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 Practices for Project-Level Analyses for Air QualityOctober 11, 2021 The nature of the transportation project-level air quality arena is evolving, and there are potentially significant impacts to project schedules and budgets should air quality issues arise. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 576: Practices for Project-Level An...
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 Temporary Pavement Markings Placement and Removal Practices in Work ZonesOctober 1, 2021 Agencies must consider many factors, such as work zone duration and weather conditions, in selecting appropriate pavement marking materials to effectively guide drivers through work zones. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 574: Temporary Pavement Markings Pla...
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 Practices for Integrated Flood Prediction and Response SystemsSeptember 10, 2021 State departments of transportation (DOTs) and other state and local agencies have implemented integrated flood warning and response systems to mitigate the effects of floods. These systems are critical for staging personnel, deciding when to close roads, inspecting bridges, tracking floods throu...
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 Night and Weekend Movement of Oversize/Overweight LoadsAugust 19, 2021 Permitted movements of oversize and overweight (OS/OW) loads traditionally occur during the daytime on weekdays to allow for adequate staffing support and safety-focused practices. Due to increases in traffic congestion, safety concerns over fleet mixes, and other factors, many states began allow...
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 Portland Cement Concrete Pavement Joint Sealant Practices and PerformanceJuly 9, 2021 Portland cement concrete (PCC) pavement joint sealing material technology has evolved in recent decades, and the effect of current joint sealant practice has not been well documented. Therefore, it is necessary to establish a standardized approach to joint sealant evaluation as well as to investi...
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 Summary State DOT Practices for Developing and Implementing TSMO PlansJuly 30, 2021 Transportation Systems Management and Operations (TSMO) programs include elements of operations, planning, design, construction, maintenance, and safety. They are frequently complex and cross jurisdictional boundaries, involving traditional state departments of transportation (DOTs), local DOTs, ...
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 Practices for Bridge Approach SystemsJuly 9, 2021 Bridge approach systems are used by state departments of transportation (DOTs) to form a smooth transition between the roadway and bridges. Adequate performance of bridge approaches is of extreme importance to transportation agencies as they affect both safety and the public perception of ride qu...
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 Practices for Selecting Pedestrian and Bicycle ProjectsMay 6, 2021 State departments of transportation (DOTs) conduct planning and administer funding programs for the implementation of pedestrian and bicycle projects. The amount of federal funds available for these projects has grown steadily since 1992 under programs implemented as part of the Intermodal Surfac...
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 Performance Metrics for Public–Private PartnershipsMay 5, 2021 Public–private partnerships (P3) allow public transportation agencies to attract private financing to deliver needed highway infrastructure and not have to wait until the required funding is fully in place via traditional state and federal sources. The TRB National Cooperative Highway Research Pr...
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 Repair and Maintenance of Post-Tensioned Concrete BridgesMay 3, 2021 The use of post-tensioning in concrete structures has allowed for the construction of economical long-span bridges. However, very limited information is available to guide bridge owners on how to maintain existing structures or, more specifically, to repair degraded post-tensioned structures. The...
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 Practices for Construction-Ready Digital Terrain ModelsMarch 5, 2021 Digital terrain models (DTMs) are three-dimensional (3D) models of the ground surface showing natural features such as ridges and breaklines. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 560: Practices for Construction-Ready Digital Terrain Models documents processes an...
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 Emerging Challenges to Priced Managed LanesSeptember 9, 2020 There is a wide disparity between the goals that state departments of transportation (DOTs) have for priced managed lanes and the public assumption for those goals. The public tends to be highly skeptical of priced managed lanes because the concept is difficult to explain to a nontechnical audien...
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 Utility Pole Safety and Hazard Evaluation ApproachesSeptember 8, 2020 In 2017, the latest year for which data are available, 887 fatal utility pole crashes occurred in the United States, accounting for 914 fatalities. These numbers were about the same as those in recent years but lower than such fatality numbers from a decade or two ago. The TRB National Cooperativ...
