The Combined Effects of Impact Direction and Impact Location on Serious-to-Maximum Injuries Among Drivers in Motor Vehicle Frontal Crashes

This paper investigates the combined effects of specific impact direction and impact location on the serious-to-maximum (AIS3–6) thoracic injuries of drivers in frontal impacts based on the 1995–2009 data from the United States Department of Transportation (US DOT) National Automotive Sampling System/Crashworthiness Data System (NASS/CDS). The selected sample is limited to three impact locations near the driver side (distributed, offset and corner) and two impact directions (pure frontal and oblique) treated as the frontal direction, resulting in a total of six crash configurations. The risks of thoracic injury for drivers in all frontal crash configurations are evaluated. The relative risks with 95% confidence intervals are calculated. Binary logistic regressions are fitted to the datasets for further examination of the effects of impact direction and impact location on the serious-to-maximum thoracic injuries. Occupant characteristics and crash severity are also included as explanatory variables. Overall, impact location and impact direction have considerable influences on thoracic injury pattern and severity for drivers. For distributed and corner deformation, oblique loading is approximately 3 times more likely to lead to thoracic injures than pure frontal loading. Conversely, the relative risk is 3.44 for offset deformation, which indicates that, for this impact location, frontal impact is more associated thoracic injuries compared to oblique impact. The effects of impact location and impact direction on serious-to-maximum injuries for three types of anatomical structures (organ, skeletal and vessel) are assessed as well. In addition to crash related variables (impact location and impact direction), results of the binary logistic regressions also indicate that crash severity (OR, 7.67–81.35) and occupant characteristics, including age (OR, 4.80–20.83), gender (OR, 1.16) and BMI (OR, 1.81), significantly affect the risks of thoracic injuries in frontal motor vehicle collisions.