 Developing a Guide for New Mobility Options in Travel Demand Forecasting and ModelingMay 27, 2024 The transportation field is undergoing a transformative change in response to several technological innovations resulting in the emergence and widespread adoption of new mobility options (NMOs) such as shared micromobility, transportation networking companies (TNCs), and connected and autonomous vehicles (CAVs). NCHRP Web-Only Document 399: Developing a Guide for New Mobility Options in Travel ...
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 Impacts of Connected, Automated Vehicle Technologies on Traffic Incident Management ResponseMarch 15, 2024 Traffic Incident Management (TIM) is the process to detect, respond to, and clear traffic incidents so that traffic flow may be restored as safely and quickly as possible. Traffic incidents are unplanned events, such as crashes, that impact traffic flow, and TIM refers to the coordinated process to respond to and clear the incidents. NCHRP Web-Only Document 395: Impacts of Connected, Automated ...
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 User’s Guide for Quantifying the Effects of Vehicle Mix on Crash Frequency and Crash SeverityFebruary 13, 2024 Heavy vehicle traffic and vehicle mix have a substantial impact on crash frequency and severity. The consideration of vehicle mix would improve predictive methods for crash frequency and severity. Improved methods will result in better use of the limited funds and resources available for improving the safety of the highway system and supporting performance-based approaches. NCHRP Web-Only Docum...
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 Response Planning, Assessment, and Rapid Restoration of Service of Bridges in Extreme Events: Background and SummaryMay 16, 2024 Extreme events, such as hurricanes, tornados, floods, earthquakes, fires, and collisions, pose a threat to the transportation infrastructure that millions of people depend on daily. NCHRP Web-Only Document 390: Response Planning, Assessment, and Rapid Restoration of Service of Bridges in Extreme Events: Background and Summary , from TRB's National Cooperative Highway Research Program, sup...
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 Ruggedness of Laboratory Tests to Assess Cracking Resistance of Asphalt MixturesDecember 1, 2023 Cracking and durability issues of asphalt pavements have been primary concerns of departments of transportation the last two decades. Several modes of asphalt pavement cracking exist—fatigue, top-down, reflective, and thermal—and all are influenced by thermal loading, traffic loading, or a combination of both. NCHRP Web-Only Document 389: Ruggedness of Laboratory Tests to Assess Cracking Resist...
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 Framework for Implementing Constructability Throughout Project Development from NEPA to Final DesignDecember 22, 2023 Since the inception of using sets of plans for construction purposes, a persistent challenge has been the miscommunication between designers and constructors, even when they were part of the same organization. NCHRP Web-Only Document 388: Framework for Implementing Constructability Throughout Project Development from NEPA to Final Design , from TRB's National Cooperative Highway Research Progra...
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 Safety Prediction Model for Freeway Facilities with High Occupancy LanesDecember 27, 2023 In an effort to relieve highway congestion and promote the movement of people, some state departments of transportation have modified their freeway facilities to include high occupancy vehicle lanes, high occupancy toll lanes (HOT, or HO lanes), and other managed lane strategies. NCHRP Web-Only Document 387: Safety Prediction Model for Freeway Facilities with High Occupancy Lanes , from TRB's N...
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 Quantifying the Impacts of Corridor ManagementJanuary 26, 2024 Transportation corridors are defined by the infrastructure, services, and relationships connecting places. A corridor can be a national resource connecting large cities, a regional passage connecting a state’s trade centers, or local pathways connecting through a city or town. NCHRP Web-Only Document 386: Quantifying the Impacts of Corridor Management , from TRB's National Cooperative Highway R...
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 Business Case and Communications Strategies for State DOT Resilience EffortsDecember 7, 2023 As transportation agencies face an increasing frequency and magnitude of risks, strategies and tools are essential for demonstrating, communicating, and gaining support for integrating resilience into transportation decisions and investments. NCHRP Web Only Document 385: Business Case and Communications Strategies for State DOT Resilience Efforts , from TRB's National Cooperative Highway Resear...
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 Developing an Emergency Response Playbook for State Transportation AgenciesNovember 10, 2023 Transportation plays a crucial role before, during and after an emergency. Transportation agencies’ unique role stems from their broad range of capabilities and responsibilities. NCHRP Web-Only Document 384: Developing an Emergency Management Playbook for State Transportation Agencies , from TRB’s National Cooperative Highway Research Program, helps develop a playbook to support emergenc...
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 Seismic Site Response Analysis with Pore Water Pressure Generation: Resources for EvaluationFebruary 16, 2024 There are many seismic site response analysis programs that operate in either the time domain or the frequency domain. These programs are available as public domain software, as commercial products, and/or through direct contact with the authors. NCHRP Web-Only Document 383: Seismic Site Response Analysis with Pore Water Pressure Generation: Resources for Evaluation , from TRB's National Cooper...
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 Traffic Safety Culture: Conduct of Research ReportFebruary 5, 2024 Traffic safety culture is a complex topic spanning a range of sociological and philosophical concepts as they relate to transportation safety and the systemic framework that produces different kinds of traffic safety-related outcomes. NCHRP Web-Only Document 382: Traffic Safety Culture: Conduct of Research Report , from TRB's National Cooperative Highway Research Program, contributes to the bod...
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 Developing Laboratory Methods and Specification Language to Test Tack Coat MaterialsNovember 15, 2023 Most asphalt pavement design methodologies assume pavements as monolithic structures composed of multiple layers to transfer the traffic loads on the surface to the bottom layers. However, this assumption is compromised when the pavement layers are not fully bonded. NCHRP Web-Only Document 381: Developing Laboratory Methods and Specification Language to Test Tack Coat Materials , from TRB's Nat...
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 Accessing America's Great Outdoors: Forecasting Recreational Travel DemandOctober 26, 2023 Recreational travel is a major and growing activity in the United States. Recreation trips to outdoor parklands tend to have different characteristics than trips for other types of recreation, such as entertainment, sporting events, and regular exercise. NCHRP Web-Only Document 380: Accessing America's Great Outdoors: Forecasting Recreational Travel Demand , from TRB's National Cooperative High...
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 Deploying Transportation Security Practices in State DOTsNovember 10, 2023 System-disrupting events, including those stemming from integrated cyber and physical components, intentional criminal acts, a global pandemic, accidents or unintentional human intervention, and natural causes, have only become more sophisticated since NCHRP Research Report 930: Update of Security 101: A Physical Security and Cybersecurity Primer for Transportation Agencies . NCHRP Web-Only Doc...
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 Emergency Response: Organizational and Operational Models Used by State DOTsOctober 10, 2023 Large-scale emergencies and disasters (weather-related and other) may be somewhat rare but are not as rare as they used to be, and are generally increasing in intensity and frequency. How state departments of transportation (DOTs) train and coordinate prior to emergencies makes a big difference in how effectively they respond to an emergency. NCHRP Web-Only Document 378: Emergency Response: Org...
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 Background and Development of a Guide for Intersection Control EvaluationFebruary 8, 2024 A variety of intersection control evaluation processes and metrics are used by highway agencies for evaluating intersection geometry and control options and identifying an optimal geometric and control solution for an intersection. These processes usually address safety, operational, multimodal, environmental, right-of-way, and cost impacts and other considerations. NCHRP Web-Only Document 377:...
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 Rapid Tests and Specification Language for Construction of Asphalt-Treated Cold Recycled PavementsOctober 10, 2023 NCHRP Web-Only Document 376: Rapid Tests and Specification Language for Construction of Asphalt-Treated Cold Recycled Pavements , from TRB's National Cooperative Highway Research Program, provides the results and analysis of field testing conducted to verify the short-pin raveling test (SPRT) and long-pin shear test (LPST) threshold values recommended in NCHRP Research Report 960: Proposed AAS...
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 Developing a Guide to Shared-Risk Insurance Pools for Transit Agencies: Conduct of Research ReportNovember 30, 2023 In states where there is a Transit Risk-Sharing Insurance Pool, state departments of transportation (DOTs) indicate cost reduction and access to insurance as the main objectives of the pools. Among pool benefits, transit agencies find that their insurance premiums were reduced by 15%, they are mostly satisfied with their pool services, and they participate in risk reduction programs. NCHRP Web-...
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 Incorporating Maintenance Costs into a Transportation Asset Management PlanOctober 11, 2023 Since 2018, state departments of transportation (DOTs) have been required to develop risk-based transportation asset management plans (TAMPs) and to update these plans every four years. However, the absence of maintenance cost data in a TAMP prevents agencies from fully capturing the total investment made to preserve and improve highway infrastructure assets. NCHRP Web-Only Document 372: Incorp...
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 Impact of New Disruptive Technologies on the Performance of DOTsOctober 11, 2023 Technology is at the core of the surface transportation system and is embodied in existing and new scientific knowledge and infrastructure, hardware, and software processes. It is designed to improve performance and cost-effectiveness of infrastructure and the vehicles, systems, and services that utilize the infrastructure. In recent years, a series of rapid advances in key technology areas suc...
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 LTPP Data Analysis: Practical Tools and Procedures to Improve WIM Data QualityAugust 31, 2023 Highway agencies use weigh-in-motion (WIM) technology to collect vehicle weight and axle load data on roadways. NCHRP Web-Only Document 370: LTPP Data Analysis: Practical Tools and Procedures to Improve WIM Data Quality , from TRB's National Cooperative Highway Research Program, is a supplemental document to NCHRP Research Report 1070: Tools for Assuring WIM Data Quality: Practical Guide , and ...
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 Estimating Effectiveness of Safety Treatments in the Absence of Crash DataOctober 4, 2023 The last decade has seen tremendous growth in resources available to state and local transportation agencies for conducting data-driven safety analysis. NCHRP Web-Only Document 369: Estimating Effectiveness of Safety Treatments in the Absence of Crash Data , from TRB's National Cooperative Highway Research Program, describes the process of developing a guide for using alternative, or surrogate,...
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 Risk Assessment Techniques for Transportation Asset Management: AppendicesNovember 9, 2023 To effectively manage the condition and performance of transportation infrastructure, state transportation agencies must assess and manage risks to transportation assets. NCHRP Web-Only Document 366: Risk Assessment Techniques for Transportation Asset Management: Appendices , from TRB's National Cooperative Highway Research Program, presents the risk management resources summarized in NCHRP Res...
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 Implementation of Life-Cycle Planning Analysis in a Transportation Asset Management FrameworkSeptember 18, 2023 Highway infrastructure assets are designed and built to serve long, useful lives. These assets undergo structural aging and degradation driven by traffic and environmental factors, natural and human hazards, and changes in demand and functional use. NCHRP Web-Only Document 365: Implementation of Life-Cycle Planning Analysis in a Transportation AssetManagement Framework , from TRB's National Coo...
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 Construction Guidelines for Cold Central Plant Recycling and Cold In-Place RecyclingMarch 30, 2023 Cold In-place Recycling (CIR) and Cold Central Plant Recycling (CCPR) are two paving techniques that are experiencing increased use as agencies strive to find cost effective, sustainable solutions to rebuild the national roadway infrastructure without compromising performance. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 363: Construction Guidelines for Cold C...
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 Pollinator Habitat Conservation Along Roadways, Volume 3: FloridaMay 25, 2023 Transportation agencies can make a difference for imperiled pollinators by managing existing roadside vegetation and designing new revegetation plantings with habitat needs in mind. This can generate public support for the agency and help to mitigate the negative ecological effects of roads. NCHRP Web-Only Document 362: Pollinator Habitat Conservation Along Roadways, Volume 3: Florida , from TR...
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 Pollinator Habitat Conservation Along Roadways, Volume 4: Great BasinMay 25, 2023 Transportation agencies can make a difference for imperiled pollinators by managing existing roadside vegetation and designing new revegetation plantings with habitat needs in mind. This can generate public support for the agency and help to mitigate the negative ecological effects of roads. NCHRP Web-Only Document 362: Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin , fro...
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 Pollinator Habitat Conservation Along Roadways, Volume 10: MidwestJune 9, 2023 Transportation agencies can make a difference for imperiled pollinators by managing existing roadside vegetation and designing new revegetation plantings with habitat needs in mind. This can generate public support for agencies and help to mitigate the negative ecological effects of roads. NCHRP Web-Only Document 362: Pollinator Habitat Conservation Along Roadways, Volume 10: Midwest , from TRB...
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 Pollinator Habitat Conservation Along Roadways, Volume 15: Southern PlainsJune 23, 2023 Transportation agencies can make a difference for imperiled pollinators by managing existing roadside vegetation and designing new revegetation plantings with habitat needs in mind. This can generate public support for agencies and help to mitigate the negative ecological effects of roads. NCHRP Web-Only Document 362: Pollinator Habitat Conservation Along Roadways, Volume 15: Southern Plains , ...
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 Pollinator Habitat Conservation Along Roadways, Volume 16: SouthwestJune 23, 2023 Transportation agencies can make a difference for imperiled pollinators by managing existing roadside vegetation and designing new revegetation plantings with habitat needs in mind. This can generate public support for agencies and help to mitigate the negative ecological effects of roads. NCHRP Web-Only Document 362: Pollinator Habitat Conservation Along Roadways, Volume 16: Southwest , from T...
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 Pollinator Habitat Conservation Along Roadways, Volume 6: HawaiiJune 2, 2023 Transportation agencies can make a difference for imperiled pollinators by managing existing roadside vegetation and designing new revegetation plantings with habitat needs in mind. This can generate public support for agencies and help to mitigate the negative ecological effects of roads. NCHRP Web-Only Document 362: Pollinator Habitat Conservation Along Roadways, Volume 6: Hawaii , from TRB's...
