NCHRP Research Results Digest最新文献

{"title":"Sample Size Implications of Multi-Day GPS-Enabled Household Travel Surveys","authors":"L. Rizzo, Gregory D. Erhardt","doi":"10.17226/24614","DOIUrl":"https://doi.org/10.17226/24614","url":null,"abstract":"","PeriodicalId":320718,"journal":{"name":"NCHRP Research Results Digest","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130935918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Independent Cost Estimates for Design and Construction of Transit Facilities in Rural and Small Urban Areas","authors":"S. Anderson, K. Molenaar, C. Schexnayder","doi":"10.17226/22086","DOIUrl":"https://doi.org/10.17226/22086","url":null,"abstract":"Estimating design and construction costs in a consistent, reliable, and accurate way is critical for an organization since the information generated is the basis for projecting program funds, prioritizing projects by financial analysis, determining required funds, and providing a baseline for project control. This research focused on cost estimating methods and database development for design and construction of rural and small urban area transit facilities, which are usually small, numerous, and geographically dispersed. The objectives of this study were to determine the distinct characteristics of rural and small urban area transit facilities, collect actual historical cost data, and develop a cost estimating database and prototype tool to assist agencies with preparing conceptual estimates. This research included a literature review, telephone interviews, and an online survey. A cost estimating database was constructed based on historical cost data collected through the survey. Analysis of historical cost data was the basis for development of the cost estimating prototype tool. The general conclusions are: 1) project design and construction costs depend on various factors, such as facility types, project size, location, and facility features; 2) many construction projects for rural and small urban area transit facilities were suspended or delayed due to lack of funding; 3) most transit projects in rural and small urban areas include more than one type of facility; 4) state departments of transportation (DOTs) and transit agencies rely on estimates prepared by consultants; 5) both design and construction costs are estimated based on similar projects; 6) risk factors were identified through telephone interviews, and the frequency of the risk factors was obtained from the online survey; and 7) in order to address project risks, contingency is estimated as a percentage of construction cost. The ranges of contingency percentage given by the interviewees and survey results provided a reference for determining the default contingency range for the cost estimating prototype tool.","PeriodicalId":320718,"journal":{"name":"NCHRP Research Results Digest","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115711110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimating the Long-Term Impacts of Map-21 on the Nation’s Local Rural Transit Bus Infrastructure","authors":"S. Libberton, C. Cummings, Lisa Koch, Ihsaan Patel, Amanda Wall Vandegrift","doi":"10.17226/22124","DOIUrl":"https://doi.org/10.17226/22124","url":null,"abstract":"This digest focuses on the impacts of the Moving Ahead for Progress for the 21st Century Act (MAP-21) on rural transit, and, more specifically, on the impact of capital funding levels on the long-term reinvestment needs of the nation’s rural transit infrastructure. The digest accomplishes four specific things: it summarizes the key changes of MAP-21 of particular interest to rural transit operators and state departments of transportation (DOTs) charged with administering federal rural transit programs; presents the results of an analysis of historical funding levels for rural public transportation, and how they compare with funding provided under MAP-21; considers the future condition of the nation’s rural transit infrastructure; and summarizes the effectiveness of the research methodology and its potential applicability to broader capital investment analyses.","PeriodicalId":320718,"journal":{"name":"NCHRP Research Results Digest","volume":"108 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115075898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Claims Related to Stormwater Discharge","authors":"M. Hines, Jocelyn D Nettles","doi":"10.17226/22133","DOIUrl":"https://doi.org/10.17226/22133","url":null,"abstract":"This publication explores transportation agencies’ legal liability for contaminated stormwater discharge, even if they obtained and complied with a National Pollutant Discharge Elimination System (NPDES) permit. The report discusses the function and parameters of an NPDES permit and its relationship to the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, commonly known as the “Superfund.” The report provides an analysis of the decisions in United States v. Washington State Department of Transportation and Natural Resources Defense Council v. County of Los Angeles. Lastly, the digest examines the results of a survey that explored the impact of the court decisions and the nature of noncompliance claims asserted against state transportation agencies with current NPDES permits.","PeriodicalId":320718,"journal":{"name":"NCHRP Research Results