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 Continuing Project to Synthesize Information on Highway Problems: 2018January 22, 2018 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 402: Continuing Project to Synthesize Information on Highway Problems provides a 2018 update on current knowledge and practice, in a compact format, without the detailed directions usually found in handbooks or design manuals. Each report in the series provides a compendium of the best knowledge available on tho...
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 Continuing Project to Synthesize Information on Highway Problems: 2017January 16, 2017 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 401: Continuing Project to Synthesize Information on Highway Problems is a digest of the progress and status of NCHRP Project 20-5, “Synthesis of Information Related to Highway Problems.”
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 Sample Size Implications of Multi-Day GPS-Enabled Household Travel SurveysNovember 21, 2016 TRB's National Cooperative Highway Research Program (NCHRP) Research Results Digest 400: Sample Size Implications of Multi-Day GPS-Enabled Household Travel Surveys summarizes an NCHRP project that studied the design of household travel surveys. Multi-day travel surveys are now more feasible, given global positioning system (GPS) technology. This project explores if surveys using a GPS device pr...
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 Continuing Project to Synthesize Information on Highway Practices: 2016January 14, 2016 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 398: Continuing Project to Synthesize Information on Highway Practices is a digest of the progress and status of NCHRP Project 20-5, “Synthesis of Information Related to Highway Practices.”
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 Approach to Level-of-Service Target Setting for Highway AssetsOctober 14, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 396: Approach to Level-of-Service Target Setting for Highway Assets identifies methodologies and provides guidance for selecting level-of-service targets for maintaining and operating highway assets. In the past, targets have often been established based on the expert opinion of individuals and have not ne...
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Claims Related to Stormwater DischargeJune 4, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 395: Claims Related to Stormwater Discharge is being revised. It will be reposed on this site as soon as revisions are completed.
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 Estimating the Long-Term Impacts of MAP-21 on the Nation’s Local Rural Transit Bus InfrastructureJune 20, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 394: Estimating the Long-Term Impacts of MAP-21 on the Nation’s Local Rural Transit Bus Infrastructure explores an analysis of the long-term impacts of the Moving Ahead for Progress in the 21st Century Act (MAP-21) on the nation’s rural transit infrastructure. This analysis includes a review of funding levels be...
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 Selected Indirect Benefits of State Investment in Public TransportationApril 8, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 393: Selected Indirect Benefits of State Investment in Public Transportation explores the full range of benefits that may be associated with investment in public transportation programs, including those that could help offset the cost of transit investments and operations. Specifically, this report identifies an...
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 Continuing Project to Synthesize Information on Highway Problems: 2015January 13, 2015 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 392: Continuing Project to Synthesize Information on Highway Problems is a digest of the progress and status of NCHRP Project 20-5, “Synthesis of Information Related to Highway Problems.”
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 Precision Estimates of AASHTO T 201, AASHTO T 202, and AASHTO T 49May 7, 2014 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 388: Precision Estimates of AASHTO T 201, AASHTO T 202, and AASHTO T 49 presents new, updated precision statements for three asphalt binder test methods. The new methods are based on the analysis of 168 proficiency data sets.
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 Alternative Delivery Methods for Winter Maintenance OperationsJuly 21, 2014 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 387: Alternative Delivery Methods for Winter Maintenance Operations develops a decision-making framework to guide public road agencies’ delivery of winter maintenance operations.
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 Continuing Project to Synthesize Information on Highway Problems: 2014January 3, 2014 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 386: Continuing Project to Synthesize Information on Highway Problems is a digest of the progress and status of NCHRP Project 20-5, “Synthesis of Information Related to Highway Problems.”
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 The Legal Definitions of “First Responder”December 30, 2013 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 385: The Legal Definitions of “First Responder” explores the definition of “first responders.” The report also contains an analysis of grants available from the federal government to aid state and local governmental entities in preparing for and responding to natural or man-made disasters and emergencies.
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 New Urban Areas: A Transit Guidance BriefDecember 21, 2013 TRB’s National Cooperative Highway Research Program (NCHRP) RRD 384: New Urban Areas: A Transit Guidance Brief addresses issues that are likely to be encountered in starting transit service or implementing urban transit service.
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 Potential Impacts of Federal Health Care Reform on Public Transit July 5, 2013 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 383: Potential Impacts of Federal Health Care Reform on Public Transit explores provisions of the Patient Protection and Affordable Care Act that are likely to have the largest and most direct impacts on public transit agencies and operations, particularly those in rural and small urban areas. The report also de...
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 Measuring Cement Particle Size and Surface Area by Laser DiffractionMay 10, 2013 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 382: Measuring Cement Particle Size and Surface Area by Laser Diffraction evaluates the practicality and effectiveness of the laser diffraction method to measure the particle size distribution and total surface area of cement powder.
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 Guidebook for Construction Management Practices for Rural ProjectsMarch 27, 2013 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 381: Guidebook for Construction Management Practices for Rural Projects focuses on tools and techniques that may be used to help improve aspects of construction management in the rural environment. Tools and techniques covered in the report address issues such as construction administration, engineering, op...
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 Guidelines for Geofoam Applications in Slope Stability ProjectsApril 2, 2013 TRB's National Cooperative Highway Research Program (NCHRP) Research Results Digest 380: Guidelines for Geofoam Applications in Slope Stability Projects explores the use of expanded polystyrene-block geofoam for slope stabilization projects. For the purpose of the report, slope stabilization projects include new roadways as well as repair of existing roadways that have been damaged by slope ins...
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 Evaluation of Bridge Scour ResearchSeptember 17, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 378: Evaluation of Bridge Scour Research summarizes key finding of three NCHRP projects that explored processes and predictions related to pier scour, abutment and contraction scour, and geomorphic scour. The results of the three research projects summarized in NCHRP RRD 378 were each published separately in the...
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 Continuing Project to Synthesize Information on Highway Problems: 2013February 4, 2013 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 377: Continuing Project to Synthesize Information on Highway Problems is a digest of the progress and status of NCHRP Project 20-5, “Synthesis of Information Related to Highway Problems.”
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 Data Needs for Assessing Rural Transit Needs, Benefits, and Levels of ServiceSeptember 14, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 376: Data Needs for Assessing Rural Transit Needs, Benefits, and Levels of Service assesses the data elements that are available through the Rural National Transit Database and identifies levels of service options that are potentially more accurate or useful for future evaluation of rural service.
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 A Proposed Technology Evaluation Program for Warm-Mix AsphaltAugust 20, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Research Result Digest 374: A Proposed Technology Evaluation Program for Warm-Mix Asphalt summarizes the key findings of a project that was charged with defining a warm-mix asphalt technology evaluation program that would be compatible with a centralized system of testing, evaluation, and data reporting of engineering materials for the...
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 A Toolkit for Reporting Rural and Specialized Transit Data--Making Transit CountAugust 31, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 373: A Toolkit for Reporting Rural and Specialized Transit Data—Making Transit Count presents the results of an analysis of automated transit data collection and analysis procedures in state department of transportation transit units. The report also provides a toolkit for next-generation transit data analysis f...
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 Sensitivity Evaluation of MEPDG Performance PredictionApril 5, 2013 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 372: Sensitivity Evaluation of MEPDG Performance Prediction summarizes the results of a study that evaluates the sensitivity of pavement performance predicted by the Mechanistic-Empirical Pavement Design Guide (MEPDG) to the values of the design inputs.
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 Quality-Related Pay Adjustment Factors for PavementsJanuary 31, 2013 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 371: Quality-Related Pay Adjustment Factors for Pavements offers guidance pertaining to the quality-related pay adjustment factors used for flexible and rigid pavement construction.
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 AASHTO T 209: Effect of Agitation Equipment Type on Theoretical Maximum Specific Gravity ValuesFebruary 17, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 369: AASHTO T 209: Effect of Agitation Equipment Type on Theoretical Maximum Specific Gravity Values evaluates the effect of using various devices and methods on measured values of theoretical maximum specific gravity (Gmm) used to determine the air void content and the in-place density of hot-mix asphalt (HMA) ...
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 State DOT Financial Auditing Requirements for Public Transportation Assistance ProgramsMarch 26, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 368: State DOT Financial Auditing Requirements for Public Transportation Assistance Programs identifies various financial policies and procedures used by states for conducting grantee financial audits. The report documents policies, procedures, and practices used by some state departments of trans...
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 Continuing Project to Synthesize Information on Highway Problems: 2012February 9, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 367: Continuing Project to Synthesize Information on Highway Problems is a digest of the progress and status of NCHRP Project 20-5, “Synthesis of Information Related to Highway Problems.”
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 Local and State Partnerships with Taxicab CompaniesFebruary 6, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 366: Local and State Partnerships with Taxicab Companies discusses how states and local governments might promote partnerships with taxicab companies for provision of public transportation. In the context of the report, a “partnership” typically involves some form of contract for service, but also includes less ...
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 Sustainable Pavement Maintenance PracticesJanuary 19, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 365: Sustainable Pavement Maintenance Practices highlights the current practice in sustainable pavement maintenance and preservation. The report is designed to help quantify and understand how pavement maintenance and preservation practices minimize environmental impacts. As part of the development of this repor...
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 Validation of LRFD Metal Loss and Service-Life Strength Reduction Factors for Metal-Reinforced SystemsOctober 11, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 364: Validation of LRFD Metal Loss and Service-Life Strength Reduction Factors for Metal-Reinforced Systems summarizes the results of research to further validate some key results of a project that resulted in publication of NCHRP Report 675: LRFD Metal Loss and Service-Life Strength Reduction Factors for Metal-...
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 Hydroacoustic Impacts on Fish from Pile InstallationOctober 26, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 363: Hydroacoustic Impacts on Fish from Pile Installation explores the prediction and mitigation of the negative impacts on fish from underwater sound pressure during pile and casing installation and removal. Appendices A through H for RRD 363 are available online.
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 Review of Mexican Experience with the Regulation of Large Commercial Motor VehiclesOctober 28, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 362: Review of Mexican Experience with the Regulation of Large Commercial Motor Vehicles reviews and summarizes the Mexican experience with changes in truck size and weight limits. The report also evaluates the potential applicability to size and weight limits in the United States.
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 State DOT Public Transportation Performance Measures: State of the Practice and Future NeedsOctober 6, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) RRD 361: State DOT Public Transportation Performance Measures: State of the Practice and Future Needs includes information on performance measures and performance management approaches that may be used by state departments of transportation (DOTs) in relation to public transportation programs.
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 Rheological Characterization of Flow Table Reference MaterialJuly 29, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) 360: Rheological Characterization of Flow Table Reference Material summarizes the key findings of a project that characterized available batches of cement and concrete reference laboratory (CCRL) flow table reference material. The project also explored more efficient, stable, and reproducible methods for future production of the refere...
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 Models to Support State-Owned Park and Ride Lots and Intermodal FacilitiesNovember 13, 2012 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 359: Models to Support State-Owned Park and Ride Lots and Intermodal Facilities addresses the needs and issues associated with state park and ride lots and intermodal commuter facilities and programs. The report identifies deficiencies, best practices, and promising innovations. RRD 359 was released in January 2...
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 Statewide Transit Goal SettingAugust 11, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 358: Statewide Transit Goal Setting explores current and best practices in statewide transit goal setting by state departments of transportation.
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 Test Methods and Specification Criteria for Mineral Filler Used in Hot-Mix AsphaltJuly 27, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 357: Test Methods and Specification Criteria for Mineral Filler Used in Hot-Mix Asphalt summarizes the key findings of a project that identified test methods for mineral filler that characterize its physical and chemical effects on the performance of mastics and hot-mix asphalt. The project also explored propose...
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 Analysis of State Rural Intercity Bus Strategies: Requirements for Utilization of S.5311(f) FundingNovember 28, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 356: Analysis of State Rural Intercity Bus Strategies: Requirements for Utilization of S.5311(f) Funding provides a snapshot of the current status of the program across the nation, and also provides states with examples and recommendations for program implementation. Section 5311(f) funds intercity bus service i...
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 Summary of Cast-In-Place Concrete Connections for Precast Deck SystemsJuly 26, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) RRD 355: Summary of Cast-In-Place Concrete Connections for Precast Deck Systems summarizes the results of a project that developed recommended design and construction specifications and examples for the design and construction of durable cast-in-place reinforced concrete connections for precast deck systems. The project focused on syst...
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 A Review of Human Services Transportation Plans and Grant ProgramsSeptember 14, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 354: A Review of Human Services Transportation Plans and Grant Programs explores the level of effort and costs associated with the development of coordinated public transit-human services transportation plans. The report also discusses the perceived success of the Coordination Plans and the perceived success sta...
