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National Cooperative Highway Research Program (NCHRP) Synthesis 485: Converting Paved Roads to Unpaved explores how common and under what conditions paved roads are converted to unpaved. NCHRP Synthesis 485 found that the pract...
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National Cooperative Highway Research Program (NCHRP) Synthesis 485: Converting Paved Roads to Unpaved explores how common and under what conditions paved roads are converted to unpaved. NCHRP Synthesis 485 found that the practice of converting paved roads to unpaved is relatively widespread; recent road conversion projects were identified in 27 states. These are primarily rural, low-volume roads that were paved when asphalt and construction prices were low. Those asphalt roads have now aged well beyond their design service life, are rapidly deteriorating, and are both difficult and expensive to maintain. Instead, many local road agencies are converting these deteriorated paved roads to unpaved as a more sustainable solution. According to the report, local road agencies have experienced positive outcomes by converting roads. Many local road agencies reported cost savings after converting, compared with the costs of continuing maintenance of the deteriorating paved road, or repaving. One key to successful conversion is early involvement of the public in the planning process. Other techniques that can be used to improve the overall results of a project include treating or stabilizing granular surfaces to control dust, limiting the rate of aggregate loss, and reducing motor grader/blade maintenance frequency. Stabilization procedures can also improve safety, increase public acceptance, and reduce life-cycle costs and environmental impacts after a conversion has taken place. Project: Project Information
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The purpose of this study was to identify agencies that have converted roads from paved to unpaved. The study also identified tools, metrics, and procedures that have been used in the decision-making process for when and how to c...
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The purpose of this study was to identify agencies that have converted roads from paved to unpaved. The study also identified tools, metrics, and procedures that have been used in the decision-making process for when and how to convert a road; impacts of road conversions; public outreach efforts; and knowledge gaps and research needs.
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National Cooperative Highway Research Program (NCHRP) Report 821: Effective Project Scoping Practices to Improve On-Time and On-Budget Delivery of Highway Projects demonstrates how a state department of transportation (state DOT) ...
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National Cooperative Highway Research Program (NCHRP) Report 821: Effective Project Scoping Practices to Improve On-Time and On-Budget Delivery of Highway Projects demonstrates how a state department of transportation (state DOT) can enhance its scoping process and practices to produce a project cost estimate and schedule that facilitate improved programming decision making and accountability. The guidebook illustrates the effort needed to develop a robust cost estimate and then manage to a baseline budget and scope throughout the project delivery cycle. The guidebook is applicable to a range of project types and is scalable in its ability to accommodate projects of varying complexity. Increasing or otherwise changing the scope of a project to improve facility performance is a common source of cost increases and schedule delays, as is failure to adequately consider project impacts on utilities, communities, or the environment. Industrial and commercial building construction sectors have experienced similar problems with construction project scope growth, cost increases, and time delays that occur after a project has been authorized for detailed design and construction. Recent research in these sectors has produced a structured and systematic process to help owners meet project cost and schedule objectives by defining a project to a suitable level of development prior to authorization of detailed design. Statistical evidence indicates that earlier and more detailed scoping efforts can reduce total design and construction cost by as much as 20%, and shorten total design and construction schedules by as much as 39%. Such scoping processes, with supporting indices and tools to calibrate the level of scoping effort required to achieve these results, have become standard procedures that many private U.S. corporations use in their capital facilities development efforts. With modifications, these processes and tools may be transferable to the transportation industry.
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This report presents guidance for state departments of transportation (DOTs) and other agencies for estimating preconstruction services (PCS) costs for transportation project development. PCS refers to a varied assortment of pr...
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This report presents guidance for state departments of transportation (DOTs) and other agencies for estimating preconstruction services (PCS) costs for transportation project development. PCS refers to a varied assortment of project-specific engineering and other professional services required before construction begins on a bridge, highway, or other transportation project, whether provided by agency staff or consultants. The guidance—a guidebook and supporting research report—addresses principal sources and components of PCS costs, PCS estimating methodologies, trends (such as changes in design and construction technology, design standards, program requirements, and professional workforce) likely to affect PCS costs, and advice on agency policies and practices that can help control program risk through improved PCS cost estimation. The report will be helpful particularly to DOT staff and management responsible for the agency’s project development and delivery activities.
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摘要 :
This report presents guidance for state departments of transportation (DOTs) and other agencies for estimating preconstruction services (PCS) costs for transportation project development. PCS refers to a varied assortment of pr...