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 Pollinator Habitat Conservation Along Roadways, Volume 12: Northern PlainsJune 9, 2023 Transportation agencies can make a difference for imperiled pollinators by managing existing roadside vegetation and designing new revegetation plantings with habitat needs in mind. This can generate public support for agencies and help to mitigate the negative ecological effects of roads. NCHRP Web-Only Document 362: Pollinator Habitat Conservation Along Roadways, Volume 12: Northern Plains , ...
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 Pollinator Habitat Conservation Along Roadways, Volume 11: NortheastJune 9, 2023 Transportation agencies can make a difference for imperiled pollinators by managing existing roadside vegetation and designing new revegetation plantings with habitat needs in mind. This can generate public support for agencies and help to mitigate the negative ecological effects of roads. NCHRP Web-Only Document 362: Pollinator Habitat Conservation Along Roadways, Volume 11: Northeast , from T...
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 Pollinator Habitat Conservation Along Roadways, Volume 5: Great LakesJune 2, 2023 Transportation agencies can make a difference for imperiled pollinators by managing existing roadside vegetation and designing new revegetation plantings with habitat needs in mind. This can generate public support for agencies and help to mitigate the negative ecological effects of roads. NCHRP Web-Only Document 362: Pollinator Habitat Conservation Along Roadways, Volume 5: Great Lakes , from ...
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 Pollinator Habitat Conservation Along Roadways, Volume 9: Mid-AtlanticJune 9, 2023 Transportation agencies can make a difference for imperiled pollinators by managing existing roadside vegetation and designing new revegetation plantings with habitat needs in mind. This can generate public support for agencies and help to mitigate the negative ecological effects of roads. NCHRP Web-Only Document 362: Pollinator Habitat Conservation Along Roadways, Volume 9: Mid-Atlantic , from...
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 Pollinator Habitat Conservation Along Roadways, Volume 2: CaliforniaMay 25, 2023 Transportation agencies can make a difference for imperiled pollinators by managing existing roadside vegetation and designing new revegetation plantings with habitat needs in mind. This can generate public support for the agency and help to mitigate the negative ecological effects of roads. NCHRP Web-Only Document 362: Pollinator Habitat Conservation Along Roadways, Volume 2: California , from...
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 Pollinator Habitat Conservation Along Roadways, Volume 1: AlaskaMay 25, 2023 Transportation agencies can make a difference for imperiled pollinators by managing existing roadside vegetation and designing new revegetation plantings with habitat needs in mind. This can generate public support for agencies and help to mitigate the negative ecological effects of roads. NCHRP Web-Only Document 362: Pollinator Habitat Conservation Along Roadways, Volume 1: Alaska , from TRB's...
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 Pollinator Habitat Conservation Along Roadways, Volume 7: Inland NorthwestJune 2, 2023 Transportation agencies can make a difference for imperiled pollinators by managing existing roadside vegetation and designing new revegetation plantings with habitat needs in mind. This can generate public support for agencies and help to mitigate the negative ecological effects of roads. NCHRP Web-Only Document 362: Pollinator Habitat Conservation Along Roadways, Volume 7: Inland Northwest , ...
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 Pollinator Habitat Conservation Along Roadways, Volume 8: Maritime NorthwestJune 2, 2023 Transportation agencies can make a difference for imperiled pollinators by managing existing roadside vegetation and designing new revegetation plantings with habitat needs in mind. This can generate public support for agencies and help to mitigate the negative ecological effects of roads. NCHRP Web-Only Document 362: Pollinator Habitat Conservation Along Roadways, Volume 8: Maritime Northwest ...
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 Pollinator Habitat Conservation Along Roadways, Volume 14: SoutheastJune 23, 2023 Transportation agencies can make a difference for imperiled pollinators by managing existing roadside vegetation and designing new revegetation plantings with habitat needs in mind. This can generate public support for agencies and help to mitigate the negative ecological effects of roads. NCHRP Web-Only Document 362: Pollinator Habitat Conservation Along Roadways, Volume 14: Southeast , from T...
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 Pollinator Habitat Conservation Along Roadways, Volume 13: Rocky MountainsJune 23, 2023 Transportation agencies can make a difference for imperiled pollinators by managing existing roadside vegetation and designing new revegetation plantings with habitat needs in mind. This can generate public support for agencies and help to mitigate the negative ecological effects of roads. NCHRP Web-Only Document 362: Pollinator Habitat Conservation Along Roadways, Volume 13: Rocky Mountains , ...
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 Acquisition of Utility Property Interests and Compensation Practices for Utility RelocationsJune 29, 2023 There is a need for guidance on how to acquire utility property interests and reimburse utility owners for eligible utility relocation costs. NCHRP Web-Only Document 360: Acquisition of Utility Property Interests and Compensation Practices for Utility Relocations , from TRB's National Cooperative Highway Research Program, develops guidelines that provide a framework for practitioners to follow ...
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 Developing a Guide to Effective Methods for Setting Transportation Performance TargetsMay 19, 2023 Performance management has become increasingly important for transportation agencies in recent years. A key component of performance management is setting targets, which can be challenging. NCHRP Web-Only Document 358: Developing a Guide to Effective Methods for Setting Transportation Performance Targets , from TRB's National Cooperative Highway Research Program, is supplemental to NCHRP Resear...
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 Wrong-Way Driving Solutions, Policy, and GuidelinesAugust 3, 2023 There are many strategies and treatments that agencies can consider for implementation to address wrong-way driving maneuvers, ranging from conventional traffic control devices to specialized geometric design elements and various intelligent transportation systems-based solutions. NCHRP Web-Only Document 357: Wrong-Way Driving Solutions, Policy, and Guidelines , from TRB's National Cooperative ...
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 Development of a Guide for Accommodating Utilities within Highways and FreewaysApril 13, 2023 AASHTO is the author of two documents that have guided utility accommodation highways for decades. The first document primarily applies to utility accommodation on highways that are part of the Federal Aid system. The second document primarily applies to utilities on state highways. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 356: Development of a Guide for A...
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 Safe and Effective Temporary Traffic Control for Mobile Operations on Two-Lane RoadwaysFebruary 3, 2023 Mobile operations can either move continuously along the roadway as during most striping operations, or intermittently as during a pothole patching operation. Mobile operations on two-lane roadways present unique challenges to transportation agencies, not the least of which is the highly variable conditions encountered in the field. The TRB National Cooperative Highway Research Program's NCHRP ...
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 Risk-Based Inspection and Strength Evaluation of Suspension Bridge Main Cable SystemsJanuary 20, 2023 Most suspension bridges in use today have cables composed of thousands of steel wires and most of these bridges are aging and carry high volumes of traffic. Deterioration of the elements of the suspension system is a problem, replacement of these elements can be expensive and problematic, while failure could be catastrophic. The TRB National Cooperative Highway Research Program's NCHRP Web-Only...
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 Crash Modification Factors in the Highway Safety Manual: Resources for EvaluationApril 20, 2023 Highway safety practitioners were given a significant new tool in 2010 with the publication of the AASHTO Highway Safety Manual . In the HSM, crash modification factors (CMFs) were provided to estimate the safety effects for a variety of treatments or countermeasures. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 352: Crash Modification Factors in the Highway S...
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 Development and Application of Crash Severity Models for Highway Safety: Conduct of Research ReportMay 8, 2023 The first edition of the Highway Safety Manual has provided methods and procedures for estimating total crashes, crashes by type, and crashes by severity at the site level, project level and corridor level. Crash prediction models are critical in the entire safety management system recommended by HSM, including network screening, economic analysis, project prioritization, and safety effectivene...
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 Long-Term Vegetation Management Strategies for Roadsides and Roadside AppurtenancesJanuary 26, 2023 Long-term vegetation management strategies that decrease the need for routine chemical and mechanical vegetation control can reduce recurring maintenance costs, highway worker exposure to traffic, impacts to the environment and cultural resources, and maintenance-related delays to the traveling public. However, these strategies vary in their effectiveness, longevity, initial construction costs,...
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 Virtual Public Involvement: Lessons from the COVID-19 PandemicDecember 14, 2022 During the COVID-19 pandemic, transportation agencies' most used public-engagement tools were virtual public meetings, social media, dedicated project websites or webpages, email blasts, and electronic surveys. As the pandemic subsides, virtual and hybrid models continue to provide opportunities and challenges. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 349:...
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 Macro-Level Analysis of Safety Planning and Crash Prediction Models: A GuideJune 21, 2023 The Highway Safety Manual (HSM) is a tool that helps transportation agencies make data-driven decisions about safety. It includes methods for quantifying safety performance and predicting crash frequencies. The HSM is currently being updated to include macro-level crash prediction models, which can be used to assess safety trends at a regional or national level. NCHRP Web-Only Document 348: Mac...
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 Background and Summary of a Guide for RoundaboutsJune 1, 2023 Roundabout implementation in the United States has increased in the last decade, and practitioners have learned lessons in successfully applying roundabouts in various land use and transportation environments and contexts. Associated with NCHRP Research Report 1043: Guide for Roundabouts , which provides information and guidance on all aspects of roundabouts, the TRB National Cooperative Highwa...
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 Programmatic Issues of Future System PerformanceNovember 18, 2022 State transportation agencies (STAs) may need to focus their strategic planning and programmatic initiatives over the next two decades to mitigate threats to, and take advantage of, opportunities for system performance and agency effectiveness. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 346: Programmatic Issues of Future System Performance details a unified ...
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 State Transportation Agency Decision-Making for System Performance: Conduct of Research ReportMay 11, 2023 Transportation agencies must grapple with a broad range of trends and issues that influence and act upon the systems they manage and operate. Issues include climate change, goods movement, changing centers of population and economic activity, and telework, among others. NCHRP Web-Only Document 345: State Transportation Agency Decision-Making for System Performance: Conduct of Research Report , ...
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 Risk-Based Construction Inspection: Conduct of Research ReportJune 9, 2023 Limited availability of construction-inspector resources for transportation infrastructure is a major challenge and can lead to accepting material or workmanship without sufficient examination, which can result in quality risks, safety concerns, functional failures, and reduced performance life of highway infrastructure. NCHRP Web-Only Document 344: Risk-Based Construction Inspection: Conduct o...
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 Traffic Modeling DocumentMay 16, 2023 Freeway congestion usually occurs at freeway merge, diverge, and weaving segments that have the potential to develop bottlenecks. To alleviate or mitigate the impacts of congestion at these segments, a number of active management operational strategies have been implemented such as ramp metering, hard shoulder running, managed lanes, and others. The TRB National Cooperative Highway Research Pro...
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 Roadway Cross-Section Reallocation: Conduct of Research ReportOctober 17, 2023 Trade-offs between uses of roadway cross sections are understood through a variety of lenses, from safety and operations to comfort and mode choice. Estimates of the impacts of cross-section decision-making on outcome measures include environmental, equity, and economy. NCHRP Web-Only Document 342: Roadway Cross-Section Reallocation: Conduct of Research Report , from TRB's National Cooperative ...
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 Roadside Database Coding ManualJune 22, 2023 NCHRP Web-Only Document 341: Roadside Database Coding Manual , from TRB's National Cooperative Highway Research Program, is supplemental to NCHRP Research Report 1033: Long-Term Roadside Crash Data Collection Program . The document provides a coding manual for the NCHRP Project 17-43 database , a relational database that interfaces with the NASS CDS database, incorporating additional informati...
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 Developing a Toolkit to Measure and Communicate the Value of Access ManagementApril 21, 2023 Access management has many benefits, including, but not limited to, improved safety, reduced delay, better multimodal quality of service, and livability. Yet government agencies often find themselves under intense pressure to yield to requests for more (or poorly located) access connections, or to forego a raised median that will preserve or restore roadway safety. The TRB National Cooperative ...
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 Quantifying the Effects of Implements of Husbandry on Pavements: AppendicesDecember 1, 2022 Implements of husbandry (IoH) are vehicles designed for agricultural purposes and exclusively used in the conduct of agricultural operations. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 338: Quantifying the Effects of Implements of Husbandry on Pavements: Appendices is supplemental to NCHRP Research Report 1019: Quantifying the Effects of Impleme...
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 Training and Certification of Construction Inspectors for Transportation InfrastructureJanuary 27, 2023 Construction inspectors (CIs) are the frontline workforce that ensures the work on transportation infrastructure projects meets the design and contract requirements and that the finished product meets or exceeds the quality standards. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 337: Training and Certification of Construction Inspectors for Transportation Infr...
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 Proposed Guidelines for Fixed Objects in the Roadside Design GuideOctober 19, 2022 Crash data show that more than 18,000 traffic fatalities per year result from roadway departures, and over 7,000 of those roadway departure crashes involved collisions with roadside fixed objects. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 336: Proposed Guidelines for Fixed Objects in the Roadside Design Guide helps develop an evaluation methodology and desi...
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 A Guide to Computation and Use of System-Level Valuation of Transportation AssetsJune 8, 2022 Determining the value of a transportation organization's physical assets is important for both financial reporting and transportation asset management (TAM). The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 335: A Guide to Computation and Use of System-Level Valuation of Transportation Assets details how to calculate asset value and use it to support application i...
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 Multi-State In-Service Performance Evaluations of Roadside Safety HardwareSeptember 29, 2022 The evolution of roadside hardware in the past has been largely dictated by changes to crash testing guidelines rather than observed field performance. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 332: Multi-State In-Service Performance Evaluations of Roadside Safety Hardware develops a unified format and nationally compatible "in-service performance evaluatio...