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 Precision Statements for AASHTO Standard Methods of Test T 148, T 265, T 267, AND T 283February 8, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 351: Precision Statements for AASHTO Standard Methods of Test T 148, T 265, T 267, AND T 283 summarizes the findings of four interlaboratory studies conducted in 2009 and 2010 to develop precision statements for the AASHTO standard methods of measuring length of drilled concrete cores, laboratory determination o...
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 Continuing Project to Synthesize Information on Highway Problems: 2011February 3, 2011 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 350: Continuing Project to Synthesize Information on Highway Problems is a digest of the progress and status of NCHRP Project 20-5, “Synthesis of Information Related to Highway Problems.”
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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) Research Results Digest 346: Optical Sizing and Roundness Determination of Glass Beads Used in Traffic Markings summarizes the results of 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 measureme...
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 Alternate Strategies for Safety Improvement InvestmentsMay 13, 2010 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 345: Alternate Strategies for Safety Improvement Investments explores the “black spot” analysis and “systematic” methods currently being used by states to help make decisions on the allocation of safety resources.
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 Thermally Sprayed Metallic Coatings to Protect Steel Pilings: 5-Year Performance UpdateMarch 11, 2010 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 344: Thermally Sprayed Metallic Coatings to Protect Steel Pilings: 5-Year Performance Update explores the performance of several types of thermally sprayed metallic coating applied over steel, in accordance with procedures detailed in NCHRP Report 528, Thermally Sprayed Metal Coatings to Protect Steel Pili...
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 Continuing Project to Synthesize Information on Highway Problems: 2010January 29, 2010 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 343: Continuing Project to Synthesize Information on Highway Problems is a digest of the progress and status of NCHRP Project 20-5, “Synthesis of Information Related to Highway Problems.”
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 Recommended Precision Statements for AASHTO Standard Methods of Test T22, T 104, T 105, T 154, T 186, and T 242February 8, 2010 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 342: Recommended Precision Statements for AASHTO Standard Methods of Test T22, T 104, T 105, T 154, T 186, and T 242 summarizes the findings of research conducted to recommend new or updated precision statements of the American Association of State Highway and Transportation Officials (AASHTO) standard methods o...
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 Compliance Monitoring ToolsMarch 25, 2010 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 341: Compliance Monitoring Tools provides an electronic library of tools that state departments of transportation can use to monitor compliance with Federal Transit Administration requirements for the subrecipients of FTA funds. The library of tools included in RRD 341 was published in a CD-ROM format. Links to ...
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 State DOT Best Practices for Title VI ComplianceJanuary 12, 2010 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 340: State DOT Best Practices for Title VI Compliance explores state department of transportation (DOT) transit requirements and best practices related to Title VI of the Civil Rights Act of 1964. A companion report, NCHRP Web-Only Document 147 , includes a collection of material related to best practices. Title...
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 Improving the Safety of Mobile Lane ClosuresSeptember 23, 2009 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digests 339: Improving the Safety of Mobile Lane Closures explores practices employed by transportation agencies during mobile lane closures and summarizes research carried out on different components of mobile lane closure. Appendices A through D for NCHRP RRD 339 are available online.
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 Utilization by States of the Flexibility to Transfer Federal Funds Among Eligible Federal ProgramsAugust 28, 2009 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 338: Utilization by States of the Flexibility to Transfer Federal Funds Among Eligible Federal Programs examines the recent history of states reallocating specific sources of federal transit funding into their urbanized area grant (Section 5307) and non-urbanized area grant (Section 5311) programs. The report is...
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 Design Flexibility Considerations for Built Urban Environments July 9, 2009 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 337: Design Flexibility Considerations for Built Urban Environments explores issues related to the use of roadway design exceptions or variances. The report also examines processes designed to help manage the use of exceptions or variances, and highlights potential means to provide a timely procedure for ...
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 Benefit/Cost Analysis of Converting a Lane for Bus Rapid TransitAugust 14, 2009 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 336: Benefit/Cost Analysis of Converting a Lane for Bus Rapid Transit examines issues, potential solutions, and outstanding questions related to converting a roadway lane to bus rapid transit use. The appendixes to RRD 336 are available online.
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 Performance Measures for Snow and Ice Control OperationsApril 13, 2009 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 335: Performance Measures for Snow and Ice Control Operations explores methods and measures for assessing agency and contractor performance in snow and ice control operations. Additional information on the project, including information on the current practices regarding methods and measures to assess con...
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 A Guide to Planning Resources on Transportation and HazardsSeptember 29, 2009 TRB's National Cooperative Highway Research Program (NCHRP) and Transit Cooperative Research Program (TCRP) have jointly released A Guide to Planning Resources on Transportation and Hazards. The report was published as NCHRP Research Results Digest (RRD) 333 and as TCRP RRD 90. The report highlights a framework for thinking about the stages of a disaster, and identifies some of the most current...
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 Continuing Project to Synthesize Information on Highway Problems: 2009February 20, 2009 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 332: Continuing Project to Synthesize Information on Highway Problems is a digest of the progress and status of NCHRP Project 20-5, “Synthesis of Information Related to Highway Problems.”
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 Preparing Coordinated Transportation Plans: A Guidebook for State Departments of TransportationMay 6, 2009 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 331: Preparing Coordinated Transportation Plans: A Guidebook for State Departments of Transportation explores existing coordinated planning processes within state departments of transportation (DOTs) that meet the Federal Transit Administration’s (FTA’s) requirements. The report also examines aspects of th...
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 Temporary Bridging to Avoid or Minimize Impacts to Waters and Wetlands During Highway ConstructionSeptember 24, 2008 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 330: Temporary Bridging to Avoid or Minimize Impacts to Waters and Wetlands During Highway Construction explores criteria designed to assist in selecting an appropriate temporary bridging alternative. Temporary bridging includes prefabricated, portable, and reusable bridging as well as built-in-place stru...
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 Highway Safety Manual Data Needs GuideJune 16, 2008 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 329: Highway Safety Manual Data Needs Guide is designed to help potential users of the 1st edition of the Highway Safety Manual (HSM) anticipate the data needs for using the HSM. The guide focuses on the data needed to use the HSM Part C methodologies for rural two-lane highways, rural multilane highways, ...
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 Color Effectiveness of Yellow Pavement Marking Materials: SummaryJune 2, 2008 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digestion 328: Color Effectiveness of Yellow Pavement Marking Materials explores range of chromaticity coordinates that observers classify as yellow and white under daytime and incandescent illumination. The full report of the project described by NCHRP Research Results Digest 328 was produced as NCHRP Web...
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 Transportation Implications of Emerging Economic Development TrendsSeptember 1, 2008 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 327: Transportation Implications of Emerging Economic Development Trends explores economic development trends and how transportation relates to these trends. The report focuses on business production, inventory, and logistics and distribution trends and practices; site selection research and practices; la...
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 State Public Transportation Division Involvement in State Emergency Planning, Response, and RecoveryMay 15, 2008 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 326: State Public Transportation Division Involvement in State Emergency Planning, Response, and Recovery explores the best policies and practices of state transit divisions pertaining to weather-related emergencies. The report highlights lessons learned from recent emergencies, issues associated wi...
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 Continuing Project to Synthesize Information on Highway ProblemsJanuary 17, 2008 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 325: Continuing Project to Synthesize Information on Highway Problems is a digest of the progress and status of NCHRP Project 20-5, “Synthesis of Information Related to Highway Problems.”
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 Simulating the Effects of Hot-Mix Asphalt Aging for Performance Testing and Pavement Structural DesignOctober 1, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 324: Simulating the Effects of Hot-Mix Asphalt Aging for Performance Testing and Pavement Structural Design summarizes the results of an NCHRP effort that examined the limitations associated with provisional protocols on hardening potential of asphalt binders and mixes, and explored ways to enhance the pr...
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 Using the Results of Contractor-Performed Tests in Quality AssuranceDecember 17, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 323: Using the Results of Contractor-Performed Tests in Quality Assurance explores whether state departments of transportation can effectively use contractor-performed test results in the quality-assurance process. Select chapters of the contractor’s final report are available as NCHRP Web-Onl...
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 Public Information and Education in the Promotion of Highway SafetyNovember 9, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 322: Public Information and Education in the Promotion of Highway Safety assesses the role of public information and education programs in contributing to behavior change in the highway safety area.
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 Guide for Pavement Friction: Background and ResearchJune 5, 2009 TRB's National Cooperative Highway Research Program (NCHRP) Research Results Digest 321: Guide for Pavement Friction: Background and Research examines research related to frictional characteristics and performance of pavement surfaces, related tire-pavement noise, and other relevant issues. The final report on this project was published by TRB as NCHRP Web-Only Document 108 : Guide for P...
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 Buy America Issues Associated with the State DOT Procurement of Paratransit Vehicles Using FTA FundsJuly 12, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 319: Buy America Issues Associated with the State DOT Procurement of Paratransit Vehicles Using FTA Funds examines the Buy America requirements applicable to state departments of transportation (DOTs) and their sub-recipients in purchases of paratransit vehicles and examines opportunities for change. ...
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 An Expert System for Recommending Speed Limits in Speed ZonesJune 7, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 318: An Expert System for Recommending Speed Limits in Speed Zones explores the development of a knowledge-based expert system decision-support tool to help identify speed limits in speed zones on highways and local roads that are considered credible and enforceable. The decision-support tool softwa...
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 Prototype Software for an Environmental Information Management and Decision Support SystemApril 25, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 317: Prototype Software for an Environmental Information Management and Decision Support System explores an effort to design, test, and demonstrate a prototype software program for an environmental information management system (EIMS) that state departments of transportation and others could use to support thei...
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 Using Surface Energy Measurements to Select Materials for Asphalt PavementsMay 10, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 316: Using Surface Energy Measurements to Select Materials for Asphalt Pavements summarizes an investigation of the effectiveness and practicality of surface energy measurement as a tool for routine screening and selection of materials for optimum performance of hot-mix asphalt pavements. The summar...
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 State DOT Staff Resources for Administering Federal Public Transportation ProgramsMay 3, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 314: State DOT Staff Resources for Administering Federal Public Transportation Programs examines the staff resources that state departments of transportation (DOTs) devote to public transportation programs and explores the ability of the states to adequately administer existing and emerging Federal Transi...
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 Guide to Effective Freeway Performance MeasurementMarch 19, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 312: Guide to Effective Freeway Performance Measurement explores the framework that was used to develop a guide on 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. ...
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 FMCSA Regulations as They Apply to FTA Section 5310/5311 Providers: A HandbookFebruary 28, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 311, FMCSA regulations as they Apply to FTA Section 5310/5311 Providers: A Handbook is designed to help state and local governments, transit agencies, and others who provide transportation services supported by U.S. Federal Transit Administration Section 5310 and 5311 grants identify the Federal Motor Car...
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 Integrating Geospatial Technologies into the Right-of-Way Data-Management ProcessFebruary 16, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 310: Integrating Geospatial Technologies into the Right-of-Way Data-Management Process describes the first steps in automating the information technology process required for right-of-way acquisition and management. The appendices for RRD 310 have been produced as NCHRP Web-Only Document 95 .
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Continuing Project to Synthesize Information on Highway ProblemsFebruary 15, 2007 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 309: Continuing Project to Synthesize Information on Highway Problems is a digest of the progress and status of NCHRP Project 20-5, “Synthesis of Information Related to Highway Problems.”
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 Changes to the Mechanistic Empirical Pavement Design Guide Software Through Version 0.900, July 2006December 5, 2006 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 308: Changes to the Mechanistic Empirical Pavement Design Guide Software Through Version 0.900, July 2006, summarizes numerous changes made to the original Version 0.7 of the Mechanistic-Empirical Pavement Design Guide (MEPDG) software. Specifically, the digest describes the corrections incorporated in Ve...
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 Independent Review of the Mechanistic Empirical Pavement Design Guide and SoftwareDecember 15, 2006 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 307: Independent Review of the Mechanistic Empirical Pavement Design Guide (MEPDG) and Software explores the findings, conclusions, and recommendations of the independent review of new hot-mix asphalt pavement design, new Portland cement concrete pavement design, composite pavement design, and design reli...
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 Pavement Marking Materials and Markers: Testing the Relationship Between Retroreflectivity and SafetyOctober 13, 2006 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 305 - Pavement Marking Materials and Markers: Testing the Relationship Between Retroreflectivity and Safety explores the safety impact of pavement markings and markers with their performance, principally measured in terms of their retroreflectivity. The digest summarizes the final report on the proj...
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 Safety Impacts and Other Implications of Raised Speed Limits on High-Speed RoadsMay 24, 2006 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 303: Safety Impacts and Other Implications of Raised Speed Limits on High-Speed Roads explores the effects of raised speed limits from 55 miles per hour or greater on freeways and non-freeways in rural and urban settings. The effects considered included impacts on safety and operations, as well as socioec...
