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National Cooperative Highway Research Program (NCHRP) Synthesis Reports

Syntheses report on the state of the practice based on literature reviews and surveys of recent activities in critical areas. Syntheses also inform airport managers about innovations being used by others to solve problems.  

This page included a list of NCHRP Synthesis Reports that have been produced since June 2001.  All NCHRP Synthesis Reports can be searched for via the TRB Online Bookstore or the TRB Publication Index.

Implementation of Subsurface Utility Engineering for Highway Design and ConstructionImplementation of Subsurface Utility Engineering for Highway Design and Construction
May 18, 2022
While it is recognized to be in the public interest to permit the installation of utility infrastructure in roadway rights-of-way, the practice has contributed to utility-related issues being one of the leading causes of delays for transportation projects. Subsurface utility engineering (SUE) is ...

Highway Infrastructure Inspection Practices for the Digital AgeHighway Infrastructure Inspection Practices for the Digital Age
May 20, 2022
Historically, state departments of transportation (DOTs) have employed on-site workforces to execute infrastructure inspection using traditional inspection methods. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 582: Highway Infrastructure Inspection Practices for the Dig...

Rehabilitation of Culverts and Buried Storm Drain PipesRehabilitation of Culverts and Buried Storm Drain Pipes
May 16, 2022
Departments of transportation (DOTs) are increasing employment of asset management strategies in response to federal and state initiatives. Low-cost and effective treatments applied throughout the life of the asset can be employed prior to significant asset degradation, which otherwise would like...

Practices for Ensuring the Smoothness of Concrete Bridge DecksPractices for Ensuring the Smoothness of Concrete Bridge Decks
April 14, 2022
Rough bridge surfaces can increase user costs by accumulative wear and tear on vehicles, increase freight costs resulting from damage to goods or packaging, add to potential safety concerns with nonuniform tire loads, decrease the life of a structure by increasing dynamic loads, and reduce user s...

Subsurface Drainage Practices in Pavement Design, Construction, and MaintenanceSubsurface Drainage Practices in Pavement Design, Construction, and Maintenance
April 22, 2022
Subsurface drainage is known to pavement professionals to be an important factor affecting pavement performance and preservation of public investment, and numerous studies have emphasized its importance. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 579: Subsurface Drain...

Use of Unmanned Aerial Systems for Highway ConstructionUse of Unmanned Aerial Systems for Highway Construction
March 24, 2022
In the last decade, new technologies have transformed all stages of highway construction as more industry stakeholders have begun incorporating new technologies into their daily construction activities. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 578: Use of Unmanned A...

Collaborative Practices for Performance-Based Asset Management Between State DOTs and MPOsCollaborative Practices for Performance-Based Asset Management Between State DOTs and MPOs
September 17, 2021
The degree of collaboration between state departments of transportation (DOTs) and metropolitan planning organzations (MPOs) on goals and performance targets for management of transportation assets varies. Collaboration may also involve investment decisions. The TRB National Cooperative Highway R...

Practices for Project-Level Analyses for Air QualityPractices for Project-Level Analyses for Air Quality
October 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...

Lighting Practices for Isolated Rural IntersectionsLighting Practices for Isolated Rural Intersections
January 26, 2022
Roadway lighting is a widely recognized intervention for reducing nighttime crashes and isolated rural intersection lighting appears to be beneficial overall, but predicting the benefits likely at a specific location is very difficult. The TRB National Cooperative Highway Research Program's NCHRP...

Temporary Pavement Markings Placement and Removal Practices in Work ZonesTemporary Pavement Markings Placement and Removal Practices in Work Zones
October 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...

Practices for Integrated Flood Prediction and Response SystemsPractices for Integrated Flood Prediction and Response Systems
September 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...

Night and Weekend Movement of Oversize/Overweight LoadsNight and Weekend Movement of Oversize/Overweight Loads
August 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...

Load Rating of Bridges and Culverts with Missing or Incomplete As-Built InformationLoad Rating of Bridges and Culverts with Missing or Incomplete As-Built Information
February 11, 2022
Load ratings are used in part to allocate federal funding to agencies and to plan for repairing, replacing, and rehabilitating bridges. Therefore, load ratings can affect the movement of goods throughout a region and are vitally important to the continued safe and efficient operation of the highw...

Practices for Closing Out Highway Projects from Substantial Completion to Final PaymentPractices for Closing Out Highway Projects from Substantial Completion to Final Payment
August 13, 2021
Although project closeout only entails a small portion of actual construction work, closing out highway construction projects for state departments of transportation (DOTs) is a complex and vital process that is a part of project delivery for highway construction projects. The TRB National Cooper...

