Mitigating Work Zone Safety and Mobility Challenges through Intelligent Transportation Systems

Case Studies

CHAPTER 1 - INTRODUCTION

Intelligent Transportation Systems, or ITS, is the application of electronics, communications, and/or information processing to improve the efficiency and/or safety of surface transportation systems (1). ITS can improve transportation safety, mobility, and societal productivity through the integration of advanced communications technologies into the transportation infrastructure and in vehicles. ITS encompasses a broad range of wireless and wire line communications-based information and electronics technologies (2).

One application where ITS can have substantial benefits is in work zones. ITS has been successfully used in work zones for several purposes, including:

• Traffic monitoring and management,
• Provision of traveler information,
• Incident management,
• Safety enhancement,
• Capacity enhancement,
• Enforcement,
• Performance-based contracting, and
• Work zone planning.

Work zone ITS has seen ongoing technological development for more than 10 years. A significant amount of testing has occurred to prove concepts, identify and address challenges in communications, and automate decision algorithms for control and information dissemination. From this, much has been learned and documented in various case studies (3-11). However, work zone ITS is now evolving from being an developmental strategy for improving safety, operations, and productivity to more of a “mainstream” tool available to the work zone planner/designer and developers of transportation management plans (TMPs) to mitigate specific safety and mobility challenges that can exist on a project.

A range of approaches to using technology and data, including ITS, in work zones are now available. These include:

• Commercial off-the-shelf (COTS) systems,¹
• Tailored systems,
• Third-party traffic data, and
• Application and enhancement of permanent ITS for work zone purposes.

A number of COTS systems are now available to provide traffic monitoring and meet specific traveler information dissemination needs. Most commonly, these systems are implemented to mitigate safety concerns that arise from non-recurrent congestion developing because of the work zone, to provide real-time travel time and delay information, and to improve motorist awareness and reduce anxiety about travel conditions ahead.

The second work zone ITS deployment option that occurs less frequently (but which is still a viable approach) is the tailored design and integration of specific ITS devices into a customized system to meet unique work zone traffic management and control needs. Creation of a traffic monitoring system to assess contractor compliance with a mobility-based performance specification would be an example of this approach.

Still another option for implementing work zone ITS is to use (and possibly supplement) existing permanent ITS technologies (where available) to address work zone safety and mobility challenges. The breadth of coverage of permanent ITS has increased significantly across the U.S. in recent years. With proper planning, these systems can (and should) be used to effectively manage traffic during the work zone period. In some cases, additional devices are needed to address temporary bottlenecks or other impacts in and around the work zone or to maintain system capabilities when the permanent devices are temporarily disabled and/or removed.

The primary objective of this report is to document several case studies of work zone ITS used to mitigate safety and/or mobility issues in the work zone. It is valuable to understand how agencies and contractors are deciding when, where, and what to apply (i.e., the decision-making process), as well as the results of those decisions. This report provides examples of the decision-making processes and steps followed by the agency/contractor in designing, selecting, and implementing a system and the deployment results.

The report follows a traditional systems engineering design process as a roadmap to describe each implementation. In general, a systems engineering design process consists of these steps:

1. Define the problem,
2. Specify requirements of a solution,
3. Identify and evaluate alternatives, as necessary,
4. Select, design, and implement the best solution, and
5. Evaluate (i.e., describe the lessons learned).

Successful implementation of ITS applications in work zones requires a systematic approach to provide a technical solution that accomplishes a set of clearly defined objectives. A systems engineering process should be applied to determine the feasibility and design of work zone ITS for a given application by walking through key phases, from project concept through operation. Although the overall scope of a given project ultimately determines the complexity and level of effort required during planning, a systems engineering process should apply equally to the range of deployments, from small-scale, temporary deployments lasting a few months using COTS systems to complex, multi-year ITS deployments that may eventually be incorporated into permanent traffic monitoring and management systems.

Work zone ITS deployments at five case study sites are presented to illustrate four types of applications:

1. Mitigating High-Speed Rear-End Work Zone Crashes: Illinois DOT Experiences in Effingham and Mount Vernon – examples of selecting and deploying COTS systems.
2. Traffic Mobility Performance Specification Monitoring: The Utah DOT Bangerter Highway Project Experience – an example of a tailored design and integration of ITS for a specific work zone purpose.
3. Managing Traffic During Construction: The Utah DOT I-15 CORE Project Experience – an example of supplementing existing permanent ITS.
4. Managing Work Zone Traffic: The Las Vegas Transportation Management Center (FAST) Experience – examples of using permanent ITS for work zone management purposes.

The report concludes with a summary of key concepts drawn from the case studies to assist practitioners with deciding when and how to apply ITS to address safety and mobility issues in their work zones. Additional information on planning, procuring, deploying, and evaluating work zone ITS can be found in Work Zone Intelligent Transportation Systems Implementation Guide (FHWA-HOP-14-008).

¹Stand-alone, commercially available products that serve specific functions (i.e., smart work zone systems that can perform queue warning, travel time and delay information dissemination, dynamic late or early merge warnings at lane closures, etc.).

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