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 Mobility on Demand and Automated Driving Systems: A Framework for Public-Sector AssessmentDecember 6, 2022 Innovative and emerging mobility services offer travelers more options to increase mobility and access goods and services. In addition, various technological developments have the potential to alter the automotive industry and traveler experience, as well as mobility and goods access. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 331: Mobility on Demand and Aut...
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 Accessibility Measures in PracticeNovember 3, 2022 With an accessibility perspective, land use changes can bring transportation improvements by bringing activity locations closer together. If incorporated into transportation performance management, accessibility has the potential to highlight projects that would otherwise be overlooked because of their congestion-related impacts. The TRB National Cooperative Highway Research Program's NCHRP Web...
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 Bonded Concrete Overlays on Asphalt Pavements: Resources for EvaluationOctober 13, 2022 The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 329: Bonded Concrete Overlays on Asphalt Pavements: Resources for Evaluation provides Appendices A through G of the contractor’s final report, which detail survey responses from transportation agencies on bonded concrete overlays on asphalt pavements as well as agency plans and projects. The document is supple...
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 Safety Effects of Raising Speed Limits to 75 mph and HigherOctober 17, 2022 Across the United States, maximum speed limit laws vary dramatically. In the mid-1990s, many states increased speed limits to 75 mph on select roads. More recently, some states have established speed limits greater than 75 mph. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 328: Safety Effects of Raising Speed Limits to 75 mph and Higher is supplemental to NCHRP...
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 Serious and Fatal Motorcycle Crashes into Traffic Barriers: Injury InformationOctober 27, 2022 Motorcycle riders account for more fatalities than the passengers of any other vehicle type involved in a guardrail collision. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 327: Serious and Fatal Motorcycle Crashes into Traffic Barriers: Injury Information is a supplemental document to NCHRP Research Report 1005: Motorcycle Crashes into Traffic Barriers: Factor...
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 Consideration of Roadside Features in the Highway Safety ManualMay 2, 2022 Highway engineers are constantly redesigning and rebuilding roadways to meet higher standards, provide safer highways and increase mobility. For the last forty years this has included designing and building roadways that are more forgiving when a driver inadvertently encroaches onto the roadside. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 325: Consideration ...
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 Guide to Implementation of the Toward Zero Deaths National Strategy on Highway SafetyJune 27, 2022 In June 2014, eight associations that represent government agencies involved in highway safety released the document Toward Zero Deaths: A National Strategy on Highway Safety . This national strategy describes a long-term vision of zero traffic-related deaths and outlines the current challenges that need to be tackled. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Docum...
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 Highway Safety Manual User GuideMarch 31, 2022 The Highway Safety Manual can be used to identify sites with the most potential for crash frequency or severity reduction; identify contributing factors to crashes and mitigation measures; and estimate the potential crash frequency and severity on highway networks, among other uses. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 323: Highway Safety Manual User G...
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 Command-Level Decision Making for Transportation Emergency ManagersMay 16, 2022 Command-level decision making is a critical factor in successfully managing and mitigating critical incidents. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 321: Command-Level Decision Making for Transportation Emergency Managers is a document done in collaboration with TRB's Transit Cooperative Research Program (TCRP) and Airport Cooperative Research Pro...
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 Aligning Geometric Design with Roadway ContextMarch 21, 2022 Since 1984, AASHTO’s “Green Book” and other roadway design criteria have been primarily based on a functional classification system of a hierarchical network composed of arterials, collector, and local roads. However, this hierarchical functional classification system is in lack of flexibility in design, especially for a modern multimodal roadway system. The TRB National Cooperative Highwa...
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 Roadside Safety Analysis Program (RSAP) UpdateMarch 11, 2022 Motor vehicle crashes cost society more than $230 billion annually. On an average day, 117 fatal crashes occur on U.S. roadways, and 30 percent of these fatalities are people under the age of 25. In total, this amounts to a societal loss of $630 million per day. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 319: Roadside Safety Analysis Program (RSAP) Update de...
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 Safety Prediction Models for Six-Lane and One-Way Urban and Suburban ArterialsMarch 10, 2022 The Highway Safety Manual (HSM) provides a predictive method for two- and four-lane urban and suburban arterial facilities with both undivided and divided cross-sections. The manual does not cover arterials with six or more lanes or one-way streets. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 318: Safety Prediction Models for Six-Lane and One-Way Urban and Su...
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 Developing a Guide for Managing Performance to Enhance Decision-MakingJune 9, 2022 Transportation agencies largely have performance structures in place, but these structures alone do not guarantee progress on meeting performance targets. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 317: Developing a Guide for Managing Performance to Enhance Decision-Making provides guidance on how agencies can strengthen their gathering and use of feedback t...
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 Human Factors Guidelines for Road Systems 2021 Update, Volume 2: Conduct of Research Report January 27, 2022 Human factors principles and concepts can be used by highway designers and traffic engineers to improve roadway design and traffic safety. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 316: Human Factors Guidelines for Road Systems 2021 Update, Volume 2: Conduct of Research Report describes the process of updating guidelines, which were delivered in NCHRP Web-O...
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 Human Factors Guidelines for Road Systems 2021 Update, Volume 1: Updated and New ChaptersJanuary 27, 2022 In 2015, there were more than 6 million police-reported crashes in the United States. While crashes are complex and it is generally interactions between road users, vehicles, and the environment that lead to crashes, some form of driver error is a contributing factor in most crashes. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 316: Human Factors Guidelines fo...
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 Details of the Study on the Use of 0.7-in Diameter Strands in Precast Pretensioned GirdersAugust 3, 2022 The use of precast pretensioned girders using 0.7-in. diameter strands would help bridge designers extend the spans of the existing girder shapes. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 315: Details of the Study on the Use of 0.7-in Diameter Strands in Precast Pretensioned Girders is supplemental to NCHRP Research Report 994: Use of 0.7-in. Diameter Stra...
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 Updating the AASHTO LRFD Movable Highway Bridge Design SpecificationsNovember 5, 2021 There are approximately 1,000 movable highway bridges in the U.S. inventory. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 314: Updating the AASHTO LRFD Movable Highway Bridge Design Specifications allows bridge owners the option of employing site-specific conditions to develop the design wind speed and provides other general updates to previous research from 2...
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 Selecting Ramp Design Speeds, Volume 2: Conduct of Research ReportNovember 23, 2021 Designing extended sections of highway based on the design speed process is relatively straightforward. However, when applied to interchange ramps where high-speed facilities meet low-speed facilities and drivers are expected to accelerate or decelerate over short distances, application of the design speed process is more complex. The TRB National Cooperative Highway Research Program's NCHRP We...
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 Selecting Ramp Design Speeds, Volume 1: GuideNovember 23, 2021 Selection of a design speed should be based upon the anticipated operating speed, topography, adjacent land use, modal mix, and functional classification of the roadway. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 313: Selecting Ramp Design Speeds, Volume 1: Guide provides further detail for selecting an appropriate ramp design speed than presented in the 201...
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 Evaluation and Synthesis of Connected Vehicle Communication TechnologiesOctober 13, 2021 In 1999, the Federal Communications Commission (FCC) allocated the intelligent transportation system (ITS) band, also known as the “5.9 GHz band,” for transportation purposes including connected and automated vehicle (CAV) technologies. These technologies enable a host of applications for vehicle‐to-vehicle, vehicle‐to‐infrastructure, and vehicle‐to‐pedestrian communication — collectively known...
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 Safety Performance of Part-Time Shoulder Use on Freeways, Volume 2: Conduct of Research Report November 5, 2021 Part-time shoulder use is a congestion relief strategy that allows use of the left or right shoulders as travel lanes during some, but not all, hours of the day. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 309: Safety Performance of Part-Time Shoulder Use on Freeways, Volume 2: Conduct of Research Report describes the development of crash predicti...
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 Methods for State DOTs to Reduce Greenhouse Gas Emissions from the Transportation SectorMarch 14, 2022 Many technical and institutional issues related to estimating and reducing greenhouse gas emissions (GHGs) lie across a wide spectrum of the activities undertaken by state departments of transportation (DOTs). The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 308: Methods for State DOTs to Reduce Greenhouse Gas Emissions from the Transportation Sector documents the...
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 Recommended Guidelines for the Selection of Test Levels 2 Through 5 Bridge RailingsSeptember 27, 2021 Since bridges cross over large spans of space they often cross significant features such as busy transportation corridors. In addition, bridges carry heavy vehicles sometimes with dangerous cargos, such as fuel and hazardous chemicals. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 307: Recommended Guidelines for the Selection of Test Levels 2 Through 5 Bridge R...
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 Safety Prediction Methodology and Analysis Tool for Freeways and InterchangesOctober 11, 2021 Prior to this research project, state highway agencies did not have tools for reflecting safety in their decisions concerning freeway and interchange projects. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 306: Safety Prediction Methodology and Analysis Tool for Freeways and Interchanges documents a safety prediction method for freeways that is suitable for inc...
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 Validation of a Performance-Based Mix Design Method for Porous Friction CoursesSeptember 15, 2021 Porous Friction Course (PFC) mixtures are designed with an open aggregate structure to yield high inplace air voids (i.e., typically between 15 and 20 percent). This allows rainwater to drain horizontally through the layer toward the edge of the pavement structure, thereby improving pavement surface friction. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 305: V...
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 Criteria for Restoration of Longitudinal Barriers, Phase II August 27, 2021 Guardrails are an important feature of the roadside that are used to shield errant motorists from becoming involved in even more catastrophic crashes by redirecting vehicles away from fixed hazards such as trees and poles and terrain hazards such as steep roadside slopes and fill embankments. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 304: Criteria for Resto...
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 Understanding and Communicating Reliability of Crash Prediction ModelsDecember 16, 2021 Understanding and communicating consistently reliable crash prediction results are critical to credible analysis and to overcome barriers for some transportation agencies or professionals utilizing these models. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 303: Understanding and Communicating Reliability of Crash Prediction Models provides guidance on being ab...
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 Development of Guidelines for Quantifying Benefits of Traffic Incident Management StrategiesFebruary 4, 2022 Traffic Incident Management activities have advanced in recent years to become a critical part of transportation operations, as well as a significant budget expenditure. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 301: Development of Guidelines for Quantifying Benefits of Traffic Incident Management Strategies seeks to improve uniformity in measurement, acces...
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 Guidance to Predict and Mitigate Dynamic Hydroplaning on RoadwaysJuly 29, 2021 Hydroplaning is a serious problem that is associated with a relatively small but significant number of crashes. Statistics from various parts of the world indicate that approximately 15% to 20% of all road traffic crashes occur in wet weather conditions. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 300: Guidance to Predict and Mitigate Dynamic Hydroplaning on ...
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 Investigating the Relationship of As-Constructed Asphalt Pavement Air Voids to Pavement PerformanceJune 11, 2021 Several controlled laboratory studies have shown that air voids (AV) can have a large effect on the performance of asphalt pavements. AVs that are either too high or too low can cause a reduction in pavement life. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 299: Investigating the Relationship of As-Constructed Asphalt Pavement Air Voids to Pavement Performanc...
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 Developing a Systematic Approach for Determining Construction Contract TimeMarch 18, 2022 Excessive contract time is costly because it extends a construction crew’s exposure to traffic, prolongs the inconvenience to the public, and subjects motorists to less than desirable safety conditions for longer periods. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 298: Developing a Systematic Approach for Determining Construction Contract Timeseeks to provid...
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 Intersection Crash Prediction Methods for the Highway Safety ManualApril 11, 2021 The first edition of the Highway Safety Manual (HSM), in 2010, included Safety Performance Functions (SPFs) for roadway segments and intersections. However, not all intersection types are covered in the first edition of the HSM. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 297: Intersection Crash Prediction Methods for the Highway Safety Manual develops ...
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 Guidelines for Cost-Effective Safety Treatments of Roadside DitchesApril 2, 2021 Run-off-road traffic crashes account for almost one-third of the deaths and serious injuries each year on U.S. highways. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 296: Guidelines for Cost-Effective Safety Treatments of Roadside Ditches provides new proposed design guidance for the configuration of ditches adjacent to the roadway. A supplemental PowerPoint S...
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 Improved Prediction Models for Crash Types and Crash SeveritiesApril 29, 2021 The release of the Highway Safety Manual (HSM) by the American Association of State Highway and Transportation Officials (AASHTO) in 2010 was a landmark event in the practice of road safety analysis. Before it, the United States had no central repository for information about quantitative road safety analysis methodology. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Do...
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 Revised Clear-Water and Live-Bed Contraction Scour Analysis Training ManualJuly 16, 2021 A workshop, "Revised Contraction Scour Analysis," is presented in this training manual. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 294: Revised Clear-Water and Live-Bed Contraction Scour Analysis Training Manual adheres to the guidance promulgated by the National Highway Institute and the International Association of Continuing Education and Training for adu...
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 Deploying Transportation Resilience Practices in State DOTsJune 24, 2021 Over the past 15 years, the nation’s transportation systems have experienced numerous significant disruptions that have resulted in economic loss and loss of human life. The 2020 COVID-19 pandemic is a recent example of how unexpected events can affect the performance and role of transportation systems. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 293: Deployi...
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 Roadside Hardware Replacement Analysis: User GuideFebruary 11, 2021 Highway agencies can use a method to assess roadside hardware and establish priorities on how upgrades of hardware should occur for individual projects or establish policy guidelines on roadside hardware assessments. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 292: Roadside Hardware Replacement Analysis: User Guide presents how to implement and plan for asses...