Practice and Performance of Cold In-Place Recycling and Cold Central Plant RecyclingPractice and Performance of Cold In-Place Recycling and Cold Central Plant Recycling
August 25, 2021
Cold in-place recycling (CIR) is a process in which 3 to 4 inches of the existing asphalt pavement layers are pulverized, mixed with a recycling agent, and repaved in place. It provides agencies with cost-effective and environmentally friendly pavement maintenance and rehabilitation options for a...

Portland Cement Concrete Pavement Joint Sealant Practices and PerformancePortland Cement Concrete Pavement Joint Sealant Practices and Performance
July 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...

Summary State DOT Practices for Developing and Implementing TSMO PlansSummary State DOT Practices for Developing and Implementing TSMO Plans
July 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, ...

Practices for Bridge Approach SystemsPractices for Bridge Approach Systems
July 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...

Maintenance and Surface Preparation Activities Prior to Pavement Preservation TreatmentsMaintenance and Surface Preparation Activities Prior to Pavement Preservation Treatments
October 14, 2021
Pavement preservation is broadly acknowledged to provide network-wide benefits such as extending pavement life, enhancing system performance, reducing operation and maintenance costs, and improving safety. However, the performance of each pavement preservation project hinges on many factors. The ...

Practices for Selecting Pedestrian and Bicycle ProjectsPractices for Selecting Pedestrian and Bicycle Projects
May 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...

Performance Metrics for Public–Private PartnershipsPerformance Metrics for Public–Private Partnerships
May 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...

Repair and Maintenance of Post-Tensioned Concrete BridgesRepair and Maintenance of Post-Tensioned Concrete Bridges
May 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...

Use of Vehicle Probe and Cellular GPS Data by State Departments of TransportationUse of Vehicle Probe and Cellular GPS Data by State Departments of Transportation
March 10, 2021
Over the last decade, state departments of transportation (DOTs) have begun to use vehicle probe and cellular GPS data for a variety of purposes, including real-time traffic and incident monitoring, highway condition, and travel demand management. DOTs are also using vehicle probe and cellular GP...

Practices for Construction-Ready Digital Terrain ModelsPractices for Construction-Ready Digital Terrain Models
March 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...

Emerging Challenges to Priced Managed LanesEmerging Challenges to Priced Managed Lanes
September 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...

Availability and Use of Pedestrian Infrastructure Data to Support Active Transportation PlanningAvailability and Use of Pedestrian Infrastructure Data to Support Active Transportation Planning
November 18, 2020
In March 2010, the U.S. Department of Transportation (DOT) released a policy statement supporting the development of fully integrated transportation networks. The policy is to “incorporate safe and convenient walking and bicycle facilities into transportation projects.” The TRB National Cooperati...

Utility Pole Safety and Hazard Evaluation ApproachesUtility Pole Safety and Hazard Evaluation Approaches
September 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...

Asset Management Approaches to Identifying and Evaluating Assets Damaged Due to Emergency EventsAsset Management Approaches to Identifying and Evaluating Assets Damaged Due to Emergency Events
June 2, 2020
Current legislation and subsequent asset management rules require state departments of transportation (DOTs) to conduct statewide evaluations of roads, highways, and bridges that have required repair and reconstruction activities two or more times since 1997 due to emergency events as declared by...

Estimating and Contracting Rock Slope Scaling Adjacent to HighwaysEstimating and Contracting Rock Slope Scaling Adjacent to Highways
May 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...

Advances in Unstable Slope Instrumentation and MonitoringAdvances in Unstable Slope Instrumentation and Monitoring
August 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 ...

Performance-Based Pavement Warranty PracticesPerformance-Based Pavement Warranty Practices
July 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...

Practices for Fabricating Asphalt Specimens for Performance Testing in LaboratoriesPractices for Fabricating Asphalt Specimens for Performance Testing in Laboratories
June 22, 2020
Performance testing of asphalt mixtures is becoming more widespread for a variety of reasons and with a variety of testing devices. The tests results are sensitive to the procedures used in preparation of the specimens. Guidelines exist for conducting the tests; however, they do not all provide u...

Highway Hydraulic Engineering State of PracticeHighway Hydraulic Engineering State of Practice
June 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...

Alternative Intersection Design and SelectionAlternative Intersection Design and Selection
May 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...

Incorporating Roadway Access Management into Local OrdinancesIncorporating Roadway Access Management into Local Ordinances
March 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 ...

