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4 Chapter 2. What are 3R Projects? This chapter discusses the definition of 3R projects and how they differ from new construction and reconstruction projects, the objectives of 3R projects, and typical improvements considered in 3R projects in addition to resurfacing. 2.1 New Construction vs. Reconstruction vs. 3R Projects Understanding of the context for design of 3R projects requires understanding of the distinctions between new construction, reconstruction, and 3R work. Each of these types of projects is defined below. 2.1.1 New Construction Projects New construction projects typically consist of projects on new alignment where no highway facility has existed before (e.g., projects on greenfield sites). Some projects on existing roads might be classified as new construction if the existing roadway is completely removed, a new alignment or cross section is developed for the facility, and the new alignment and cross section are not substantially constrained by development adjoining the existing road; this situation is rare, but can occur. New construction projects are designed using the criteria in the AASHTO Green Book (4). The design guidelines presented here do not apply to new construction projects. 2.1.2 Reconstruction Projects Reconstruction projects include projects on existing roads that are not considered new construction and in which: ï· the entire pavement structure, down to the subgrade, is removed and replaced, for all or most of the project length, ï· a substantial proportion of the existing alignment is modified, or ï· the basic roadway cross section is changed (e.g., expanding an existing two-lane highway to four lanes) Reconstruction projects are designed using the criteria in the AASHTO Green Book (4). The design guidelines presented here do not apply to reconstruction projects.
5 2.1.3 3R Projects 3R projects include projects in which the scope is limited to resurfacing, restoration, and/or rehabilitation of existing roads. 3R projects do not involve new construction or reconstruction, as defined above. Therefore, by definition, 3R projects do not involve a substantial amount of road construction on a new alignment, removal of the entire pavement structure down to the subgrade, realignment of substantial portions of the project, or a change in the basic roadway cross section. If only a limited or isolated portion of a project involves new construction or reconstruction, the remainder of the project can be designed as 3R work. Projects with overlays of any depth and projects involving cold milling to remove an obsolete surface course and/or maintain a pavement surface elevation consistent with vertical clearance design may be considered 3R projects. For purposes of the design guidelines presented in this document, projects may be classified as 3R projects regardless of whether they are funded as part of the Federal 3R program or any other designated 3R program. The design guidelines presented here are applicable to projects that are not considered new construction or reconstruction and involve only resurfacing, restoration, and/or rehabilitation, regardless of the project funding source. Chapters 2 through 5 present general design guidance applicable to all 3R projects. Chapter 6 presents design guidelines applicable to 3R projects on specific roadway types. Chapter 7 summarizes all of the design guidelines. 2.2 Objectives of 3R Projects The primary objective of most 3R projects is to preserve and extend the life of the pavement by resurfacing. Thus, 3R projects are normally initiated because pavement management systems indicate the need for pavement resurfacing. Furthermore, the timing of most 3R projects is set based on the timing of the need for pavement resurfacing to preserve and extend the life of the pavement structure. A few 3R projects are initiated to address needs other than pavement resurfacing and, as long as they do not involve new construction or reconstruction, they can be considered as 3R projects for design purposes. While the primary objective of most 3R projects is pavement preservation, the development of a 3R project provides an opportunity for geometric design improvements to enhance traffic operations, reduce crashes, improve drainage, or improve the roadway or roadside in other ways. The project would still be considered 3R work as long as the design changes do not constitute new construction or reconstruction. It is to the advantage of both the highway agency and the traveling public for any needed design changes to be made in conjunction with the pavement resurfacing project; coordination of such improvements reduces implementation costs and reduces travel delays in work zones, in comparison to implementing separate projects at separate times. Federal guidelines require highway agencies to consider the need for traffic operational and safety improvements in the project development process for 3R projects funded through the Federal 3R program. The guidelines presented in this document show a structured process for
6 considering the need for traffic operational and safety improvements in 3R projects that is intended to focus such improvements on locations where the improvement will be cost-effective. The guidelines indicate that design improvements should not necessarily be made in all 3R projects, but only when engineering analyses confirm that the proposed improvements are appropriate and cost-effective or where a specific need is otherwise demonstrated. 2.3 Typical Improvements Made in 3R Projects in Addition to Resurfacing A broad range of highway infrastructure improvements may be considered in 3R projects in conjunction with pavement resurfacing. A recent survey found that most highway agencies routinely consider the need for specific design improvements intended to reduce crash frequency and severity in 3R projects (7). Another survey identified the types of design improvements most commonly cited by highway agencies as among the top five improvement types made in conjunction with 3R projects (7,8). These include: ï· Guardrail addition or improvement (including improvement of guardrail end treatments) ï· Shoulder paving, grading, or widening ï· Clear zone improvements ï· Signing improvements ï· Shoulder or centerline rumble strips ï· Striping and delineation ï· Superelevation restoration ï· Pavement surface condition/friction ï· Intersection design/turn lanes/turn radius ï· Roadway/lane widening ï· Roadside slope flattening These improvement types and others that may be incorporated in 3R projects are addressed in Chapter 6 of these guidelines.