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This report presents guidance for state departments of transportation (DOTs) and other agencies for estimating preconstruction services (PCS) costs for transportation project development. PCS refers to a varied assortment of project-specific engineering and other professional services required before construction begins on a bridge, highway, or other transportation project, whether provided by agency staff or consultants. The guidance—a guidebook and supporting research report—addresses principal sources and components of PCS costs, PCS estimating methodologies, trends (such as changes in design and construction technology, design standards, program requirements, and professional workforce) likely to affect PCS costs, and advice on agency policies and practices that can help control program risk through improved PCS cost estimation. The report will be helpful particularly to DOT staff and management responsible for the agency’s project development and delivery activities.
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National Cooperative Highway Research Program (NCHRP) Synthesis 489: Extending Bridge Service Like Through Field Welded Repairs and Retrofits documents practices associated with field welded repairs on existing steel bridges used ...
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National Cooperative Highway Research Program (NCHRP) Synthesis 489: Extending Bridge Service Like Through Field Welded Repairs and Retrofits documents practices associated with field welded repairs on existing steel bridges used by bridge owners. The information presented includes the extent to which field welding is performed on existing bridges, common types of field welded repairs and retrofits, specifications, and quality control practices.
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National Cooperative Highway Research Program (NCHRP) Report 823: Guidelines for Certification and Management of Flexible Rockfall Protection Systems provides advice on rockfall fence systems for transportation agencies. It also o...
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National Cooperative Highway Research Program (NCHRP) Report 823: Guidelines for Certification and Management of Flexible Rockfall Protection Systems provides advice on rockfall fence systems for transportation agencies. It also outlines data that are needed to evaluate the results of rockfall fence systems tested using the procedure recommended for acceptance. Finally, the report presents guidelines for asset management for rockfall fence systems to assist transportation agencies in incorporating these systems into existing transportation asset management plans.
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National Cooperative Highway Research Program (NCHRP) has released a non-edited, pre-publication version of Report 828: Guidelines for Nighttime Visibility of Overhead Signs. While the Manual on Uniform Traffic Control Devices (MU...
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National Cooperative Highway Research Program (NCHRP) has released a non-edited, pre-publication version of Report 828: Guidelines for Nighttime Visibility of Overhead Signs. While the Manual on Uniform Traffic Control Devices (MUTCD) provides minimum retro-reflectivity standards for overhead signs, there are few guidelines that agencies can reference to decide how to provide sufficient nighttime performance of overhead signs in site-specific situations. This report explores legibility distances for drivers in controlled conditions and the effects of sign luminance and visual complexity on the distance at which a driver can read overhead signs and street signs. The report presents proposed guidelines for nighttime overhead sign visibility, formatted as a potential replacement for the current Chapter 10, Roadway Sign Lighting, in the 2005 AASHTO Roadway Lighting Design Guide.
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National Cooperative Highway Research Program (NCHRP) Synthesis 494: Life-Cycle Cost Analysis for Management of Highway Assets documents the state of the practice of life-cycle cost analysis (LCCA) and risk-based analysis into sta...
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National Cooperative Highway Research Program (NCHRP) Synthesis 494: Life-Cycle Cost Analysis for Management of Highway Assets documents the state of the practice of life-cycle cost analysis (LCCA) and risk-based analysis into state highway agencies' asset management plans for pavements and bridges on the National Highway System. The objective of this project was to develop an inventory of quantitative asset-level, project-level, or corridor-level processes and models for predicting life-cycle costs associated with the preservation and replacement of highway assets. The report includes a literature review, a survey of highway agencies, and case studies that document specific highway agency experiences with LCCA.
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National Cooperative Highway Research Program (NCHRP) Report 827: Navigating Multi-Agency NEPA Processes to Advance Multimodal Transportation Projects analyzes approaches taken by state departments of transportation (DOTs), their ...
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National Cooperative Highway Research Program (NCHRP) Report 827: Navigating Multi-Agency NEPA Processes to Advance Multimodal Transportation Projects analyzes approaches taken by state departments of transportation (DOTs), their local partners, and other project sponsors to satisfy National Environmental Policy Act (NEPA) requirements for transportation projects involving more than one mode. Case studies illustrate successful practices and provide examples of institutional arrangements used to comply with NEPA requirements for two or more U.S. DOT agencies. Project: Project Information
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