Incidence and Mechanism of Head, Cervical Spine, Lumbar Spine, and Lower Extremity Injuries for Occupants in Low- to Moderate-Speed Frontal Collisions 2021-01-0902

Automotive accidents and subsequent personal injury claims incur substantial costs annually. While three-point restraint usage, dual-stage airbags, and knee bolster and side curtain airbags have become more ubiquitous and, in some cases, governmentally mandated for front seat occupants, occupant safety and injury risk assessment continue to be at the forefront of automotive innovation. In this study, we combined analyses of the National Automotive Sampling System Crashworthiness Data System (NASS-CDS; 2007-2015) and the Crash Investigation Sampling System (CISS; 2017) with data acquired from vehicle-to-vehicle crash tests conducted with instrumented anthropomorphic test device (ATD) occupants. Together, these analyses were used to compare and relate field injury rates with potential injury mechanisms in low- to moderate-speed frontal collisions. First, low- to moderate-speed (delta-V ≤ 24 km/h) frontal crash data from NASS-CDS and CISS were analyzed to estimate the rate of AIS 2+ and AIS 3+ cervical spine, lumbar spine, and lower extremity injuries, as well as a subset of AIS 2+ and 3+ head injuries including recorded unconsciousness and concussion. The results of these analyses were related to occupant loading data from comparative frontal crash tests, conducted at delta-Vs ranging from 6 to 19 km/h. Kinematic and kinetic data for the head, cervical spine, lumbar spine, and femur collected in the frontal crash tests were well below injury thresholds. Analysis of the NASS-CDS and CISS data demonstrated low rates of injury to the head, cervical spine, lumbar spine, and lower extremities in low- to moderate-speed frontal collisions. Review of these frontal crashes revealed that several factors, outside of collision severity, may affect injury likelihood, including muscle activation, seatbelt status, frontal and knee bolster airbag deployment, seat track position, out-of-positioning, age, gender, interaction with vehicle interior structures, and vehicle-to-vehicle impact orientation, which includes both degree of overlap and obliquity.