Correlating Hard-Braking Activity with Crash Occurrences on Interstate Construction Projects in Indiana

Studies on work zone crashes typically examine a combination of injury, fatal, and property damage crashes to identify factors that contribute to unsafe conditions within work zones. Few studies focus on fatal crashes within work zones, although a clear understanding of the driver, roadway, and work zone conditions associated with fatal crashes will facilitate the development of strategies aimed at improving safety and reducing fatal as well as nonfatal crashes. The Georgia Department of Transportation recently performed a study to identify the manner of collision, location, and construction activity associated with fatal crashes in work zones. This study is expanded further to examine the difference between fatal crash activity within work zones compared with fatal crashes in non-work-zone locations. Using data from three work zone locations in Georgia, fatal crash activity within work zones also was compared with nonfatal crashes within work zones. Finally, fatal crash activity was examined to determine the influence of the work zone activity on the frequency of fatal crashes. The overall findings of the study indicate that the work zone influences the manner of collision, light conditions, truck involvement, and roadway functional classification under which fatal crashes occur. The study also indicates that fatal crashes in work zones are more likely to involve another vehicle than non-work-zone fatal crashes, and fatal crashes in work zones are less influenced by horizontal and vertical alignment than are non-work-zone crashes.

<b>Objective:</b> Work zone safety is one of the top priorities for transportation agencies. In recent years, a considerable volume of research has sought to determine work zone crash characteristics and causal factors. Unlike other non–work zone–related safety studies (on both crash frequency and severity), there has not yet been a comprehensive review and assessment of methodological approaches for work zone safety. To address this deficit, this article aims to provide a comprehensive review of the existing extensive research efforts focused on work zone crash-related analysis and modeling, in the hopes of providing researchers and practitioners with a complete overview.<b>Methods:</b> Relevant literature published in the last 5 decades was retrieved from the National Work Zone Crash Information Clearinghouse and the Transport Research International Documentation database and other public digital libraries and search engines. Both peer-reviewed publications and research reports were obtained. Each study was carefully reviewed, and those that focused on either work zone crash data analysis or work zone safety modeling were identified. The most relevant studies are specifically examined and discussed in the article.<b>Results:</b> The identified studies were carefully synthesized to understand the state of knowledge on work zone safety. Agreement and inconsistency regarding the characteristics of the work zone crashes discussed in the descriptive studies were summarized. Progress and issues about the current practices on work zone crash frequency and severity modeling are also explored and discussed. The challenges facing work zone safety research are then presented.<b>Conclusions:</b> The synthesis of the literature suggests that the presence of a work zone is likely to increase the crash rate. Crashes are not uniformly distributed within work zones and rear-end crashes are the most prevalent type of crashes in work zones. There was no across-the-board agreement among numerous papers reviewed on the relationship between work zone crashes and other factors such as time, weather, victim severity, traffic control devices, and facility types. Moreover, both work zone crash frequency and severity models still rely on relatively simple modeling techniques and approaches. In addition, work zone data limitations have caused a number of challenges in analyzing and modeling work zone safety. Additional efforts on data collection, developing a systematic data analysis framework, and using more advanced modeling approaches are suggested as future research tasks.

Identifying risk factors for road traffic injuries can be considered one of the main priorities of transportation agencies. More than 12,000 fatal work zone crashes were reported between 2000 and 2013. Despite recent efforts to improve work zone safety, the frequency and severity of work zone crashes are still a big concern for transportation agencies. Although many studies have been conducted on different work zone safety-related issues, there is a lack of studies that investigate the effect of adverse weather conditions on work zone crash severity. This paper utilizes probit–classification tree, a relatively recent and promising combination of machine learning technique and conventional parametric model, to identify factors affecting work zone crash severity in adverse weather conditions using 8 years of work zone weather-related crashes (2006–2013) in Washington State. The key strength of this technique lies in its capability to alleviate the shortcomings of both parametric and nonparametric models. The results showed that both presence of traffic control device and lighting conditions are significant interacting variables in the developed complementary crash severity model for work zone weather-related crashes. Therefore, transportation agencies and contractors need to invest more in lighting equipment and better traffic control strategies at work zones, specifically during adverse weather conditions.

Highway work zone safety has been a concern nationwide and will likely draw ever increasing attention as more highway funds are invested in the maintenance of existing highways. To improve work zone safety, the Indiana Department of Transportation (DOT) established a special fund for work zone patrolling, and this study was commissioned to help the Indiana DOT achieve the maximum safety benefits within its budget constraint. With help from the Indiana DOT, a survey of project engineers was conducted to collect work zone information. The findings from the survey were linked with other available data. A random-effect negative binomial model was developed to identify the contributing factors and to estimate crash frequency in highway work zones. The results from the model provided insight for better understanding of crashes in work zones. Various factors, including roadway information, traffic volume, work zone–specific features, and police presence, were identified as things that affect crash frequency in work zones. These and other findings will be used to plan police enforcement activities in future Indiana DOT work zones.