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 Development of a Posted Speed Limit Setting Procedure and ToolJune 4, 2021 Several types of speed limits exist, including statutory speed limit, posted speed limit, school zone speed limit, work zone speed limit, variable speed limit, and advisory speed. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 291: Development of a Posted Speed Limit Setting Procedure and Tool documents the research efforts and findings from an NCHRP Project 17-...
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 Highway Capacity Manual Methodologies for Corridors Involving Freeways and Surface StreetsOctober 19, 2020 The procedures detailed in the 6th Edition of the Highway Capacity Manual (HCM) estimate capacity and several operational measures, including those determining Level of Service, for freeway facilities as well as surface streets. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 290: Highway Capacity Manual Methodologies for Corridors Involving Freeways and Surface ...
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 Standard Definitions for Common Types of Pavement CrackingSeptember 16, 2020 New definitions will help pavement cracking survey providers and pavement engineers at state highway administrations conduct objective cracking measurements and encourage continuing technological innovations by researchers and vendors. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 288: Standard Definitions for Common Types of Pavement Cracking helps develop sta...
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 Planning and Implementing Multimodal, Integrated Corridor Management: GuidebookAugust 18, 2020 Integrated Corridor Management (ICM) is an operational concept that seeks to reduce congestion and improve performance by maximizing the use of available multimodal capacity across a corridor, including highways, arterial roads, and transit systems. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 287: Planning and Implementing Multimodal, Integrated Corridor Mana...
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 Principles and Guidance for Presenting Active Traffic Management Information to DriversMarch 5, 2021 Active Traffic Management (ATM) strategies have become more common in the United States as state departments of transportation grapple with increasing congestion and fewer dollars available to add capacity to keep pace. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 286: Principles and Guidance for Presenting Active Traffic Management Information to Drivers deve...
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 Developing a Guide for Quantitative Approaches to Systemic Safety AnalysisDecember 14, 2020 Highway agencies have traditionally managed the safety improvement process by identifying and correcting high-crash locations (“hot-spots”), where concentrations of crashes and, often, patterns of crashes of similar types, were found. However, when crashes are evaluated over too short a period of time (3 years or less), locations may be identified as hot-spots simply due to the random nature of...
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 Decision-Making Guide for Traffic Signal PhasingAugust 17, 2020 Few resources provide information related to selecting the most appropriate traffic signal phasing for the various geometric and operational situations encountered in the field. This is especially true for left-turn signal phasing decisions with respect to the level of control for the left-turn movement and whether left turns should precede or follow the main through movement. The TRB National ...
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 Improving Mid-Term, Intermediate, and Long-Range Cost Forecasting for State Transportation AgenciesOctober 28, 2020 Predicting the future of the construction market is always a challenging task - regardless of whether it is over the next one or 20 years - since it involves several uncertainties. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 283: Improving Mid-Term, Intermediate, and Long-Range Cost Forecasting for State Transportation Agencies documents the research that led...
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 Framework for Managing Data from Emerging Transportation Technologies to Support Decision-MakingOctober 21, 2020 The amount of data surrounding the application of emerging technologies is expanding, producing “big data” at magnitudes not previously seen. While a few agencies have found some success with individual projects, most are uncertain on how to handle this level of big data at an organizational level. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 282: Framework fo...
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 Integrating Tribal Expertise into Processes to Identify, Evaluate, and Record Cultural ResourcesApril 7, 2020 There is a lot of evidence that Native American tribes could be better involved in planning transportation projects. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 281: Integrating Tribal Expertise into Processes to Identify, Evaluate, and Record Cultural Resources explores how unique tribal perspectives and expertise could inform the tribal engagement and consu...
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 Valuing Wildlife Crossings and Enhancements for Mitigation CreditsFebruary 27, 2020 There is mounting evidence demonstrating the effectiveness of wildlife overpasses and underpasses in improving motorist safety and conserving wildlife. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 280: Valuing Wildlife Crossings and Enhancements for Mitigation Credits synthesizes current practices used by state DOTs and their partners for calculating and apply...
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 Information Findability Implementation Pilots at State Transportation AgenciesJuly 28, 2020 With a quick online search, you can discover the answers to all kinds of questions. Findability within large volumes of information and data has become almost as important as the answers themselves. Without being able to search various types of media ranging from print reports to video, efforts are duplicated and productivity and effectiveness suffer. The TRB National Cooperative Highway Resear...
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 Implementing Alternative Technical Concepts in All Types of Highway Project Delivery MethodsJuly 13, 2020 There is an emerging view in the construction industry that better performance or better value for money can be achieved by integrating teamwork for planning, design, and construction of projects. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 277: Implementing Alternative Technical Concepts in All Types of Highway Project Delivery Methods seeks to assist integr...
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 Evaluating Strategies for Work Zone Transportation Management PlansSeptember 18, 2020 Transportation management plans (TMPs) are a set of coordinated strategies designed to help agencies achieve work zone project goals related to traffic mobility, efficient system operation, motorist and worker safety, and other operational targets. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 276: Evaluating Strategies for Work Zone Transportation Management P...
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 Zero Emission Vehicles: Forecasting Fleet Scenarios and their Emissions ImplicationsFebruary 1, 2020 Vehicle electrification is one of the emerging and potentially disruptive technologies that are being considered to reduce emissions of criteria pollutants, mobile source air toxics (MSATs), and greenhouse gases (GHGs) from motor vehicles. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 274: Zero Emission Vehicles: Forecasting Fleet Scenarios and their Emissions ...
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 Road User Understanding of Bicycle Signal Faces on Traffic SignalsJanuary 6, 2020 Prior to 2013, the use of bicycle-specific signals in the U.S. was limited to a few jurisdictions. However, in recent years, the number of installations has grown rapidly. This research identified more than 500 intersections using bicycle signals in a variety of contexts. Despite the recent approval and practice, the TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 27...
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 Existing and Emerging Highway Infrastructure Preservation, Maintenance, and Renewal Definitions, Practices, and ScenariosApril 23, 2020 The National Cooperative Highway Research Program's NCHRP Web-Only Document 272: Existing and Emerging Highway Infrastructure Preservation, Maintenance, and Renewal Definitions, Practices, and Scenarios provides appendices to NCHRP Report 750, Volume 7: Preservation, Maintenance, and Renewal of Highway Infrastructure .
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 Guide Specification for Service Life Design of Highway BridgesJanuary 3, 2020 The majority of instances of explicit consideration of service life design has been limited to signature bridges and other projects where extended service lives (in other words, greater than 100 years) are specified by the owner. Many state departments of transportation and other transportation agencies have recognized the importance of implementing service life design for typical highway bridg...
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 Developing a Guide to Emergency Management at State Transportation AgenciesJuly 22, 2020 Transportation plays a critical role in emergency management. After all, state transportation agencies have large and distributed workforces, easy access to heavy equipment, and a robust communications infrastructure capable of sustained mobilization. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 267: Developing a Guide to Emergency Management at State Transpor...
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 Developing a Physical and Cyber Security Primer for Transportation Agencies July 17, 2020 Small events pose threats of great consequences since the impact of any incident is magnified when a transportation network is operating at or past its capacity—as is the case in portions of many states as travel demand on their transportation networks grows. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 266: Developing a Physical and Cyber Security Primer for ...
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 White Papers for Right-Sizing Transportation InvestmentsSeptember 4, 2020 While not all right-sizing projects involve a change in jurisdictional responsibility and ownership, jurisdictional transfer can be a key tool for implementing right-sizing plans and agreements. As a supplemental document to NCHRP Research Report 917: Right-Sizing Transportation Investments:A Guidebook for Planning and Programming , the TRB National Cooperative Highway Research Program's NCHRP ...
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 Sustainable Highway ConstructionJanuary 31, 2020 A programmatic approach to sustainable materials procurement in highway construction may be better than one-off attempts. For now, there is little guidance on procuring sustainability in highway construction and sustainability is not as important as cost or schedule. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 262: Sustainable Highway Construction describes t...
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 Case Studies of Truck Activity Data for Emissions Modeling June 12, 2019 NCHRP Web-Only Document 261: Case Studies of Truck Activity Data for Emissions Modeling consists of seven case studies that are appendices A to G of NCHRP Report 909: Guide to Truck Activity Data for Emissions Modeling. NCHRP Research Report 909 explores methods, procedures, and data sets needed to capture commercial vehicle activity, vehicle characteristics, and operations to assist in estimat...
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 Guidelines to Improve the Quality of Element-Level Bridge Inspection DataMarch 8, 2019 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 259: Guidelines to Improve the Quality of Element-Level Bridge Inspection Data is intended to assist inspectors in identifying defects and assigning the appropriate condition state for bridge elements. To ensure the safety and serviceability of bridges, the guidelines include accuracy requirements designed to help pro...
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 Manual on Subsurface InvestigationsFebruary 6, 2019 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 258: Manual on Subsurface Investigations provides an update to the American Association of State Highway Transportation Officials (AASHTO) 1988 manual of the same name. This report reflects the changes in the approaches and methods used for geotechnical site characterization that the geotechnical community has develop...
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 A Mechanistic–Empirical Model for Top–Down Cracking of Asphalt Pavements LayersOctober 31, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 257: A Mechanistic–Empirical Model for Top–Down Cracking of Asphalt Pavements Layers develops a calibrated mechanistic-empirical (ME) model for predicting the load-related top-down cracking in the asphalt layer of flexible pavements. Recent studies have determined that some load-related fatigue cracks in asphalt pavem...
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 Assessing Interactions Between Access Management Treatments and Multimodal Users December 28, 2018 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 256: Assessing Interactions Between Access Management Treatments and Multimodal Users describes operational and safety relationships between access management techniques and the automobile, pedestrian, bicycle, public transit, and truck modes. This contractor's report may help assist in the selection of alternati...
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 Improved Analysis of Two-Lane Highway Capacity and Operational PerformanceJuly 2, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 255: Improved Analysis of Two-Lane Highway Capacity and Operational Performance supplements the sixth edition of the Highway Capacity Manual (HCM). Specifically, this project includes the following updates: the development of a more realistic speed-flow relationship the introduction of a new service measure—follower d...
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 Implications of Connected and Automated Driving Systems, Vol. 6: Implementation PlanOctober 26, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 253: Implications of Connected and Automated Driving Systems, Vol. 6: Implementation Plan provides a technical memorandum on how to put the research findings and products into practice; identifies possible institutions that might take leadership in applying the research findings/products; and identifies issues affecti...
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 Implications of Connected and Automated Driving Systems, Vol. 4: Autonomous Vehicle Action Plan October 26, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 253: Implications of Connected and Automated Driving Systems, Vol. 4: Autonomous Vehicle Action Plan (AVAP) develops awareness of the legislative landscape and the foundational laws and regulations that may need to be prioritized for modification for Connected and Automated Driving Systems (C/ADSs) technologies. The A...
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 Implications of Connected and Automated Driving Systems, Vol. 2: State Legal and Regulatory AuditOctober 26, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 253: Implications of Connected and Automated Driving Systems, Vol. 2: State Legal and Regulatory Audit assists state agencies as they work to adapt their legal programs to reflect the realities of Connected and Automated Driving Systems (C/ADSs)—a term that in this report encompasses both vehicle connectivity and an A...
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 Implications of Connected and Automated Driving Systems, Vol. 1: Legal LandscapeOctober 26, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 253: Implications of Connected and Automated Driving Systems, Vol. 1: Legal Landscape explores federal, state, and international legal activities and practices regarding Connected and Automated Vehicles and Highly Automated Vehicles (C/AV/HAVs): Section 1 reviews United States federal activities within the sphere of r...
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 A Strategic Approach to Transforming Traffic Safety Culture to Reduce Deaths and InjuriesOctober 16, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 252: A Strategic Approach to Transforming Traffic Safety Culture to Reduce Deaths and Injuries provides guidance on developing a strategic approach to transform the traffic safety culture of road users and stakeholders. The goal is to use this approach to sustain improvements in traffic safety for all road users, incl...
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 Spot Painting to Extend Highway Bridge Coating Life: Volume 2: Research Overview April 12, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 251: Spot Painting to Extend Highway Bridge Coating Life: Volume 2: Research Overview documents the evaluation method for a guidance document that provides approaches for employing spot painting in a cost-effective, safe, and environmentally compliant manner. Bridge coatings are the primary means of corrosion pro...
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 Spot Painting to Extend Highway Bridge Coating Life: Volume 1: Guidance April 12, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 251: Spot Painting to Extend Highway Bridge Coating Life: Volume 1: Guidance provides approaches for employing spot painting in a cost-effective, safe, and environmentally compliant manner. Bridge coatings are the primary means of corrosion protection for steel bridges in the United States. Most bridge coatings tend t...
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 Use of Automated Machine Guidance within the Transportation IndustryApril 3, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 250: Use of Automated Machine Guidance within the Transportation Industry studies automated machine guidance (AMG) implementation barriers and develop strategies for effective implementation of AMG technology in construction operations. AMG links design software with construction equipment to direct the operations of ...
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 Combining Individual Scour Components to Determine Total ScourMarch 6, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 249: Combining Individual Scour Components to Determine Total Scour explores the relationships among individual scour components observed in the same flow event at a bridge. The report provides insight into ways to combine scour components to produce realistic estimates of total scour depth for safe and economical des...
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 Research on Creating and Sustaining a Culture of Innovation for Departments of TransportationNovember 6, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 248: Research on Creating and Sustaining a Culture of Innovation for Departments of Transportation documents the research process and provides key guidance to implement the research produced in NCHRP Research Report 885 : Guide to Creating and Sustaining a Culture of Innovation for Departments of Transportation. This ...
