The magnitude and characteristics of safety problems associated with moving vehicular traffic through and around highway work zones are examined through an analysis of all of the reported work zone accidents that occurred in Virginia during 1977. The accident characteristics analyzed include: the general and specific location of the accident, time of the accident, roadway and environmental factors, characteristics of the work zone, causes of the accidents, and accident severity. Comparisons were made between the work zone accidents, the entire Virginia accident data base, and the work zone accident characteristics reported by others. An assessment was also made of the consistency and completeness of work zone accident reporting. It was found that: (1) Some aspect of the work zone was cited as the cause of roughly 17 percent of all work zone accidents; (2) there was substantial evidence of a rear end accident problem in work zones; and (3) there was an overrepresentation of work zone accidents in urban areas.