Spatial and Temporal Analyses of Work Zone Crashes and Investigation of Relationships Between Work Zone Traffic Control Measures and Crash Characteristics

The deterioration of highway infrastructure requires reconstruction, rehabilitation, resurfacing, widening, etc to better serve the users. In order to efficiently and safely manage the traffic for all types of work conditions, appropriate traffic control devices need to be selected for the work zones. Therefore, in order to find relationship between traffic control measures and crash occurrences (crash type and severity level) viewed from both spatial and temporal aspects and to develop a set of guidelines for adopting certain types of traffic control measures given the nature and characteristics of planned work zones, an exploratory data mining for spatial and temporal analyses of work zone crashes, a full-scale data mining and analysis, an aggregated estimation of traffic control cost, and a comparative analysis of the crash characteristics between construction time and non-construction time at the same highway sections were conducted. Based on the findings from these analyses, a set of guidelines for insuring traffic safety in work zones was provided. Some of the findings include the followings: (a) Work zones on urban highways are the most dangerous in terms of crash frequency and rate; (b) Rural highways have larger increase in crash rates in work zones; (c) Primary contributors to work zone crashes had consistent trends — there are more crashes at sections in work zones where alignment, pavement condition, and weather are good; and (d) When crash rates were compared before and during construction at the highway sections where work zones took place, the existence of work zones did not necessarily increased their crash rates.