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 Managing Geotechnical Risks in Design–Build Projects September 18, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 247: Managing Geotechnical Risks in Design–Build Projects documents the research effort to produce NCHRP Research Report 884 : Guidelines for Managing Geotechnical Risks in Design–Build Projects. NCHRP Research Report 884 provides guidelines for the implementation of geotechnical risk management measures for des...
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 Volume 2: TRAQS: A Combined Interface for Project-Level Air Quality AnalysisAugust 24, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 246: Volume 2: TRAQS: A Combined Interface for Project-Level Air Quality Analysis documents the development of TRAQS (TRansportation Air Quality System), a Graphical User Interface-based software application that simplifies project-level air quality analysis of mobile source emissions. TRAQS integrates the “modeling c...
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 Volume 1: TRAQS User GuideAugust 24, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 246: Volume 1: TRAQS User Guide provides guidance for using the TRansportation Air Quality System (TRAQS). TRAQS is an open source software designed to conduct mobile air quality assessments for three primary purposes: Project-Level Conformity (Hot-Spot Analyses) National Environmental Policy Act (NEPA) General Transp...
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 Bridge Superstructure Tolerance to Total and Differential Foundation MovementsFebruary 23, 2018 TRB's National Highway Cooperative Research Program (NCHRP) Web-Only Document 245: Bridge Superstructure Tolerance to Total and Differential Foundation Movements develops an understanding of the levels of support movements that bridges may tolerate before exceeding strength or service limit states. This research explores analytical procedures to objectively determine the acceptable levels of br...
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 Recommended AASHTO Guide Specifications for ABC Design and ConstructionFebruary 16, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 242: Recommended AASHTO Guide Specifications for ABC Design and Construction documents the results of a synthesis of past research regarding Accelerated Bridge Construction (ABC), leading to the development of Guide Specifications for Accelerated Bridge Construction. Part 1 of the report includes Design Specifications...
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 Development and Management of Sustainable Enterprise Information PortalsJanuary 23, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Web Only Document 241: Development and Management of Sustainable Enterprise Information Portals documents the research approach and methodology to develop NCHRP Research Report 865 : Guidance for Development and Management of Sustainable Enterprise Information Portals. The guidance addresses the development and managem...
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 Impacts of Laws and Regulations on CV and AV Technology Introduction in Transit OperationsOctober 9, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 239: Impacts of Laws and Regulations on CV and AV Technology Introduction in Transit Operations explores the potential barriers imposed by operating policies, agency regulations, and governmental laws relative to the transit environment. Without adjustment, the combination of new technology with old rules could result...
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 Developing the Guide to Retaining Essential Consultant-Developed Knowledge Within DOTs December 27, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 238: Developing the Guide to Retaining Essential Consultant-Developed Knowledge Within DOTs documents the methodology used to develop NCHRP Research Report 867 : Keeping What You Paid For—Retaining Essential Consultant-Developed Knowledge Within DOTs . The document also provides key findings of the project...
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 Environmental Justice Analyses When Considering Toll Implementation or Rate Changes—Final ReportJanuary 12, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 237: Environmental Justice Analyses When Considering Toll Implementation or Rate Changes—Final Report presents information gathered in the development of NCHRP Research Report 860 : Assessing the Environmental Justice Effects of Toll Implementation or Rate Changes: Guidebook and Toolbox. This web-only document summari...
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 Incorporating Slab/Underlying Layer Interaction into the Concrete Pavement Analysis ProceduresJuly 28, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 236: Incorporating Slab/Underlying Layer Interaction into the Concrete Pavement Analysis Procedures develops mechanistic-empirical (M-E) models (and software) to consider the interaction between the concrete slab and base layer and its effect on pavement performance. The current American Association of State Hig...
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 Quantifying the Influence of Geosynthetics on Pavement PerformanceJuly 26, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 235: Quantifying the Influence of Geosynthetics on Pavement Performance develops a methodology for quantifying the influence of geosynthetics on pavement performance for use in pavement design and analysis. This project focused on the use of geosynthetics in unbound base/subbase layers or as a base/subgrade interface ...
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 Developing a Method Selection Tool for Travel ForecastingOctober 20, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 234: Developing a Method Selection Tool for Travel Forecasting documents research undertaken to provide guidance on travel forecasting methods to agencies with diverse planning needs. This project sought to produce applicable methods by evaluating agencies’ planning programs, desired performance metrics, requirements,...
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 Mainstreaming Transportation Hazards and Security Risk Management: CAPTA Update and Implementation June 8, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 233: Mainstreaming Transportation Hazards and Security Risk Management: CAPTA Update and Implementation provides an update and enhancement of the CAPTA methodology and CAPTool for realistic costing . The suite of materials produced include a quick start guide to use the CAPTool, as well as a dataset populated with exa...
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 Communications Worker Credentialing RequirementsMay 16, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 232: Communications Worker Credentialing Requirements focuses on credentialing requirements needed for communications workers to physically access disaster-impacted areas to restore damaged wireline telecommunication networks. Under the advice of a Federal Communications Commission (FCC) panel that reviewed the impact...
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 Challenges to CV and AV Applications in Truck Freight OperationsApril 15, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 231: Challenges to CV and AV Applications in Truck Freight Operations explores connected vehicle (CV) and automated vehicle (AV) technology, focusing on heavy trucking. The report identifies existing and emerging freight regulatory, planning, policy, and operational environments and challenges for connected and autono...
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 Developing an Expanded Functional Classification System for More Flexibility in Geometric DesignJune 29, 2018 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 230: Developing an Expanded Functional Classification System for More Flexibility in Geometric Design, which documents the methodology of NCHRP Research Report 855 : An Expanded Functional Classification System for Highways and Streets builds upon preliminary engineering of a design project, including developing...
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 Methods and Technologies for Pedestrian and Bicycle Volume Data Collection: Phase 2March 23, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 229: Methods and Technologies for Pedestrian and Bicycle Volume Data Collection: Phase 2 explores automated count technologies that capture pedestrian and bicycle volume data. The publication focuses on technologies that came onto the market too late to be included in previous Phase 1 research. Findings from Phase 1 a...
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 Safety Impacts of Intersection Sight DistanceApril 2, 2018 TRB's National Cooperative Highway Research Program ( NCHRP) Web-Only Document 228 : Safety Impacts of Intersection Sight Distance documents the methodology and presents the results from NCHRP Research Report 875 : Guidance for Evaluating the Safety Impacts of Intersection Sight Distance. It provides the underlying research on estimating the safety effects of intersection sight distance (...
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 Design of Interchange Loop Ramps and Pavement/Shoulder Cross-Slope BreaksFebruary 2, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 227: Design of Interchange Loop Ramps and Pavement/Shoulder Cross-Slope Breaks is presented in two parts. Part 1 presents design guidance for interchange loop ramps based on observational field studies and safety analyses and includes suggestions for the next edition of A Policy on Geometric Design of Highways and Str...
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 Data Visualization Methods for Transportation AgenciesApril 2, 2017 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 226: Data Visualization Methods for Transportation Agencies provides techniques for planners who have various levels of experience with displaying and reporting information in a visual format. The publication includes practices for developing visualization skills, enhancing transportation analysis, and improving publi...
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 Research Supporting the Development of Guidelines for Implementing Managed LanesDecember 25, 2016 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 224: Research Supporting the Development of Guidelines for Implementing Managed Lanes documents the contractor's final report used to develop NCHRP Report 835 : Guidelines for Implementing Managed Lanes. The report includes detailed background material, gap analysis, design elements, safety performance parameters, and...
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 Protection of Transportation Infrastructure from Cyber Attacks: A PrimerMay 13, 2016 TRB's Protection of Transportation Infrastructure from Cyber Attacks: A Primer provides transportation organizations with reference materials concerning cybersecurity concepts, guidelines, definitions, and standards. The primer is a joint product of two TRB Cooperative Research Programs, and is categorized as Transit Cooperative Research Program (TCRP) Web-Only Document 67 and National Cooperat...
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 Estimating the Life-Cycle Cost of Intersection DesignsFebruary 11, 2016 TRB’s National Cooperative Highway Research Program (NCHRP ) Web-Only Document 220: Estimating the Life-Cycle Cost of Intersection Designs describes the Life-Cycle Cost Estimation Tool (LCCET). The LCCET spreadsheet allows users to compare alternative intersection designs based on initial construction costs, ongoing maintenance and operations costs, operational efficiencies for a variety of mod...
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 Hamburg Wheel-Track Test Equipment Requirements and Improvements to AASHTO T 324February 3, 2016 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 219: Hamburg Wheel-Track Test Equipment Requirements and Improvements to AASHTO T 324 evaluates the capability of the Hamburg Wheel Tracking (HWT) devices available in the United States market and identifies potential issues with different aspects of American Association of State Highway and Transportation Officials (...
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 Field Evaluation of Reflected Noise from a Single Noise Barrier—Phase 1January 26, 2016 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 218: Field Evaluation of Reflected Noise from a Single Noise Barrier—Phase 1 studies the change in sound levels and characteristics caused by sound reflections off a reflective, non-absorptive noise barrier on the opposite side of a highway.
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 Precision and Bias Statements for AASHTO Standard Methods of Test TP 98 and TP 99 November 30, 2015 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 217: Precision and Bias Statements for AASHTO Standard Methods of Test TP 98 and TP 99 documents and presents results of a study of precision and bias associated with two AASHTO standards used to measure tire-pavement noise. The research team digitally recorded audio and video of traffic on segments of highways that w...
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 Emergency Exit Signs and Marking Systems for Highway TunnelsNovember 20, 2015 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 216: Emergency Exit Signs and Marking Systems for Highway Tunnels focuses on determining effective messages for encouraging drivers to leave their vehicles and evacuate a tunnel on foot; determining sign and marking formats that most effectively lead people to emergency tunnel exits; and determining the most visible s...
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 Incident Command System (ICS) Training for Field-Level Supervisors and StaffMarch 4, 2016 NCHRP Web-Only Document 215: Incident Command System (ICS) Training for Field-Level Supervisors and Staff , from TRB's National Cooperative Highway Research Program, provides training materials and guidance for transportation field personnel to help their organizations operate safely in an emergency or traffic management event. This course is intended to review the basic ICS structures an...
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 Transportation Agency Self-Assessment of Data to Support Business Needs: Final Research ReportNovember 7, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 214: Transportation Agency Self-Assessment of Data to Support Business Needs: Final Research Report describes the research and methods used to develop NCHRP Report 814 : Data to Support Transportation Agency Business Needs: A Self-Assessment Guide. The guide provides methods to evaluate and improve the value of t...
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 Alternative Quality Management Systems for Highway ConstructionJune 13, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 212: Alternative Quality Management Systems for Highway Construction documents the research process, data collection and analysis used to develop NCHRP Report 808: Guidebook on Alternative Quality Management Systems for Highway Construction .
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 Close to Home: A Handbook for Transportation-Efficient Growth in Small Communities and Rural AreasFebruary 12, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 211: Close To Home: A Handbook for Transportation-Efficient Growth in Small Communities and Rural Areas provides a vocabulary of land use characteristics in small communities and rural areas. It also estimates the per person change in daily driving after hypothetical growth occurs according to different development vi...
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 Input Guidelines for Motor Vehicle Emissions Simulator Model, Volume 3: Final ReportFebruary 2, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 210: Input Guidelines for Motor Vehicle Emissions Simulator Model, Volume 3: Final Report documents the research process for developing the Practitioners’ Handbooks and tools, and provides additional documentation not included in the handbook. NCHRP Web-Only Document 210 Volume 1: Practitioners’ Handbook: Regional Lev...
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 Design Guidance for Channelized Right-Turn LanesDecember 2, 2014 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 208: Design Guidance for Channelized Right-Turn Lanes develops guidance for channelized right-turn lanes based on balancing the needs of motor vehicles, pedestrians, and bicycles.
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 Methods and Technologies for Pedestrian and Bicycle Volume Data Collection January 23, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 205: Methods and Technologies for Pedestrian and Bicycle Volume Data Collection, documents the research that led to the guidance of NCHRP Report 797: Guidebook on Pedestrian and Bicycle Volume Data Collection . Research included the testing and evaluation of a range of automated count technologies that captu...
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 Crash Experience Warrant for Traffic SignalsSeptember 21, 2014 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 204: Crash Experience Warrant for Traffic Signals develops a procedure for evaluating and quantifying the safety of stop-controlled and signal-controlled intersections. The findings from this evaluation were used to develop a proposed crash experience warrant. The main products of the research are the proposed crash e...
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 Operation of Traffic Signal Systems in Oversaturated Conditions, Volume 1 – Practitioner GuidanceSeptember 23, 2014 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 202: Operation of Traffic Signal Systems in Oversaturated Conditions, Volume 1 – Practitioner Guidance presents an approach for identifying traffic control strategies for mitigating oversaturated conditions at signalized intersections. Specifically, the guidance assists in the process of matching mitigation strategies...
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 Operation of Traffic Signal Systems in Oversaturated Conditions, Volume 2 – Final Report September 23, 2014 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 202: Operation of Traffic Signal Systems in Oversaturated Conditions, Volume 2 – Final Report documents the procedures and methodology used to develop quantitative metrics for oversaturated traffic conditions, identify operational objectives based on observed conditions, develop a methodology for generating timing pla...
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 Calibration of AASHTO LRFD Concrete Bridge Design Specifications for ServiceabilityApril 13, 2014 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 201: Calibration of AASHTO LRFD Concrete Bridge Design Specifications for Serviceability explores calibrating the service limit states related to concrete bridges in the American Association of State Highway and Transportation Officials’ Load Resistance Factor Design Bridge Design Specifications (AASHTO LRFD). A limit...
