Modeling the Crash Injury Severity in Work Zone Areas on Freeways
Abstract
The rising frequency of crashes in work zones on American freeways is a growing issue inherently linked to the degrading state of our transportation infrastructure. As travel demand increases and our infrastructure continues to age and wear out, work zones will need to be implemented to add capacity or repair and replace those components that pose elevated risk for public safety. Despite the fact that work zones have received national attention for more than two decades due to elevated risk for crash and injury, very little decrease in work zone crash or injury has occurred as a result of this national awareness. Decreasing work zone crashes and injury is an issue that still needs to be addressed. With work zone definitions still being largely determined at the state level, identifying work zone characteristics and modeling risk or crash injury severity is important in assisting those state Departments of Transportation (DOTs) with the design of safer work zones. More specifically, highlighting aspects of design that contribute to the most severe injuries in road crashes have recently become the focus as economic policies have dictated more conservative fiscal budget allocations. The purpose of this research is to develop and evaluate models that can help not only identify, but also quantify the different contributing factors and their role in the severity of work zone crashes. The data used in this research is obtained from the North Carolina Department of Transportation (NCDOT) maintained Traffic Engineering Accident Analysis System (TEAAS) for the years 2007-2014. TEAAS utilizes DMV-349 reports filed by law enforcement officials at the scene of every reported crash. The dataset was organized into three different categories: human factors, roadway environmental factors, and vehicle factors. Multinomial Logit models were developed for the overall work zone, as well as the different work zone types and areas. The results obtained indicated that alcohol was associated with more fatal & A injury severity type crashes, whilst speed was prevalent across all areas of work zones. The construction work zone contained the vast majority of the crashes, as well as the highest severity crashes. The high severity crashes most often occurred during the morning and evening peak traffic hours of 9:00-11:59 AM and 3:00-5:59 PM. The most dangerous and high risk area in the work zone was within the construction work zone transition/activity area. This area was found to have a higher risk in comparison to the advance warning and termination area.Overall, the results obtained from this research provide details on specific risk factors for work zone crashes, which have aided in developing a better understanding of these high risk work zone traffic environments. These results will be helpful to both government and highway industries, as well as safety engineers and researchers when determining potential countermeasures to help eliminate those risks.