Data from the Large Truck Crash Causation Study (LTCCS) were used to compare the crashes involving Combination-Unit Trucks (CUTs) to those of Single-Unit Trucks (SUTs). Forty-four variables relating to crash characteristics, conditions of occurrence, key causal variables, and associated factors, including those relating to driver fatigue and Hours-of-Service, were examined. In this webinar, Dr. Ron Knipling of the Virginia Tech Transportation Institute will discuss how the LTCCS statistics were disaggregated and analyzed. He will provide details about the results which indicate CUT and SUT crashes were more similar than different, and that crash characteristics had stronger associations with causality than did vehicle type. 90 minutes