Development and Use of As-Built Plans by State Departments of TransportationDevelopment and Use of As-Built Plans by State Departments of Transportation
May 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...

Advancements in Use of Geophysical Methods for Transportation ProjectsAdvancements in Use of Geophysical Methods for Transportation Projects
May 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...

Use of Weigh-in-Motion Data for Pavement, Bridge, Weight Enforcement, and Freight Logistics ApplicationsUse of Weigh-in-Motion Data for Pavement, Bridge, Weight Enforcement, and Freight Logistics Applications
April 24, 2020
Most U.S. state departments of transportation (DOTs) are collecting weigh-in-motion data with a wide variety of sensor types and using them in a variety of applications. Many agencies use WIM data to aid in pavement design, although most are not currently using a Pavement ME (mechanistic-empirica...

Electronic Ticketing of Materials for Construction ManagementElectronic Ticketing of Materials for Construction Management
June 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...

Concrete Technology for Transportation ApplicationsConcrete Technology for Transportation Applications
January 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...

Transportation Workforce Planning and Development StrategiesTransportation Workforce Planning and Development Strategies
November 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 ...

Prioritization of Freight Investment ProjectsPrioritization of Freight Investment Projects
September 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...

Leveraging Private Capital for Infrastructure RenewalLeveraging Private Capital for Infrastructure Renewal
September 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...

Landscape Development and Management Practices for Urban Freeway RoadsidesLandscape Development and Management Practices for Urban Freeway Roadsides
August 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...

Practices for Online Public InvolvementPractices for Online Public Involvement
July 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...

Impact of Asphalt Thickness on Pavement QualityImpact of Asphalt Thickness on Pavement Quality
July 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,...

Bridge Demolition PracticesBridge Demolition Practices
May 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...

Pedestrian Safety Relative to Traffic-Speed ManagementPedestrian Safety Relative to Traffic-Speed Management
October 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...

Emerging Technologies for Construction DeliveryEmerging Technologies for Construction Delivery
August 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...

Very Short Duration Work Zone Safety for Maintenance and Other ActivitiesVery Short Duration Work Zone Safety for Maintenance and Other Activities
July 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...

Seismic Design of Non-Conventional BridgesSeismic Design of Non-Conventional Bridges
June 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...

Automated Pavement Condition SurveysAutomated Pavement Condition Surveys
July 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...

Construction and Rehabilitation of Concrete Pavements Under TrafficConstruction and Rehabilitation of Concrete Pavements Under Traffic
August 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...

How Transportation Agencies Assess the Value of Added Capacity Highway Projects Versus Other Modal Projects and StrategiesHow Transportation Agencies Assess the Value of Added Capacity Highway Projects Versus Other Modal Projects and Strategies
August 13, 2018
TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 529: How Transportation Agencies Assess the Value of Added Capacity Highway Projects Versus Other Modal Projects and Strategies summarizes the methods and policies used by state departments of transportation (DOTs) and metropol...

Analyzing Data for Measuring Transportation Performance by State DOTs and MPOsAnalyzing Data for Measuring Transportation Performance by State DOTs and MPOs
January 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...

Resilience in Transportation Planning, Engineering, Management, Policy, and AdministrationResilience in Transportation Planning, Engineering, Management, Policy, and Administration
January 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...

Inertial Profiler Certification for Evaluation of International Roughness IndexInertial Profiler Certification for Evaluation of International Roughness Index
July 27, 2018
TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 526: Inertial Profiler Certification for Evaluation of International Roughness Index determines the state of practice of certification of inertial profilers at the national and international levels. Inertial profilers are used ...

Practices in One-Lane Traffic Control on a Two-Lane Rural HighwayPractices in One-Lane Traffic Control on a Two-Lane Rural Highway
June 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...

Aggregate Quality Requirements for PavementsAggregate Quality Requirements for Pavements
July 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 ...

Integration of Roadway Safety Data from State and Local Sources 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...

Managing State Transportation Research ProgramsManaging State Transportation Research Programs
April 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...

Investment Prioritization Methods for Low-Volume RoadsInvestment Prioritization Methods for Low-Volume Roads
May 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 ...

Integrated Transportation and Land Use ModelsIntegrated Transportation and Land Use Models
July 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 ...

The Renewal of Stormwater Systems Using Trenchless TechnologiesThe Renewal of Stormwater Systems Using Trenchless Technologies
June 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...

Staffing for Alternative Contracting MethodsStaffing for Alternative Contracting Methods
August 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...

