Predictions of AIS3+ Thoracic Risks for Belted Occupants in Full-Engagement, Real-World Frontal Impacts: Sensitivity to Various Theoretical Risk Curves

Abstract

<div class="section abstract"><div class="htmlview paragraph">A new, AIS3+ thoracic risk equation based on chest deflection was derived and assessed for drivers subjected to concentrated (belt-like) loading. The new risk equation was derived from analysis of an existing database of post mortem human subjects in controlled, laboratory sled tests. Binary logistic regression analysis was performed on a subset of the data, namely, 25th-75th percentile men (by weight) from 36-65 years old whose thoracic deformation patterns were due to concentrated (belt-like) loading. Other subsets of data had insufficient size to conduct the analysis. The resulting thoracic risk equation was adjusted to predict the AIS3+ thoracic risks for average-aged occupants in frontal crashes (i.e., 30 years old). Biomechanical scaling was used to derive the corresponding relationships for the small female and large male dummies.</div><div class="htmlview paragraph">The new thoracic risk equations and three other sets of existing equations were evaluated as predictors of real-world crash outcomes. Specifically, thoracic risks associated with belt-only drivers in 1985-1997 model year passenger cars were derived via the four different sets of equations. Comparisons were made from two standpoints: (1) point estimates for 48 km/h potentially barrier-like frontal crashes and (2) aggregate risk estimates derived from simulations of full-engagement, non-rollover, tow-away frontal crashes through 56 km/h. In both cases, the new risk equation agreed with field results. Moreover, an existing thoracic risk equation with a commonly held assumption was shown to significantly overstate observed thoracic field risks.</div></div>