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 Core Competencies for Highway Safety ProfessionalsAugust 3, 2006 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 302 examines to what extent core competencies for highway safety professionals are incorporated into existing safety curricula and suggests strategies to expand their application to a broader audience.
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Continuing Project to Synthesize Information on Highway ProblemsJanuary 12, 2006 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 301: Continuing Project to Synthesize Information on Highway Problems outlines the NCHRP synthesis research process, and provides a list of ongoing and completed NCHRP synthesis reports.
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 Outcomes of the Environmental Streamlining Pilot ProjectsDecember 14, 2005 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 300: Outcomes of the Environmental Streamlining Pilot Projects describes the analysis of 10 environmental streamlining projects and suggests a “toolbox” of best practices for reducing the time associated with highway-project environmental reviews and approvals. The digest discusses the main points presented in ...
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Use of Event Data Recorder (EDR) Technology for Highway Crash Data AnalysisAugust 25, 2005 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 298: Use of Event Data Recorder (EDR) Technology for Highway Crash Data Analysis examines the benefits and the costs of using EDR data in highway crash data analysis and research. The report also summarizes the final report of NCHRP Project 17-24 that is available as NCHRP Web-Only Document 75 . Web...
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 New Facility for Calibrating RetroreflectometersJune 22, 2005 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 297: New Facility for Calibrating Retroreflectometers announces the results of NCHRP Project 05-16 (National Calibration Facility for Retroreflective Traffic Control Materials), which developed dedicated reference instrumentation to provide national calibration standards for retroreflectivity, thereby improving...
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 Comprehensive Human Factors Guidelines for Road Systems (Research Results Digest)May 31, 2005 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 296: Comprehensive Human Factors Guidelines (HFG) for Road Systems summarizes NCHRP Web Document 70 of the same title that examines the recommended content, format, organization, and capabilities of the planned HFG. Web Document 70 includes an outline of the HFG and a detailed work plan for development of...
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Transit-Oriented Development: Developing a Strategy to Measure SuccessMay 6, 2005 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 294: Transit-Oriented Development: Developing a Strategy to Measure Success identifies and evaluates various indicators of the impacts of transit-oriented development, provides the results of a survey of transit-oriented development indicators, and identifies ten indicators that may be used to systematically mo...
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 Training Program for Night Road Work to Improve Safety and OperationsDecember 16, 2004 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 293: Training Program for Night Road Work to Improve Safety and Operations describes development of a self-contained training package that complements NCHRP Report 475: A Procedure for Assessing and Planning Nighttime Highway Construction and Maintenance , which presented a decision process to assis...
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Continuing Project to Synthesize Information on Highway ProblemsNovember 9, 2004 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 292: Continuing Project to Synthesize Information on Highway Problems outlines the NCHRP synthesis research process, and provides a list of ongoing and completed NCHRP synthesis reports. Suggestions for synthesis topics may be sent to NCHRP at any time by contacting the Cooperative Research Programs Staff...
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 Recommended Mechanistic-Empirical Pavement Design Guide and Software: Available for EvaluationSeptember 15, 2004 TRB's National Cooperative Highway Research Program (NCHRP) Research Results Digest 290: Recommended Mechanistic-Empirical Pavement Design Guide and Software: Available for Evaluation announces the availability of key products from Development of the 2002 Guide for the Design of New and Rehabilitated Pavement Structures: Phase II project. Information on downloading a research version of ...
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 Highway Capacity Manual Applications Guidebook (NCHRP Research Results Digest 287)March 16, 2004 TRB's National Cooperative Highway Research Program (NCHRP) Research Results Digest 287: Highway Capacity Manual Applications Guidebook summarizes the contents of the Highway Capacity Manual Applications Guidebook , which uses real-world case studies to illustrate how the Highway Capacity Manual and other analysis tools can be used.
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 Development of a Highway Safety ManualApril 6, 2004 TRB's National Cooperative Highway Research Program (NCHRP) Research Results Digest 286: Development of a Highway Safety Manual presents a summary of the results of a study that developed an annotated outline, prototype chapter, and work plan for the first edition of the Highway Safety Manual. More detailed information on the study is available in NCHRP Web Document 62: Development of a Highway...
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 Laboratory Determination of Resilient Modulus for Flexible Pavement DesignFebruary 24, 2004 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 285: Laboratory Determination of Resilient Modulus for Flexible Pavement Design describes test methods for measurement of the resilient modulus of hot-mix asphalt (HMA) and for measurement of the resilient modulus of unbound granular base and sub-base materials and sub-grade soils.
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 Jackknife Testing--An Experimental Approach to Refine Model Calibration and ValidationDecember 15, 2003 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 283: Jackknife Testing -- An Experimental Approach to Refine Model Calibration and Validation summarizes efforts to develop a detailed, statistically sound, and practical experimental plan to refine the calibration and validation of performance models incorporated in the pavement design guide with laboratory-mea...
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 Fiber Reinforced Polymer Composites for Concrete Bridge Deck ReinforcementDecember 12, 2003 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 282: Fiber Reinforced Polymer Composites for Concrete Bridge Deck Reinforcement describes the material requirements for fiber reinforced polymer composites used as internal reinforcement for concrete bridge decks and presents test procedures for evaluating these composites.
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 Aggregate Tests for Portland Cement Concrete Pavements: Review and RecommendationsNovember 7, 2003 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 281 - Aggregate Tests for Portland Cement Concrete Pavements: Review and Recommendations identifies aggregate tests related to the performance of portland cement concrete pavements and provides guidance on their use for evaluating and selecting aggregates for use in specific pavement applications. The informatio...
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Continuing Project To Synthesize Information on Highway ProblemsSeptember 29, 2003 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 280: Continuing Project To Synthesize Information on Highway Problems outlines the NCHRP synthesis research process and provides a list of ongoing and completed NCHRP synthesis reports.
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 Making the Business Case for Translating Non-English Transportation InformationOctober 7, 2003 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 279: Making the Business Case for Translating Non-English Transportation Information provides an assessment of the benefits that could be realized through translation of non-English language transportation technical information.
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 Summary of Accessible Pedestrian Signals: Synthesis and Guide to Best PracticeAugust 5, 2003 TRB's National Cooperative Highway Research Project (NCHRP) Research Results Digest 278 summarizes Accessible Pedestrian Signals: Synthesis and Guide to Best Practice. The full report is available on the Pedestrian and Bicycle Information Center Web site at https://www.walkinginfo.org/aps/home.cfm . HTML Version
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 Ways To Evaluate Cultural ResourcesMay 28, 2003 The Transportation Research Board's National Cooperative Highway Research Program Research Results Digest 277: Review and Improvement of Existing Processes and Procedures for Evaluating Cultural Resource Significance describes information-technology solutions for improving development and use of resource inventories and historic contexts as tools for determining resource significance.
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 Business Needs for Pavement EngineeringOctober 31, 2003 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 276: Business Needs for Pavement Engineering summarizes the primary thrust areas of “business needs” for pavement engineering adopted by the American Association of State Highway and Transportation Officials (AASHTO) Joint Task Force on Pavements to help guide in identifying, evaluating, and prioritizing researc...
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 Application of European 2+1 Roadway DesignsMay 1, 2003 TRB's National Cooperative Highway Research Program Research Results Digest 275, Application of European 2+1 Roadway Designs, describes when a European 2+1 roadway design is likely to be effective in the United States and presents recommendations for designing 2+1 roads. A 2+1 road design has a continuous three-lane cross section with alternating passing lanes.
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 Quality Assurance of Structural MaterialsSeptember 15, 2003 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 274: Quality Assurance of Structural Materials examines the state of the practice of quality assurance (QA) related to critical structural materials and components -- those for which failure poses a threat to public safety or to the integrity of the transportation system (e.g., bridge girders, bridge columns, an...
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 Development of an Improved Roadside Barrier System - Phase IFebruary 27, 2003 TRB's Research Results Digest 273, Development of an Improved Roadside Barrier System--Phase I, provides a summary of the state of the art on the use of various guardrail systems, defines strengths and weaknesses of the current systems, and provides recommendations for changes to the strong-post w-beam barrier.
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 A Process for Selecting Strategies for Rehabilitation of Rigid PavementsJanuary 29, 2003 TRB's NCHRP Research Results Digest 272, A Process for Selecting Strategies for Rehabilitation of Rigid Pavements, summarizes strategies for rehabilitation of rigid pavements subjected to high traffic volumes and a process to help state highway agency decision makers identify the most appropriate maintenance, rehabilitation, and reconstruction strategy for specific project conditions.
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Studying Portland Cement Characteristics and DurabilityOctober 31, 2002 TRB's National Cooperative Highway Research Program (NCHRP) Research Results Digest Number 270: Relationship of Portland Cement Characteristics to Concrete Durability examines the effects of cement characteristics on certain aspects of concrete durability and recommends changes to cement specifications.
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Air Voids and Pavement PerformanceSeptember 27, 2002 The significance of as-constructed air void content on hot-mix asphalt pavement performance is examined in NCHRP Research Results Digest 269.
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 Digest Reviews Performance of Pavement Subsurface DrainageDecember 12, 2002 TRB's NCHRP Research Results Digest 268, Performance of Pavement Subsurface Drainage, provides a summary of the effects of subsurface pavement drainage features on the performance of asphalt concrete and portland cement concrete pavements.
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Utility of Translation SoftwareJune 17, 2002 An assessment of the state of the art of software for translating foreign-language documents into English is offered in TRB's NCHRP Research Results Digest 267: Utility of Machine Translation Software.
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Asset Management Guidance for Transportation AgenciesApril 29, 2002 Descriptions of three reports on synthesis, framework, and recommended research on asset management for transportation agencies are included in the National Cooperative Highway Research Program (NCHRP) Research Results Digest 266: Asset Management Guidance for Transportation Agencies.
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AASHTO Strategic Highway Safety Plan--Case StudiesApril 29, 2002 Findings of five case studies documenting the use of the AASHTO Strategic Highway Safety Plan in developing state strategic safety plans are documented in the National Cooperative Highway Research Program (NCHRP) Research Results Digest--Number 265: AASHTO Strategic Highway Safety Plan--Case Studies.
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LTTP Data Analysis: Factors Affecting Pavement SmoothnessFebruary 7, 2002 TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 264: LTTP Data Analysis: Factors Affecting Pavement Smoothness highlights the factors affecting pavement smoothness, identified in National Cooperative Highway Research Program (NCHRP) Project 20-50(08/13), on the basis of the data available from the Long-Term Pavement Performance (LTPP) studies. The research, c...
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Continuing Project to Synthesize Information on Highway Problems (Superseded)September 4, 2002 There exists a vast storehouse of information relating to nearly every subject of concern to highway administrators and engineers. Much of it is from research and much from the work of practitioners faced with problems in their day-to-day work. There has been no systematic means for assembling and evaluating such useful information and making it available to the entire highway community. The Am...
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Field Shear Test for Hot Mix AsphaltFebruary 1, 2002 This digest summarizes key results of National Cooperative Highway Research Program (NCHRP) Project 9-18, "Field Shear Test for Hot Mix Asphalt." Of particular interest is the description of the redesign of the field shear test (FST) device which was developed as a potential quality control and quality assurance (QC/QA) tool. The redesigned FST was found capable of performing a variety of tests...
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Continuing Project to Synthesize Information on Highway Problems (Superseded)September 5, 2001 There exists a vast storehouse of information relating to nearly every subject of concern to highway administrators and engineers. Much of it resulted from research and much from successful application of the ideas of practitioners faced with problems in their day-to-day work. Because there had been no systematic means for bringing such useful information together and making it available to the...
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Guidelines for the Effective Use and Procurement of Advanced Warning Arrow PanelsNovember 5, 2001 This digest provides procedures to ensure the proper visibility, deployment, and maintenance of advanced warning arrow panels. The digest also includes recommended specifications for arrow panels. The contents are as follows: Introduction; Technical Requirements for Arrow Panel Recognition; Development of a Specification for Arrow Panel Lamps; Development of a General Arrow Panel Specification;...
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Development of a Computer Model for Multimodal, Multicriteria Transportation Investment AnalysisSeptember 25, 2001 This digest provides the details on and discusses the concepts of a software package (the Transportation Decision Analysis Software, or TransDec) to assist state and local planners in making alternative decisions on modal investment. Working with multiple investment alternatives, objectives that are often contradictory, and measures that do not lend themselves well to quantification is a daunti...
