The work zones on the United States highway system have created an inevitable disruption on regular traffic flows and resulted in traffic safety problems. Understanding the characteristics and major causes of highway work zone crashes is a critical step towards developing effective safety countermeasures in highway work zones. In 2004, the Kansas Department of Transportation (KDOT) initiated a project (K-TRAN Project No. KU-05-01) to study the fatal crashes in Kansas highway work zones between 1992 and 2004. The study results including crash characteristics and major crash contributing factors were published in Bai and Li (2006). Built on the previous success, KDOT sponsored this research project (K-TRAN Project No. KU-06-01) to further study the injury crashes during the same period in Kansas highway work zones. The primary objectives of this study were to investigate the characteristics of the injury crashes, to identify risk factors that contributed to the injury crashes, and to compare characteristics between fatal and injury crashes in highway work zones. Frequency analysis was utilized to discover the basic characteristics reflected by single-variable frequencies as well as the complicated characteristics based on cross-categorized frequencies. The variable combinations used for analyzing cross-categorized frequencies were identified through independence test methods such as Pearson Chi-Square Test and Likelihood-Ratio Chi-Square Test. The characteristic comparison between fatal and injury crashes further helps to document the general characteristics of both fatal and injury crashes and to discover the unique factors that characterize different severities. The researchers found significant characteristics of Kansas highway work zone injury crashes and summarized them in six categories. The researchers also discovered noteworthy characteristic differences between work zone fatal and injury crashes and concluded the important factors that could have increased the severity of work zone crashes. Potential safety improvements were recommended accordingly and future research were suggested. The significant insights from this study are valuable for the design of safer highway work zones and for the development of safety countermeasures that have potential not only in reducing the number of crashes but also in mitigating the crash severity
