Relationship between occupant compartment intrusion and injury by crash counterpart relevant to MASH requirements

This study used recent crash data to quantify the correlation between MASH intrusion limits and injury outcomes for crashes with roadside hardware, vehicles, or fixed objects. The study also provides additional descriptive statistics and characteristics about the intrusion environment, resulting injuries, and the associated crash environment.

This study uses the latest crash data from NHTSA's CISS database to investigate the relationship and potential correlations between injuries and vehicle intrusion disaggregated by crash counterpart: roadside hardware, vehicles, or fixed objects. Statistical analyses are used to quantify the parameter effects and their significance in predicting injury as a direct result of intrusion into the occupant compartment. The data are summarized at the occupant level and selected crashes are analyzed in detail to highlight potential injury mechanisms.

Occupant compartment intrusion in crashes is relatively rare, generally, and even more rare in crashes with roadside hardware. For crashes with roadside hardware that resulted in occupant compartment intrusion, the crash was most often more severe than the test-level 3 conditions required by MASH. While the severity of injury for injured occupants in roadside hardware crashes was lower compared to those in fixed object and vehicle crashes, the rate of lower extremity injuries was much higher. Occupants that experienced intrusion at their seat location that exceeded MASH thresholds were more likely (OR = 16.02 to 24.57) to suffer a severe or greater injury than those that did not.

Roadside hardware crashes are distinct from fixed-object and vehicle-to-vehicle crashes with regard to occupant compartment intrusion and injury outcomes. The MASH intrusion requirements are a significant predictor of injury outcome. These results can be used to enhance and improve the requirements of MASH and may lead to additional and more robust occupant injury metrics.