mineral composition of their bones change, with older bones being stiffer but more brittle [49]. These changes mean that older individuals have lower tolerance to deflect forces from the seat belt that lead to torso injuries [50] Innovations in seat belt design [52,53] and greater penetration of pretensioners and load limiters [44,[54][55][56], may also improve torso and other injury outcomes in older adults.…”

Section: Discussionmentioning

confidence: 99%

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Age-based variability in the association between restraint use and injury type and severity

Benedetti¹,

Humphries²,

Codden

et al. 2022

Preprint

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Purpose: Previous studies have shown elderly individuals receive less relatively less protection from seat belts against fatal injuries, however it is less clear how seat belt protection against severe and torso injury changes with age. We estimated age-based variability in seat belt protection against fatal injuries, injuries with maximum abbreviated injury scale greater than 2 (MAIS3+), and torso injuries. Methods: We leveraged the Crash Outcome Data Evaluation System (CODES) to analyze binary indicators of fatal, MAIS3+, and torso injuries. Using a matched cohort design and conditional Poisson regression, we estimated age-based relative risks (RR) of the outcomes associated with seat belt use. Results: Seat belts were highly protective against fatal injuries for all ages. For ages 16-30, seat belt use was associated with 66% lower risk of MAIS3+ injury (RR 0.34, 95% CI 0.30, 0.38), whereas for ages 75 and older, seat belt use was associated with 38% lower risk of MAIS3+ injury (RR 0.62; 95% CI 0.45, 0.86). The association between restraint use and torso injury also appeared to attenuate with age. Conclusions: Seat belt protection against MAIS3+ and torso injury attenuated with age. We encourage that injury prevention continues to be tailored to vulnerable populations like the elderly.

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Section: Discussionmentioning

confidence: 99%

“…Because repositioning can lead to suboptimal belt fit, Brown and colleagues underscored the importance of elderly adults being aware of proper belt fit. Innovations in seat belt design [52, 53] and greater penetration of pretensioners and load limiters [44, 54-56], may also improve torso and other injury outcomes in older adults.…”

Section: Discussionmentioning

confidence: 99%

Age-based variability in the association between restraint use and injury type and severity

Benedetti¹,

Humphries²,

Codden

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…Such a system could vary load limiting, pretensioning and airbag deployment according to crash type, occupant type, and seating position, for optimal occupant protection. Several studies have reported that intelligently varying the restraint deployment characteristics by accounting for differences in age related injury tolerance may better manage the restraint forces acting on the chest in frontal crashes (Ekambaram et al 2015;Hynd et al 2011;Hardy et al 2005;Bosch et al 2005). Ekambaram et al (2015) showed some promising results when just one component of the restraint system was varied.…”

Section: Discussionmentioning

confidence: 99%

“…Several studies have reported that intelligently varying the restraint deployment characteristics by accounting for differences in age related injury tolerance may better manage the restraint forces acting on the chest in frontal crashes (Ekambaram et al 2015;Hynd et al 2011;Hardy et al 2005;Bosch et al 2005). Ekambaram et al (2015) showed some promising results when just one component of the restraint system was varied. They estimated the real world injury reduction benefit of adaptive load limiters by applying numerical crash simulations results to a real world crash injury database.…”

Section: Discussionmentioning

confidence: 99%

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

Ekambaram

Frampton

Lenard

2019

Traffic Injury Prevention

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Objective: Improving crash protection for older car occupants is a matter of urgency since the number of older car users is forecast to grow dramatically over the next two decades. The thorax is particularly vulnerable in older occupants, and this study aimed to provide real-world in-depth analysis of factors contributing to chest injuries in frontal impacts involving European cars. 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 air bags, pretensioners and load limiters were present. Results: The chest was the most often injured body region at 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 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.

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“…Addressing the safety of occupants in high speed impacts is necessary, however it is also important to test crashworthiness in lower speed impacts which occur more frequently. In low speed impacts, traditional restraints may be too rigid and may not fully utilise the available ride down space (Ekambaram et al 2015, Hynd et al 2011. Crash severity is also determined by the amount of frontal overlap of the vehicle.…”

Section: Introductionmentioning

confidence: 99%

Adapting load limiter deployment for frontal crash diversity

Ekambaram

Frampton

Jackson

2019

Traffic Injury Prevention

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Objective: Current European restraint systems may not realise their full protection potential in real world frontal crashes because they are highly optimised 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, a 3-point belt with retractor, buckle pretensioner and load limiting at the shoulder. Load limiting threshold was varied in five 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 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 optimised load limiting; taking into account occupant seating position, impact scenario, occupant size and occupant age, and assuming 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 50 th and 95 th percentile dummy in both front seating positions. In high severity impacts, the low limit was not recommended since 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 50 th 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 5 th percentile drivers. Utilising the best load limit threshold in real world crashes, could reduce the number of occupants with AIS 2+ chest injury from belt loading from 377 to 251 (a 33% reduction). Correspondingly reducing the number of occupants with AIS 2+ chest injury (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 injury associated with restraining loads and an overall reduction in AIS 2+ chest injury rate in frontal crashes from 6.4 to 4.8%

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Improving the Chest Protection of Elderly Occupants in Frontal Crashes Using SMART Load Limiters

Cited by 6 publications

References 9 publications

Age-based variability in the association between restraint use and injury type and severity

Age-based variability in the association between restraint use and injury type and severity

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

Adapting load limiter deployment for frontal crash diversity

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