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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
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    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
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      <title>Managing Highway Rock Slope Scaling: Design and Construction State of the Practice: Presentations from the 97th Annual Meeting of the Transportation Research Board</title>
      <link>https://trid.trb.org/View/1688103</link>
      <description><![CDATA[Scaling loose rocks from slopes adjacent to highways is a simple and effective measure for temporarily reducing the risk of rockfall potential on naturally occurring bedrock outcrops and highway rock–soil cuts. This document includes a synopsis of eleven presentations from the workshop “Managing Highway Rock Slope Scaling: Design and Construction State of the Practice” held at the 97th Annual Meeting of the Transportation Research Board. This workshop was sponsored by the Standing Committee on Engineering Geology, the Subcommittee on Rockfall Management, and the Standing Committee on Geotechnical Site Characterization. The speakers addressed:  scaling basics; questionnaire results; case histories; designer, owner and contractor perspectives; plans and specification examples; research needs; and a wrap-up.]]></description>
      <pubDate>Wed, 08 Apr 2020 10:57:34 GMT</pubDate>
      <guid>https://trid.trb.org/View/1688103</guid>
    </item>
    <item>
      <title>Designing Road Diet Evaluations: Lessons Learned from San José’s Lincoln Avenue Road Diet</title>
      <link>https://trid.trb.org/View/1511572</link>
      <description><![CDATA[Road diets are street reconfiguration projects that reduce the number of travel lanes in a street, most often converting a four-lane, undivided roadway to a three-lane roadway with two through-travel lanes and a two-way center left-turn lane. This paper analyzes traffic impacts from the 2015 implementation of a pilot road diet on Lincoln Avenue, in the Willow Glen neighborhood of San Jose, California, comparing data on traffic volumes and speeds from before and after the road diet was implemented. The analysis also compares impacts over different time periods: all day, during the am and pm peak periods, and by hour of the day. Despite growing interest in road diets among transportation planners and community members, there is limited empirical evidence on the effects of these roadway conversions. While some local governments and researchers have conducted evaluations on road diets, these vary widely in the metrics they evaluate and the quality of data collected. Further, many road diet evaluations are not formally published and archived in a permanent, accessible location, making them difficult to access. In short, transportation planners have limited high quality resources to review when they want to understand how road diets perform in practice.]]></description>
      <pubDate>Wed, 09 May 2018 09:44:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/1511572</guid>
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      <title>What Do Americans Think About Federal Tax Options to Support Transportation? Results from Year 8 of a National Survey</title>
      <link>https://trid.trb.org/View/1495960</link>
      <description><![CDATA[This paper summarizes the results of the eighth year of a national random-digit-dial public opinion poll asking 1,201 respondents if they would support various tax options for raising federal transportation revenues. Ten specific tax options tested were variations on raising the federal gas tax rate, creating a new mileage tax, and creating a new federal sales tax. In addition, the survey collected data on standard sociodemographic factors, travel behavior (public transit usage, annual miles driven, and vehicle fuel efficiency), respondents’ views on the quality of their local transportation system, and their priorities for government spending on transportation in their state. All of this information is used to assess support levels for the tax options among different population subgroups. Among the key findings, the survey results show that a majority of Americans would support higher taxes for transportation – under certain conditions. For example, 78% of respondents supported a gas tax increase of 10¢ per gallon to improve road maintenance, whereas support dropped to just 36% if the revenues were to be used more generally to maintain and improve the transportation system.]]></description>
      <pubDate>Tue, 08 May 2018 09:25:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/1495960</guid>
    </item>
    <item>
      <title>Taking Street Evaluation to the Next Level (of Service)</title>
      <link>https://trid.trb.org/View/1495406</link>