Work zones are unique construction sites having multiple elements and complex scenarios. Existing studies have utilized crash data to explore the key factors contributing to work zone crashes. However, studies covering various elements comprehensively are missing, especially in Indiana. Also, there is a lack of studies exploring how to identify the representative scenarios from a large number of work zone crashes. Thus, this study aims to investigate the key factors contributing to work zone crashes covering multiple elements and propose a procedure to select representative scenarios based on crash data. Three Indiana crash data resources and the Natural Language Processing method were applied. There are several key findings. The key factors from multiple resources were summarized, including road conditions, work zone elements, and environment. Traffic activities were the top factors, followed by construction vehicles and weather conditions. Then, a seven-step procedure to extract the representative scenarios from crash records was proposed. Applying the procedure, two representative cases were identified from Indiana crash data. The study enhances the comprehensive understanding of work zone crashes based on large- scale data and helps improve safety for workers, drivers, and pedestrians.

Inferring heterogeneous treatment effects of work zones on crashes

This article discusses the state of the art in work zone safety in the United States (US). It describes how work zones are places where, perhaps more than anywhere else on the road network, mobility and safety are strongly linked. Historically, field crews and contractors wanted vehicles in work zones to move as slowly as possible. The article shows how the industry is starting to see a shift in such thinking with the realization that excessive delays or slow-downs not only affect traveler mobility but also gives rise to more instances of road rage and other undesirable behavior. Back in the early 2000s, the USDOT’s Federal Highway Administration (FHWA) decided that it was essential that state and highway agencies design and implement work zones which give adequate consideration to the traveler. As a result, the Work Zone Safety and Mobility Rule (Subpart J) was established. Subpart J decrees that state transportation agencies have a policy in place to consider and mitigate the safety and mobility impacts of work zones. Subpart J decrees that state transportation agencies have a policy in place to consider and mitigate the safety and mobility impacts of work zones. If there are to be significant delays as a result of work zone activity, a transportation management plan needs to be developed that encompasses the work zone itself, public information, diversions to other routes and modal shifts as appropriate. Since implementation of the Rule in 2004, state transportation agencies have worked steadily to comply, which has led to an overall improvement in the mindsets of both the public and private sectors.

Advancing safety in short-term utility work zones: Assessing the role of work zone intrusion alert technologies (WZIATs)

IntroductionHighway work zones (HWZ) may lead to an increased road traffic crash (RTC) risk. Little is known about such crashes in low-income countries (LICs).ObjectiveTo assess burden and factors associated with...

This paper presents the results of an analysis focusing on large truck-involved work zone fatal crashes using seven-year crash data in the State of Florida. Decision tree/random forest models were applied to specifically detect critical crash patterns that result in a fatality outcome. Because of the imbalanced nature of crash severity data (very low frequency of fatal crashes compared with property damage only or injury), data were treated using random and systematic over-sampling techniques. Marginal effects were addressed using Shapley values to increase model explainability. From a methodological perspective, results showed that the combination of over-sampling techniques with ensemble random forests could significantly improve model performance in predicting fatal crashes (compared with conventional logistic regression models). Primary contributors included pedestrian involvement, lighting conditions, safety equipment, driver condition, driver age, and work zone locations. For pedestrian crashes, factors such as dark-not lighted conditions, distracted truck driver, and driver’s age (young drivers outside city limits, senior drivers inside city limits) were highly likely to be fatal. For non-pedestrian crashes, the combination of front airbag deployment with any restraint system other than shoulder and belt was quite likely to be fatal. Also, abnormal driver conditions increased the risk of a fatal outcome. Additionally, the presence of female drivers (as the second driver in multiple vehicle crashes) highly decreased crash severity, probably because females typically drive more carefully than males. Interestingly, truck driver actions and maneuvers as well as roadway design and other physical environment features (i.e., number of lanes, median type, roadway grade, and alignment) did not show significant contribution to the model.

Modern vehicles know more about the road conditions than transportation agencies. Enhanced vehicle data that provides information on “close calls” such as hard braking events or road conditions during winter such as wheel slips and traction control will be critical for improving safety and traffic operations. This research applied conflict analyses techniques to process approximately 1.5 million hard braking events that occurred in the state of Indiana over a period of one week in August 2019. The study looked at work zones, signalized intersections, interchanges and entry/exit ramps. Qualitative spatial frequency analysis of hard-braking events on the interstate demonstrated the ability to quickly identify temporary and long-term construction zones that warrant further investigation to improve geometry and advance warning signs. The study concludes by recommending the frequency of hard-braking events across different interstate routes to identify roadway locations that have abnormally high numbers of “close calls” for further engineering assessment.

