Developing Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects (2021)

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1 Chapter 1. Introduction 1.1 Introduction Geometric design criteria have historically been established by American Association of State Highway and Transportation Officials (AASHTO) policies, updated most recently in the 2011 Green Book (1), which apply to new construction and reconstruction projects. After each updated AASHTO policy is published, FHWA typically adopts the AASHTO geometric design criteria by regulation for application to the National Highway System (NHS) (2). Until 1976, Federal highway funds could be used only for new construction or reconstruction projects. The Federal-Aid Highway Act of 1976 first permitted state and local highway agencies to use Federal funds for resurfacing, restoration, and rehabilitation (3R) projects on existing federal-aid highways. Congress specified safety as one of the criteria to be considered in designing 3R projects, but did not specify any particular set of geometric design criteria. In 1977, AASHTO (3) proposed a set of geometric design criteria for 3R projects (the “purple pamphlet”) that were less restrictive than the geometric design criteria in use for new construction and reconstruction. This proposal brought criticism from safety advocates who wanted all geometric elements on 3R projects to be upgraded to full new construction criteria in the name of safety. One of the controversies questioned whether resurfacing of 3R projects without accompanying geometric improvements resulted in speed increases that, in turn, increased crash rates. Congress held hearings on this issue in 1981 and, as a result, the Surface Transportation Assistance Act of 1982 mandated a study of the cost-effectiveness of geometric design standards and the development of minimum standards for 3R projects on roads other than freeways. The result of this Congressional mandate was the formation of a study committee and the publication in 1987 of TRB Special Report 214, Designing Safer Roads: Practices for Resurfacing, Restoration, and Rehabilitation (4). Special Report 214 proposed geometric criteria for 3R projects that have become the basis for the 3R design policies of many highway agencies. There have been many changes in both the state of knowledge and highway agency policies since the publication of TRB Special Report 214 in 1987. These include:  Five updates to the AASHTO Green Book (in 1990, 1994, 2001, 2004, and 2011)  Establishment of agreements between FHWA and a number of state highway agencies on 3R design policies  Publication of the AASHTO Guidelines on Geometric Design of Very Low-Volume Local Roads (ADT ≤ 400) (5) in 2001  Publication of the latest safety knowledge in the first edition of the AASHTO Highway Safety Manual (HSM) (6) in 2010, with a supplement on freeways in 2014 (7)

2  Completion of additional safety research leading toward a second edition of the HSM  Updates of the TRB Highway Capacity Manual (HCM) (8) in 2000, 2010, and 2016 Given all of these changes, updating of TRB Special Report 214, which was written nearly 30 years ago, is very timely. Since the 1980s, fewer new roads have been built, shifting the emphasis of highway agencies to reconstruction or rehabilitation of the existing highway system. The aging highway system, coupled with fiscal constraints, is placing increased pressures on highway agencies to maintain the highway system in a cost-effective manner and is, thus, creating greater needs for 3R projects. To meet the current needs of highway agencies, the updated guidelines do not focus on dimensional geometric design criteria, but provide a benefit– cost analysis approach to assist agencies with geometric design decisions, together with tools to implement that approach. 1.2 Research Objective and Scope The objective of the research is to develop guidelines for safe and cost-effective practices for resurfacing, restoration, and/or rehabilitation projects. The primary focus of the guidelines is on rural two-lane roads, but the guidelines also address rural multilane roads, urban and suburban arterials, and freeways. The guidelines address both the roadway and the roadside. The guidelines developed in the research are based on the current state of knowledge concerning the effects of design improvements on crash frequency and severity. The guidelines include appropriate procedures for use by highway agencies to consider the tradeoffs between costs and benefits. The guidelines apply to 3R projects regardless of their funding source, including both projects funded with Federal funds and projects funded solely by state and local highway agencies. The guidelines focus on geometric design issues, but also address the role of pavement condition, traffic control devices (including pavement markings), road user characteristics, and tort liability in the 3R design process. 1.3 Research Approach The research began with a review of literature and current practice. The research documented current knowledge of the effects of design improvements typically used in 3R projects on crash frequency and severity. The research also documented current 3R design practices, including the guidance provided by TRB Special Report 214 (4) and current highway agency design practices. Highway agency design practices were documented through a highway agency survey and a review of highway agency design manuals. Guidance for design of 3R projects has been developed as part of the research and is presented in a stand-alone guidelines document (9). The guidelines are supplemented with two spreadsheet-based benefit–cost analysis tools that were developed specifically for assessment of 3R projects. Spreadsheet Tool 1 is used to assess a single design alternative (or combination of alternatives) for a specific 3R project. Spreadsheet Tool 2 is used to consider multiple design alternatives (or combinations of alternatives) and identify the alternative (or combination of alternatives) that provides the largest net benefits while not exceeding the available budget.

3 1.4 Organization of This Report The remainder of this report is organized as follows. Chapter 2 summarizes the findings of the literature and current practice review. Chapter 3 presents the highway agency survey results. Chapter 4 summarizes current highway agency 3R guidelines. Chapter 5 presents current knowledge on the crash reduction effectiveness of specific design improvement types typically implemented in 3R projects. Chapter 6 explains the procedures used to estimate 3R improvement implementation costs. The benefit–cost analysis procedures for assessment of 3R projects are presented in Chapter 7. The spreadsheet tools that implement the benefit–cost analysis procedures are introduced in Chapter 8, and the design development of guidelines for 3R projects is summarized in Chapter 9. Chapter 10 presents the conclusions of the research. Appendix A documents the cost estimation procedures for 3R improvements used in the spreadsheet tools. Appendix B presents the questionnaire used for the highway agency survey. Appendix C documents the updating of the crash costs (i.e., the benefits of reducing crashes of specific crash severity levels) used in the research.