      <description><![CDATA[Representing seconds of motorist delay, level of service (LOS) is the most widely utilized metric of roadway performance in environmental assessments and transportation project planning. However, focusing almost exclusively on a street’s ability to move vehicles, LOS disregards a street’s efficiency from the perspectives of pedestrians, cyclists, or transit users. In recent years, a growing awareness of the shortcomings of this methodology has swept across departments of transportation and metropolitan planning organizations. Increasingly concerned about transportation systems’ impacts on climate change, as well as the myriad benefits of densification, cities and states across the country have begun taking a multimodal approach to roadway performance measurement. Drawing largely from in-depth interviews with transportation planners and engineers from across the country, this paper seeks to understand why—in spite of a widespread recognition across the American transportation industry that this is an ineffective approach, particularly in urban contexts—vehicle-based LOS remains the dominant methodology for roadway performance measurement. First, this paper identifies the issues with a vehicle-based methodology, then, through a review of case studies of multimodal performance measurement, illuminates progress that has been made across the country toward multimodality. Next, it examines some of the challenges inherent in the movement away from vehicle-based LOS. Finally, it proposes a path forward for the transportation industry, with the goal of a universally applicable approach to urban street evaluation.]]></description>
      <pubDate>Thu, 12 Apr 2018 13:38:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/1495406</guid>
    </item>
    <item>
      <title>Long-Run Construction Costs: Trends and Implications</title>
      <link>https://trid.trb.org/View/1496958</link>
      <description><![CDATA[Decision-support tools for infrastructure planning assume that the real cost of construction will remain constant over the life cycle of a facility. This paper is the first of its kind to evaluate the validity of this assumption by assessing the long-run nature of construction costs. This study begins by testing for the possibility that Baumol’s cost disease, a phenomenon found in some industries in which wage growth outpaces productivity gains, thus giving way to real cost growth, afflicts the construction sector. To do so, a series of regression models are developed using historical macroeconomic data from the U.S. Bureau of Economic Analysis on construction costs, compensation, productivity, and the price of intermediate and capital goods. Since construction cost growth is also closely tied to price changes for inputs, this research extracts long-run real price trends of important intermediate goods used in construction via time-series methods applied to publically available data from the U.S. Bureau of Labor Statistics and U.S. Geological Survey. The results of this study provide strong empirical evidence that Baumol’s cost disease is present within the construction sector, while the real price of most construction commodities has not exhibited a negative nor positive secular trend over the last century. These two findings suggest that, contrary to the conventional assumption found in current analytical frameworks, the real cost of construction will rise in the long run. This study’s contribution should motivate decision-makers to re-examine their existing decision-support tools, as the value of policies that reduce project completion times and increase the service life of facilities is potentially much higher than currently anticipated.]]></description>
      <pubDate>Thu, 12 Apr 2018 13:38:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/1496958</guid>
    </item>
    <item>
      <title>Impacts of Expressway Toll-Free Policy on Inter-City Travel Behavior During Chinese Spring Festival</title>
      <link>https://trid.trb.org/View/1496312</link>
      <description><![CDATA[Travelling during main national holidays is proved to be challenging. Since the significant increase in holiday travel demand, lacks of capacity and severe congestion have been observed all kinds of transport modes connecting mega cities. To accommodate the holiday travel demand, transport policies like toll-free expressway have been introduced to mitigate expressway congestion by increasing the capacity at toll stations and to reduce the load on the rail and air transport networks by encouraging public transport travellers to switch to private vehicle. More comprehensive understanding of factors influencing holiday travel C patterns is critical for designing effective policies to mitigate the holiday traffic congestion. This paper analysed inter-city journeys from Beijing to other provinces during the Chinese Spring Festival holiday 2017 and investigated the effectiveness of expressway toll-free policy on exodus travel behaviour using a stated choice experiment. Two Mixed Logit models were developed to investigate the policy’s influence on mode and departure date choice. The results indicate that the policy encourages travellers to change mode from public transport to private car. The effects differ between travellers using different public transport modes. Moreover, the effects of toll-free policy on mode change decrease with increasing travel distance. Furthermore, the policy would attract travellers to adjust their departure date to the toll-free period to avoid paying toll. The effect of the toll exemption differs for the different days around the holiday period. The propensity to change departure date also depends on travellers’ initial departure dates and initial stay durations at their destination.]]></description>