Studies have shown that a large percentage of vehicles involved in work zone crashes are traveling at excessive speeds. Although traditional speed enforcement has been shown to reduce speeds through the work area, enforcement under these conditions can be dangerous to both the motoring public and enforcement officers. The work zone layout often limits the locations at which an officer can set up to enforce the speed limit and the locations at which violators can be stopped. Automated speed enforcement technology could help eliminate the need to stop violators in a work zone, but it is not currently a popular concept in the United States because of concerns about motorist privacy. Researchers hypothesized that this technology could be useful for work zone enforcement if adapted to a more real-time operation. The initial testing of the concept of remote speed enforcement is summarized. An automated speed enforcement system (consisting of digital video and lidar technology) was meshed with a wireless communications system. The unit determined when vehicles exceeded a certain speed threshold. If a vehicle was detected as exceeding the threshold, a digital photograph was taken of the violator. This photograph was then transmitted to an observer stationed downstream of the site. The technical feasibility of the system was assessed through field tests. Focus groups of law enforcement personnel were used to determine potential acceptance of the system in the law enforcement community. Recommendations for future improvements and possible applications of the system are made.

Intelligent work zone (IWZ) systems use innovative technologies in real time to mitigate the negative impacts of work zones on the traveling public. The automatic queue detection (AQD) system is one type of IWZ being promoted by the Federal Highway Administration. Several field studies found that AQD systems were successful in reducing average travel speeds which led to a reduction in the number of rear-end crashes and in user costs. It has been shown that well-calibrated microsimulation models are appropriate analysis tools for traditional work zone traffic. To date, there are no tools in the literature that have been developed for AQD operations that have been calibrated and validated with empirical data. This paper aims to fill this gap by providing a comprehensive guideline for calibrating and validating a microsimulation model that can emulate traffic conditions and their impacts on freeway IWZ equipped with AQD systems. Specifically, the methodology includes (1) developing the base work zone model, (2) replicating the AQD warning messages, (3) calibrating the key simulation parameters using three types of data, and (4) validating the resulting simulation model using segment travel times. This comprehensive approach was demonstrated on a Nebraska work zone that was equipped with an AQD system. VISSIM simulation model was used for the underlying tool in the demonstration. The results presented in this paper are useful to both practitioners and scholars who wish to study the impact of the IWZ accurately through microsimulation.

Pakistan has a population of over 199 million and total road network of approximately 264,400 kilometers that serve about 16.2 million vehicles of all types. According to WHO estimates, there were approximately 30,000 annual Road Crash Fatalities (RCF) in Pakistan in year 2010. Work zone crashes account for significant proportion of all traffic crashes in Pakistan due to higher crash rate as compared to other parts of the highway network. Highway work zone is referred to road area where highway construction, maintenance or activity related to utility maintenance takes place. Workers in highway work zone are exposed to a variety of hazards and face risk of injury and death from construction equipment as well as passing motor vehicles. Safety measures and better understanding of risks involved while moving through the work zone have significant effects on the overall safety climate at work zones. Mismanaged work zone traffic increases the travel time delays, safety issues, vehicle operating costs (VOC) and other associated costs. Performance measures for the work zone traffic management includes user costs (travel time delay, crash cost, VOC), incident response and clearance time, queue length and community complaint. Different work Zone Traffic Management methodologies are being practiced worldwide and extensive research has been carried out at international level on country specific highway work zone safety but in Pakistan very few studies have been carried out on highway work zones. This research aims to critically analyze the impacts of the different Work Zone Traffic Management methods and recommend the best option for Expressways / Motorways in Pakistan. For the purpose of research, the author has selected a section of Motorway (M-2). Two different work zone traffic management methods are being followed in rehabilitation of M-2 .i.e. Parallel / Adjacent Method and Median Cross-Over Method. Performance measures selected for purpose of analysis are Travel Time Delay, Crash Cost (Safety) and VOC and data collected on section of M-2. After critical analysis, it is concluded that Parallel/ Adjacent Method results in lesser Travel Time delay and lesser VOC due to higher operating speeds and thus has higher savings, whereas Median Cross over Methods yield more Crash Cost savings. Keeping in view the driving habits / skills, poor maintenance of vehicles in Pakistan and risk of fatal accidents involved in parallel /adjacent method, median cross over method is preferred.

Central to the effective design of work zones is being able to understand how drivers behave as they approach and enter a work zone area. States use simulation tools in modeling freeway work zones to predict work zone impacts and to select optimal design and deployment strategies. While simple and complex microscopic models have been used over the years to analyze driver behavior, most models were not designed for application in work zones. Using data collected from an instrumented research vehicle and model components from two PhD dissertations, FHWA created the Work Zone Driver Model and programed the Work Zone Driver Model DLL v1.0, a software that could override car-following in commercial microsimulation software packages so that practitioners can better predict work zone impacts. This paper demonstrates the capabilities of the FHWA Work Zone Driver Model DLL v1.0, interfaced with VISSIM and tested on an Interstate work zone in Springfield, Massachusetts. The dynamic link library’s (DLL’s) performance is compared with field data collected using an instrumented research vehicle and to Weidemann 99 in VISSIM. Performance metrics were selected to align with state department of transportation work zone management efforts. Results showed acceptable performance from the DLL, as it predicted queue locations and travel speeds that were near field observations. Limitations of the DLL and interface are discussed, and opportunities for improving version 2.0 are described.