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Effective Motivation of Highway MaintenanceAugust 3, 2001 This digest describes a training course for motivating highway maintenance personnel. The course is particularly suited for first and second line supervisors of state, county, and city maintenance organizations. National Cooperative Highway Research Program (NCHRP) Project 14-11, completed in 1992, developed a training manual and corresponding teaching materials for a course on effective motiva...
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Strategic Plan for Improving Roadside SafetyJune 22, 2001 This digest provides an overview of a strategic plan for improving roadside safety. Many of the action items outlined in the plan can be immediately implemented by safety practitioners at minimal or no cost. The strategic plan represents the ideas and thoughts of nearly 200 roadside safety professionals. The final report, which this digest is based on, is published on-line as NCHRP Web Document...
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Impacts of Resurfacing Projects With and Without Additional Safety ImprovementsJune 18, 2001 This digest describes the findings of a study to determine if there is a difference in the crash performance of resurfacing projects with and without safety improvements. Although the results were inconclusive, the study provides recommendations for conducting future studies and will be of interest to safety practitioners. This digest is based on a draft final report prepared by W.E. Hughes, L....
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Assessing Pavement Layer Condition Using Deflection DataJuly 5, 2001 An NCHRP digest of the findings from the final report on NCHRP Project 10-48, "Assessing Pavement Layer Condition Using Deflection Data," conducted by North Carolina State University. Dr. Y. R. Kim served as Principal Investigator. The agency's final report gives a detailed account of the project, findings, and conclusions, including software for the analysis of the condition of layers of full-...
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Recommended Use of Reclaimed Asphalt Pavement in the Superpave Mix Design Method: GuidelinesMarch 26, 2001 These guidelines are intended as reference material for agencies and hot- mix asphalt (HMA) producers using reclaimed asphalt pavement (RAP) in Superpave (registered trademark). They include recommendations on aspects of sampling, testing, designing, producing, and placing Superpave mixtures with RAP. The guidelines are written for the engineers and supervisors selecting or approving RAP mixtur...
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Development and Demonstration of StratBENCOST ProcedureApril 30, 2001 This digest provides the details and concepts of a strategic, decision- support tool (StratBENCOST) that will be of interest to highway-planning and budget professionals. It summarizes the capabilities of the StratBENCOST software and highlights example applications. StratBENCOST is designed to assist in comparing large numbers of project options in a jurisdiction, including project options in ...
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Guidance for Selecting Compensatory Wetland Mitigation OptionsJanuary 30, 2001 This digest summarizes the research and findings to date of National Cooperative Highway Research Program Project 25-16, "Guidance for Selecting Compensatory Wetland Mitigation Options." This digest presents state department of transportation managers with the best available information on wetland mitigation options and compares the success rates of individual mitigation with those of consolida...
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Improved Visibility for Snowplowing OperationsNovember 15, 2000 This digest describes several means, identified in National Cooperative Highway Research Program Project 6-12, that could improve visibility for snowplowing operations. The research, completed in 1999, identified several means for improving visibility for snowplowing operations. However, limited tests were conducted in this project to fully evaluate the merits of these means or the practicalit...
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Continuing Project to Synthesize Information on Highway Problems (Superseded)October 17, 2000 There exists a vast storehouse of information relating to nearly every subject of concern to highway administrators and engineers. Much of it resulted from research and much from successful application of the ideas of practitioners faced with problems in their day-to-day work. Because there had been no systematic means for bringing such useful information together and making it available to the...
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Continuing Project to Synthesize Information on Highway Problems (Superseded)August 24, 1999 There exists a vast storehouse of information relating to nearly every subject of concern to highway administrators and engineers. Much of it resulted from research and much from successful application of the ideas of practitioners faced with problems in their day to day work. Because there had been no systematic means for bringing such useful information together and making it available to the...
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Proposed Design Guidelines for Reducing Hydroplaning on New and Rehabilitated PavementsOctober 14, 1999 This digest summarizes proposed design guidelines for reducing hydroplaning on new and rehabilitated pavements developed in NCHRP Project 1-29, "Improved Surface Drainage of Pavements." In this study, and in the PAVDRN computer program, tread depth was assumed to be 3/32 in. (2.38 mm) and tire pressure was assumed to be 24.0 psi (16.75 kPa). These values were selected because the data that were...
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Metrication and Enhancement of MicroBENCOST Software PackageJuly 13, 1999 This is a digest of National Cooperative Highway Research Program ( NCHRP) Project 7-12(2), "Metrication and Enhancements of MicroBENCOST Software Package." The digest provides details and concepts about a software package consisting of two independent programs on separate disks--an English units version (C:/ MBE) and a metric units version ( C:/ MBM)--that update and enhance the original Engli...
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1998 Scanning Review of European Practice for Bridge Scour and Stream Instability CountermeasuresAugust 5, 1999 This digest summarizes the findings of an international technology scanning review conducted with the support of National Cooperative Highway Research Program (NCHRP) Project 20-36, "Highway Research and Technology--International Information Sharing." The scanning review team consisted of representatives from U.S. federal and state agencies as well as the private sector. The review included vis...
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Conversion of AASHTO Documents to Metric UnitsJuly 18, 1999 This digest summarizes the findings from the final report on National Cooperative Highway Research Program (NCHRP) Project 20-40, "Conversion of AASHTO Publications to Metric Units." The work involved converting 16 major American Association of State Highway and Transportation Officials (AASHTO) publications to the SI (metric) system of measurement units and providing them to AASHTO in reproduc...
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Improved Safety Information for Highway DesignJune 1, 1999 This digest of NCHRP Project 17-12, "Improved Safety Information for Highway Design," provides details and concepts for improved safety information systems that will be of interest to highway designers, safety professionals, and information managers. The project identified the critical safety information needed to support project- and policy- level decision making in highway design and to devel...
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Report on the 1998 Scanning Review of European Winter Service TechnologyMay 27, 1999 This digest describes the findings of the 1998 International Scanning Review of European Winter Service Technology organized jointly under the auspices of the Federal Highway Administration's (FHWA's) International Outreach Program and the American Association of State Highway and Transportation Officials (AASHTO) through the National Cooperative Highway Research Program (NCHRP). The review was...
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Superpave Gyratory Compaction GuidelinesApril 1, 1999 This digest summarizes key results of NCHRP Project 9-9, "Refinement of the Superpave Gyratory Compaction Procedure." Of particular interest, it presents a recommended reduction in the Ndesign table in AASHTO PP28, "Practice for Designing Superpave HMA," from the original 28 traffic and climate combinations to 4, provides specific Ndesign levels for base mixes, and recommends setting the Superp...
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Assessment of Impacts of Bridge Deck Runoff Contaminants on Receiving WatersJanuary 24, 1999 This digest summarizes the initial results of in-progress research associated with the assessment of bridge deck runoff impacts on receiving waters. It presents the findings of a critical review of scientific and technical literature on water-quality impacts and assessment methods for bridge deck runoff, maintenance practices, and spills. The digest also presents the results of a survey of stat...
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Manual for Bridge Rating Through Load TestingOctober 1, 1998 This digest describes the research findings from National Cooperative Highway Research Program (NCHRP) Project 12-28(13)A, Bridge Rating Through Nondestructive Load Testing. The project developed and documented processes for performing load tests and using the test results to calculate bridge ratings. The research results are presented in the form of a manual, which provides guidelines for inte...
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Summary of Economic Development Research ProjectsJanuary 24, 1999 This staff digest summarizes the scope and status of current or recently completed National Cooperative Highway Research Program ( NCHRP) and Transit Cooperative Research Program (TCRP) research activities associated with economics and economic development. The digest provides brief descriptions, summaries of objectives, status, and other information. It is intended to give a quick overview of ...
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Report on the 1997 Scanning Review of Asian Bridge StructuresDecember 31, 1998 This digest describes the findings of an international scanning tour undertaken to obtain a broad overview of bridge design, materials technology, construction procedures, and maintenance practices in Asia. The scanning team focused on identifying technological developments in Asia that have the potential for application in the United States. In addition, the team shared information with their ...
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Economic Effects of Restricting Left TurnsOctober 1, 1998 This digest summarizes the findings from the final report on National Cooperative Highway Research Program (NCHRP) Project 25-4, Economic Effects of Restricting Left Turns, conducted by Cambridge Systematics, Inc., JHK & Associates, Inc., and HBRS, Inc. G.E. Weisbrod and R. Neuwirth were the principal investigators. This digest will help analysts assess the effect of left-turn restrictions ...
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Review of Travel Assumptions Employed in Emission Factor ModelsNovember 21, 1998 This is a digest of the findings from National Cooperative Highway Research Program (NCHRP) Project 8-33, Quantifying Air Quality and Other Benefits and Costs of Transportation Control Measures. The objective of the project is to develop an improved analytical framework for evaluating the air quality and other benefits and costs of transportation control measures. The objective of the task summ...
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Developing Measures of Effectiveness for Truck Weight Enforcement ActivitiesAugust 1, 1998 This digest describes the findings of National Cooperative Highway Research Program (NCHRP) Project 20-34, Developing Measures of Effectiveness for Truck Weight Enforcement Activities, conducted by Fred R. Hanscom, Transportation Research Corporation, Haymarket, Virginia. The digest provides the practitioner with procedures for evaluating truck weight enforcement activities. It employs a set of...
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Development of Training Material for Highway Construction PersonnelJuly 1, 1998 This digest reports the findings from the final report on National Cooperative Highway Research Program (NCHRP) Project 20-25(3), Development of Training Material for Highway Construction Personnel, conducted by SNI International Resources, Inc. Mr. Richard P. White served as Principal Investigator. In this third phase of the research project, completed in 1997, comprehensive training packages ...
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Systems for Design of Highway PavementsAugust 1, 1998 This digest provides a summary of the findings from the final report on National Cooperative Highway Research Program (NCHRP) Project 1-32, Systems for Design of Highway Pavements conducted by ERES Consultants, Inc., for which Dr. Michael I. Darter served as Principal Investigator. The research, completed in 1997, provided (1) a catalog of current state pavement design features, (2) a catalog o...
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Multimodal Transportation: Development of a Performance-Based Planning ProcessAugust 1, 1998 In recent years, national transportation policy has evolved to support the development of multimodal systems and services tailored to local conditions for improved efficiency and performance. This digest describes how performance-based transportation planning and decision making can be established to effectively guide transportation investment and operational decisions. It is intended to assist...
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Putting Research Into Practice: A Synopsis of Successful Strategies and Case HistoriesJune 3, 1998 This digest summarizes implementation practices leading to the successful and timely application of research findings, and illustrates the use of these practices in several case studies drawn from the research findings. The contents are organized as follows: (I) Introduction; (II) Background Conditions Favoring Innovation; (III) Strategies to Put Research into Practice; (IV) Long-Term Success; ...
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Continuing Project to Synthesize Information on Highway Problems (Superseded)September 1, 1998 There exists a vast storehouse of information relating to nearly every subject of concern to highway administrators and engineers. Much of it resulted from research and much from successful application of the ideas of practitioners faced with problems in their day-to-day work. Because there had been no systematic means for bringing such useful information together and making it available to the...
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Pavement Marking Assessment System (PAMAS)January 14, 1998 This digest contains a brief description of and the operating instructions for a computer program that simplifies the semiquantitative process for measuring the engineering performance, environmental performance, including the impact of volatile organic compounds (VOCs), and health concerns, including an evaluation of the hazardous air pollutants (HAPs), of various classes of conventional pavem...
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Strategies for Improving Roadside SafetyDecember 19, 1997 This digest is an excerpt of a report prepared under National Cooperative Highway Research Program (NCHRP) Project 17-13, Strategic Plan for Improving Roadside Safety. The digest includes the following sections: (1) Roadside Crashes: A Serious Highway Safety Problem; (2) Addressing the Roadside Safety Problem; (3) A Vision for Improved Roadside Safety; and (4) Translating the Vision into Actions.
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Continuing Project to Synthesize Information on Highway Problems (Superseded)September 3, 1997 There exists a vast storehouse of information relating to nearly every subject of concern to highway administrators and engineers. Much of it resulted from research and much from successful application of the ideas of practitioners faced with problems in their day-to-day work. Because there has been no systematic means for bringing such useful information together and making it available to the...
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A Generic Data Model for Linear Referencing SystemsSeptember 24, 1997 This digest describes a consensus location referencing data model that was developed under NCHRP Project 20-27(2), Systems and Applications Architecture for GIS-T. The model allows linkages to various types of data over all modes. This information will be of use to persons involved with the design and implementation of field location referencing systems as well as the structuring of agency data...
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Relationship Between Implemented Transportation Control Measures and Measured Pollutant LevelsJuly 28, 1997 This digest summarizes partial findings from Phase I of NCHRP Project 8- 33, Quantifying Air Quality and Other Benefits and Costs of Transportation Control Measures. The objective of the project is to develop an improved analytical framework for evaluating transportation control measures (TCMs). The objective of the task summarized in this digest was to examine the relationships between impleme...