Corrosion Prevention for Extending the Service Life of Steel BridgesCorrosion Prevention for Extending the Service Life of Steel Bridges
July 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...

Tack Coat Specifications, Materials, and Construction PracticesTack Coat Specifications, Materials, and Construction Practices
May 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...

Practices for Preventing Roadway DeparturesPractices for Preventing Roadway Departures
June 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...

Statewide and Megaregional Travel Forecasting Models: Freight and PassengerStatewide and Megaregional Travel Forecasting Models: Freight and Passenger
October 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...

Evolving Debt Finance Practices for Surface TransportationEvolving Debt Finance Practices for Surface Transportation
June 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...

Use of Fiber-Reinforced Polymers in Highway InfrastructureUse of Fiber-Reinforced Polymers in Highway Infrastructure
September 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...

Relationship Between Chemical Makeup of Binders and Engineering PerformanceRelationship Between Chemical Makeup of Binders and Engineering Performance
August 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 ...

Resource Allocation of Available Funding to Programs of WorkResource Allocation of Available Funding to Programs of Work
May 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...

Highway Worker SafetyHighway Worker Safety
April 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...

Data Management and Governance PracticesData Management and Governance Practices
April 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.

Traffic Signal Preemption at Intersections Near Highway–Rail Grade CrossingsTraffic Signal Preemption at Intersections Near Highway–Rail Grade Crossings
April 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...

Effective Utility Coordination: Application of Research and Current PracticesEffective Utility Coordination: Application of Research and Current Practices
February 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...

Current Practices and Guidelines for the Reuse of Bridge FoundationsCurrent Practices and Guidelines for the Reuse of Bridge Foundations
February 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 ...

Strategic Program Delivery MethodsStrategic Program Delivery Methods
April 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 ...

Leveraging Technology for Transportation Agency Workforce Development and TrainingLeveraging Technology for Transportation Agency Workforce Development and Training
February 13, 2017
TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 503: Leveraging Technology for Transportation Agency Workforce Development and Training documents how state and local transportation agencies are using information and communication technologies (ICT) to train their workforce. ...

Practices for Establishing Contract Completion Dates for Highway ProjectsPractices for Establishing Contract Completion Dates for Highway Projects
March 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 ...

Pavement Management Systems: Putting Data to WorkPavement Management Systems: Putting Data to Work
January 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...

Control of Concrete Cracking in BridgesControl of Concrete Cracking in Bridges
February 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...

Alternate Design/Alternate Bid Process for Pavement-Type SelectionAlternate Design/Alternate Bid Process for Pavement-Type Selection
January 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...

Application of Pedestrian Crossing Treatments for Streets and HighwaysApplication of Pedestrian Crossing Treatments for Streets and Highways
December 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...

Post-Extreme Event Damage Assessment and Response for Highway BridgesPost-Extreme Event Damage Assessment and Response for Highway Bridges
December 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...

Minimizing Roadway Embankment Damage from FloodingMinimizing Roadway Embankment Damage from Flooding
August 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...

Use of Reclaimed Asphalt Pavement and Recycled Asphalt Shingles in Asphalt MixturesUse of Reclaimed Asphalt Pavement and Recycled Asphalt Shingles in Asphalt Mixtures
September 12, 2016
TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 495: Use of Reclaimed Asphalt Pavement and Recycled Asphalt Shingles in Asphalt Mixtures summarizes current practices for the use of reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS) in the design, production...

Life-Cycle Cost Analysis for Management of Highway AssetsLife-Cycle Cost Analysis for Management of Highway Assets
May 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...

Practices for High-Tension Cable BarriersPractices for High-Tension Cable Barriers
May 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...

Performance Specifications for Asphalt Mixtures 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...

Uses of Mobile Information Technology Devices in the Field for Design, Construction, and Asset ManagementUses of Mobile Information Technology Devices in the Field for Design, Construction, and Asset Management
March 7, 2016
TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 491: Uses of Mobile Information Technology Devices in the Field for Design, Construction, and Asset Management documents the state-of-the-practice and state-of-the-art applications of state transportation agencies related to th...

Practice of Rumble Strips and Rumble StripesPractice of Rumble Strips and Rumble Stripes
May 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 ...

Extending Bridge Service Life Through Field Welded Repairs and Retrofits 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...

Roundabout Practices 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...

Public Perception of Mileage-Based User FeesPublic Perception of Mileage-Based User Fees
February 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...

State Practices for Local Road SafetyState Practices for Local Road Safety
January 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...

Converting Paved Roads to Unpaved 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...