Analyzing highway work zone crashes and traffic control effectiveness

Dissertation (Ph.D.)--University of Kansas, Civil Engineering, 2007.Work zones on the United States highway system create an inevitable disruption to regular traffic flows and have resulted in traffic safety problems. Systematically investigating work zone crashes is a critical step towards developing effective safety countermeasures to reduce these crashes. In this research, a comprehensive analysis of severe work zone crashes was conducted in an effort to catalyze improvement to highway work zone safety. The primary objectives of the research were: (1) to discover the general and unique characteristics of fatal and injury crashes in highway work zones, (2) to evaluate and quantify the effectiveness of work zone temporary traffic control (TTC) devices and suggest traffic control improvements accordingly, (3) to identify the risk factors that could lead to high-severity crashes in highway work zones, and (4) to develop crash-severity-index (CSI) models for evaluating the risk levels of work zones with given travel conditions and relevant environmental factors. The crash data analyzed in the study included the fatal and injury crashes between 1992 and 2004 in Kansas highway work zones. The researcher utilized a variety of statistical methods to achieve the objectives. The crash characteristic investigation employed both single-variable and multi-variable frequency analyses and chi-square tests; the logistic regression technique was used in the evaluation of traffic control effectiveness and the development of CSI models; and chi-square statistics and Cochran-Mantel-Haenszel (CMH) statistics were employed to identify work zone risk factors. Outcomes of this research included the general and unique characteristics of fatal and injury work zone crashes, the quantified effectiveness of work zone TTC devices, the identified work zone risk factors, and a set of developed CSI models for work zone risk evaluation. Based on these findings, potential work zone safety improvements were recommended in the areas of traffic control, public education, and crash reporting. In addition, the application of CSI models in work zone planning or work zone safety inspection was also recommended to improve work zone safety. Promising future research tasks are suggested at the end of the dissertation, as well