      <pubDate>Thu, 12 Apr 2018 13:38:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/1496312</guid>
    </item>
    <item>
      <title>U.S. Surface Transportation Public–Private Partnerships: Objectives and Evidence</title>
      <link>https://trid.trb.org/View/1496389</link>
      <description><![CDATA[Effective public-private partnership (P3) policy evaluations must acknowledge the multiple and varied reasons why public agencies pursue alternative procurement approaches. While economic efficiency and private sector funding typically rank high among evaluation criteria, they rarely represent a public agency’s sole or primary P3 objectives. As a result, the research reported here conducted six U.S. surface transportation P3 case studies to identify the objectives pursued and the evidence available for effectiveness evaluations. The case findings demonstrate that the studied agencies pursued 1) private sector funding and financing; 2) private sector expertise and innovation; 3) accelerated project delivery; 4) cost, schedule, and quality certainty; 5) risk transfer and management; and 6) broader transit and development opportunities. The public agencies largely achieved these goals, although disagreements among public sector stakeholders and force majeure events affected performance. To further increase P3 benefits, public agencies should consider: 1) pursuing private-sector expertise and innovation earlier; 2) elevating risk transfer objectives; 3) incorporating broader transit, local development, and value capture opportunities; and 4) improving outcome measurement, analysis, and transparency practices.]]></description>
      <pubDate>Thu, 12 Apr 2018 13:38:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/1496389</guid>
    </item>
    <item>
      <title>Estimation of Rail Grade and Horizontal Curvature from non-Proprietary Data Sources</title>
      <link>https://trid.trb.org/View/1497239</link>
      <description><![CDATA[Train energy use and emissions depend on running resistance. Running resistance depends on grade, curve radius, and other factors. Practical methods to measure or estimate grade and curve radius are identified and evaluated. Grades and curve radius can be obtained from track design drawings or track inspection data. However, such data are proprietary. Low-cost global positioning system (GPS) receivers fitted with barometric altimeters measure position and elevation from which grade and curve radius can be estimated. Digital Elevation Models (DEMs) based on light detection and ranging (LIDAR) data provide position and elevation of general ground topography, except for rail bridges. A track route geographic information systems (GIS) shapefile can be used to estimate track radius. Grade is estimated by fitting a linear regression between elevation versus distance for consecutive track segments. Curve radius is estimated by fitting a least-squares circle through track position coordinates within each track segment. Grade and radius estimates were compared to design drawings available for a limited number of segments on a case study route. Except at station stops, GPS data were found to provide reliable estimates of grades. DEM data provided more precise and accurate grade estimation for 60 percent of segments but led to inaccurate estimates on segments with bridges and sloping terrain adjacent to tracks. Both GPS and GIS data provided curvature estimates comparable to design drawings.]]></description>
      <pubDate>Thu, 12 Apr 2018 13:38:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/1497239</guid>
    </item>
    <item>
      <title>Mode Choice and Policy Impact Analysis for Car-Sharing in China</title>
      <link>https://trid.trb.org/View/1495015</link>
      <description><![CDATA[There are substantial benefits associated with car-sharing and many research attempts have been made with respect to car-sharing’s demand. However, there is a lack of clear evidence about if more people choosing car-sharing would reduce the use of private cars or if, instead, there would be a loss in public transport users. This is the information that policy makers are keen to find out, especially when they need to determine whether or not to endorse car-sharing. This study aims to bridge the gap by 1) finding the factors that could affect the choice of car-sharing while taking into account the choices of alternative modes; 2) estimating the modal splits in various scenarios and identifying the policy options that could bring down private car usage instead of sacrificing the demand for public transport. A stated preference survey was conducted in the case study city, Taiyuan, China. Two multinomial logit models, for separately studying mid-dist (2km to 5km) trips and long-dist (more than 5km) trips, are developed based on the data collected from 9,499 individuals. From the scenario analysis, it is found that when car-sharing became more attractive, its increasing demand mainly came from a shrinking demand for bus, if, without complementary policies suppressing the usage of private car. Moreover, the implementation of polices on car-sharing and private car must be cautious to avoid inefficient outcome. According to the modal split results, policy making should avoid being aggressive in pushing up parking cost in both mid- and long-dist cases if wishing to reduce private car usage; for promoting car-sharing usage, aggressive policies should be avoided in the mid-dist case for bringing down car-sharing’s travel cost. In addition, a number of informative indicators (e.g. value of travel time savings, direct and cross point elasticity) are derived to generate wider insights.]]></description>