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Illumination Guidelines for Nighttime Highway WorkDecember 11, 1996 This digest presents the findings from the final report on NCHRP Project 5-13, Illumination Guidelines for Nighttime Highway Work. Nighttime construction and maintenance work is performed by at least 24 state departments of transportation. The preliminary guidelines are intended to assist in planning, designing, and operating nighttime highway work zone lighting systems. These guidelines addres...
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Protocol for In-Service Evaluation of Bridges with Epoxy-Coated Reinforcing SteelJanuary 2, 1997 This digest announces the results of NCHRP Project 10-37B, Protocol for the Evaluation of Existing Bridges Containing Epoxy-Coated Reinforcing Steel. Research and experience indicate the potential for future failures in the performance of epoxy-coated reinforcing steel in concrete bridges. Although not yet experiencing failures and seeing little sign they will, many transportation departments w...
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On-Site Evaluation and Calibration Procedures for Weigh-In-Motion SystemsFebruary 7, 1997 This digest presents the findings from the final report on NCHRP Project 3-39(2), On-Site Evaluation and Calibration Procedures for Weigh-In-Motion Systems. Widely accepted procedures do not exist for on-site evaluation and calibration of Weigh-In-Motion (WIM) systems. The feasibility of two approaches for evaluating and calibrating these systems were examined. One approach involves a combinati...
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Nondestructive Testing of Unknown Subsurface Bridge Foundations - Results of NCHRP Project 21-5December 11, 1996 This digest presents the findings of NCHRP Project 21-5, Determination of Unknown Subsurface Bridge Foundations, which evaluates existing and new technologies for use in determining unknown subsurface bridge foundation characteristics. The digest contains information about the feasibility of using nondestructive test (NDT) methods for the determination of unknown depths of bridge foundations. T...
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Continuing Project to Synthesize Information on Highway Problems (Superseded)July 11, 1996 There exists a vast storehouse of information relating to nearly every subject of concern to highway administrators and engineers. Much of it resulted from research and much from successful application of the ideas of practitioners faced with problems in their day-to-day work. Because there has been no systematic means for bringing such useful information together and making it available to the...
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Current State Practices in Transportation-Tourism InterfaceApril 2, 1996 This digest presents the findings of Phase I of NCHRP Project 2-17(6), Tourism Travel Contributions to Economic Development. This two-phase project is designed to examine and refine the institutional practices of the agencies that are counterparts in the transportation-tourism interface: state transportation agencies (DOTs) and state tourism offices (STOs). Phase I involved a series of data col...
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Effects of Highway Bypasses on Rural Communities and Small Urban AreasMay 9, 1996 This staff digest summarizes a study conducted as part of NCHRP Project 20-5, Synthesis of Information Related to Highway Problems, on the impacts of highway bypasses on rural communities and urban areas of less than 50,000 population, and current practices in using this knowledge in the planning of bypass development. The study involved a survey questionnaire to all U.S. state and Canadian pro...
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Continuing Project to Synthesize Information on Highway Problems (Superseded)December 31, 1995 There exists a vast storehouse of information relating to nearly every subject of concern to highway administrators and engineers. Much of it resulted from research and much from successful application of the ideas of practitioners faced with problems in their day-to-day work. Because there has been no systematic means for bringing such useful information together and making it available to the...
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Durability Testing of High-Strength Concrete Containing High-Range, Water-Reducing AdmixturesMarch 8, 1996 This digest has been derived by excerpting the agency report for NCHRP Project 10-32A, Durability Testing of High-Strength Concrete Containing High-Range, Water-Reducing Admixtures. For this project, laboratory freezing and thawing tests were used to evaluate the durability of concretes containing high-range, water-reducing admixtures (i.e., superplasticizers). Two types of concretes were studi...
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On the Implementation of Research Findings in Surface TransportationJune 20, 1995 To improve technology transfer and facilitate the rapid use of research findings in surface transportation, there is a need to recognize and address the significant factors that influence implementation, to identify the characteristics of organizations that have succeeded in being innovative, and to develop and apply strategies for the creation of an environment conducive to innovation and time...
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Training for Highway Construction PersonnelMarch 24, 1995 An initial phase of research conducted under NCHRP Project 20-25, Training Needs for Highway Construction Personnel, developed a national training program that included 62 training courses and determined that the National Institute for Certification in Engineering Technologies (NICET), founded by the National Society of Professional Engineers (NSPE), is the most reliable yardstick available for...
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Requirements for Application of Light Emitting Diodes (LEDs) to Traffic Control SignalsApril 18, 1995 Incandescent lamps are presently the major illumination source for traffic signals. They are, however, inefficient compared with other light sources. Maintenance costs are high for these lamps, and the light output degrades as the lamp ages. These problems--plus the ever- increasing cost of energy--justify considering other light sources. One alternative is light emitting diodes (LEDs). Before ...
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Winter Maintenance Technology and Practices - Learning from AbroadFebruary 9, 1995 An International Winter Maintenance Technology Scanning Tour was organized jointly under the auspices of the Federal Highway Administration's International Outreach Program and the AASHTO- sponsored National Cooperative Highway Research Program to examine snow and ice control operations in Japan and Europe for technology with potential for domestic application. The scanning team travelled to Ja...
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Continuing Project to Synthesize Information on Highway Problems (Superseded)February 8, 1995 There exists a vast storehouse of information relating to nearly every subject of concern to highway administrators and engineers. Much of it resulted from research and much from successful application of the ideas of practitioners faced with problems in their day-to-day work. Because there has been no systematic means for bringing such useful information together and making it available to the...
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Congestion Impacts on Business and Strategies to Mitigate ThemSeptember 18, 1995 This NCHRP digest summarizes the findings from the final report of NCHRP Project 2-17(5), Impact of Urban Congestion on Business, conducted by Cambridge Systematics, Inc. Principal authors were L.R. Grenzeback and M.G. Warner. A copy of the report, which will not be published, has been sent to each state department of transportation. The digest provides a typology of congestion impacts, discuss...
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BRI-STARS (Bridge Stream Tube Model for Alluvial River Simulation)July 26, 1994 This NCHRP digest describes the BRIdge Stream Tube model for Alluvial River Simulation (BRI-STARS), Version 3.3, an innovative, operational computer program developed for NCHRP Project 15-11, Computer-aided Analysis of Highway Encroachments on Mobile Boundary Streams. It is a semi-two-dimensional model capable of computing alluvial scour/ deposition through subcritical, supercritical, and a com...
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Objectives and Decision Criteria for Infrastructure InvestmentFebruary 21, 1995 The National Cooperative Highway Research Program (NCHRP) has undertaken various research efforts to develop cost-benefit analysis techniques. NCHRP Project 2-17(1), Methodologies for Evaluating the Effects of Transportation Policies on the Economy, developed a Primer for applying the cost-benefit techniques to analyze transportation investments considering a wide range of factors. This Digest ...
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Rapid Static Surveying Using the Global Positioning SystemJanuary 1, 1994 This Research Results Digest (RRD) is an update on RRD Number 185: NCHRP Supports Advances in Differential GPS Satellite Surveying, published in April 1992. The research has resulted in a technique by which highway engineers and surveyors may rapidly obtain precise positions necessary to maintain geodetic control. The technique uses measurements of the Global Positioning System (GPS), commercia...
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 Development of Comprehensive Bridge Specifications and CommentaryJune 15, 1998 TRB's National Cooperative Highway Reserach Program (NCHRP) Research Results Digest 198: Development of Comprehensive Bridge Specifications and Commentary details the development of the American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) Bridge Design Specifications. The contents are organized as follows: (1.0) Historical Developm...
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Fatigue Behavior of Welded and Mechanical splices in Reinforcing SteelJuly 18, 1994 This NCHRP Digest contains suggested revisions to the AASHTO Standard Specifications for Highway Bridges based on findings from the final report under NCHRP Project 10-35, which was initiated to evaluate the fatigue behavior of welded and mechanical splices for reinforcing bars in bridges and to develop practical design provisions. The research was accomplished by carrying out the following fou...
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A Unique, Hands-On Educational Program for High School Mathematics and Science ClassesJanuary 1, 1994 This digest summarizes the background, research results, and prototype materials produced under the NCHRP Project 20-24(3)A, Civil Engineering Careers in Transportation--Outreach Program. The discussion provides information on the high school educational outreach program called TRAC (TRAnsportation and Civil engineering). TRAC, which began as a pilot project in September 1991, is working in six...
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Continuing Project to Synthesize Information on Highway Problems (Superseded)January 1, 1993 This is a digest of the progress and status of NCHRP Project 20-5, Synthesis of Information Related to Highway Problems, for which the Transportation Research Board is the agency conducting the research. This project is intended to search out and synthesize useful knowledge from all possible sources and to prepare documented reports on current practices in the subject areas of concern. Reports ...
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Low-Service-Level Guardrail SystemsJanuary 1, 1994 This is an NCHRP digest of the findings from the final report on NCHRP Project 22-5A, Warrants for the Installation of Low-Service-Level Guardrail Systems, conducted by Wilbur Smith Associates. Five low- service-level barrier systems were developed and evaluated by full- scale crash testing. In addition, a user's guide was prepared to provide design details for the developed systems and to outl...
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Administration of Highway and Transportation Agencies Project 20-24 SeriesJanuary 1, 1993 This is a digest on the progress of projects emanating from NCHRP Project 20-24, Administration of Highway and Transportation Agencies. To date, ten projects have been initiated. Four of these have been completed and the others are in progress. Brief synopses of the ten projects are provided. The completed projects are: Project 20- 24(1) - Using Market Research to Improve Management of Transpor...
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Procedure for Determining Work Zone Speed LimitsOctober 4, 1996 This NCHRP Digest summarizes the findings of NCHRP Project 3-41, Procedure for Determining Work Zone Speed Limits. The Manual on Uniform Traffic Control Devices for Streets and Highways has no uniform guidelines for determining work zone speed limits. At their 1988 joint meeting, the AASHTO Highway Subcommittee on Traffic Engineering and the Maintenance Technical Committee of the National Commi...
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Management Guide for Implementation of Geographic Information Systems (GIS) in State DOTsJanuary 1, 1993 The purpose of this Management Guide is (1) to provide a basic understanding of geographic information systems (GIS) and geographic information systems for transportation (GIS-T); (2) to describe the factors involved in successful planning and implementation of GIS-T; ( 3) to provide a basic understanding of how GIS-T can benefit transportation agencies; and (4) to describe benefit-cost conside...
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Continuing Project to Synthesize Information on Highway Problems (Superseded)January 1, 1992 This staff digest reports on the progress and status of NCHRP Project 20-5, Synthesis of Information Related to Highway Problems, for which the Transportation Research Board is the agency conducting the research. This study is intended to search out and synthesize useful knowledge from all possible sources and to prepare documented reports on current practices in the subject areas of concern. R...
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Instrumentation for Measuring Scour at Bridge Piers and AbutmentsJanuary 1, 1993 This Digest summarizes the findings from the Phase I final report under NCHRP Project 21-3, which was conducted by Resource Consultants, Inc. NCHRP Project 21-3 was initiated in 1989 to develop, test, and evaluate instrumentation that would be technically and economically feasible for use in monitoring and measuring maximum scour depth at bridge piers and abutments. The research is being conduc...
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Distribution of Wheel Loads on Highway BridgesJanuary 1, 1992 This NCHRP digest presents the findings from NCHRP Project 12-26, Distribution of Wheel Loads on Highway Bridges. The project was initiated in the mid-1980s in order to develop comprehensive specification provisions for distribution of wheel loads in highway bridges. The study was performed in two phases: Phase I concentrated on beam-and-slab and box girder bridges; Phase II concentrated on sla...
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Data Interchange Standards for Bridge Management Systems and Integrated Highway Information SystemsJanuary 1, 1992 This digest provides a summary of existing and emerging standards for data interchange that might be adapted to bridge and other infrastructure management systems, and contains a brief account of what might constitute a universal standard. The material for this digest was developed under NCHRP Project 20-7, Task 46, AASHTO Guidelines for Bridge Management Systems, conducted by The Urban Institu...
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NCHRP Supports Advances in Differential GPS Satellite SurveyingJanuary 1, 1992 This Digest is a status report on National Cooperative Highway Research Program (NCHRP) Project 20-23, Kinematic Differential GPS Satellite Surveying. Although the Global Positioning System (GPS) is a satellite system being developed by the Department of Defense, some civilian applications are allowed. Presently, 15 satellites providing positioning information are in orbit. An 18-satellite cons...
