Managed lanes are highway facilities or a set of lanes where operational strategies are proactively implemented, such as pricing, vehicle eligibility, access control, traffic control, or a combination of these strategies. Numerous domestic and international agencies either have constructed or are planning managed lanes. Each facility is unique and presents issues and challenges because these facilities are often implemented in high-demand, congested, or constrained corridors. There has been no singular guidance to assist transportation agencies implementing managed lanes. Some information on managed lanes has been included in American Association of State and Highway Transportation Officials (AASHTO) and Federal Highway Administration (FHWA) guides, but they do not explicitly address the wide range of issues and complexity associated with managed lanes in sufficient detail to serve as a national guide on the subject. Practitioners seek a better understanding of the unique planning, design, operations, and maintenance considerations associated with managed lanes, and how these factors interact. Managed lanes also have unique aspects related to financing, project delivery, public outreach, enforcement, and system integration that should be considered in each step of the project development process. The objective of National Cooperative Highway Research Program (NCHRP) Project 15-49 was to develop guidelines for the planning, design, operations, and maintenance of managed lanes. The final product–NCHRP Research Report 835: Guidelines for Implementing Managed Lanes–will become the primary reference on managed lanes and complement other national guidelines. It was designed to be applicable to practitioners at all levels of experience with managed lanes and to be used to support informed decision-making. The scope of this project was limited to managed lanes on freeways and expressways. The work on this project was conducted in two phases; Phase I consisted of four tasks, and Phase II contained three additional tasks. In Task 1 of the project, the research team conducted a review of literature on the planning, design, implementation, and maintenance considerations of managed lanes. A number of references serve as manuals or guidelines with national or widespread importance and are relevant to managed lane planning, design, implementation, operations, or maintenance. Researchers considered 14 such documents with information or guidance that could be referenced for multiple topics within the anticipated outline for the guidelines document that was produced as part of this project. Researchers also reviewed an additional 150 sources and summarized their information on a variety of topics related to planning considerations, design elements, implementation and deployment, and operations and maintenance; those sources are summarized in Appendix A of this report. As part of Task 2 efforts, the research team conducted a review of current policies, guidelines, and other documents in use by agencies that operate managed lanes. Rather than attempting to review documents from every agency in the United States, the research team reviewed 36 online documents from 16 state, regional, and local agencies considered to be among the leaders and innovators in managed lanes. The agencies are located in the states of Arizona, California, Colorado, Florida, Georgia, Maryland, Minnesota, Nevada, Tennessee, Texas, Virginia, and Washington. The documents reviewed contain guidance or policy statements on a wide variety of topics related to the planning, design, implementation, and operation of managed lanes. The information from those documents is summarized by topic in Appendix B of this report. In a separate effort within Task 2, research team members contacted managed lane practitioners in two ways to explore priority gaps in understanding and guidance for the development of new managed lanes. The first process involved one-on-one stakeholder interviews; 18 state departments of transportation (DOTs) and regional operating agencies were contacted for on-eon-one phone interviews, with 11 successfully completed. The second process consisted of a group survey conducted with the Transportation Research Board (TRB) Managed Lanes Committee (AHB35), concurrent with the 2014 TRB Annual Meeting in Washington, DC. The purpose of the stakeholder interviews was to explore stakeholders’ guidance for specific topical areas of managed lane planning, development, implementation, and operations from which operators/agencies believe they could benefit. Three primary questions were posed to interviewees: 1. For which topics did you seek guidance but found available guidance to be lacking? 2. Looking at the next 5—10 years, what emerging trends require additional consideration? 3. What lessons learned and/or best practices has your organization uncovered? In the Managed Lanes Committee meeting, researchers provided an overview of the project and participants were asked to provide suggested areas of focus for the research effort, keeping the following two questions in mind: * What do you wish you had known while developing your managed lane project(s)? * What information would be helpful to you that is not readily available in other sources? Nine research topics emerged through the course of both the stakeholder interviews and the committee discussion: * Pricing approach and messaging to travelers. * Access considerations. * Interconnected facilities. * Designing for reduced standards. * Operational differences between one- and two-lane facilities. * Toll system design. * Vehicle class preferences and enforcement. * Inter-jurisdictional issues. * The business case for managed lanes (i.e., under what conditions do they make sense and how can they be developed). These topics are described in more detail in Appendix C of the report. Based on the information compiled