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 Estimating and Contracting Rock Slope Scaling Adjacent to HighwaysMay 29, 2020 Scaling loose rock from highway rock slopes is an important aspect of improving rock slope safety in mountainous areas, according to input from 42 state departments of transportation and two regional divisions of the Office of Federal Lands Highway. The TRB National Cooperative Highway Research P...
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 Advances in Unstable Slope Instrumentation and MonitoringAugust 10, 2020 Geotechnical instrumentation and monitoring technologies have been used to inform safety, operational, and treatment decisions for unstable slopes. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 554: Advances in Unstable Slope Instrumentation and Monitoring documents and ...
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 Performance-Based Pavement Warranty PracticesJuly 20, 2020 Pavement warranties have been common in the United States at various points in time, coming back into favor during the 1990s. While there is no national pavement warranty standard, agencies have developed their own specifications with varying criteria. The TRB National Cooperative Highway Researc...
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 Highway Hydraulic Engineering State of PracticeJune 30, 2020 The TRB National Cooperative Highway Research Program's NCHRP Synthesis 551: Highway Hydraulic Engineering State of Practice documents significant changes in highway hydraulic engineering practices implemented by state departments of transportation (DOTs) over the past decade. The synthesis focus...
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 Alternative Intersection Design and SelectionMay 13, 2020 State departments of transportation often encounter public resistance to alternative intersections, with 86% of respondents in a new survey of state DOTs agreeing or strongly agreeing that public resistance hinders their implementation. Public resistance can vary among projects based on intersect...
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 Incorporating Roadway Access Management into Local OrdinancesMarch 24, 2020 Managing access connections to roadways is vital to safety and operational performance of roadways for all users. Given the separation of authority between state and local governments over land development and access, intergovernmental coordination is integral to effective access management. The ...
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 Development and Use of As-Built Plans by State Departments of TransportationMay 8, 2020 Sixty-eight percent of the states who responded to a survey indicated their agency has a documented process for as-built development. They said handwritten notes were the most commonly used method to capture as-built data (86%), followed by electronic notes (76%), and then photographs (33%). Some...
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 Advancements in Use of Geophysical Methods for Transportation ProjectsMay 12, 2020 Geophysical methods provide a means to rapidly and economically characterize subsurface conditions and infer soil properties over a spatial extent that is not possible with conventional methods. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 547: Advancements in Use of Ge...
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 Electronic Ticketing of Materials for Construction ManagementJune 16, 2020 Collecting paper load delivery tickets at highway construction projects is an outdated practice that exposes construction inspectors to many safety hazards. State transportation agencies (STAs) have looked for decades toward automating this process through electronic ticketing, or e-ticketing. Th...
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 Concrete Technology for Transportation ApplicationsJanuary 29, 2020 The past few years have seen some significant advances in concrete technology. For example, newer concrete incorporating advances in admixtures and cementitious materials has emerged. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 544: Concrete Technology for Transportati...
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 Transportation Workforce Planning and Development StrategiesNovember 6, 2019 Estimates indicate that more than 14 million jobs—about 11% of civilian jobs in the United States—are related to infrastructure. Transportation has the potential to be a major U.S. job creator with projections to add 417,000 net jobs from 2012 to 2022. An additional 4.2 million workers will need ...
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 Prioritization of Freight Investment ProjectsSeptember 26, 2019 Freight investment project prioritization, which is used to assist in planning and programming decisions, differs widely in importance across states. One of the reasons for the difference in importance is the fact that freight projects are costly, and state departments of transportation (DOTs) fa...
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 Leveraging Private Capital for Infrastructure RenewalSeptember 3, 2019 Public–private partnerships (P3s) can provide solutions to the project delivery challenges faced by state departments of transportation (DOTs) and local transportation agencies in delivering surface transportation infrastructure by aligning risks and rewards between public and private sectors, ac...
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 Landscape Development and Management Practices for Urban Freeway RoadsidesAugust 9, 2019 Current practices used by state departments of transporttion to design and manage the urban freeway roadsides (UFRs) environment is the focus of National Cooperative Highway Research Program (NCHRP) Synthesis 539: Landscape Development and Management Practices for Urban Freeway Roadsides. The urb...
