Three years of data from the Large Truck Crash Causation Study (LTCCS) were analyzed to identify accidents involving heavy trucks (GVWR >10,000 lbs.). Risk of rollover and ejection was determined as well as belt usage rates. Risk of ejection was also analyzed based on rollover status and belt use. The Abbreviated Injury Scale (AIS) was used as an injury rating system for the involved vehicle occupants. These data were further analyzed to determine injury distribution based on factors such as crash type, ejection, and restraint system use. The maximum AIS score (MAIS) was analyzed and each body region (head, face, spine, thorax, abdomen, upper extremity, and lower extremity) was considered for an AIS score of three or greater (AIS 3+).
The majority of heavy truck occupants in this study were belted (71%), only 2.5% of occupants were completely or partially ejected, and 28% experienced a rollover event. In the analyzed data set, none of the belted occupants experienced a complete ejection while 4.4% of unbelted occupants did experience a complete ejection. There was a higher, but not statistically significant, risk of complete and of partial ejection for occupants of heavy trucks that experienced a rollover than for occupants of heavy trucks that did not experience a rollover. An MAIS score of one or two (minor or moderate injury, respectively) accounted for 85% of the injuries to the heavy truck occupants. The MAIS score shifted towards greater injury severity in the cases of rollover, ejection, and unbelted occupants. The head, thorax, and lower extremities contained the highest percentages of AIS 3+ injuries. The head was the most commonly injured body region of ejected occupants, while injuries of belted occupants were most commonly found to the thorax.