      <pubDate>Thu, 12 Apr 2018 13:38:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/1495015</guid>
    </item>
    <item>
      <title>Assessing Inclusionary Policies Among Canada’s Pedestrian Plans</title>
      <link>https://trid.trb.org/View/1495678</link>
      <description><![CDATA[Canadian policymakers promote walking to meet several goals related to transportation demand management, public health, and economic welfare. However, unequal pedestrian outcomes stubbornly persist across Canadian society. Recent debates at the intersection of social inclusion and transportation policy underscore the responsibility of stakeholders to address such inequalities and promote social engagement among excluded groups in planning procedures and their outcomes. Pedestrian plans are rare opportunities to strategize across the disparate stakeholders impacting walkable spaces, e.g., private developers, transit, parks and recreation, yet the social inclusion measures of pedestrian plans remain understudied in Canada and elsewhere.  The authors examine pedestrian plans from 27 municipalities across the country using a social inclusion framework with participation and policy criteria. Results find that Canadian pedestrian plans fall short in promoting social inclusion: infrequent opportunities for collaborative contributions by the public; lacklustre outreach to socially-excluded stakeholder representatives, and; oversight of socioeconomic groups among accountable policies. In addition, exploratory means-testing of content suggests associations between plan policies and stakeholder involvement, city population, and the inclusion of land use and other transportation modes in plan scope. The authors discuss recommendations to augment social inclusion in plan development such that vulnerable groups can more substantially benefit from accessible and safe walkable spaces conducive to personal well-being and engagement with society.]]></description>
      <pubDate>Thu, 12 Apr 2018 13:38:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/1495678</guid>
    </item>
    <item>
      <title>Fuel Price Differentials and Car Ownership: A Spatial Analysis of Diesel Cars in Northern Ireland</title>
      <link>https://trid.trb.org/View/1496152</link>
      <description><![CDATA[This paper investigates whether the availability of relatively cheap diesel fuel in the Republic of Ireland affected the rate of diesel car ownership in Northern Ireland. A geographic approach is used, which involves generating spatial variables measuring nearness to the Republic of Ireland at a high geographic resolution, and comparing these with the proportion of the local car stock that is fuelled by diesel. A series of spatial regression models are specified to determine if this association between nearness to the Republic and diesel ownership persists after accounting for the effect of socioeconomic, travel, and household characteristics. The results of the analysis show that network distance to the closest fuel station in the Republic of Ireland is negatively associated with diesel car ownership in Northern Ireland. This supports the hypothesis that the availability of cheaper fuel in the Republic of Ireland is not only generating fuel-tourism, but is also affecting the structure of the car fleet registered in Northern Ireland. The findings are relevant beyond the case study and imply that the structure of a country’s car fleet is not only dependent on domestic policies, but is also affected by the policies of neighbouring countries.]]></description>
      <pubDate>Thu, 12 Apr 2018 13:38:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/1496152</guid>
    </item>
    <item>
      <title>Prioritizing Locations for Installing Street Lights: A Case Study on the City of Doral</title>
      <link>https://trid.trb.org/View/1494930</link>