Digest","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129418156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Selected Indirect Benefits of State Investment in Public Transportation","authors":"C. Porter, Jonathan Lee, Taylor Dennerlein, P. Dowell","doi":"10.17226/22174","DOIUrl":"https://doi.org/10.17226/22174","url":null,"abstract":"This study 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 and documents potential indirect government benefits arising from transit investments and services, and provides ways to help states make the case for strategic investment. These indirect benefits can result from improved access to jobs, health care, and education, which can reduce the demand for government services. The report also covers methods and tools for quantifying benefits and provides a conceptual framework for including these benefits along with other economic impact and benefit/cost analysis for transit.","PeriodicalId":320718,"journal":{"name":"NCHRP Research Results Digest","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134398109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Precision Estimates of AASHTO T 324, “Hamburg Wheel-Track Testing of Compacted Hot Mix Asphalt (HMA)”","authors":"H. Azari","doi":"10.17226/22242","DOIUrl":"https://doi.org/10.17226/22242","url":null,"abstract":"The Hamburg wheel tracking test (HWTT) has been extensively used to identify asphalt mixtures prone to rutting or moisture damage. AASHTO T 324, “Hamburg Wheel-Track Testing of Compacted Hot Mix Asphalt (HMA),” describes the procedure for testing asphalt mixture samples using the HWTT device. The method specifies the testing of submerged, compacted asphalt mixture in a reciprocating rolling-wheel device. The test results provide information about the rate of permanent deformation from a moving concentrated load. However, there is no information on the precision of the test method, including the allowable differences between two replicate measurements in one laboratory or measurements in two laboratories. In addition, important aspects of the test are not sufficiently specified in the test method; these include position of the wheel with respect to specimen, verification of the location of the measurements, specimen preparation and assembly, and analysis and reporting of test data. Because these factors could significantly affect HWTT measurements and performance verification of asphalt mixtures, it is important to identify the factors causing variability of measurements and further specify their limits in the test method. The objective of this study was to determine precision estimates for AASHTO T 324. To accomplish this objective, the research: determined the variability of the deformation measurements after specified number of load passes and the creep slope for well-performing mixtures; determined the variability of the number of passes to threshold deformation, creep slope, stripping slope, and number of passes to the stripping inflection point for poorly performing mixtures; compared the mean and variance of the measured properties of gyratory and slab specimens; compared the mean and variance of properties measured using all measurement locations with those measured using all except the three middle measurement locations and all except two measurement locations at each end; identified causes of variability of the test results; and proposed modifications to the test method for optimum use of the deformation measurements, improvement to the specimen preparation and assembly, and necessary adjustments to the machine components.","PeriodicalId":320718,"journal":{"name":"NCHRP Research Results Digest","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124881395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Alternative Delivery Methods for Winter Maintenance Operations","authors":"Amir N Hana","doi":"10.17226/22345","DOIUrl":"https://doi.org/10.17226/22345","url":null,"abstract":"Different approaches for delivery of maintenance operations have been employed by highway agencies in recent years— many of which aimed at outsourcing government services. Although some of these approaches have been adopted for winter maintenance operations, a systematic decision-making framework is not readily available for identifying the delivery method for winter maintenance operations that is best suited for a specific situation. Thus, there was a need to develop a decision-making framework to guide public road agencies in identifying the effective methods of providing this essential service and selecting the preferred method while considering prevailing legislative, societal, and resource constraints. National Cooperative Highway Research Program Project 20-07(329), “Alternative Delivery Methods for Winter Operations,” was conducted to address this need. This digest summarizes the findings of this research. The research obtained information through a review of international literature, responses to a questionnaire provided by public- and private-sector transportation agencies, and telephone interviews with transportation specialists. This information was used to identify the different delivery methods applicable to winter maintenance that are employed in the United States and other countries. The information also identified relevant issues surrounding decisions on highway-service delivery, such as financial risks, quality of