An overview of NHTSA’s crash reconstruction software WinSMASH

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Sharma, Dinesh¹; Stern, Seymour¹; Brophy, John¹; Choi, Eun-Ha²

An overview of NHTSA’s crash reconstruction software WinSMASH

Proceedings of the 20th International Technical Conference on the Enhanced Safety of Vehicles (ESV)

Affiliations

¹National Highway Traffic Safety Administration, USA

²Rainbow Technology, USA
Abstract

The National Highway Traffic Safety Administration (NHTSA) uses WinSMASH computer software to estimate the change in velocity, delta-V, of the vehicles involved in crashes. The software uses detailed measurements from the crash scene, vehicle damage and vehicle stiffness characteristics to compute energy absorbed by the vehicle and estimate the delta-V and Barrier Equivalent Speed (BES). The WinSMASH is a Microsoft Windows based, enhanced and updated version of the accident reconstruction software CRASH3 previously used by NHTSA. The purpose of this paper is to describe the new enhancements in the program.

The damage algorithm used in CRASH3 has been reformulated in WinSMASH. The new damage algorithm in WinSMASH is based on an assumed linear relationship between crash energy and crush and uses intercept d0 and slope d1 to describe vehicle stiffness. The software uses generic vehicle size and stiffness categories based on the vehicle’s wheelbase. However, the program also allows the users to enter the vehicle specific stiffness coefficients. The stiffness coefficients for a large number of vehicles have been calculated from crash test results and integrated into WinSMASH. An automated procedure to select the vehicle specific stiffness coefficients is currently under development. A statistical model is also being developed for estimating the stiffness coefficients of a vehicle that is not crash tested. The paper provides an overview of these procedures.

The WinSMASH estimated delta-V of the vehicles is compared with the corresponding delta-V obtained from the Event Data Recorder (EDR) installed in the crashed vehicles to assess the accuracy of the software. The staged crash tests used to validate the software are also discussed in the paper.
Links

URL: http://www-nrd.nhtsa.dot.gov/pdf/esv/esv20/07-0211-W.pdf

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2011	Hallman JJ, Yoganandan N, Pintar FA, Maiman DJ. Injury differences between small and large overlap frontal crashes. In: 55th Annual Proceedings, Association for the Advancement of Automotive Medicine (AAAM). October 3-5, 2011; Paris, France.147-157.
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2017	Gabler HC, Sharma D. Accuracy of WinSMASH in rear crashes using event data recorders. In: Proceedings of the 25th International Technical Conference on the Enhanced Safety of Vehicles (ESV). June 5-8, 2017; Detroit, MI.
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2013	Stadter GW, Yoganandan N, Halloway DE, Pintar FA. Analysis of nearside narrow object impacts with and without shoulder injuries in real‐world crashes. In: Proceedings of the 2013 International IRCOBI Conference on the Biomechanics of Injury. September 11-13, 2013; Gothenburg, Sweden.698-709.
2016	Klinich KD, Flannagan CAC, Hu J, Reed MP. Potential safety effects of low‐mass vehicles with comprehensive crash avoidance technology. In: Proceedings of the 2016 International IRCOBI Conference on the Biomechanics of Injury. September 14-16, 2016; Malaga, Spain.755-764.
2018	Riexinger LE, Gabler HC. A preliminary characterisation of driver manoeuvres in road departure crashes. In: Proceedings of the 2018 International IRCOBI Conference on the Biomechanics of Injury. September 12-14, 2018; Athens, Greece.484-492.
2023	Bangert LG, Collins CJ, Riexinger LE. Do females have a higher risk of suffering distal tibia fractures in frontal car crashes? In: Proceedings of the 2023 International IRCOBI Conference on the Biomechanics of Injury. September 13-15, 2023; Cambridge, United Kingdom.244-253.
2024	Ressi F, Klug C. Stochastic replication of injury risks in frontal collisions with different human body models in a generic vehicle interior. In: Proceedings of the 2024 International IRCOBI Conference on the Biomechanics of Injury. September 11-13, 2024; Stockholm, Sweden.1168-.
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