      <description><![CDATA[Adequate street lighting has positive impacts on communities. Although the benefits of installing street lights outweigh the costs, agencies do not have the resources to install street lights on their entire road network. It is therefore critical to identify the most suitable locations for installing street lights such that they yield the maximum benefit. The main objective of this research was to determine a suitable approach to prioritize locations for installing street lights in the City of Doral, Florida. Two methods, a modified version of simple ranking method and the Analytic Network Process (ANP), were compared to prioritize roadway locations for installing street lights. The locations were prioritized based on Annual Average Daily Traffic (AADT), nighttime crash ratio, presence of parks, and presence of bus stops. The ranking of the top 25 locations for installing street lights based on the Modified Simple Ranking (MSR) and the ANP methods were compared, and it was found that the ranks were similar. The selection of the most suitable method should therefore be based on the available statistical expertise. Agencies that have resources to conduct extensive statistical analyses are encouraged to use the ANP method to prioritize their locations, while those agencies with fewer resources are encouraged to use the MSR method. Nonetheless, these two methods would yield better results compared to the simple ranking method]]></description>
      <pubDate>Thu, 12 Apr 2018 13:38:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/1494930</guid>
    </item>
    <item>
      <title>Justice, Exclusion, and Equity: An Analysis of 48 U.S. Metropolitan Areas</title>
      <link>https://trid.trb.org/View/1496441</link>
      <description><![CDATA[Injustice in transportation services experienced by disadvantaged demographic groups account for much of these groups’ social exclusion. Unfortunately, there is little agreement in the field about what theoretical foundation should be the basis of measures of the justice of transportation services, limiting the ability of transportation professionals to remedy the issues. Accordingly, there is a need for an improved measure of the justice of the distribution of transportation services, which relates to the effectiveness of transportation services for all members of disadvantaged groups rather than for only segregated members of these disadvantaged groups. To this end potential measures of distributive justice, based on the accessibility to jobs provided by various modes, are evaluated in 48 of the top 50 largest metropolitan areas in the United States. The purpose of the study is to inform recommendations for appropriate use of each measure.]]></description>
      <pubDate>Thu, 12 Apr 2018 13:38:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/1496441</guid>
    </item>
    <item>
      <title>Advocacy in Regional Transportation Funding Referendums</title>
      <link>https://trid.trb.org/View/1497054</link>
      <description><![CDATA[This study examines five metro areas in the US that have developed regional transportation systems using funding from multi-jurisdictional ballot referendums. This study focuses on the role of advocacy groups in contributing to the proposal given to the electorate, and in supporting or opposing it at the polls. This study examines how best practices for regions conducting transportation referendums should differ from those already in the literature for cities and counties doing the same. Through interviews in five regions that have conducted regional transportation referendums since 1990, the evidence indicates that advocacy groups became involved in the process earlier, and were more likely to support the transportation plan when the state government had preauthorized the ballot referendum, and when the process was led by an established regional agency. Advocacy groups were less likely to do the same when the referendum required special state legislation, and when there was no regional transportation provider to lead the effort.]]></description>
      <pubDate>Thu, 12 Apr 2018 13:38:13 GMT</pubDate>
      <guid>https://trid.trb.org/View/1497054</guid>
    </item>
    <item>
      <title>Transportation Benefits of Parking Cash Out, Pre-Tax Commuter Benefits, and Parking Surtaxes</title>
      <link>https://trid.trb.org/View/1497077</link>
      <description><![CDATA[For many workers, the decision to drive to work is an economically rational one that minimizes their commute costs. Most employers offer free parking at the workplace as an employment benefit, with a relative few offering subsidies towards transit, bicycle, vanpool, and other travel modes. In many cases, the value of free parking is greater than the cost of riding transit. In effect, by providing such a high-value asset for free, employers are incentivizing behavior that increases roadway congestion, reduces physical activities, and increases emissions. Several policies associated with employer-provided commute benefits can begin to level the playing field among travel modes by allowing employees to select a travel option that is most suitable to them, without incurring a financial penalty. This paper identifies six policy scenarios cities could implement that combine elements of cash out, pre-tax commuter benefits, and parking surtaxes. The impacts of the policies were analyzed for nine United States cities and it was found that they could reduce drive-alone commute trips from a low of 1 percent to a high of 22 percent depending on the policy and city. The results clearly show that policies designed to make employer-provided commute incentives mode neutral can lead to a significant reduction in commute-related vehicle trips.]]></description>
      <pubDate>Thu, 12 Apr 2018 13:38:13 GMT</pubDate>
      <guid>https://trid.trb.org/View/1497077</guid>
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