Incidence and Mechanism of Head, Cervical Spine, Lumbar Spine, and Lower Extremity Injuries for Occupants in Low- to Moderate-Speed Frontal Collisions

Automotive accidents and subsequent personal injury claims incur significant costs annually. While three-point restraint usage has become more ubiquitous and governmentally mandated for front seat occupants, occupant safety and injury risk assessment in frontal collisions continue to be at the forefront of automotive innovation. In this study, we combined statistical analyses of nine years (2007-2015) of data from the National Automotive Sampling System Crashworthiness Data System (NASS-CDS) database and one year (2017) of data from the Crash Investigation Sampling System (CISS) database with data acquired from vehicle-to-vehicle crash tests conducted with instrumented anthropomorphic test device (ATD) occupants in order to compare and relate field injury rates with potential mechanisms underlying head, cervical spine, lumbar spine, and lower extremity injuries in low-to moderate-speed frontal collisions. In the first portion of the study, we performed statistical analyses of the NASS-CDS and CISS databases to estimate the incidence rate of AIS 2+ and AIS 3+ head, cervical spine, lumbar spine, and lower extremity injuries, as well as a subset of AIS 1 head injuries including recorded headaches, unconsciousness, and concussion. The results of these analyses were compared to measured occupant loading data from frontal crash tests without airbag deployment performed at various delta-V’s ranging from 6 to 19 km/h, using restrained, nominally positioned, and instrumented Hybrid III 50th percentile male ATDs. Kinematic and kinetic data for the head, cervical spine, lumbar spine, and femur collected in the low- to moderate-speed frontal crash tests were found to be well below injury thresholds. Analysis of the NASS-CDS and CISS databases demonstrated low rates of injury to the head, cervical spine, lumbar spine, and lower extremities in low- to moderate-speed frontal collisions. A review of these frontal crashes revealed that several factors, outside of collision speed and crash severity, may play a role in increasing the likelihood of injury, including muscle activation, seatbelt status, airbag deployment, occupant age and gender, interaction with vehicle interior structures, and vehicle to vehicle impact orientation, which includes both degree of overlap and obliquity.