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 Command-Level Decision Making for Transit Emergency ManagersDecember 10, 2013 TRB’s Transit Cooperative Research Program (TCRP) Web-Only Document 60 and National Cooperative Highway Research Program (NCHRP) Web -Only Document 200: Command-Level Decision Making for Transit Emergency Managers describes a Transit Emergency Response Application (TERA) that is designed to train transit command-level decision makers through simulation guided experiential learning. TERA provide...
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 Estimating Joint Probabilities of Design Coincident Flows at Stream ConfluencesAugust 30, 2013 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 199: Estimating Joint Probabilities of Design Coincident Flows at Stream Confluences documents procedures for estimating joint probabilities of coincident flows at stream confluences and guidelines for applying the procedures to design problems.
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 Sag Vertical Curve Design Criteria for Headlight Sight DistanceMarch 19, 2013 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 198: Sag Vertical Curve Design Criteria for Headlight Sight Distance reviews the current methodologies used in the design of sag vertical curves and changes in headlamp technologies. The report also highlights potential changes to the American Association of State Highway and Transportation Officials (AASHTO) design g...
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 Final Research Report: A Transportation Guide for All-Hazards Emergency EvacuationMay 14, 2013 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 196: Final Research Report: A Transportation Guide for All-Hazards Emergency Evacuation documents the development of the NCHRP Report 740 that focuses on the transportation aspects of evacuation--particularly large-scale, multijurisdictional evacuation.
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 Driving Forces Influencing Future Freight FlowsMarch 29, 2013 TRB National Cooperative Highway Research Program (NCHRP) Web-Only Document 195: Driving Forces Influencing Future Freight Flows includes a detailed discussion on the driving forces behind high-impact economic and social changes as well as sourcing patterns that may affect the U.S. freight transportation system. An analysis of the driving forces was published as NCHRP Report 750: Strategic Issu...
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 Traffic Law Enforcement in Work Zones: Phase II ResearchMay 19, 2013 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 194: Traffic Law Enforcement in Work Zones: Phase II Research is contractor’s final report providing background information for the project that produced NCHRP Report 746 Traffic Enforcement Strategies for Work Zones. NCHRP Report 746 presents guidance for the safe and effective deployment of traffic enforcement strat...
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 Development of Left-Turn Lane Warrants for Unsignalized IntersectionsApril 18, 2013 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 193: Development of Left-Turn Lane Warrants for Unsignalized Intersections provides background on the development of NCHRP Report 745 : Left-Turn Accommodations at Unsignalized Intersections.
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 Deployment, Use, and Effect of Real-Time Traveler Information SystemsJanuary 11, 2013 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 192: Deployment, Use, and Effect of Real-Time Traveler Information Systems explores the deployment, use, and effect of real-time traveler information (TI) systems. The report examines transportation agency dissemination practices, assesses traveler perception and use of TI systems, and offers best practices on ways to...
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 Analysis of Managed Lanes on Freeway FacilitiesDecember 12, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 191: Analysis of Managed Lanes on Freeway Facilities evaluates the performance of managed lane facilities on freeways.
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 Structural Design of Culvert JointsJuly 20, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 190: Structural Design of Culvert Joints explores the effect of longitudinal bending on joints in rigid (reinforced concrete) and flexible (corrugated steel and thermoplastic) culverts. The report examines two joint types--those that release the longitudinal bending moments (denoted ‘moment-release joints’) like gaske...
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 Design and Management of Historic RoadsMay 24, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 189: Design and Management of Historic Roads explores how the inherent flexibility in the current policies, manuals, criteria, rules, standards, and data sets that underlie the transportation planning and project development process may be used to preserve historic roads and roads in historic districts and settings.
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 Survey of State Funding for Public Transportation—Ways to Improve ItApril 26, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 188: Survey of State Funding for Public Transportation—Ways to Improve It includes suggestions on ways to potentially improve the Survey of State Funding for Public Transportation. Areas covered by the report include definition of major terms, post-submission data checks, improved accessibility, non-transit related fe...
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 Seismic Design of Geosynthetic-Reinforced Soil Bridge Abutments with Modular Block FacingApril 5, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 187: Seismic Design of Geosynthetic-Reinforced Soil Bridge Abutments with Modular Block Facing explores design methods and construction guidelines for using geosynthetic-reinforced soil (GRS) systems in bridge abutments in seismically active regions. The report focuses on single-span, simply-supported bridges subjecte...
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 The Superpave Mix Design System: Anatomy of a Research ProgramMarch 24, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 186: The Superpave Mix Design System: Anatomy of a Research Program describes how the original Strategic Highway Research Program (SHRP) effort was conceived, funded, and managed. The report outlines the research and implementation efforts that brought SHRP products into routine use and summarizes some of the key less...
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 Going the Distance Together: A Citizen’s Guide to Context Sensitive Solutions for Better TransportationApril 9, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 184: Going the Distance Together: A Citizen’s Guide to Context Sensitive Solutions for Better Transportation is designed to help people ask the right questions at the right time during the transportation planning process in order to help ensure that transportation projects fit the context of their community. Context s...
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 Appendices to NCHRP Report 693February 20, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 182: Appendices to NCHRP Report 693 includes a set of tables showing systems operations and management job categories, number of positions, and educational requirements for all 50 states. NCHRP Report 693 : Attracting, Recruiting, and Retaining Skilled Staff for Transportation System Operations and Management provides...
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 Truck Tolling: Understanding Industry Tradeoffs When Using or Avoiding Toll FacilitiesDecember 19, 2011 TRB’s National Cooperative Freight Research Program (NCFRP) and National Cooperative Highway Research Program (NCHRP) have jointly released NCFRP Web-Only Document 3/NCHRP Web-Only Document 185: Truck Tolling: Understanding Industry Tradeoffs When Using or Avoiding Toll Facilities. The report explores the value that shippers, trucking companies, and truck drivers seek from toll roads.
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 Evaluation of Bridge-Scour Research: Abutment and Contraction Scour Processes and PredictionOctober 27, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 181: Evaluation of Bridge-Scour Research: Abutment and Contraction Scour Processes and Prediction examines bridge-abutment scour and the effectiveness of the leading methods used for estimating design scour depth. In September 2012 TRB released NCHRP Research Results Digest 378: Evaluation of Bridge Scour Researc...
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 Assessment of Auxiliary Through Lanes at Signalized IntersectionsJanuary 9, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 178: Assessment of Auxiliary Through Lanes at Signalized Intersections describes a project that investigated the operational, safety, and design characteristics of auxiliary through lanes (ATLs) at signalized intersections. The project resulted in the development of guidelines for the evaluation and application of ATL...
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 Evaluation of Bridge Scour Research: Geomorphic Processes and PredictionsMay 11, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 177: Evaluation of Bridge Scour Research: Geomorphic Processes and Predictions explores the impact of long-term aggradation and degradation, and lateral river channel migration, on highway structures. In September 2012 TRB released NCHRP Research Results Digest 378: Evaluation of Bridge Scour Research , which summariz...
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 Cost-Effective Connection Details for Highway Sign, Luminaire, and Traffic Signal StructuresJune 6, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 176: Cost-Effective Connection Details for Highway Sign, Luminaire, and Traffic Signal Structures presents the results of research that evaluated fatigue performance of several critical welded connections in the highway sign, signal, and high-level luminaire support structures.
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 Evaluation of Bridge Scour Research: Pier Scour Processes and PredictionsMay 6, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 175: Evaluation of Bridge Scour Research: Pier Scour Processes and Predictions explores the current state of knowledge regarding bridge-pier scour, assesses several methods for design estimates of scour depth, examines a structured methodology for scour-depth estimation for design purposes, and highlights aspects of&n...
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 Performance Measurement and Evaluation of Tolling and Congestion Pricing ProjectsJanuary 31, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 174: Performance Measurement and Evaluation of Tolling and Congestion Pricing Projects provides an overview of the purpose, scope, and methodology, and a complete compilation of the work products that were used to develop NCHRP Report 694. NCHRP Report 694 : Evaluation and Performance Measurement of Congestion Pricing...
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 Cast-in-Place Concrete Connections for Precast Deck SystemsMarch 9, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 173: Cast-in-Place Concrete Connections for Precast Deck Systems offers suggested design and construction guidance for and includes five illustrative examples of durable case-in-place reinforced concrete connections for precast deck systems that emulate monolithic construction, considering issues including speed of co...
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 Adapting Specification Criteria for Simple Performance Tests to HMA Mix DesignMarch 1, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 172: Adapting Specification Criteria for Simple Performance Tests to HMA Mix Design describes the inputs and outputs of the excel based program for Integrated Analysis of HMA Mix And Structural Designs. The report also reviews the program’s underlying performance prediction models, and highlights examples that illustr...
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 Determining Guidelines for Ramp and Interchange SpacingApril 7, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 169: Determining Guidelines for Ramp and Interchange Spacing documents the research effort related to the development of NCHRP Report 687: Guidelines for Ramp and Interchange Spacing. NCHRP Report 687 explores guidelines for ramp and interchange spacing based on design, operations, safety, and signing considerat...
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 Precision Estimates of AASHTO T148: Measuring Length of Drilled Concrete CoresNovember 16, 2010 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 165: Precision Estimates of AASHTO T148: Measuring Length of Drilled Concrete Cores includes the results of a round robin study to prepare precision estimates for American Association of State Highway and Transportation Officials (AASHTO) T148 test method used for determining the length of a core drilled from a concre...
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 Precision Estimates of AASHTO T265: Laboratory Determination of Moisture Content of SoilsNovember 13, 2010 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 164: Precision Estimates of AASHTO T265: Laboratory Determination of Moisture Content of Soils includes the results of an interlaboratory study to prepare precision estimates for the American Association of State Highway and Transportation Officials (AASHTO) T265 test method used for laboratory determination of moistu...
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 Precision Estimates of AASHTO T267: Determination of Organic Content in Soils by Loss on IgnitionNovember 11, 2010 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 163: Precision Estimates of AASHTO T267: Determination of Organic Content in Soils by Loss on Ignition includes the results of an interlaboratory study to prepare precision estimates for the American Association of State Highway and Transportation Officials T267 test method used for the determination of organic conten...
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 Top-Down Cracking of Hot-Mix Asphalt Layers: Models for Initiation and PropagationSeptember 8, 2010 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 162: Top-Down Cracking of Hot-Mix Asphalt Layers: Models for Initiation and Propagation explores mechanistic-based models for predicting top-down cracking in hot-mix asphalt layers for use in mechanistic-empirical procedures for design and analysis of new and rehabilitated flexible pavements.
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 System Trials to Demonstrate Mileage-Based Road Use ChargesDecember 10, 2010 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 161: System Trials to Demonstrate Mileage-Based Road Use Charges explores factors to be considered in designing and implementing large-scale trials of mechanisms for collecting road-user charges based on vehicle-miles of travel.
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 Supporting Material to NCHRP Report 674January 24, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 160 includes appendices B through N to NCHRP Report 674 : Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities, which explores information related to establishing safe crossings at roundabouts and channelized turn lanes for pedestrians with vision disabilities. App...
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 Supporting Materials for NCHRP Report 673June 2, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 159: Supporting Materials for NCHRP Report 673 contains the final report on the project that developed NCHRP Report 673: A Manual for Design of Hot Mix Asphalt with Commentary and Appendixes C through F to the report. NCHRP Report 673 contains a mix design manual for hot-mix asphalt (HMA) that incorporates ...
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 Field Test Results of the Multimodal Level of Service Analysis for Urban StreetsJune 7, 2010 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 158: Field Test Results of the Multimodal Level of Service Analysis for Urban Streets (MMLOS) explores the result of a field test of the MMLOS in 10 metropolitan areas in the United States. NCHRP Web-Only Document 158 represents the third and final phase of a project that included development of NCHRP Report 616 ...
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 Volume I: Evaluation of Existing Roadside Safety Hardware Using Updated Criteria—Technical ReportAugust 30, 2010 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 157: Volume I: Evaluation of Existing Roadside Safety Hardware Using Updated Criteria—Technical Report explores the process that was followed in developing NCHRP Research Results Digest (RRD) 349: Evaluation of Existing Roadside Safety Hardware Using Manual for Assessing Safety Hardware (MASH) Criteria. NCHRP RR...
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 Optical Sizing and Roundness Determination of Glass Beads Used in Traffic MarkingsOctober 14, 2010 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 156: Optical Sizing and Roundness Determination of Glass Beads Used in Traffic Markings is the final report on a project that examined the precision and bias of both optical and traditional mechanical methods for different glass bead types. The project also compared the precision and bias of various measurement method...
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 Design Guidelines for Durability of Bonded CFRP Repair/Strengthening of Concrete BeamsAugust 12, 2010 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 155: Design Guidelines for Durability of Bonded CFRP Repair/Strengthening of Concrete Beams explores a methodology for the evaluation of durability-related strength loss of bonded carbon fiber-reinforced polymer (CFRP) systems applied to concrete beams. The report also examines test methods to help establish a durabil...
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 Geometric Design of DrivewaysAugust 5, 2010 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 151: Geometric Design of Driveways includes material related to and supporting contents of NCHRP Report 659: Guide for the Geometric Design of Driveways. NCHRP Report 659 explores guidelines related to the geometric design of driveways. The report includes driveway-related terms and definitions, an examinat...
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 Accessible Pedestrian Signals: A Guide to Best Practices (Workshop Edition 2010)January 18, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 150: Accessible Pedestrian Signals: A Guide to Best Practices (Workshop Edition 2010) provides an introduction to accessible pedestrian signals (APS) and highlights issues related to the design, installation, operation, and maintenance of APS. The report also addresses public education, U.S. case studies, and internat...
