In this study, the magnitude and characteristics of work zone crashes were examined using accident data files from 1991 and 1992 for three HSIS States. About 2 to 3 percent of all police-reported crashes were work zone crashes. In 2 States, work zone crashes were slightly less severe than non-work zone crashes. Work zone crashes were more likely to be rear-end and sideswipe than non-work zone crashes. As of 1992, 14 States explicitly recorded work zone crashes on their police crash report forms. In another 21 States, work zone crashes could be identified through other items on their police forms. It is recommended that: (1) uniform definitions of "work zone type" and "work zone crash" should be developed and implemented; (2) methods for determining exposure in work zones should be developed; (3) issues related to work zone crashes should be considered during the development of new accident reporting technologies; and (4) a "special study" of work zone safety should be conducted in cooperation with selected States to develop a more detailed understanding of the relationships between work zone designs and crashes.