NHTSA oblique crash test results:​ vehicle performance and occupant injury risk assessment in vehicles with small overlap countermeasures

Saunders, James<sup>1</sup>; Parent, Dan<sup>1</sup>; Ames, Eva<sup>1</sup>

Affiliations

¹National Highway Traffic Safety Administration (NHTSA), USA

Abstract

Objective: The National Highway Traffic Safety Administration (NHTSA) has been developing a research test protocol representative of real-world injury potential in frontal offset oblique impacts. This paper will address the vehicle and occupant responses from the latest research test series.

Methods: In this series, the Oblique Moving Deformable Barrier (OMDB) impacted stationery vehicles in both left and right side impacts. Vehicles were selected only if their performance in the Insurance Institute for Highway Safety (IIHS) Small Overlap (SOI) test condition earned a “Good” or “Acceptable” rating and had side curtain air bags meeting the requirements of Federal Motor Vehicle Safety Standard (FMVSS) No. 226, Ejection Mitigation. The vehicle responses studied included total velocity change (delta-V, DV), interior intrusion and steering wheel displacement, and the occupant responses studied included Brain Injury Criterion (BrIC), Multipoint Thoracic Injury Criterion, and Ankle Moment.

Results: Generally, delta-V (DV) in the X-direction decreased as the weight of the vehicle increased in both left and right side impacts, and the interior intrusion increased toward the center of the vehicle for both impact directions as well. A significant correlation between lap belt loads and vehicle mass was not found, but there was a general decreasing trend of peak lap belt loads with increase in vehicle mass. Occupant kinematics were generally mirror images for left and right side impacts, with the occupant’s head moving forward and toward the direction of impact. The near-side occupants’ heads moved toward the gap between the frontal and side curtain air bags, while the far-side occupants’ heads rotated off of the frontal air bag and impacted the center instrument panel.

Discussion: The Honda Accord showed the greatest difference between left and right side impact vehicle response. The highest probability of injury for both near- and far-side occupants was predicted to occur in the head, chest, and ankle, agreeing with the findings from previous real-world oblique crash injury analysis. The test mode predicted a high risk of ankle injury, primarily due to ankle inversion and/or eversion. Left and right side impacts resulted in similar magnitudes of vehicle response, but occupant responses differed enough that it may be important to consider both left and right side oblique impacts in restraint system design.

Conclusions: The interior intrusions on the toe pan increased towards vehicle center, and toe pan point TP3 consistently showed the highest intrusion measurement. Vehicle deformation from left and right side impacts can differ due to the stack up of nonsymmetrical vehicle component layouts. The latest NHTSA Oblique test series involving vehicles with a “Good” or “Acceptable” rating in the IIHS SOI test condition and with side curtain air bags meeting the requirements of FMVSS No. 226 suggest that additional countermeasures may reduce injury risk in this test mode.

Links

URL: http://www-esv.nhtsa.dot.gov/Proceedings/24/files/24ESV-000108.PDF

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2017	Katagiri M, Zhao J. Axial dependence of rotationally-induced brain injuries in frontal and oblique crashes. In: Proceedings of the 25th International Technical Conference on the Enhanced Safety of Vehicles (ESV). June 5-8, 2017; Detroit, MI.
2017	Pipkorn B, Wass J. Pre-crash triggered pretensioning of the seat belt for improved safety. In: Proceedings of the 25th International Technical Conference on the Enhanced Safety of Vehicles (ESV). June 5-8, 2017; Detroit, MI.
2017	Gepner B, Bollapragada V, Montesinos Acosta S, Park G, Forman J. Comparison of THOR LX xversion and dorsiflexion response in component tests, sled tests and full vehicle crash tests. In: Proceedings of the 25th International Technical Conference on the Enhanced Safety of Vehicles (ESV). June 5-8, 2017; Detroit, MI.
2019	Forman J, Acosta SM, Bollapragada V, Gepner B, Wernicke P. Comparing restraint system sensitivity between the THOR and the Hybrid III, and potential implications in restraint optimization. In: Proceedings of the 26th International Technical Conference on the Enhanced Safety of Vehicles (ESV). June 10-13, 2019; Eindhoven, Netherlands.
2016	Pipkorn B, Lopez‐Valdes FJ, Juste‐Lorente O, Maza M, Sunnevång C. Study of the kinematics of the THOR dummy in nearside oblique impacts. In: Proceedings of the 2016 International IRCOBI Conference on the Biomechanics of Injury. September 14-16, 2016; Malaga, Spain.637-648.
2016	Rudd RW. Investigating a relationship between standardised crash classification and occupant kinematics in real‐world frontal crashes. In: Proceedings of the 2016 International IRCOBI Conference on the Biomechanics of Injury. September 14-16, 2016; Malaga, Spain.61-79.
2017	Osvalder A, Bohman K, Hansson I. Adult’s and children’s attitudes towards extra seat belts in the rear seats. In: Proceedings of the 2017 International IRCOBI Conference on the Biomechanics of Injury. September 13-15, 2017; Antwerp, Belgium.341-352.
2017	Edwards MA, Nash CE. Inflatable shoulder belts and inboard upper anchor shoulder‐belt geometry in far‐side oblique impacts. In: Proceedings of the 2017 International IRCOBI Conference on the Biomechanics of Injury. September 13-15, 2017; Antwerp, Belgium.373-389.
2017	Östling M, Saito H, Vishwanatha A, Ding C, Pipkorn B, Sunnevång C. Potential benefit of a 3+2 criss cross seat belt system in frontal and oblique crashes. In: Proceedings of the 2017 International IRCOBI Conference on the Biomechanics of Injury. September 13-15, 2017; Antwerp, Belgium.390-409.
2018	Tylko S, Tang K, Giguère F, Bussières A. Effects of shoulder‐belt slip on the kinetics and kinematics of the THOR. In: Proceedings of the 2018 International IRCOBI Conference on the Biomechanics of Injury. September 12-14, 2018; Athens, Greece.593-607.
2023	Firey LML, Rudd RW, Lockerby J, Craig MJ. Identification of influential factors among fatalities of restrained first-row occupants in recent frontal crashes. In: Proceedings of the 2023 International IRCOBI Conference on the Biomechanics of Injury. September 13-165, 2023; Cambridge, United Kingdom.17-43.
2017	Parent D, Craig M, Moorhouse K. Biofidelity evaluation of the THOR and Hybrid III 50th percentile male frontal impact anthropomorphic test devices. Stapp Car Crash J. November 2017;61:227-276. SAE 2017-22-0009.
2017	Gabler LF. Development of Improved Metrics for Predicting Brain Strain in Diverse Impacts [PhD thesis]. Charlottesville, VA: University of Virginia; December 2017.