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 Recommended LRFD Minimum Flexural Reinforcement RequirementsFebruary 10, 2010 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 149: Recommended LRFD Minimum Flexural Reinforcement Requirements explores the minimum reinforcement requirements for the design of concrete bridge structures and examines flexural cracking of concrete structures.
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 Debris Photographic Archive and Supplemental Materials for NCHRP Report 653June 2, 2010 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 148: Debris Photographic Archive and Supplemental Materials for NCHRP Report 653 includes the debris photographic archive, the survey questionnaire and list of respondents, and the report on the field pilot study related to development of NCHRP 653. NCHRP Report 653 : Effects of Debris on Bridge Pier Scour explores gu...
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 Replacement Processes for Light Emitting Diode (LED) Traffic SignalsSeptember 30, 2009 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 146: Replacement Processes for Light Emitting Diode (LED) Traffic Signals explores the photometric requirements, measurement, and maintenance of traffic signal modules using light emitting diodes (LEDs). _______________________ NCHRP Web-Only Document 146 contains an incomplete Acknowledgments section. The complete Ac...
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 Recommended Practice for Stabilization of Sulfate-Rich Subgrade SoilsOctober 15, 2009 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 145: Recommended Practice for Stabilization of Sulfate-Rich Subgrade Soils examines the nature of minerals ettringite and thaumasite, and explores the mechanism of their formation in soils stabilized with lime, cement, or fly ash.
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 Recommended Practice for Stabilization of Subgrade Soils and Base MaterialsOctober 13, 2009 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 144: Recommended Practice for Stabilization of Subgrade Soils and Base Materials explores a methodology to determine which stabilizers should be considered as candidates for stabilization for a specific soil, pavement, and environment.
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 Precision Estimates of AASHTO T 242September 15, 2009 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 142: Precision Estimates of AASHTO T 242 examines precision estimates for AASHTO (American Association of State Highway and Transportation Officials) T 242, “Frictional Properties of Paved Surfaces Using a Full-Scale Tire.”
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 Precision Estimates for AASHTO Test Method T 104, Determined Using AMRL Proficiency Sample DataSeptember 3, 2009 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 141: Precision Estimates for AASHTO Test Method T 104, Determined Using AMRL Proficiency Sample Data explores the use of data from the AASHTO Materials Reference Laboratory (AMRL) Proficiency Sample Program (PSP) used to update precision estimates for American Association of State Highway and Transportation Officials ...
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 Precision Estimates for AASHTO Test Method T 105, Determined Using CCRL Proficiency Sample DataAugust 26, 2009 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 139: Precision Estimates for AASHTO Test Method T 105, Determined Using CCRL Proficiency Sample Data explores the use of data from the Cement and Concrete Reference Laboratory (CCRL) Proficiency Sample Program (PSP) that was collected from state laboratories to update precision estimates for American Association of St...
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 Annotated Literature Review for NCHRP Report 640October 16, 2009 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 138: Annotated Literature Review for NCHRP Report 640 includes summaries of various items that were found in the literature review associated with the production of NCHRP Report 640 : Performance and Maintenance of Permeable Friction Courses.
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 Guidance for Transportation Project ManagementJune 11, 2009 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 137: Guidance for Transportation Project Management explores tools designed to potentially enhance an agencies’ transportation project management process and examines innovative way to manage a project.
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 Performance Measures for Snow and Ice Control Operations: Supplemental MaterialApril 13, 2009 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 136: Performance Measures for Snow and Ice Control Operations highlights information on the current practices regarding the methods and measures used for assessing agency and contractor performance in snow and ice control operations. Additional information on the project was published as NCHRP Research Results ...
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 Protocols for Collecting and Using Traffic Data in Bridge DesignMarch 26, 2009 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 135: Protocols for Collecting and Using Traffic Data in Bridge Design explores a set of protocols and methodologies for using available recent truck traffic data to develop and calibrate live load models for load and resistance design factor bridge design. This report has been superseded by NCHRP Report 683: Protocol...
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 An Experimental Plan for Validation of an Endurance Limit for HMA PavementsMarch 5, 2009 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 134: An Experimental Plan for Validation of an Endurance Limit for HMA Pavements explores a research plan and associated cost estimate for a future study to validate the endurance limit for hot-mix asphalt (HMA) and to improve mechanistic-empirical pavement design.
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 Supporting Materials for NCHRP Report 626 June 2, 2009 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 133 documents the research associated with the production of NCHRP Report 626 : NDT Technology for Quality Assurance of HMA Pavement Construction, which explores the application of nondestructive testing (NDT) technologies in the quality assurance of hot-mix asphalt (HMA) pavement construction.
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 Right-of-Way Methods and Tools to Control Project Cost EscalationOctober 2, 2009 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 132: Right-of-Way Methods and Tools to Control Project Cost Escalation explores the data-gathering and analysis processes used to create a procedures guide for right-of-way cost estimating.
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Communicating the Value of Research: Contractor's Final Report June 24, 2009 TRB’s NationalCooperative Highway Research Program (NCHRP) Web-Only Document 131: Communicating the Value of Transportation Research is the contractor’s final report on the research associated with NCHRP Report 610: Communicating the Value of Transportation Research .
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 A Guide to Emergency Quarantine and Isolation Controls of Roads in Rural AreasOctober 13, 2008 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 130 is an annotated bibliography that reviews several state emergency response plans associated with traffic control of rural roads in an agricultural emergency. The material contained in Web-Only Document 130 was used to help produce NCHRP Report 525, Vol. 13: A Guide to Traffic Control of Rural Roads in an Ag...
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 Pedestrian Safety Prediction MethodologyJuly 25, 2008 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 129, Phase 3: Pedestrian Safety Prediction Methodology explores development of improved pedestrian safety prediction models for use in the Highway Safety Manual.
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 Methodology to Predict the Safety Performance of Urban and Suburban ArterialsJuly 18, 2008 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 129, Phases I and II: Methodology to Predict the Safety Performance of Urban and Suburban Arterials explore the development of a draft Highway Safety Manual chapter that explore a safety prediction methodology for urban and suburban arterials.
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 Multimodal Level of Service Analysis for Urban Streets: Users GuideSeptember 15, 2008 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 128, Multimodal Level of Service Analysis for Urban Streets: Users Guide explores a set of procedures for predicting traveler perceptions of quality of service and performance measures for urban streets. Quality of service and performance are considered in terms of the needs of auto drivers, bus passenger...
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 Performance Measurement Tool Box and Reporting System for Research Programs and ProjectsJune 5, 2008 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 127: Performance Measurement Tool Box and Reporting System for Research Programs and Projects explores the integration of standard performance measures and tools to assist users in implementing performance measures into the Research Performance Measurement (RPM) System.
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 Methodology to Predict the Safety Performance of Rural Multilane HighwaysMay 29, 2008 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 126: Methodology to Predict the Safety Performance of Rural Multilane Highways explores a methodology designed to predict the safety performance of various elements considered in the planning, design, and operation of nonlimited-access rural multilane highways.
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 Color Effectiveness of Yellow Pavement Marking Materials: Full ReportJune 2, 2008 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 125: Color Effectiveness of Yellow Pavement Marking Materials explores the range of chromaticity coordinates that observers classify as yellow and white under daytime and incandescent illumination. A summary of the report described in Web-Only Document 125 was produced as NCHRP Research Results Digest 328.
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 Development of a Comprehensive Modal Emissions ModelMay 6, 2008 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 122 explores development of a modal emissions model that reflects light-duty vehicle emissions produced as a function of the vehicle’s operating mode.
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 Guidelines for Accessible Pedestrian Signals: Final ReportJune 4, 2008 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 117B: Guidelines for Accessible Pedestrian Signals (Final Report) provides details on research used to develop a one-day training course on accessible pedestrian signals (APS) and to produce an APS intersection prioritization tool. For additional information on the training program, contact S.A. Parker of TRB a...
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 Accessible Pedestrian Signals: A Guide to Best PracticeJune 4, 2008 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 117A: Accessible Pedestrian Signals: A Guide to Best Practice is designed to serve as a companion resource document to a one-day training course on accessible pedestrian signals. For information on the training program, contact S.A. Parker of TRB at SAParker@nas.edu. An appendix to Web-Only Document 117A includ...
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 Corrosion Study and Implementation Plan for NCHRP Report 597April 24, 2008 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 116 includes the corrosion study and implementation plan for NCHRP Report 597: Development of a Recommended Practice for Use of Controlled Low-Strength Material in Highway Construction. NCHRP Report 597 explores the use of controlled low-strength material (CLSM) in highway construction applications, in pa...
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 Using the Results of Contractor-Performed Tests in Quality Assurance: Contractor's Final ReportDecember 17, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 115: Using the Results of Contractor-Performed Tests in Quality Assurance includes select chapters of the contractor’s final report on this project, which explores whether state departments of transportation can effectively use contractor-performed test results in the quality-assurance process. NCHR...
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 Precision Estimates for AASHTO Test Method T 269 Determined Using AMRL Proficiency Sample DataAugust 22, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 114: Precision Estimates for AASHTO Test Method T 269 Determined Using AASHTO Materials Reference Laboratory (AMRL) Proficiency Sample Data explores the use of data from the AMRL Proficiency Sample Program (PSP) to update precision estimates for the American Association of State Highway and Transportation Offic...
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 Environmental Effects in Pavement Mix and Structural Design SystemsOctober 1, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 113: Environmental Effects in Pavement Mix and Structural Design Systems examines limitations associated with provisional protocols on hardening potential of asphalt binders and mixes, and explores ways to enhance the predictive capabilities of these protocols. A summary of this effort was published as NC...
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 Integrating Freight into Transportation Planning and Project-Selection ProcessesDecember 13, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 112: Integrating Freight into Transportation Planning and Project-Selection Processes documents the approach and findings resulting from a project that explored techniques designed to help states and MPOs more fully incorporate freight throughout the entire transportation planning and programming process and mo...
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Supplementary Cementitious Materials to Enhance Durability of Concrete Bridge DecksSeptember 14, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 110: Supplementary Cementitious Materials to Enhance Durability of Concrete Bridge Decks includes background information and a hypothetical case study used to help develop NCHRP Report 566. The Statistical Experimental Design for Optimizing Concrete ( SEDOC ) , the computational tool for the concrete mixture o...
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 Precision Estimates of Selected Volumetric Properties of HMA Using Absorptive AggregateJuly 16, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 109: Precision Estimates of Selected Volumetric Properties of HMA Using Absorptive Aggregate explores precision estimates for the American Association of State Highway and Transportation Officials and ASTM standards used to determine selected volumetric properties of hot-mix asphalt (HMA) using absorptive aggre...
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 Guide for Pavement FrictionJune 5, 2009 TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 108: Guide for Pavement Friction examines the management of pavement friction on existing highways and explores the design of new highway surfaces with adequate pavement friction. The report also highlights the importance of pavement friction in highway safety; factors affecting pavement friction; and the equip...
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 Risk-Based Management Guidelines for Scour at Bridges with Unknown FoundationsAugust 15, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 107: Risk-Based Management Guidelines for Scour at Bridges with Unknown Foundations examines a risk-based approach to managing bridges in the absence of foundation information. A risk assessment tool and instructions are available online.
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 Criteria for Selecting Hydraulic ModelsSeptember 26, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 106: Criteria for Selecting Hydraulic Models explores develop a decision tool for selecting either a one- or a two-dimensional hydraulic model when examining flow through bridge crossings. The decision tool is designed to provide a procedure for selecting the most appropriate model for a particular applic...
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 Final Report for NCHRP Report 581: Design of Construction Work Zones on High-Speed HighwaysMay 16, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 105 is the contractor’s final report on the research activities used to develop NCHRP Report 581: Design of Construction Work Zones on High-Speed Highways. NCHRP Report 581 explores an approach for the selection of an appropriate construction work zone type; offers suggested guidance for the design of geometric...
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 Future Financing Options to Meet Highway and Transit NeedsFebruary 13, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 102: Future Financing Options to Meet Highway and Transit Needs explores the viability of a range of conventional and innovative options for financing investments and operations of highway and transit systems.
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 Examples of Best Practices for Communicating the Economic Benefits of TransportationOctober 10, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 100: Examples of Best Practices for Communicating the Economic Benefits of Transportation explores strategies and techniques that have been employed in the field to effectively communicate transportation’s importance to the economy. The report also examines the circumstances under which the strategi...
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 Guide to Effective Freeway Performance Measurement: Final Report and GuidebookMarch 19, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 97: Guide to Effective Freeway Performance Measurement: Final Report and Guidebook examines the effective use of freeway performance measures in operating a freeway system and in meeting the information needs of a large spectrum of potential local, regional, and national users. The report includes detaile...
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 Appendixes to NCHRP Report 572: Roundabouts in the United StatesApril 5, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 94, Appendixes to NCHRP Report 572: Roundabouts in the United States includes detailed reviews of the literature on safety performance and operational models, the master inventory of U.S. roundabouts assembled for this project, and the results of the statistical testing of various models associated with the productio...
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 Technical Appendix to NCHRP Report 571: Standardized Procedures for Personal Travel SurveysMay 13, 2008 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 93 is the technical appendix to NCHRP Report 571: Standardized Procedures for Personal Travel Surveys , which explores the aspects of personal travel surveys that could be standardized with the goal of improving the quality, consistency, and accuracy of the resulting data.