service, impact on workforce, performance standards and measures, industry qualification/capabilities, and actions to maintain competition in procurement and continuing availability of service providers. The research then organized and used these findings to develop the decision-making framework. It also documented sources of additional supporting information, and discussed different scenarios by which the decision framework could be applied and refined.","PeriodicalId":320718,"journal":{"name":"NCHRP Research Results Digest","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133037440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Precision Estimates of AASHTO T 304, AASHTO T 96, and AASHTO T 11 and Investigation of the Effect of Manual and Mechanical Methods of Washing on Sieve Analysis of Aggregates","authors":"H. Azari","doi":"10.17226/22374","DOIUrl":"https://doi.org/10.17226/22374","url":null,"abstract":"This digest summarizes key findings of research conducted in Task Order #2 of National Cooperative Highway Research Program (NCHRP) Project 10-87, “Precision Statements for AASHTO Standard Methods of Test,” by the American Association of State Highway and Transportation Officials (AASHTO) Materials Reference Laboratory. The Digest updates precision estimates of AASHTO Standard Test Methods T 96, Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Testing Machine; T 304, Uncompacted Void Content of Fine Aggregate; and T 11, Materials Finer Than 75-μm (No. 200) Sieve in Mineral Aggregates by Washing. The report also examines the significance of the difference between variability of percent passing No. 200 sieve of 300-g and 500-g fine aggregate samples measured according to AASHTO T 11. In addition, the report evaluates the effect of manual versus mechanical washing, by comparing the results of sieve analysis of Proficiency Sample Program samples, washed manually or mechanically prior to being tested according to AASHTO T 11, T 27(Sieve Analysis of Fine and Coarse Aggregates), or T 30 (Mechanical Analysis of Extracted Aggregate).","PeriodicalId":320718,"journal":{"name":"NCHRP Research Results Digest","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126607411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Precision Estimates of AASHTO T 201, AASHTO T 202, and AASHTO T 49","authors":"H. Azari","doi":"10.17226/22392","DOIUrl":"https://doi.org/10.17226/22392","url":null,"abstract":"This digest presents results of Task Order #2 of National Cooperative Highway Research Program (NCHRP) Project 10-87, “Precision Statements for AASHTO Standard Methods of Test.” This work was conducted to update precision estimates of three test methods pertaining to asphalt binder: T 201, “Kinematic Viscosity of Asphalts (Bitumens)”; T 202, “Viscosity of Asphalts by Vacuum Capillary Viscometer”; and T 49, “Penetration of Bituminous Materials.\" Using the computed precision estimates, new precision statements for the three test methods have been prepared and are presented in this digest.","PeriodicalId":320718,"journal":{"name":"NCHRP Research Results Digest","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121256017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New Urban Areas: A Transit Guidance Brief","authors":"A. Bond, M. Minkoff, Lindsay Martin, A. Santalucia","doi":"10.17226/22454","DOIUrl":"https://doi.org/10.17226/22454","url":null,"abstract":"After each decennial census, a list of urban areas is published. Urban areas are densely populated areas with more than 50,000 persons. When a region becomes an urban area, it becomes eligible for new types of federal transportation funding. The most important federal funding program— and the largest change driver—is the Section 5307 Urbanized Area Formula Grants. As funding increases, oversight and regulatory requirements associated with urban transit service can become complex. This digest offers a variety of resources—along with original research—for newly constituted urban areas that will be offering transit service for the first time, or converting from rural to urban fixed-route service. The digest begins with an overview of the Census, a definition of urban areas, and definitions of transit administration. The digest continues with an overview of federal transit policy. In this section, federal transit funding programs are analyzed for their applicability to small urban areas. The digest also discusses the governance structures required to receive federal funding. Most new requirements are enforced during the triennial review. The Federal Transit Administration conducts triennial reviews with all urban transit providers receiving federal grants to evaluate compliance with 24 specific subject areas. The digest goes into detail on meeting the requirements of most of the triennial review areas. Several key steps to starting a new urban transit operation are discussed, and a checklist of suggested start-up steps for new urban transit operators is included. A series of three case studies also are included in this digest. These case studies examine the start-up of urban transit service, funding issues, and administrative and organizational challenges.","PeriodicalId":320718,"journal":{"name":"NCHRP Research Results Digest","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117200808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}