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NCHRP Research on PavementsJanuary 1, 1992 This Digest outlines the status of all National Cooperative Highway Research Program (NCHRP) research related to highway pavements. Most NCHRP research in this area focuses on design, materials, construction, evaluation, and management of pavements. This information is provided in five tables. Table 1 concerns research is progress. Table 2 provides information on pending research. Tables 3, 4 a...
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Administration of Highway and Transportation Agencies Project 20-24 SeriesJanuary 1, 1992 This Digest reports on the progress of projects emanating from Project 20-24, "Administration of Highway and Transportation Agencies". To date ten projects have been initiated. Four of these have been completed and the others are in progress. A table is included showing the following: Project Number; Title; Research Agency; Contract Amount; Start Date; Completion Date; and Project Status.
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Continuing Project to Synthesize Information on Highway Problems (Superseded)January 1, 1991 This staff digest reports on the progress and status of NCHRP Project 20-5, "Synthesis of Information Related to Highway Problems," for which the Transportation Research Board is the agency conducting the research. This study is intended to search out and synthesize useful knowledge from all possible sources and to prepare documented reports on current practices in the subject areas of concern....
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Video Image Processing for Evaluating Pavement Surface DistressJanuary 1, 1991 This digest presents the findings from the final report on NCHRP Project 1-27, which was conducted by Triple Vision, Inc., Dr. R.A. Fundakowski, Principal Investigator. The objective of NCHRP Project 1- 27 was to develop a system for processing video images to identify, quantify, and classify pavement distress in terms of types, severity, and extent.
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Implementation of Geographic Information Systems (GIS) in State DOTsJanuary 1, 1991 This digest presents the essential findings from the interim report on NCHRP Project 20-27, Adaptation of Geographic Information Systems for Transportation, by A. Vonderohe, L. Travis, and R. Smith, University of Wisconsin, Madison. Geographic Information Systems (GIS) offer the potential to assemble and process data from a diversity of sources and present it in an easily understood graphical f...
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Financing Highway Improvements Through Public and Private PartnershipsJanuary 1, 1991 This digest presents the findings from NCHRP Project 2-14, "Public/ Private Partnerships for Financing Highway Improvements," which was conducted by Kimley-Horn and Associates. The overall objective of the research project was to provide guidance to state and local highway officials, and to private developers, on existing and potential public- private partnership mechanisms, including present s...
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NCHRP Research on Maintenance EngineeringJanuary 1, 1990 This digest summarizes the progress and status of maintenance engineering research under the National Cooperative Highway Research Program (NCHRP). Five tables are included which list the following: Research in Progress; Pending Research; Available NCHRP Series Publications; Uncorrected Agency Final Reports; and Agency Final Reports Receiving Special Treatment.
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Continuing Project to Synthesize Information on Highway Problems (Superseded)January 1, 1990 This staff digest reports the progress and status of NCHRP Project 20- 5, Synthesis of Information Related to Highway Problems. There are five tables containing the following: (1) Syntheses of Highway Practice that have been completed under this project and Research Results Digests on topics studied under this project; (2) Topics currently being studied; (3) Membership of NCHRP Project Committe...
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NCHRP Research on Construction EngineeringJanuary 1, 1990 This digest summarizes the progress and status of construction engineering research under the National Cooperative Highway Research Program (NCHRP). Five tables are included which list the following: Research in Progress; Pending Research; Available NCHRP Series Publications; Uncorrected Agency Final Reports; and Agency Final Reports Receiving Special Treatment.
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Determination of Water:Cement Ratio in Fresh ConcreteJanuary 1, 1990 This digest presents the essential findings from NCHRP Project 10-25A, Instantaneous Determination of Water-Cement Ratio in Fresh Concrete. The objective of the research was to develop a method of measuring the water:cement ratio in concrete that could form the basis of an acceptance test at the job site. An extensive literature search did not reveal any successful development of a probe, but d...
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Continuing Project to Synthesize Information on Highway Problems (Superseded)January 1, 1990 The American Association of State Highway and Transportation Officials has, through the mechanism of the National Cooperative Highway Research Program (NCHRP), authorized the Transportation Research Board to undertake a continuing study, NCHRP Project 20-5, "Synthesis of Information Related to Highway Problems." Reports from this endeavor constitute an NCHRP report series, Synthesis of Highway ...
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Pot Bearings and PTFE SurfacesJanuary 1, 1989 This digest provides a summary of the pot bearing synthesis that was performed in Phase III of NCHRP Project 10-20, Elastomeric Bearings Design, Construction, and Materials. Phase III concerned low temperature bearing behavior and prequalifications and acceptance testing. Pot bearings and bearings with PTFE (polytetrafluorethylene) sliding surfaces are widely used in bridge construction. They s...
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Research Program Design Administration of Highway and Transportation AgenciesJanuary 1, 1989 Much of the research conducted by the NCHRP is designed to solve specific problems, experienced by practitioners, that are related to the operational and planning functions of state highway departments. Although top management is certainly affected by these problems and benefits from solutions through improved agency performance, this type of research does not necessarily address top management...
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Rapid Replacement of Portland Cement Concrete Pavement SegmentsJanuary 1, 1989 The objectives of this study were to identify, describe, and evaluate methods that have been, and are being, used for rapid replacement of full lane-width segments of both continuously reinforced and jointed portland cement concrete (PCC) pavements relative to costs, placement conditions, traffic characteristics, performance, and expected service lives. The research has accomplished these objec...
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Continuing Project to Synthesize Information On Highway Problems (Superseded)January 1, 1988 The American Association of State Highway and Transportation Officials has, through the mechanism of the National Cooperative Highway Research Program (NCHRP), authorized the Transportation Research Board to undertake a continuing study, NCHRP Project 20-5, "Synthesis of Information Related to Highway Problems." Reports from this endeavor constitute an NCHRP report series, Synthesis of Highway ...
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NCHRP Research On Bridge EngineeringJanuary 1, 1988 This Digest supersedes NCHRP Research Results Digest 155 published in February 1986. The purpose of the Digest is to outline for easy reference (in Tables 1 through 5) the status of, and inter- relationships between, all NCHRP research related to bridges. Included are projects under development, in progress, and completed. A listing of all related research reports is also provided.
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Continuing Project to Synthesize Information On Highway Problems (Superseded)January 1, 1987 There exists a vast storehouse of information relating to nearly every subject of concern to highway administrators and engineers. Much of it resulted from research and much from successful application of the ideas of practitioners faced with problems in their day-to-day work. The American Association of State Highway and Transportation Officials has, through the mechanism of the National Coope...
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Legal Techniques For Reserving Right-of-Way For Future Projects Including Corridor ProtectionJanuary 1, 1987 State highway departments and transportation agencies have a continuing need to keep abreast of operating practices and legal elements of specific problems in highway law. This report presents a general outline of highway reservation laws, discusses the constitutionality of related legal techniques, and describes some of the associated NEPA ( National Environmental Policy Act) problems. This pa...
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Rights Abutting Property Owner Upon Conversion of Uncontrolled-Access Road Into Limited-Access HighwayJanuary 1, 1987 This paper deals with the rights of a landowner whose property abuts on a conventional road that is converted into a limited-access highway. In the typical situation prior to the conversion the owner has direct access to the adjoining unlimited access highway and after the conversion his means of ingress to and egress from the new controlled- access highway is limited either to travel along a f...
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Continuing Project on Legal Problems Arising Out of Highway Programs (Superseded)January 1, 1987 The National Cooperative Highway Research Program Project 20-6, established to meet the need for the analysis and evaluation of operatiing practices and legal issues associated with highway projects is described. Part of the products of this Project (20-6 ) is the 4- volume "Selected Studies in Highway Law." The contents of these volumes are listed in this digest. Published papers from this stu...
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Public and Private Partnerships for Financing Highway ImprovementsJanuary 1, 1987 This report addresses the legal considerations related to alternative funding mechanisms being used for highway improvements. It focuses on the various approaches being used by different states and local agencies to develop funding strategies involving both the public and private sector, and the legal basis for each approach. The paper consists of 4 sections. The first section provides an intro...
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Acquisition of Uneconomic Remnants Under 23 U.S.C. 109(f)January 1, 1987 This report addresses the conflict between the provisions of 23 U.S.C. 109(f) and the terms of 42 U.S.C. 4651(9) as they relate to the purchase of uneconomic remnants of land involving Federal participation. An uneconomic remnant is defined as: A remaining part of land, after a partial acquisition, that is of little or no utility or value to the owner. This research should prove helpful to high...
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Continuing Project to Synthesize Information on Highway Problems (Superseded)January 1, 1986 This publication reports on a continuing study, "Synthesis of Information Related to Highway Problems," which searches out and synthesizes useful knowledge from all possible sources and prepares documented reports on current practices in the subject areas of concern. Reports from this effort constitute the National Cooperative Highway Research Program's series, "Synthesis of Highway Practice." ...
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Legal and Procedural Issues Related to Relocation AssistanceJanuary 1, 1986 State highway departments and transportation agencies have a continuing need to keep abreast of operating practices and legal elements of special problems in highway law. This report deals with the legal and procedural issues that public officials face in administering relocation assistance programs for the acquisition of land for transportation projects. A comprehensive analysis of these issue...
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Supplement to Licensing and Qualification of Bidders in Selected Studies in Highway LawJanuary 1, 1986 This report supplements and updates a section in Volume 3 of "Selected Studies in Highway Law" dealing with licensing and qualification of public works contractors. The report gives an overview of state legislation, and describes prequalification policies and procedures, and suspension and revocation procedures. Statutory structure and the scope of the licensing requirement are examined and a t...
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Continuing Project on Legal Problems Arising Out of Highway Programs (Superseded)January 1, 1986 The National Cooperative Highway Research Program (NCHRP) Project 20-6 was established to meet a continuing need for analysis and evaluation of operating practices and legal issues associated with highway projects. The project also compares individual state practices for possible national application. As part of this project, the Transportation Research Board introduced "Selected Studies in Hig...
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NCHRP Research on Bridge Engineering (Superseded)January 1, 1986 The purpose of this Research Results Digest is to outline for easy reference the status of all NCHRP research related to bridges. Included are projects completed, in progress, and under development. A listing of all related research reports is also provided, with directions for obtaining copies. This digest supersedes RRD 143 published in February 1984. (Author)
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Trial Strategy and Techniques in Enforcing Laws Relating to Truck Weights and SizesJanuary 1, 1986 State highway departments and transportation agencies have a continuing need to keep abreast of operating practices and legal elements of special problems in highway law. This report deals with the enforcement of load limit violations by overweight trucks through relief against the persons or corporations who load or unload the vehicles as well as the truck operators.
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Enforceability of the Requirement of Notice in Highway Construction ContractsJanuary 1, 1986 State highway departments and transportation agencies have a continuing need to keep abreast of operating practices and legal elements of special problems of highway law. This report deals with highway construction contractor claims for compensation beyond the original contract amount and the requirements for advance notification of such claims.
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Planning and Precondemnation Activities as Constituting a Taking under Inverse LawJanuary 1, 1986 State highway departments and transportation agencies have a continuing need to keep abreast of operating practices and legal elements of special problems in highway law. This report deals with the right of property owners to recover damages due to decrease in property value during the planning and precondemnation process.
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Exaction of Right-of-Way by Exercise of Police PowerJanuary 1, 1986 State highway departments and transportation agencies have a continuing need to keep abreast of operating practices and legal elements of special problems in highway law. This report deals with the legal issues related to exactions, i.e., the compulsory dedication of private property for a public use without payment of compensation. Illustrative test cases are described related to the exaction ...
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Continuing Project to Synthesize Information on Highway Problems (Superseded)January 1, 1985 The American Association of State Highway and Transportation officials, through the Natural Cooperatives Research Program, authorized the Transportation Research Board to undertake a continuing study, NCHRP 20- 5 "Synthesis of Information Related to Highway Problems" to search out and Synthesize useful knowledge from all possible sources and to prepare documented reports on current practices in...
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Mineral Rights in Rights-of-Way: Acquisition, Valuation, and DispositionJanuary 1, 1985 This report addresses three specific issues related to the acquisition and ownership of highway rights of way: the status of the title acquired by the highway agency, valuation of mineral lands, and disposal methods for minerals underlying highway rights of way. The paper explores several valuation questions that have plagued courts and describes the recent cases that may indicate a trend towar...
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Minority and Disadvantaged Business Enterprise Requirements in Public ContractingJanuary 1, 1985 This paper deals with the history and development of the minority and women business enterprise programs in public contracting and reviews the treatment these programs have received in the courts including an extensive discussion of the United States Supreme Court regarding affirmative action. It concludes with a practical discussion regarding the certification process in dealing with potential...
