Best Practices for INDOT-Funded Work Zone Police Patrols

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.

<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.

Emphasis on work zone safety and improving the identification of work zone problems has been increased by recent legislation and federal programs. There is a critical need for better data related to highway work zone safety. Results are presented of an investigation to (a) determine what is known about the magnitude of highway work zone crashes, (b) examine characteristics of highway work zone crashes using the Highway Safety Information System, (c) investigate how work zone accidents are reported on police accident report forms and within state accident report systems, (d) identify critical voids in the knowledge of the relative safety of work zones, and (e) examine possible ways to address unfulfilled information needs related to work zone safety. Deficiencies of data reporting practices and issues of data needs pertaining to work zone safety are discussed. Recommendations to improve data collection and fulfill information needs are presented, including suggested data elements to be added to police accident report forms.

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)

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.

Median openings are an effective traffic organization mode for freeway crossover work zones, and their length is one of the most important control indicators to ensure traffic safety in work zones. In this paper, a theoretical calculation model of the median opening length was established according to the lane-changing demands of vehicles crossing through the median opening of the freeway. Based on the calculation model, the influencing factors of the median opening length were analyzed, and the calculation values of the median opening length under different speed limits, median widths and cross slopes were proposed. A naturalistic driving experiment of drivers’ safety and comfort, with 48 participants at four opening lengths of 40, 70, 100 and 130 m in a typical freeway work zone, was carried out based on the calculated length values and the driving workload, expressing drivers’ safety and comfort. It was found that the median opening length of the freeway had a positive correlation with the vehicles’ running speed and the drivers’ driving workload: the shorter length reduced the running speed of the vehicles and led to uncoordinated running speeds in the work zone; the longer length caused driver tension and led to the vehicles’ running speed and speed variability being too high. The research results indicated that the median opening length of freeway work zones is an important factor affecting the vehicle running speed, driving workload and speed limit compliance rate.

Mobile construction operations that are conducted at night and do not employ positive barrier systems present significant safety hazards for workers and motorists. As part of several research studies on the effectiveness of traffic control devices to enhance work zone safety, the authors investigated the impacts of construction equipment and operations on safety and exposed how a contractor could use the construction operations advantageously to benefit work zone safety. Five preservation (re-paving) projects on high-speed roadways were selected for data collection. On each project, traffic speeds were recorded prior to and at multiple points within the work zones while the work was conducted. The results reveal that the presence of large construction equipment in the work area impacts driver speed. Vehicles begin to slow down approximately 0.2 to 0.6 mi. before reaching the paver, and then increase over approximately the same distance after the paver. The amount of decrease in speed ranged from approximately 5 to 25 mph. In addition, the lateral distance between vehicles and construction equipment was also found to impact vehicle speeds. The findings reveal that contractors can utilize the presence of equipment and strategically-planned operations to benefit safety in work zones. While the findings are applicable to mobile construction operations on high-speed roadways, it is expected that equipment could be used and operations planned strategically on other types of projects, such as building projects, to benefit safety in a similar manner.

Safety of work zones is a major area of concern since it is not always possible to maintain a level of safety comparable to that of a normal highway not under construction. Proper traffic control is critical to the safety of work zones. However, traffic control devices themselves may pose a safety hazard when impacted by errant vehicles. The impact performance of many work zone traffic control devices is mostly unknown, and little, if any, crash testing has been conducted in accordance with guidelines set forth in NCHRP Report 350. The Texas Department of Transportation (TxDOT) has, in recent years, sponsored a number of studies at the Texas Transportation Institute to assess the impact performance of various work zone traffic control devices, including plastic drums and sign substrates, temporary and portable sign supports, plastic cones, vertical panels, and barricades. The results, findings, conclusions, and recommendations are presented for temporary and portable sign supports, plastic drums, sign substrates for use with plastic drums, traffic cones, and vertical panels, whereas those for barricades are covered elsewhere. Most of the work zone traffic control devices satisfactorily met the evaluation criteria set forth in NCHRP Report 350 and are recommended for field implementation. However, some of the devices failed to perform satisfactorily and are not recommended for field applications. The results from these studies are being incorporated into the TxDOT barricade and construction standard sheets for use in work zones.

Mitigation strategies for work zone congestion are used by transportation agencies to manage or reduce congestion through a work zone as part of the project's transportation management plan. The objective of this research is to assist agencies’ strategy selection by identifying strategies used by state transportation agencies (STAs) nationwide and their experiences. An online survey was developed to identify current, past, and future strategy implementation for projects similar to four developed scenarios: rural reconstruction, rural resurfacing, urban reconstruction, and urban resurfacing projects. The survey received 42 responses from individuals representing 28 states (responses were received from multiple districts or regions from a few states). It was found that agencies used several strategies to address different aspects of mobility and safety. Strategy selection varied between facility location and work activity. STAs also provided strategies that failed to meet expectations and identified strategies their agency plans to implement in the future. Based on the survey results and gaps in current literature, recommendations for strategy selection and future research are provided.

Highway work zones are associated with significant adverse impacts on safety. Mitigating these impacts can be achieved by implementing several countermeasures. This paper uses controlled experiments in a driving simulator to investigate the effects of physical and digital temporary traffic control countermeasures on work zone safety. These include variable message signs, dynamic speed displays, rumble strips, and lane widths. 116 participants were recruited for the experiment. A linear mixed-effects model was developed to capture the effects of these countermeasures on average travel speed and standard deviation of speeds in the advanced warning area and within the work zone itself. The results reveal that rumble strips installed within the work zone cause the strongest reduction in speeds. Narrower lanes cause smaller speed reductions. In general, the effects of temporary traffic control countermeasures on speeds were local and were not retained beyond their proximity.

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

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.

Improving construction work zone safety using technology: A systematic review of applicable technologies