Stiffness Coefficients of Heavy Commercial Vehicles 2013-01-0796

Accident reconstruction specialists have long relied on post-crash deformation and energy equivalence calculations to determine impact severity and the experienced change in velocity during the impact event. In order to utilize post-crash deformation, information must be known about the vehicle's structure and its ability to absorb crash energy. The Federal Motor Vehicle Safety Standards (FMVSS), the New Car Assessment Program (NCAP), and the Insurance Institute of Highway Safety (IIHS), have created databases with crash testing data for a wide range of vehicles. These crash tests allow reconstruction specialists to determine a specific vehicle's ability to absorb energy as well as to generalize the energy absorption characteristics across vehicle classes. These methods are very well publicized.

Crash tests of commercial vehicles, however, are less common; and as a result, current literature has more limited information on the energy absorption characteristics of heavy vehicles such as traditional heavy trucks, motor coaches, buses or cab-over trucks.

This paper attempts to quantify energy absorption characteristics for the aforementioned vehicle types based on publicly available frontal-impact crash tests reports and videos of heavy vehicles. In addition, video image analysis was performed. The video image analysis is validated against a NHTSA full scale frontal barrier test and then extended to other videos. This paper presents the methodology and analytical process used to derive the stiffness coefficients.

The findings and data presented in this paper will add to the body of knowledge for heavy vehicles, and may bear significant importance to the accident reconstruction field and the understanding of stiffness coefficients for heavy commercial vehicles until such time that additional full scale tests are performed and made publically available.