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First Amendment Aspects of Control of Outdoor AdvertisingJanuary 1, 1985 State highway departments and transportation agencies have a continuing need to keep abreast of operating practices and legal elements of special problems in highway law. This report deals with the significance of a recent court decision, Metromedia, Inc. vs. City of San Diego, regarding the First Amendment guarantee of free speech when applied to control of outdoor advertising. (Author)
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Continuing Project to Synthesize Information on Highway Problems (Superseded)January 1, 1984 The American Association of State Highway and Transportation Officials has, through the mechanism of the National Cooperative Highway Research Program, authorized the Transportation Research Board to undertake a continuing study, NCHRP Project 20-5, "Synthesis of Information Related to Highway Problems." This study is intended to search out and synthesize useful knowledge from all possible sour...
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NCHRP Research on Bridge EngineeringJanuary 1, 1984 The purpose of this Research Results Digest is to outline for easy reference the status of all NCHRP research related to bridges. Included are projects completed, in progress, and under development. A listing of all related research reports is also provided, with directions for obtaining copies. This digest supersedes RRD 132 published in May 1982. (Author)
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Continuing Project to Synthesize Information on Highway Problems (Superseded)January 1, 1983 The NCHRP (National Cooperative Highway Research Program) Project 20-5 " Synthesis of Information Related to Highway Problems" attempts to search synthesize useful knowledge from all possible sources and to prepare documented reports on current practices in the subject areas of concern. The reports from this project constitute a report series, " Synthesis of Highway Practice", which assembles t...
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Development of a New Highway Capacity Manual: Status Report (Superseded)January 1, 1983 A status report is provided on the research that is being directed to the development of a new Highway Capacity Manual. This research is being conducted by NCHRP (National Cooperative Highway Research Program), FHWA (Federal Highway Administration), the TRB ( Transportation Research Board) Committee on Highway Capacity and Quality of Service (A3A10), and others. The NCHRP project is a multiphas...
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Continuing Project to Synthesize Information on Highway Problems (Superseded)January 1, 1983 This staff digest of the current progress and status of NCHRP Project 20-5, "Synthesis of Information Related to Highway Problems", lists 100 published Synthesis of Highway Practice prepared under this project to date; two Research Results Digests on topics studied under the project; 23 topics currently being studied; and 18 topics selected for FY '83. All synthesis topics, whether published, c...
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Evaluation of Winter-Driving Traction AidsJanuary 1, 1982 A set of test procedures has been selected to measure the braking, driving traction, and controllability of (1) vehicles fitted with tires and tire-associated traction aids intended to increase available friction on ice and snow surfaces and (2) vehicles fitted with drive- train aids intended to make better use of available friction. The performance of traction-aids intended to increase availab...
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Continuing Project to Synthesize Information on Highway Problems (Superseded)January 1, 1982 This staff digest of the progress and states of NCHRP Project 20-5, " Synthesis of Information Related to Highway Problems," lists 88 published Syntheses of Highway Practice that have been prepared under this project to date, two Research Results Digests on topics studied under the project, 23 topics currently being studied, and 21 synthesis topics for the FY '82 program, along with an index of...
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Variability in Temperature Susceptibility of Asphalt ConcreteJanuary 1, 1981 Temperature susceptibility of asphalt cement is an important control parameter during the mixing, placing, compaction, and performance of asphaltic concrete. Early methods of measuring this characteristic involved the use of needle penetration devices. Viscosity began to appear in specifications in the 1920's. Today's specifications often make use of viscosity and penetration measurements at 14...
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Continuing Project on Highway Right-of-Way and Legal ProblemsJanuary 1, 1980 This digest reports the progress and status of NCHRP Project 20-6. It contains a list of the digests emanating from this project and presents the contents of Volumes 1, 2 and 3 of the TRB special publication, Selected Studies in Highway Law. Topics selected for study under this project but not yet completed are also listed.
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The Vehicle-Miles of Travel -- Urban Highway Supply RelationshipJanuary 1, 1980 The objective of this research was to determine whether a relationship exists between measures describing urban highway supply and VMT and, if so, to quantify the relationships. Furthermore, highway supply measures were to be related to air pollution rates and fuel consumption through the use of known VMT/air pollution/fuel consumption relationships. To be useful to practitioners, the relations...
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Performance Evaluation of Signalized Network Control StrategiesJanuary 1, 1980 This digest presents the findings from the final report on NCHRP Project 3-18(4). This Project had the objective of developing a methodology that would enable traffic engineers to select the most appropriate network performance measure of effectiveness (MOE) and to quantify that MOE using efficient, simple, and inexpensive data collection techniques.
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Continuing Project to Synthesize Information on Highway Problems (Superseded)January 1, 1980 This digest reports the progress and status of NCHRP Project 20-5. The 73 published Syntheses of Highway Practice that have been prepared under this project are listed, along with two other Digests. The 29 topics currently being studied under this project are also listed, followed by those topics selected for the FY 81 program. Finally, an index to published syntheses and topics now under study...
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A Modified Foundation for Breakaway Cable Terminals (Superseded)January 1, 1980 This digest recommends a modification to the foundation detail for the timber post version of the breakaway cable terminals (BCT), and reemphasizes a feature of the BCT which has been shown by accident experience to be crucial to proper performance. Questions which this research study attempted to answer are; how can the cost of the concrete footings for the breakaway posts be reduced; how can ...
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Evaluation of Performed Elastomeric Joint Sealing SystemsJanuary 1, 1980 This digest presents the findings from the final report on NCHRP Project 4-9. The project achieved the objective of developing guide specifications for preformed elastomeric seals. These specifications are presented in the appendix of this digest.
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Noise Barrier Acoustical Parameters -- Experimental ResultsJanuary 1, 1980 This study attempted to determine those factors which would help improve existing noise barrier prediction models such as included in FHWA's "Noise barrier design handbook" and NCHRP Report 74, "Highway Noise--A design guide for prediction and control." Three specific aspects of the models were investigated: (1) the effects of ground absorption; (2) the relative effects of different cross- sect...
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Development and Field Evaluation of Prototype Soil Moisture SensorsJanuary 1, 1980 This paper discusses a study where moisture determinations from nuclear magnetic resonance (NMR) and dielectric sensors were compared with moisture measurements obtained by nuclear depth probes and gravimetric analysis of soil borings. The following are general observations and conclusions of the field evaluation phase of the study: some operational problems were encountered with several sensor...
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Residential Dislocation -- Costs and ConsequencesJanuary 1, 1980 Research was conducted to develop techniques for predicting dislocation consequences of alternate route and design proposals and to identify related legislative or regulatory constraints and recommend modifications to ensure equity to the displacees. This digest presents recommendations for changes in compensation, in relocation practices and in the highway planning process. Recommendations to ...
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NCHRP Research on Bridge EngineeringJanuary 1, 1980 This digest outlines the status of all NCHRP research related to bridges and includes projects which are completed, in progress, and under development. A listing of all related research reports are also provided with directions for obtaining copies. Tables are provided which chronologically list all NCHRP publications of bridge research including the NCHRP Report series, the NCHRP Synthesis of ...
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Guidelines for Selecting Traffic Signal Control at Individual IntersectionsJanuary 1, 1980 An NCHRP Project 3-27 comprehensive guidelines were developed to help traffic engineers evaluate the costs and benefits of various control alternatives while taking roadway and traffic conditions into account. Although the emphasis was on traffic control at isolated intersections, adjacent intersections were considered in regard to the need for coordinated operation. This digest discusses the a...
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NCHRP Research on the Durability of Reinforced Concrete Bridge ComponentsJanuary 1, 1979 Numerous studies on the durability of reinforced concrete bridge components have been included in the National Cooperative Highway Research Program (NCHRP). In recent years, concurrently with a growing national awareness of bridge deterioration, a substantial number of research projects on this problem have been referred to NCHRP by the program sponsors, the American Association of State Highwa...
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Energy Analysis Methodology for Assessing Environmental ImpactsJanuary 1, 1979 Several years of developmental research have contributed to the evolution of an energy analysis methodology to assess the environmental impacts of transportation facilities. Recent energy analysis research projects and case study applications have indicated that the methodology may offer significant improvements to the environmental analyses used to assess the impacts of transportation faciltie...
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Control of Conflicts of Interest in Highway Construction Contract AdministrationJanuary 1, 1979 State highway departments and transportation agencies have a continuing need to keep abreast of operating practices and legal elements of special problems involving contracts, as well as highway law in general. This report deals with legal questions surrounding conflicts of interest involving public officials. An extensive body of law has been developed to control or prevent conflicts of intere...
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Continuing Project to Synthesize Information on Highway Problems (Superseded)January 1, 1979 The continuing project, "Synthesis of Information Related to Highway Problems" is intended to search out and synthesize useful knowledge from all possible sources and to prepare documented reports on current practices in the subject areas of concern. Reports from this project constitute a National Cooperative Highway Research Program (NCHRP) report series "Synthesis of Highway Practice", which ...
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Use of Waste Materials in Highway Construction and MaintenanceJanuary 1, 1979 A study of existing information is reported. Reference is made to a report prepared under the sponsorship of the Organization for Economic Co-operation and Development--"Use of Waste Materials and By-Products in Road Construction"--which reviews the use of materials from mining and quarry wastes and products, metallurgical wastes and by-products, industrial wastes and by products, municiapl was...
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Selected Acoustical Parameters of Highway Noise BarriersJanuary 1, 1978 A need existed (a) to determine the influence of selected barrier characteristics on barrier performance and (b) to develop procedures to incorporate these effects in the design process. Thus, the objective of this investigation was to examine the manner in which noise propagates over barriers of different cross-sectional shape (e.g., thin walls, sharp wedges, trapezoids, walls on trapezoids, a...
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NCHRP Research on Bridge EngineeringJanuary 1, 1978 The status of all NCHRP bridge related research projects that have been completed, are in progress, or under development, is outlined. The projects listed cover a wide range of problem areas related to design, construction, and maintenance of bridges. Both durability and structural behavior are included, with particular emphasis on methods of prevention and repair of damage caused by fatigue in...
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Retrofitting Procedures for Fatigue-Damaged Full-Scale Welded Bridge BeamsJanuary 1, 1978 Bridge beams on the east and westbound bridges of span No. 1 at Yellow Mill Pond in Bridgeport, Connecticut, were inspected for fatigue cracking and then retrofitted, using either the peening or the gas tungsten arc remelting procedures. The retrofitted beams were then subjected to fatigue strength tests. The results indicated that both procedures could be used to successfully extend the fatigu...
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Safe Conduct of Traffic Through Highway Construction and Maintenance ZonesJanuary 1, 1978 The principles for safe management of traffic at work zones that were developed are based on operational experience and limited available research results. They include, among others, the following: Traffic safety in the workzone should be an integral and high priority element of every project from the planning stage through the design and operations, careful attention should be given to provid...
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Safety at Narrow Bridge SitesJanuary 1, 1977 This study for determining methods (other than widening) for reducing the hazards associated with narrow bridges, included the developing of a bridge safety indes (BSI) for determining priorities in dealing with problems involving bridges having restricted width. The BSI approach is presented in the form of tables and figures readily usable by practicing engineers. An example problem is used to...
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Continuing Project on Highway Right-of-Way and Legal ProblemsJanuary 1, 1977 A study project has been established to meet the need of state highway and transportation departments regarding the assembly, analysis and evaluation of operating practices and the legal elements of special problems involving right-of-way acquisition and control and highway law in general. A 1976 publication, which was a product of this project and which fills a void in American legal writing, ...
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Disaggregate Travel Demand ModelsJanuary 1, 1977 Disaggregate models are policy-sensitive travel demand forecasting models that are consistent with travel choice theory using data at the level of individual travelers. Such models were found to advance the existing state-of-the-art in explaining present travel behavior. Disaggregate models can also be applied with greater ease than aggregate models to corridor and project planning within urban...
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Impact Assessment Guidelines for Evaluating the No-Build Alternative in TransportationJanuary 1, 1977 The general objective of no-build research has been to strengthen the techniques and procedures available to transportation planners and engineers in three areas: The definition of no-build alternatives; the prediction and measurement of the consequences of no-build alternatives; and, the use of no-build alternatives in plan evaluation. This objective has been partially met with the development...
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Freight Data Requirements for Statewide Transportation Systems PlanningJanuary 1, 1977 Since freight planning on a statewide basis is in the early stages of development, a basic core of knowledge about goods transport must be developed and existing freight data source material must be identified. This project determined the data requirements for statewide freight transportation planning and prepared a manual on how the states may obtain primary and secondary data. The result was ...
