The effect of impact environment on occupant risk and the belted/unbelted dilemma

Nusholtz, Guy S.; Kowsika, Murthy; Xue, Jianqing; Shi, Yibing; Rabbiolo, Guglielmo; Di Domenico, Laura; Famili, Fariba; Byers, Lynn

Affiliations

Abstract

The fleet-wide occupant risk for frontal impact is estimated using a previously developed, data-based model. The model is constructed using the National Automotive Sampling System (NASS), the Fatality Analysis Reporting System (FARS), and the New Car Assessment Program (NCAP) databases and evaluated against Insurance Institute of Highway Safety (IIHS) data. The occupant risk is obtained from the NASS and FARS databases. The accident velocity distribution is obtained from the NASS data base. The vehicle impact response characteristics that are incorporated into the model are derived from the NCAP test data. The parameters included in the investigation are “intrusion” and vehicle “stiffness”, for both belted and unbelted conditions. The model is used to demonstrate that these are not independent in terms of overall occupant risk. The optimal level of vehicle stiffness is different for the belted and the unbelted conditions: Vehicle impact response optimized for the belted may be counter-indicated for the unbelted and vehicle impact response optimized for the unbelted may be counter-indicated for the belted. The model is used to study the effects of limiting intrusion, by stiffening the front structure in the current fleet. The results indicate that limiting the vehicle’s intrusion in this manner may reduce fleet wide occupant risk at the high impact velocities; however, it is counter-productive at low impact velocities and, may have no value overall in the current fleet for the current accident velocity distribution.

Links

URL: http://www-nrd.nhtsa.dot.gov/pdf/esv/esv20/07-0453-O.pdf

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