in Tasks 1 and 2, the research team in Tasks 3 and 4 identified gaps in existing knowledge that could be explored through additional research. In some cases, these identified gaps were related to subject matter, where limited documentation of prevailing practice exists. In other cases, gaps were related to the lack of syntheses that pull together the wealth of commonly available information so that the practitioner can more easily understand what practices are prevalent and why. The third type of gap was related to the way that material was presented in prior references. Except for the Manual on Uniform Traffic Control Devices (MUTCD) and specific policy and design guidance at the state and local level, there was a dearth of prescriptive guidance for topics that are often interrelated and have rather substantial safety and operational impacts on the driver experience. Prior guidance has generally been written in synthesis perspective to capture all types of practice and give a context for how each is used, without taking the next step of identifying which may be preferred or recommended and why. Researchers documented over 40 knowledge gaps and potential research ideas, which were then categorized and presented in an interim report to correspond with chapters in the guidelines document. The research team also prepared a work plan for Phase II of the project to address some of the most important knowledge gaps, as prioritized by the research team and the project panel. In Task 5 of the project, the first task of Phase II, the research team conducted a series of studies on four topics considered to be the highest priority of the knowledge gaps identified in Phase I. Those topics included factors that affect the decision-making process, trade-offs for dimensions within managed lane envelopes, factors that affect operating speed on buffer-separated managed lanes, and factors that influence access design. Chapter 2 of this report describes a set of case studies used to develop a synthesis on the decision-making process; the two primary categories of information are project conversions (i.e., pricing implemented on high-occupancy vehicle [HOV] lanes) and new construction. The chapter provides comparative characteristics of facilities that the practitioners were responsible for designing; a summary of challenges the practitioners faced; a description of organizational and procedural practices in design; and listings of key transferable practices, identified gaps in practice, and lessons learned. Appendix D lists the actual interview questions used to prepare the synthesis, and Appendix E provides details on the regions selected for case studies. The project included two studies on the trade-offs and effects of lane, shoulder, and buffer widths on managed lane facilities. One study gathered managed lane practitioner information on the trade-offs considered when making cross-section width decisions and reviewed this information using focus groups. The other study identified the relationship as revealed through travel data between operations and cross-section width, including the type of buffer design separating the managed lanes from the general-purpose lanes. Key measures believed to be affected by lane, shoulder, and buffer widths are operating speed and lateral position because drivers may adjust their speed or position in the managed lane depending on their proximity to a concrete barrier or adjacent general-purpose lane. Chapter 3 of this report provides the details of the research team’s activities in these studies. Chapter 4 describes a field study in which speed data from Los Angeles and Orange County, California, and Dallas, Texas, were used to investigate the variables that affect operating speed in buffer-separated managed lanes. In uncongested conditions, statistical models of the managed lane operating speed had an intercept value greater than 50 mph. Factors that were found to have the most influence on uncongested managed lane speed included geometry (in Texas), managed lane volume (in both states), presence of pylons in the buffer (in Texas), speed in the adjacent general-purpose lane (in both states), and day of the week (in both states). The final Phase II study focused on characteristics of access to managed lanes, particularly how practitioners make decisions on what type of access to provide (i.e., continuous or restricted) and where access points should be located if access is restricted. Researchers contacted a group of practitioners with recent and/or ongoing experience in designing or implementing managed lane access to determine their current practices and desired topics for additional information. Details of the study on managed lane access, including key findings from the practitioner interviews, can be found in Chapter 5 of this report. Based on the information compiled in the previous tasks, the research team identified gaps in existing knowledge that could be explored through additional research. In some cases, these identified gaps were related to subject matter, where there was limited documentation of prevailing practice. In other cases, gaps were related to the lack of syntheses that pull together the wealth of commonly available information so that the practitioner can more easily understand what practices are prevalent and why. Researchers updated their list of identified knowledge gaps and potential research ideas from Phase I; those needs are categorized and presented in Chapter 6 to correspond with chapters in the guidelines document. Task 6 of the project focused on developing the final project documents including this research report and the guidelines, which has been prepared and published as a stand-alone document. A more detailed summary of the project as a whole can be found in Chapter 7 of this report. (Author/publisher)
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