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 Practices for Online Public InvolvementJuly 9, 2019 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 538: Practices for Online Public Involvement summarizes current practices regarding online public participation strategies being used by state departments of transportation (DOTs), as well as explores the effectiveness of using...
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 Impact of Asphalt Thickness on Pavement QualityJuly 2, 2019 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 537: Impact of Asphalt Thickness on Pavement Quality documents transportation agency policy for lift thickness and minimum compaction requirements on resultant asphalt pavement quality. To achieve expected pavement performance,...
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 Bridge Demolition PracticesMay 31, 2019 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 536: Bridge Demolition Practices documents practices used by bridge owners to manage and administer bridge demolition in construction projects. Each year hundreds of bridges are rebuilt or are entirely replaced as part of highw...
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 Pedestrian Safety Relative to Traffic-Speed ManagementOctober 30, 2019 Measures that are effective at reducing speed, such as speed humps and mini traffic circles, are sometimes used in low-speed areas such as school zones. But they are often not recommended or allowed (via local policy) on the higher-speed streets typically associated with the highest injury severi...
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 Emerging Technologies for Construction DeliveryAugust 7, 2019 The uses and levels of maturity of five advanced technology areas visualization and modeling, interconnected technologies, safety technologies, instrumentation and sensors, and unmanned aircraft systems in transportation highway construction projects are documented in TRB’s National Cooperative H...
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 Very Short Duration Work Zone Safety for Maintenance and Other ActivitiesJuly 18, 2019 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 533 identifies the current state of practice among state departments of transportation (DOTs) regarding selection and setup of very short duration work zone (VSDWZ). The report presents case examples of four state DOTs along wi...
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 Seismic Design of Non-Conventional BridgesJune 20, 2019 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 532: Seismic Design of Non-Conventional Bridges documents seismic design approaches and criteria used for “non-conventional” bridges, such as long-span cable-supported bridges, bridges with truss tower substructures, and arch b...
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 Automated Pavement Condition SurveysJuly 23, 2019 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 531 documents agency practices, challenges, and successes in conducting automated pavement condition surveys. The report also includes three case examples that provide additional information on agency practices for conducting a...
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 Construction and Rehabilitation of Concrete Pavements Under TrafficAugust 31, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 530: Construction and Rehabilitation of Concrete Pavements Under Traffic identifies practices from projects representing a wide range of conditions and techniques. The current state of the practice in constructing or rehabilita...
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 Analyzing Data for Measuring Transportation Performance by State DOTs and MPOsJanuary 17, 2019 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 528: Analyzing Data for Measuring Transportation Performance by State DOTs and MPOs summarizes what data state departments of transportation (DOTs) and metropolitan planning organizations (MPOs) are using and how they are measu...
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 Resilience in Transportation Planning, Engineering, Management, Policy, and AdministrationJanuary 14, 2019 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis Report 527: Resilience in Transportation Planning, Engineering, Management, Policy, and Administration documents resilience efforts and how they are organized, understood, and implemented within transportation agencies’ core fu...
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 Practices in One-Lane Traffic Control on a Two-Lane Rural HighwayJune 26, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 525: Practices in One-Lane Traffic Control on a Two-Lane Rural Highway identifies innovative practices and devices for establishing one-lane traffic control on rural two-lane highways. Temporary traffic control, also known as m...
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 Aggregate Quality Requirements for PavementsJuly 23, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 524: Aggregate Quality Requirements for Pavements Aggregate Quality Requirements for Pavements documents transportation agency requirements for the quality of aggregates for various pavement types. Constructing and maintaining ...
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 Integration of Roadway Safety Data from State and Local Sources August 29, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 523: Integration of Roadway Safety Data from State and Local Sources documents the ways in which transportation agencies are collaborating with local agencies to integrate and maintain data. This information can help inform how...
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 Managing State Transportation Research ProgramsApril 26, 2019 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 522: Managing State Transportation Research Programs identifies the current state of practice of managing state transportation research programs. The report highlights existing resources, desired individual skill sets, core com...
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 Investment Prioritization Methods for Low-Volume RoadsMay 21, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 521: Investment Prioritization Methods for Low-Volume Roads documents current practices used by transportation agencies to make investment decisions about low-volume roads. Current transportation asset management practices for ...
