Occupant injuries and fatalities in motor vehicle crashes (MVCs) have been posing significant challenges to road traffic safety globally. A comprehensive understanding of real-world injury mechanisms contributes to enhanced vehicle safety development. This study constructed a framework to identify the occupant dynamics and the injury mechanisms via multi-level accident reconstruction with application to lumbar spine fracture. A series of mechanical parameters including stress, strain, section force and the loading path on occupant lumbar spine were analyzed. Compression-bending induced stress concentration proved to be the primary injury mechanism of occupant lumbar spine fracture in frontal MVCs. Injury tolerance with regards to such complex loading conditions cannot be fully replicated by uniform compression test in laboratory. The present study demonstrated the advantage of combined field-computational approach in injury mechanism and safety strategy investigation, and the feasibility of advanced human models in identifying injury outcomes and the underlying load distribution among tissues.

Road traffic safety;Accident reconstruction;Occupant protection;Injury mechanism;Computational biomechanics