Highway work zones create an inevitable disruption to regular traffic flows and have resulted in traffic safety problems. Systematically investigating work zone vehicle crashes is a critical step towards developing effective safety countermeasures to reduce these crashes. The authors utilized a variety of statistical methods to analyze vehicle crash data in highway work zones. Outcomes of their research included the general and unique characteristics of fatal and injury work zone crashes, the quantified effectiveness of temporary traffic control devices, the identified work zone risk factors, and a set of crash severity index (CSI) models for work zone risk evaluation. Based on these findings, potential work zone safety improvements were recommended to the traffic engineers, the construction professionals, and the law enforcement in the areas of traffic control, public education, and crash reporting. In addition, the application of CSI models in work zone planning and work zone safety inspection was also recommended to the traffic and construction engineers with the purpose for improving work zone safety.