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 Integrated Transportation and Land Use ModelsJuly 17, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 520: Integrated Transportation and Land Use Models presents information on how select agencies are using sketch planning models and advanced behavioral models to support decision making. The synthesis describes the performance ...
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 The Renewal of Stormwater Systems Using Trenchless TechnologiesJune 14, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 519: The Renewal of Stormwater Systems Using Trenchless Technologies summarizes technologies used for the renewal of stormwater systems, including new, emerging, and underutilized trenchless methods, and identifies future resea...
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 Staffing for Alternative Contracting MethodsAugust 1, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 518: Staffing for Alternative Contracting Methods documents current practices in state departments of transportation (DOTs) staffing and organizational structure for alternative contracting methods (ACMs). ACMs include design–b...
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 Corrosion Prevention for Extending the Service Life of Steel BridgesJuly 15, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 517: Corrosion Prevention for Extending the Service Life of Steel Bridges documents and describes the current practice for corrosion prevention of steel bridges. This report provides information on choosing materials and coatin...
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 Tack Coat Specifications, Materials, and Construction PracticesMay 14, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 516: Tack Coat Specifications, Materials, and Construction Practices provides state agencies across the United States with guidance as they reevaluate their tack coat specifications, the materials they use, and the practices by...
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 Practices for Preventing Roadway DeparturesJune 12, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 515: Practices for Preventing Roadway Departures identifies and summarizes practices being used by state departments of transportation (DOTs) to prevent roadway departure crashes and to identify the data-driven advantages and d...
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 Statewide and Megaregional Travel Forecasting Models: Freight and PassengerOctober 16, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 514: Statewide and Megaregional Travel Forecasting Models: Freight and Passenger documents current practices and emerging trends with travel forecasting models. The report explores the motivation for and capabilities of st...
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 Evolving Debt Finance Practices for Surface TransportationJune 30, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 513: Evolving Debt Finance Practices for Surface Transportation explores a variety of debt mechanisms and tools to finance transportation infrastructure investment. The amount of debt and frequency of issuance vary substantiall...
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 Use of Fiber-Reinforced Polymers in Highway InfrastructureSeptember 13, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 512: Use of Fiber-Reinforced Polymers in Highway Infrastructure documents the current state of the practice in the use of fiber-reinforced polymers (FRPs) in highway infrastructure. The synthesis identifies FRP applications, cu...
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 Relationship Between Chemical Makeup of Binders and Engineering PerformanceAugust 4, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 511: Relationship Between Chemical Makeup of Binders and Engineering Performance documents the current practices of departments of transportation (DOTs) in the selection of the chemical composition of a binder used in pavement ...
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 Resource Allocation of Available Funding to Programs of WorkMay 15, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 510: Resource Allocation of Available Funding to Programs of Work explores the decision-making process in state departments of transportation (DOTs) and how they determine resource allocation among different programs. The repor...
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 Highway Worker SafetyApril 21, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 509: Highway Worker Safety identifies how state departments of transportation (DOTs) implement policies using highway worker safety and health data to reduce injuries and manage risk. The report is a synthesis of current proact...
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 Data Management and Governance PracticesApril 20, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 508: Data Management and Governance Practices develops a collection of transportation agency data management practices and experiences. The report demonstrates how agencies currently access, manage, use, and share data.
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 Traffic Signal Preemption at Intersections Near Highway–Rail Grade CrossingsApril 16, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 507: Traffic Signal Preemption at Intersections Near Highway–Rail Grade Crossings documents the current practices of traffic signal preemption deployed at intersections adjacent to railway grade crossing in both the United Stat...
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 Effective Utility Coordination: Application of Research and Current PracticesFebruary 16, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 506: Effective Utility Coordination: Application of Research and Current Practices documents the state of the practice regarding utility coordination. The objective of the project was to determine how previous research has been...
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 Current Practices and Guidelines for the Reuse of Bridge FoundationsFebruary 27, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 505: Current Practices and Guidelines for the Reuse of Bridge Foundations provides guidance on reusing bridge foundations, a sustainable option for many bridge replacement and rehabilitation efforts that can result in time and ...
