Society pays a high cost for work zone crashes in terms of operational disruptions, property damage, injuries and loss of life. Given narrow lanes in work zones, large trucks are of particular concern. This paper empirically examines truck-involved collisions, comparing them to non truck-involved collisions in North Carolina work zones. The paper helps us understand which work zone attributes are statistically associated with the most seriously injured occupant and total harm in a crash. Specifically, the role of several new work zone variables is explored. They include the type of work zone, presence of warning signs and cones, type of activity/work in the work zone, location of the crash in the work zone and construction impact of the work zone on the roadway. These variables were obtained from a unique dataset based on a revised North Carolina accident form that included new work zone variables and additional variables coded from crash report narratives. Using this new work zone crash data (N=3,383), for the year 2000, ordered probit models were estimated for the most seriously injured occupant in a crash and linear regression models for “total harm” in the crash. The models for total harm in the crash combine both frequency and severity of injuries by assigning economic value to injuries. Work zone crashes in North Carolina, especially those involving large trucks, were more injurious compared to non-work zone crashes. Modeling results suggest that the most injurious/harmful work zone crashes were 1) those involving a truck when the roadway was closed, requiring a detour on the opposite side, with a 38.5% higher chance of injury; 2) before the actual work area, where traffic moves out of its normal path, compared with crashes in the advance warning area or adjacent to the actual activity/work; area, and 3) on two-way undivided roads; a 19.1% higher chance of injury. The results provide valuable information on high-risk factors in work zones, pointing to strategies that can improve vehicle occupants’ safety by reducing their injury severity.