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Real-life fatal outcome in car-to-car near-side impacts--implications for improved protection considering age and crash severity.
Autoliv Res, Vargarda, Sweden.
2009 (English)In: Traffic Injury Prevention, ISSN 1538-9588, E-ISSN 1538-957X, Vol. 10, no 2Article in journal (Refereed) Published
Abstract [en]

OBJECTIVE: Recent studies have shown that current side airbags, protecting head and chest, are saving lives in near-side impacts (Kahane 2007; McCartt and Kyrychenko 2007). The aim of this study was to analyze NASS/CDS real-life data on fatal trauma in near-side car-to-car crashes, stratified by age into non-senior and senior occupants. Furthermore, a hypothetical model explaining side airbag effectiveness as a function of lateral delta-v was presented. The model together with the field data was then used to demonstrate further enhancement of side airbag restraint performance.

METHOD: Weighted NASS/CDS data from 1994 to 2006 for front seat occupants in near-side car-to-car impacts was used to calculate the exposure, incidence, and risk of fatal trauma with respect to lateral delta-v. The dataset was also divided into non-senior (10-59 years) and senior (age > or = 60 years) occupants. The hypothetical model was created to adjust the NASS/CDS data to represent a car fleet fully equipped with current side airbag protection. The model was then used to evaluate the increase in effectiveness of improved side airbag protection achieved by increasing the lateral delta-v in the range where the airbag have most mitigating effect, increasing the airbag protection level within the delta-v range currently tested, and a combination of the two approaches.

RESULTS: From the NASS/CDS data, the median delta-v for fatal injury was 37 km/h for the total sample. When stratified with respect to age, the median delta-v for fatal injury was 41 km/h for non-seniors and 28 km/h for senior occupants. The exposures for both age groups were similar. However, the fatal incidence showed a difference in delta-v range between non-senior and senior occupants. Applying the airbag model increased the median delta-v to 40 km/h for the total sample and 47 and 30 km/h for non-seniors and seniors, respectively.

CONCLUSIONS: Current side airbag systems offer very good protection for non-senior occupants up to delta-v 40 km/h. Though still high, the protection for senior occupants is lower. To enhance side airbag protection, the side airbag performance should be maximized where the fatal incidence is high. Therefore, to further reduce non-senior fatalities, the test speed should be increased. To further reduce senior fatalities, the protection level within severities currently tested should be increased. A combination of the two approaches would result in about a 40 percent increase of the side airbag effectiveness.

Place, publisher, year, edition, pages
2009. Vol. 10, no 2
Keyword [en]
side impact, WorldSID, thorax, injuries, side airbag
Keyword [sv]
sidokollision, WorldSID, thorax, injuries, side airbag
National Category
Environmental Health and Occupational Health
Identifiers
URN: urn:nbn:se:umu:diva-127276DOI: 10.1080/15389580802594127ISI: 000264847400013PubMedID: 19333834OAI: oai:DiVA.org:umu-127276DiVA: diva2:1044583
Available from: 2016-11-04 Created: 2016-11-04 Last updated: 2016-11-04Bibliographically approved
In thesis
1. Characteristics of nearside car crashes: an integrated approach to side impact safety
Open this publication in new window or tab >>Characteristics of nearside car crashes: an integrated approach to side impact safety
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Introduction: Approximately 1.25 million people globally are killed in traffic accidents yearly. To achieve the UN Global Goal of a 50% reduction of fatal and serious injuries in 2020 a safer infrastructure, as well as new safety technologies, will be needed. Side crashes represent 20% of all serious and 25 % of fatal injuries. The overall aim of this thesis is to provide guidelines for improved side impact protection. First, by characterizing nearside crashes and injury outcome, including injuries from the farside occupant, for non-senior and senior front seat occupants. Second, to determine whether the WorldSID dummy provides opportunities for improved in-crash occupant protection. And third, by relating in-crash occupant protection to pre-crash countermeasures, to explore a holistic approach for side crashes using the integrated safety chain from safe driving to crash.

Methods: NASS/CDS data for both older and modern vehicles was used to provide exposure, incidence, and risk for fatal injury as well as detailed injury distribution and crash characteristics. The WorldSID dummy was compared to Post Mortem Human Subjects (PMHS) in impactor tests at high and low severities to demonstrate the possibilities of this tool. Crash tests were performed to evaluate WorldSID crash test dummy assessments of injuries found in the NASS/CDS data. The integrated safety chain was used to demonstrate how to evaluate occupant protection in side crashes from a larger perspective, involving infrastructure and Automated Emergency Braking.

Result: Most side crashes occur at intersections. The head, thorax, and pelvis are the most frequently injured body regions, and seniors have a higher risk for rib fractures compared to non-seniors. The WorldSID dummy response was similar to the PMHS response at the higher impact speed, but not at the lower. In conjunction with improved airbags infrastructural change, and the use of Automated Emergency Braking, can effectively reduce the number of fatalities and injured occupants in side impacts.

Conclusion: Future focus for side impact protection should be on intersection crashes, improved occupant protection for senior occupants, and protection for and from the farside occupant, reducing injury risk to the head, thorax, and pelvis. The WorldSID dummy has the ability to reproduce humanlike responses in lateral and oblique impacts. However, at a low crash severity, chest deflection could be underestimated, which must be taken into consideration when evaluating, for example, pre-crash inflated side airbags. Analyzing nearside crashes using the integrated safety chain shows that speed management by means of roundabouts is an efficient countermeasure reducing the number of injurious crashes, as well as reducing variations in crash severity. In combination with an Automated Emergency Braking a large part of side crashes could be avoided or crash severity mitigated. Rather than developing structures and airbags for high-speed crashes, it is important to consider alternative countermeasures. Hence the need for an integrated approach to side impacts.

Place, publisher, year, edition, pages
Umeå: Umeå universitet, 2016. 58 p.
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 1855
Keyword
side impact, WorldSID, thorax, injuries, side airbag, sidokollision, WorldSID, thorax, injuries, side airbag
National Category
Surgery
Research subject
biomechanics; Epidemiology
Identifiers
urn:nbn:se:umu:diva-126985 (URN)978-91-7601-587-2 (ISBN)
Public defence
2016-11-11, NUS 1D - Tandläkarhögskolan, Hörsal D, Umeå, 13:00 (Swedish)
Opponent
Supervisors
Available from: 2016-10-25 Created: 2016-10-25 Last updated: 2016-11-04Bibliographically approved

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