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 Strategic Program Delivery MethodsApril 24, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 504: Strategic Program Delivery Methods explores holistic approaches to maximizing the benefits of time and cost savings when delivering transportation programs, rather than delivering individual projects. While a considerable ...
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 Practices for Establishing Contract Completion Dates for Highway ProjectsMarch 6, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 502: Practices for Establishing Contract Completion Dates for Highway Projects documents current methodologies and procedures used by state transportation agencies to estimate contract time for various highway project delivery ...
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 Pavement Management Systems: Putting Data to WorkJanuary 31, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 501: Pavement Management Systems: Putting Data to Work documents current pavement management practices in state and provincial transportation agencies. The report focuses on the use of pavement management analysis results for r...
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 Control of Concrete Cracking in BridgesFebruary 8, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 500: Control of Concrete Cracking in Bridges provides information on methods used to control concrete cracking in bridge superstructures and substructures, and on the influence of cracking on long-term durability. Cracking of c...
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 Alternate Design/Alternate Bid Process for Pavement-Type SelectionJanuary 23, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 499: Alternate Design/Alternate Bid Process for Pavement-Type Selection documents the state of the practice in alternate design/alternate bid (ADAB) for pavement-type selection by highway agencies. ADAB is a contracting techniq...
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 Application of Pedestrian Crossing Treatments for Streets and HighwaysDecember 14, 2016 TRB's NCHRP Synthesis 498: Application of Pedestrian Crossing Treatments for Streets and Highways compiles information on the state of existing practices regarding application of pedestrian crossing improvements, and does not produce new guidance. The report includes a survey of state departments...
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 Post-Extreme Event Damage Assessment and Response for Highway BridgesDecember 26, 2016 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 497: Post-Extreme Event Damage Assessment and Response for Highway Bridges reviews the procedures that state departments of transportation and two local authorities, New York City and Los Angeles County, use to assess the damag...
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 Minimizing Roadway Embankment Damage from FloodingAugust 3, 2016 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 496: Minimizing Roadway Embankment Damage from Flooding documents the state-of-the-practice on how the transportation community is protecting roadways and mitigating damage from inundation and overtopping. This report highlight...
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 Life-Cycle Cost Analysis for Management of Highway AssetsMay 11, 2016 TRB's 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...
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 Practices for High-Tension Cable BarriersMay 24, 2016 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 493: Practices for High-Tension Cable Barriers reports on the current state of the practice for high-tension cable barriers (HTCB) used in the medians of access-controlled roadways in the United States. Information on high-tens...
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 Performance Specifications for Asphalt Mixtures June 20, 2016 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 492: Performance Specifications for Asphalt Mixtures documents the performance tests used in conjunction with volumetric properties for mixtures. Performance tests are intended to extend service life by guiding material selecti...
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 Practice of Rumble Strips and Rumble StripesMay 20, 2016 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 490: Practice of Rumble Strips and Rumble Stripes documents current practices used by states installing rumble strips and rumble stripes. The report details and explores variations in state highway agency practices in terms of ...
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 Extending Bridge Service Life Through Field Welded Repairs and Retrofits March 17, 2016 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 489: Extending Bridge Service Life 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 exte...
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 Roundabout Practices June 27, 2016 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 488: Roundabout Practices summarizes roundabout policies, guidance, and practices within state departments of transportation (DOTs) as of 2015. The synthesis may be used as a reference for state agencies that are creating or up...
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 Public Perception of Mileage-Based User FeesFebruary 24, 2016 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 487: Public Perception of Mileage-Based User Fees explores proposals to replace the current motor fuel tax with a road usage charge assessed on vehicle-miles traveled, often called a mileage-base user fee (MBUF). The report ide...
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 State Practices for Local Road SafetyJanuary 23, 2016 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 486: State Practices for Local Road Safety explores state programs and practices that address local agency road safety. The report focuses on changes in local road safety programs since the legislation of Moving Ahead for Progr...
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 Converting Paved Roads to Unpaved January 20, 2016 TRB’s 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 widesprea...