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Motorist Response to Guide SigningJanuary 1, 1977 This study of the relationships among the many measures of response to signs encompassed by Sections 2E and 2F of the "Manual on Uniform Traffic Control Devices", was oriented toward methods that can be implemented readily by the staffs of traffic engineering organizations. Phase I of the project, the identification of potential MOE's (measures of guide sign effectiveness) and other sources of ...
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Continuing Project to Synthesize Information on Highway Problems (Superseded)January 1, 1976 A project is reported which is designed to search out and synthesize useful knowledge from all possible sources and to prepare documented reports on current practices in the subject areas of concern. A product of these effort is the report series, "Synthesis of Highway Practic" which assembles information into concise documents pertaining to specific problems. For each topic, the project object...
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Guidelines for Skid-Resistant Highway Pavement SurfacesJanuary 1, 1976 The work is outlined and the findings are summarized of a project to identify and evaluate procedures suitable for implementation that will improve resistance of pavements to polishing and wear caused by conventional and studded tire traffic. The project was also designed to identify innovative procedures for improved wear-resistant and skid- resistant pavements, and evaluate (by experimentatio...
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Summary of Project 3-18(3) Traffic Signal System SurveysJanuary 1, 1976 A questionnaire survey was conducted which was designed to identify and define the range of traffic surveillance and control system alternatives to which a cost effectiveness methodology (for evaluation of signalized street network surveillance and control systems) is to be applied. Tables and commentaries are presented related to responses from researchers, designers and manufacturers who were...
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Current Practices in Use of Retroreflective Signing MaterialsJanuary 1, 1976 The major findings are presented of a questionnaire survey (of what material combinations are being used and the basis for their selection) which was part of a research effort to define the optimum relationship between sign background and legend luminance as a function of several pertinent variables. The questionnaire elicited information on the types of signing material; paractices relating to...
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Bridge Deck RepairsJanuary 1, 1976 The findings are presented of the preliminary field survey stage of a study designed to determine the relative effectiveness of the various repair methods in arresting corrosion of the reinforcing steel, and whether some of these methods could actually aggrevate the corrosion problem. This effort reviews the causes of deck deterioration, and analyzes the preventive and remedial solutions that h...
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Liability of State and Local Governments for Snow and Ice ControlJanuary 1, 1901 Generalizations on the probability of jury verdicts for plaintiffs, and the relative size of jury awards where a governmental body is the defendent are noted, the erosion of sovereign immunity is discussed, the current state of liability of Federal, State and local governments is reviewed, and comments are made on the duty to remove snow and ice. Limitations of duty, care concerning use of abra...
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Design of Continuously Reinforced Concrete Pavements for HighwaysJanuary 1, 1976 This report summarizes the essential findings of a research study undertaken to develop an improved structural design procedure for continuously reinforced concrete pavement. A three-directional approach consisting of a theoretical study, field surveys, and a laboratory investigation was used in the research effort. The theoretical study produced a design behavioral model that solves for the st...
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Crash Testing and Evaluation of Attenuating Bridge Railing SystemJanuary 1, 1976 The results of the analysis (using computer program BARRIER IV) of an idealized vehicle barrier system indicate that the barrier which was designed to prevent penetration by a standard-size automobile weighting 4,000 to 5,000 lb and impacting at 25 deg. and 65 mph, would meet the desired criteria. A key feature of this steel bridge rail design is the function of the attenuator that supports the...
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Personal Liability of State Highway Department Officers and EmployeesJanuary 1, 1901 The legal questions sorrounding liability for negligence by highway department personnel and the legal authority relative thereto are reviewed. Influenced by various reasons for treating public officials differently from private persons with regard to liability for torts and other policy considerations, the law developed along the lines of conditional immunity. Cases adopting the theory of abso...
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Traffic Signal Warrants -- A BibliographyJanuary 1, 1975 This annotated bibliography of relevant literature was compiled in an effort to evaluate the adequacy of existing warrants in meeting current needs for determining whether a traffic signal should be installed, and to determine the need for revised or additional warrants. The literature reviewed in the preparation of the bibliography was restricted to material published since 1967 and the refere...
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Earth-Berm Vehicle DeflectorJanuary 1, 1975 In an attempt (limited) to provide factual information that could be of assistance toward rationalizing the selection of earth-berm configurations as safety elements in the highway system, a modified version of the Highway Vehicle Object Simulation Model (HVOSM) was used to investigate vehicle behavior on earth-berm slopes. Rigid-body mechanical equations were also used to predict vehicle paths...
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Field Evaluation of Vehicle Barrier SystemsJanuary 1, 1975 Two studies are reported. The study initiated by Calspan Corporation which concentrated on accident statistics, was planned to determine the degree to which accident data currently being accumulated by various agencies can be used to evaluate the field performance of barrier systems and, if warranted, to recommend new approaches that may better be used to make such an evaluation. The second stu...
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Development of Prototype Soil Moisture SensorsJanuary 1, 1975 In an effort to develop innovative sensors for the in situ measurement of moisture in aggregate base and soil subgrade layers of pavements, two prototypes have been developed and laboratory evaluated: a sensor based on nuclear magnetic resonance (NMR) technology and a sensor using dielectric constant technology. Both sensor types are potentially applicable to highway soil moisture measurement p...
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Electroslag Weldments in BridgesJanuary 1, 1975 In an effort to develop and verify acceptance criteria for the use of electroslag welds in bridges, a 2-phase research project has been initiated. Phase I which is designed to define the necessary acceptance specifications, will include a review of literature; a state- of-the-art report on electroslag welding; testing of laboratory specimens from full-scale welds; development of tentative accep...
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Recommended Modification of Superelevation Practice for Long-Radius CurvesJanuary 1, 1975 In an effort to develop guidelines for highway geometrics and pavement surface characteristics which will ensure adequate vehicle control during anticipated maneuvers on highway sections containing a combination of horizontal curvature and vertical grade, an extensive analysis was performed of accident data, computer simulation studies were made, and an in-depth investigation was made of two hi...
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Nondestructive Methods of Fatigue Crack Detection in Steel Bridge MembersJanuary 1, 1975 This summary of the state-of-the-art in nondestructive inspection methods, evaluates their reliability and adaptability for the detection of fatigue cracks in welded highway bridges. Emphasis is placed on in- situ testing and on the capability of techniques to define cracks accurately in terms of length and depth. The underlying concept of fatigue failure prevention in explained, and five testi...
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Design of Bent Caps for Concrete Box Girder BridgesJanuary 1, 1974 Research is reported that was planned to develop design procedures for bent caps which would include consideration for the location and distribution of critical AASHTO loading for a bent cap, the effect of flaring a column, the effective width of a bent cap, the effect of spreading bent cap reinforcement into an adjacent box girder slab, and the location of critical cross sections. The research...
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Roadway Design in Seasonal Frost AreasJanuary 1, 1974 An NCHRP Synthesis of Highway Practice reviews and synthesizes current pavement design procedures in seasonal frost areas, as well as construction and maintenance practices, and identifies those that might be of greatest value to other road agencies. The study consisted of a literature review, a questionnaire survey of North American road design agencies, and visits to ten agencies for discussi...
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Evaluating Procedures for Determining Concrete Pavement Thickness and Reinforcement PositionJanuary 1, 1974 This report summarizes the results of a study that evaluated currently available nondestructive testing systems that appeared to have potential for supplementing or replacing coring in determining concrete pavement thickness and reinforcement location. The evaluation was done primarily in the field. The principal work consisted of the systems under on-the-job conditions on eight paving projects...
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Systems Approach to Flexible Pavement Design and ManagementJanuary 1, 1974 A project is reported which resulted in the improvement of the computer program, SAMP5, to an operational program, SAMP6, which provides a basis for selecting flexible pavement design and management strategies with the lowest predicted total cost over a prescribed analysis period when considering such cost elements as initial construction, routine maintenance, periodic rehabilitation, interest ...
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Wear-Resistant and Skid-Resistant Highway Pavement SurfacesJanuary 1, 1974 Procedures for improving the resistance to wear and polishing of new pavements, and for correcting worn or needs and the associated problems, and how to implement literature was extensively reviewed and method is described for classifying pavement systems with regard to wear and skid resistance, tentative performance criteria. Recommendations are made for use of the systems judged to be most su...
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Fatigue of Welded Steel Bridge Members Under Variable-Amplitude LoadingsJanuary 1, 1974 A project is reported the objective of which is to acquire fatigue data on welded bridge members under variable-amplitude random-sequence stress spectrums, such as occur in actual bridges, and to develop an analytical method of predicting variable-amplitude fatigue behavior from constant-amplitude fatigue data. Pertinent past work was studied with particular emphasis on field mearurements of st...
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Side-Friction Factors in the Design of Highway CurvesJanuary 1, 1974 In order to provide an evaluation of the current AASHTO curve design Standards and to provide the information necessary to substantiate any proposed changes in these standards, a study was made of (part of the complex system of interaction between driver, vehicle, and pavement) those physical characteristics of the vehicle and the pavement that influence the critical cornering maneuver. The stu...
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Traffic Control in Oversaturated Street NetworksJanuary 1, 1973 The scope and magnitude of the oversaturation problem was defined and the way it may best be combatted with existing methods was determined. The paper reports the beginning of a research process leading to improved operation and controls for oversaturated networks. Six specific objectives of the research are listed. The project was planned in three phases. Phase I was concerned with the definit...
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Determining Pavement Skid Resistance Requirements at Intersections and Braking SitesJanuary 1, 1973 THE DETERMINATION OF SKID RESISTANCE REQUIREMENTS FOR ANY GIVEN SET OF ROADWAY AND TRAFFIC CONDITIONS IS REPORTED. THE STUDY FOCUSES ON WET PAVEMENT SKIDDING ACCIDENTS AT INTERSECTIONS AND CURVES. THE FEASIBILITY OF IMPLEMENTING THESE PROCEDURES WAS DEMONSTRATED IN THE FIELD. A SIMPLIFIED VERSION OF THE PROCEDURES WAS ALSO DEVELOPED. THE THREE STEPS INVOLVED IN THE PROCEDURE FOR DETERMINATION O...
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Trial Strategy and Techniques Using the Comparable Sales Approach to ValuationJanuary 1, 1901 This paper describes the various strategies and techniques that have been used successfully by the author with respect to the comparable sales approach to valuation. The psychology of a trial, the selection of the jury, the valuation witness and trial preparation are discussed as they relate to the trial outcome. Fair market value, comparable sales approach to value, admissibility of evidence o...
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Control Logic for Traffic Signal NetworksJanuary 1, 1973 In an effort to develop and spread the know-how for effective innovative methods of computer traffic control, work is reported of the formulation, development and evaluation of an operational software system that represents a significant step in the direction of attaining self- adjusting real-time control applicable in both light traffic and heavily congested conditions. The ASCOT (Adaptive Sig...
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Exclusion of Increase or Decrease in Value Caused by Public Improvement for Which Lands Are CondemnedJanuary 1, 1901 Apposite cases of both condemnor and condemnee are collated, discussed and analyzed in the light of federal legislation. Emphasis is placed on the identification of the underlying rationale in recent cases. The paper addresses the problem of whether to include or exclude, in the valuation of lands condemned for a public improvement, enhancement or dimunition value attribute to the improvement. ...
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Rigid Pavement Performance Influenced by Slab Strength and ThicknessJanuary 1, 1969 EXISTING THEORIES FOR STRUCTURAL BEHAVIOR OF RIGID PAVEMENTS WERE EXAMINED IN VIEW OF THE LARGE AMOUNT OF CONTROLLED FIELD PERFORMANCE DATA COLLECTED DURING AN AASHO ROAD TEST. A SIGNIFICANT CONTRIBUTION WAS THE DEVELOPMENT OF A RELATIONSHIP BETWEEN TENSILE STRESS IN THE PAVEMENT SLAB CAUSED BY MOVING LOADS AND THE PERFORMANCE OF PORTLAND CEMENT CONCRETE PAVEMENT. THE FINDINGS SUPPORT MOST EXIS...
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Relocation Assistance Under Chapter Five Of the 1968 Federal-Aid Highway ActJanuary 1, 1969 A SYNOPTIC REVIEW OF CHAPTER FIVE OF THE 1968 FEDERAL-AID HIGHWAY ACT IS PRESENTED. A DISCUSSION AND COMPARISON IS PRESENTED OF STATUTES THAT HAVE BEEN ENACTED TO COMPLY WITH THE NEW RELOCATION ASSISTANCE PROVISIONS. THE RULE IS DISCUSSED THAT COMPENSATION IS FOR PROPERTY TAKEN AND NOT AS A PAYMENT TO THE OWNER, CONSTITUTIONAL AUTHORITY IS DISCUSSED AS TO PROVISIONS FOR PAYMENT IN EXCESS OF THE... |