Highway work zones have become a hazardous place for both construction workers and roadway users due to the increasing risk caused by maintaining and reconstructing roadways. Both the number of crashes and fatalities in the work zones in the United States have grown between years 2013 to 2016. It is necessary for transportation agencies to understand the characteristics of work zones that are related to crashes with severe injuries and figure out countermeasures to improve work zone safety. In this study, the significant differences in crash severity among different crash types in the work zones, as well as between work zone and non-work zone conditions in Alabama were investigated by using two-sample Kolmogorov-Smirnov tests (K-S test). The work zone crash data used in this study were obtained from the hardcopy crash reports by Alabama Department of Transportation (ALDOT), and the crash data in non-work zones were retrieved from the online version of the Critical Analysis Reporting Environment (CARE). The results found that single vehicle, head-on, angle oncoming, and side impact 90-degree crashes that occurred within work zones in Alabama were significantly more severe than these crash types that occurred in non-work zones; single vehicle, head-on, angle oncoming, angle opposite direction, and side impact 90-degree crashes were significantly more severe than other crash types in Alabama work zones. From the results of the comparisons, conclusions were drawn and recommendations were provided for ALDOT to identify countermeasures and devote resources to reduce severity of the crash types that should be of greatest concern.