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 Training and Certification of Highway Maintenance WorkersJanuary 15, 2016 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 483: Training and Certification of Highway Maintenance Workers documents front-line maintenance worker training and certification practices for highway transportation agencies in the United States and Canada. The report include...
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 Work Zone Speed ManagementOctober 22, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 482: Work Zone Speed Management documents the current state of practice for work zone speed management, including data, procedures, techniques, and technical issues related to observing and comparing work zone speeds.
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 Economic and Development Implications of Transportation DisinvestmentJuly 17, 2015 TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 480: Economic and Development Implications of Transportation Disinvestment examines methods available to estimate disinvestment effects on transportation system integrity within and across modes in urban areas, regionally, and ...
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 Forecasting Transportation Revenue Sources: Survey of State PracticesMay 24, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 479: Forecasting Transportation Revenue Sources: Survey of State Practices documents current and proposed forecasting methodologies, as well as shortcomings of methods as reported by state departments of transportation (DOTs). ...
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 Design and Load Testing of Large Diameter Open-Ended Driven PilesJuly 15, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 478: Design and Load Testing of Large Diameter Open-Ended Driven Piles documents information regarding the current state of practice with respect to the selection, use, design, construction, and quality control of large diamete...
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 Methods and Practices on Reduction and Elimination of Asphalt Mix Segregation June 8, 2015 TRB's National Cooperative Highway Research Program Synthesis 477: Methods and Practices on Reduction and Elimination of Asphalt Mix Segregation provides guidance on how to reduce or eliminate segregation during aggregate production, mix design, asphalt mix production, mix transport and transfer,...
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 Practices for Permitting Superheavy Load Movements on Highway PavementsMay 3, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 476: Practices for Permitting Superheavy Load Movements on Highway Pavements documents the practices followed in issuing permits for overweight and superheavy commercial vehicles (SHCVs) or “superloads.” Superloads are trucks t...
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 Fiber Additives in Asphalt MixturesMarch 11, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 475: Fiber Additives in Asphalt Mixtures summarizes the types of fibers used in asphalt mixtures, their properties, how they are tested, how they are applied, and lab and field performance of the fiber mixes.
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 Service Life of Culverts May 21, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 474: Service Life of Culverts explores the time during which a culvert is expected to provide a desired function with a specified level of maintenance established at the design or retrofit stage. This study is an update of NCHR...
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 Indefinite Delivery/Indefinite Quantity Contracting Practices April 30, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 473: Indefinite Delivery/Indefinite Quantity Contracting Practices examines practices related to the use of Indefinite Delivery/Indefinite Quantity (IDIQ) contracting by transportation agencies for highway design, construction,...
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 Practices for Developing Transparent Best Value Selection ProceduresMarch 5, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 471: Practices for Developing Transparent Best Value Selection Procedures examines practices related to the best value bid approach to procuring highway construction services. Best value procurement is a process to select the m...
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 Maintenance Quality Assurance Field Inspection PracticesFebruary 25, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 470: Maintenance Quality Assurance Field Inspection Practices summarizes practices used by state transportation agencies to support maintenance investments. Appendices A and B are only available through the online PDF document.
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 Impacts of Energy Developments on U.S. Roads and BridgesFebruary 7, 2015 TRB’s National Cooperative Highway Research Board (NCHRP) Synthesis 469: Impacts of Energy Developments on U.S. Roads and Bridges documents the economic impact of heavy truck traffic related to energy development on the nation’s roads and bridges.
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 Alliance Contracting—Evolving Alternative Project DeliveryFebruary 13, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 466: Alliance Contracting—Evolving Alternative Project Delivery synthesizes current practices related to the use of alliance contracts around the world, and explores the procurement procedures that have been used to successfull...
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 Permanent Signs Mounted on Median BarriersJuly 24, 2014 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 465: Permanent Signs Mounted on Median Barriers reports on the current state of practice for mounting permanent highway signs on top of rigid median barriers throughout the United States.
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 Thin Asphalt Concrete OverlaysAugust 3, 2014 TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 464: Thin Asphalt Concrete Overlays documents the current state of the practice as well as research efforts on the use of thin asphalt concrete overlays for pavement maintenance, rehabilitation, and preservation.
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