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 Safety Impacts and Other Implications of Raised Speed Limits on High-Speed RoadsMarch 29, 2006 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 90: Safety Impacts and Other Implications of Raised Speed Limits on High-Speed Roads examines how safety, economic, environmental, and commercial conditions on high-speed roadway may be impacted by a change in the speed limit. Safety-related analyses included in the report were based on a comprehensive framewor...
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 Test Methods for Evaluating Field Performance of RWIS SensorsJune 14, 2006 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 87: Test Methods for Evaluating Field Performance of Road Weather Information System (RWIS) Sensors explores field testing of environmental sensor stations (ESS) sensors in order to evaluate if a sensor is providing an accurate representation of actual conditions at the installed site. The procedures cont...
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 Estimating the Impacts of the Aging Population on Transit RidershipMarch 15, 2006 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 86: Estimating the Impacts of the Aging Population on Transit Ridership outlines the key demographic factors that affect public transportation use, with a particular focus on how the aging demographics of the country will impact future transit ridership. In addition, the report describes a spreadsheet tool that can b...
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 Considerations for a Guide to Contracting ITS ProjectsApril 26, 2006 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 85: Considerations for a Guide to Contracting ITS Projects describes activities and highlights interim results associated with the research that was conducted as part of development of NCHRP Report 560: Guide to Contracting ITS Projects . Web-Only Document 85 is designed to help other researchers and profession...
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 Innovative Load Testing SystemsJune 5, 2006 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 84: Innovative Load Testing Systems explores innovative load testing methods for deep foundations and interim procedures for their use and interpretation. The report also examines additional research, testing, and analysis needed to provide guidelines for use of innovative load testing methods.
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 Scour at Contracted BridgesMarch 29, 2006 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 83: Scour at Contracted Bridges describes and quantifies the influence of processes affecting scour magnitude in contracted openings and examines physical- and numerical-model studies. The report also includes interim guidance for applying scour-prediction methodology at contracted bridge sites for a wide range...
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 Monitoring, Analyzing, and Reporting on the Environmental Streamlining Pilot ProjectsDecember 14, 2005 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 79: Monitoring, Analyzing, and Reporting on the Environmental Streamlining Pilot Projects seeks to identify ways to improve efficiency and reduce the time frame of the project development process while ensuring environmental protection, and to judge their applicability beyond the Pilot Project settings. The report in...
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 Consideration of Environmental Factors in Transportation Systems Planning: AppendixesDecember 15, 2005 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 77: Consideration of Environmental Factors in Transportation Skills Planning consists of the appendixes to NCHRP Report 541 of the same name, which examines procedures and methods for integrating environmental factors in transportation systems planning and decision making at the statewide, regional, and metropolitan ...
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 Final Report for Early-Opening-to-Traffic Portland Cement Concrete for Pavement RehabilitationAugust 11, 2005 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 76: Final Report for Early-Opening-to-Traffic Portland Cement Concrete for Pavement Rehabilitation contains the background information, experimental design, results, analysis, and conclusions of the study conducted under NCHRP Project 18-04B , “Durability of ‘Early-Opening-to-Traffic’ Portland Cement Concrete for Pav...
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 Emergency Transportation Operations: Resources Guide for NCHRP Report 525, Volume 6September 7, 2005 TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 73: Emergency Transportation Operations: Resources Guide for NCHRP Report 525, Volume 6 is a resources guide on emergency transportation operations (ETO) containing bibliographical material that may be useful to readers of NCHRP Report 525, Volume 6. NCHRP Report 525: Surface Transportation Security, Volume 6: Guide ...
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 National Calibration Facility for Retroreflective Traffic Control MaterialsJune 30, 2005 TRB’s National Cooperative Highway Research Program (NCHRP) Web Only Document 72: National Calibration Facility for Retroreflective Traffic Control Materials is the full report of NCHRP Project 05-16, which developed dedicated reference instrumentation to provide national calibration standards for retroreflectivity, thereby improving the accuracy of measurements made by other instruments. A su...
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 Comprehensive Human Factors Guidelines for Road Systems (Web-Only Document)May 9, 2005 TRB’s National Cooperative Highway Research Program (NCHRP) Web Document 70: Comprehensive Human Factors Guidelines (HFG) for Road Systems examines the recommended content, format, organization, and capabilities of the planned HFG. The report includes an outline of the document and a detailed work plan for development of the first edition of the guidelines. The report also includes...
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 Performance Measures for Context-Sensitive Solutions - A Guidebook for State DOTsNovember 30, 2004 TRB's National Cooperative Highway Research Program (NCHRP) Web Document 69: Performance Measures for Context-Sensitive Solutions - A Guidebook for State DOTs is intended to help DOTs develop their own tailored and comprehensive Context-Sensitive Solutions (CSS) performance measurement programs. As CSS becomes part of the way state DOTs do business, many agencies seek ways to gauge their perfo...
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 Relationships of HMA In-Place Air Voids, Lift Thickness, and PermeabilityNovember 23, 2004 TRB’s National Cooperative Highway Research Program (NCHRP) Web Document 68: Relationships of HMA In-Place Air Voids, Lift Thickness, and Permeability is a four-volume report that evaluates the minimum hot-mix asphalt (HMA) lift thicknesses and minimum in-place density necessary to achieve an impermeable, durable pavement. The report also evaluates enhancements to AASHTO T166 (Bulk Speci...
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 Methodology for Predicting Channel MigrationDecember 9, 2004 TRB’s National Cooperative Highway Research Program (NCHRP) Web Document 67: Methodology for Predicting Channel Migration documents and presents the results of a study to develop a practical methodology to predict the rate and extent of channel migration in proximity to transportation facilities. The principal product of this research was NCHRP Report 533: Handbook for Predicting Stream Meande...
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 Geofoam Applications in the Design and Construction of Highway EmbankmentsAugust 2, 2004 TRB’s National Cooperative Highway Research Program (NCHRP) Web Document 65: Geofoam Applications in the Design and Construction of Highway Embankments presents a design guideline, and material and construction standard, for the use of geofoam in roadway embankments and bridge approaches.
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 Appendices to a Review of DOT Compliance with GASB 34 RequirementsJuly 6, 2004 TRB’s National Cooperative Highway Research Program (NCHRP) Web Document 63 the appendices to NCHRP Report 522: A Review of DOT Compliance with GASB 34 Requirements , which examines approaches taken by state departments of transportation to comply with the requirements of Governmental Accounting Standards Board (GASB) Statement No. 34.
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 Development of a Highway Safety ManualMarch 30, 2004 TRB's National Cooperative Highway Research Program (NCHRP) Web Document 62: Development of a Highway Safety Manual documents and presents the results of a study to develop an annotated outline, prototype chapter, and work plan for the first edition of the Highway Safety Manual (HSM). The purpose of the HSM will be to provide information and tools, in a useful and widely accepted form, to facil...
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 Improving the Compatibility of Vehicles and Roadside Safety HardwareFebruary 24, 2004 TRB’s National Cooperative Highway Research Program (NCHRP) Web Document 61: Improving the Compatibility of Vehicles and Roadside Safety Hardware examines current and future vehicle characteristics that are potentially incompatible with existing roadside safety hardware, assesses opportunities for and barriers to improved compatibility, and increases the vehicle and hardware manufacturers’ awar...
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 LTPP Data Analysis: Daily and Seasonal Variations in Insitu Material PropertiesDecember 11, 2003 TRB’s National Cooperative Highway Research Program (NCHRP) Web Document 60: Long-Term Pavement Project (LTPP) Data Analysis: Daily and Seasonal Variations in Insitu Material Properties includes a data set that can be used to investigate daily and seasonal changes in pavement material properties as they relate to changes in structural capacity that would necessitate load restrictions.
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 The Outsourcing of State DOT Capital Program Delivery FunctionsNovember 24, 2003 TRB’s National Cooperative Highway Research Program (NCHRP) Web Document 59: The Outsourcing of State DOT Capital Program Delivery Functions is designed to assist state departments of transportation (DOTs) in assessing the outsourcing of their capital delivery functions.
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 A National Data-Management System for Highway Tort ClaimsSeptember 4, 2003 TRB’s National Cooperative Highway Research Program (NCHRP) Web Document 57: Development and Evaluation of a National Data-Management System for Highway Tort Claims assesses the technical feasibility of national tort data-management system. Document Parts; Front Matter , Chapter 1 , Chapter 2 , Chapter 3 , Chapter 4 , Appendicies
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 Sensitivity Evaluation of Field Shear Test Using Improved Protocol and Indirect Tension Strength TestMay 8, 2003 TRB's National Cooperative Highway Research Program (NCHRP) Web Document 56: Sensitivity Evaluation of Field Shear Test Using Improved Protocol and Indirect Tension Strength Test, evaluates the sensitivity of complex modulus measurements made using the recently improved field shear test and the sensitivity of the indirect tension strength test, performed at high temperatures in order to evaluat...
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 Feasibility of Using Friction Indicators to Improve Winter Maintenance Operations and MobilityNovember 21, 2002 TRB's National Cooperative Highway Research Program (NCHRP) Web Document 53: Feasibility of Using Friction Indicators to Improve Winter Maintenance Operations and Mobility indicates that the use of friction measurements to improve winter maintenance operations and mobility is feasible (especially when deceleration devices are used), but devices with an extra wheel may not represent a practical ...
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 LTPP Data Analysis: Feasibility of Using FWD Deflection Data to Characterize PavementNovember 6, 2002 TRB's National Cooperative Highway Research Program (NCHRP) Web Document 52: LTPP Data Analysis - Feasibility of Using FWD Deflection Data to Characterize Pavement concludes that Falling Weight Deflectometer (FWD) data is of sufficient quantity to assist in the quality control and quality assistance process during pavement construction.
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 Construction Engineering and Management Research ProgramNovember 27, 2002 TRB's National Cooperative Highway Research Program (NCHRP) Web Document 51: Construction Engineering and Management Research Program includes a research program for the American Association of State Highway Transportation Officials' Highway Subcommittee on Construction that identifies and prioritizes opportunities for improving construction engineering and management of transportation projects.
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 Repair and Rehabilitation of Bridge Components Containing Epoxy-Coated ReinforcementOctober 18, 2002 TRB's National Cooperative Highway Research Program (NCHRP) Web Document 50: Repair and Rehabilitation of Bridge Components Containing Epoxy-Coated Reinforcement contains a decision matrix that matches appropriate repair and rehabilitation strategies to the damage mode, present condition, environmental exposure, and future propensity of corrosion.
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 TRAC PAC 2--A Hands-On Educational ProgramAugust 8, 2002 TRB's National Cooperative Highway Research Program (NCHRP) Web Document 49: TRAC PAC 2--A Hands-On Educational Program includes eight modules (Bridge Builder, Design and Construction, Environmental, Maglev, Motion, Safety, SIMCITY, and Technology) with a total of 36 discrete educational activities, along with a teacher's manual, lesson plans, questions to assess student achievement, educationa...
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 LTPP Data Analysis: Variations in Pavement Design InputsJuly 31, 2002 TRB's National Cooperative Highway Research Program (NCHRP) Web Document 48: LTPP Data Analysis: Variations in Pavement Design Inputs encourages the pavement designer to consider pavement variability of input design parameters in addition to the average input values normally used.
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 LTPP Data Analysis: Effectiveness of Maintenance and Rehabilitation OptionsJuly 31, 2002 TRB's National Coopertive Highway Research Program (NCHRP) Web Document 47: LTPP Data Analysis -- Effectiveness of Maintenance and Rehabilitation Options finds that overlay thickness and preoverlay roughness level were the two factors that most influenced the performance of asphalt overlays of asphalt pavements.
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 Improved Live Load Deflection Criteria for Steel BridgesNovember 6, 2002 TRB's National Cooperative Highway Research Program (NCHRP) Web Document 46: Improved Live Load Deflection Criteria for Steel Bridges indicates that the bridges that satisfy the existing deflection limit are likely to provide poor vibration performance, while other bridges failing the existing deflection limit will provide good comfort characteristics.
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 A Process for Selecting Strategies for Rehabilitation of Rigid PavementsJune 17, 2002 TRB's National Cooperative Highway Research Program (NCHRP) Web Document 45: A Process for Selecting Strategies for Rehabilitation of Rigid Pavements describes a process that helps state highway agency decision makers identify, screen, and select the most appropriate maintenance, rehabilitation, and reconstruction strategies from a limited set of feasible, project-specific alternatives.
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 Guidance for Estimating the Indirect Effects of Proposed Transportation ProjectsJanuary 5, 2002 TRB's National Cooperative Highway Research Program (NCHRP) Web Document 43: Guidance for Estimating the Indirect Effects of Proposed Transportation Projects is an instructional course is based on research conducted for National Cooperative Highway Research Program Project 25-10: Guidance for Estimating the Indirect Effects of Proposed Transportation Projects. Research was conducted in 1996 and...
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 Issues in Pavement Smoothness: A Summary ReportApril 29, 2002 TRB's National Cooperative Highway Research Program (NCHRP) Web Document 42: Issues in Pavement Smoothness -- A Summary Report includes presentations and findings from the August 2001 workshop on pavement smoothness, as well as a review of issues and recommended strategies to address pavement smoothness.
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 Proposed Modifications to AASHTO Culvert Load Rating Specifications January 1, 2020 Over the past decade, significant state and federal resources have been expended to develop a state‐of-the-art set of reliability‐based bridge design and load rating specifications, including Load and Resistance Factor Design (LRFD) and Load and Resistance Factor Rating (LRFR). However, these design and rating methods were developed for larger bridge structures, and may result in overly conserv... |