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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <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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      <link>https://trid.trb.org/</link>
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    <item>
      <title>A cost model for road public transport sensitive to the operating program</title>
      <link>https://trid.trb.org/View/2630683</link>
      <description><![CDATA[Most models for estimating the cost per kilometer of local public transport (LPT) do not include variables attributable to the service operating program (SOP), that is the document showing lines, routes, stops, rides and related timetables. Therefore, by these tools it is not possible to take into account the impact, on the unit cost, of the different use of drivers and vehicles resulting from the number and time of the rides performed. This work, to overcome this important limitation proposes a modification, applicable to most existing models already including the other variables that most affect the cost. In particular, a statistical relationship has been built as a function of the descriptive variables of the SOP known to all, capable of providing a factor 𝘒 that, multiplied by the value of the cost derived from any model, allows it to be corrected as a result of the specific characteristics of the SOP. The methodology developed is of general validity. The model built for the calculation of 𝘒 has been calibrated on a regional LPT service offered in an area with weak demand. A specific recalibration would allow to use it in areas different in size, type and characteristics of transport demand and supply.]]></description>
      <pubDate>Mon, 02 Mar 2026 08:56:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/2630683</guid>
    </item>
    <item>
      <title>Quality trade and transportation costs</title>
      <link>https://trid.trb.org/View/2620795</link>
      <description><![CDATA[This study investigates quality trade using a declaration level customs dataset from 2014 to 2020. We find that high quality products tend to be traded with higher per-unit freight costs, lower ad valorem tariff rates, and with countries with higher GDP per capita, even after controlling firm-specific and product-specific time-invariant factors.]]></description>
      <pubDate>Tue, 17 Feb 2026 13:12:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/2620795</guid>
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    <item>
      <title>Assessment of Pay Item Specific Case–Based Reasoning Approach for Bridge Unit Cost Estimation</title>
      <link>https://trid.trb.org/View/2601281</link>
      <description><![CDATA[AbstractA pay item specific case–based reasoning (PCBR) approach was developed and assessed for estimation of bridge repair and replacement unit costs. Rather than predict overall project or unit cost as with typical case-based reasoning (CBR) methods, the goal of the approach was to allow estimation of a collective set of critical pay item unit subcosts. Here, critical pay items are defined as those contributing 5% or more to the bridge project budget. An initial set of cost predictor variables was identified by linear regression and expert opinion, then subsequently weighted and refined individually for each subcost based on cost-predictor relationship strength. A PCBR cost model was then developed for a set of the most critical bridge repair and replacement pay items. It was used to predict future year unit costs, with cost inflation estimated with a time series projection. The effectiveness of the model was compared to a traditional nonpay item–specific CBR approach, as well as single, multiple, and Lasso linear regression models. It was found that all models provided improvements to an existing expert-based cost estimation approach in most cases. It was also found that the PCBR approach improved the traditional CBR estimate of mean cost for 74% of the pay items considered, with an average improvement of 33%. Furthermore, it reduced the coefficient of variation of 58% of the cost items, with an average reduction of 29%. Although additional computational effort is required, PCBR thus has the potential to improve cost estimates over a traditional CBR approach when pay item–specific cost data are available.]]></description>
      <pubDate>Mon, 22 Dec 2025 16:07:13 GMT</pubDate>
      <guid>https://trid.trb.org/View/2601281</guid>
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    <item>
      <title>Comparative Analysis of the Economic Sustainability of Transport Systems Served by Alternative and Conventional Buses and Coaches</title>
      <link>https://trid.trb.org/View/2592172</link>
      <description><![CDATA[Today’s economic and social environment faces several problems and challenges (e.g. energy crisis, inflation, environmental protection), most of which interact with the transport system in two directions. Researchers and relevant organisations have developed several proposals and action plans to mitigate the ‘problem cloud’ for each mobility subsystem, but these tend to focus on a technological, economic or industrial solution rather than a complex one. This includes subsidising the purchase and operation of electric vehicles, encouraging the use of public transport, and developing soft modes of transport. This study develops a multi-layered, complex, cost-oriented methodology to increase the sustainability and economic stability of local and interurban bus and coach public transport. The methodology based on the main technical and operational (maintenance, energy use and storage) parameters of different conventional and alternative propulsion vehicles, as well as on the available forms of financing, taking into account discount rates. The procedure developed will be illustrated with examples from Hungarian cities. The unit costs per kilometre of the different propulsion systems will be examined. The method can be used to determine the most economically efficient and sustainable choice of vehicle propulsion for the public transport service provider, and to obtain a realistic picture of unit costs.]]></description>
      <pubDate>Fri, 14 Nov 2025 14:37:04 GMT</pubDate>
      <guid>https://trid.trb.org/View/2592172</guid>
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    <item>
      <title>Develop an Interactive Unit Price Estimation and Visualization Tool: Final Report</title>
      <link>https://trid.trb.org/View/2606204</link>
      <description><![CDATA[The Texas Department of Transportation (TxDOT) determines unit prices of pay items using the historical bids-based estimation method and then develops an engineer’s project appraisal. The engineer's estimate is used to assess the bids and select the bidder. However, the unit price of a work item is heavily affected by various project-specific and external factors, including but not limited to the project location, the quantity of the work, project complexity, time factors, and macroeconomic conditions. Therefore, accurate and reliable unit price estimation based on these project-specific and external factors is vital for the optimum use of the available project budget. The project objectives included: (1) conducting an overview analysis of factors affecting unit prices, (2) identifying factors affecting unit prices in Texas, (3) creating a unit price estimation database, (4) creating a spatio-temporal unit price estimation model considering the factors affecting unit prices, (5) developing a GIS-based visualization tool, and (6) implementing, demonstrating, and validating the interactive unit price estimation and GIS-based visualization tool on six Receiving Agency’s projects. The models that are developed based on the identified factors affecting unit prices help enhance accurate and reliable unit price estimation. Moreover, the developed GIS-based unit price visualization tool can be used for a quick retrieval of unit price values across various geographical locations. The tool helps track changes in data over time, by county, and across projects, as well as changes in the quantity of work items.]]></description>
      <pubDate>Thu, 16 Oct 2025 17:02:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/2606204</guid>
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    <item>
      <title>Analysis of the Energy Efficiency of the Port’s Activities</title>
      <link>https://trid.trb.org/View/2407920</link>
      <description><![CDATA[The following indicators are analyzed and proposed to assess the energy efficiency of sea and river ports: specific energy consumption, maximum load usage time, specific costs for cargo transportation by waterways. To solve the problem of energy saving, it is proposed to use the indicator of specific energy consumption, which can be calculated according to the technology standards for any given operating conditions of port transshipment equipment. The analysis of unit costs was performed, which showed that the rational use of portal cranes when performing cargo operations also provides energy savings. An approach is proposed to assess the qualification of crane operators for the parameters of power consumption. The information obtained as a result of a statistical study on the assessment of the dependence of the crane performance on the individual indicators of the operator, such as work experience, age, qualification, was considered as a priori. The connection between energy and production processes was established in relation to berths, individual areas of the port and the port as a whole, at the same time, the daily cargo turnover was chosen as a technological indicator, and the daily power consumption was chosen as an energy indicator. Based on the conducted analysis of energy intensity, research and modeling, real ways to reduce electricity costs and increase the energy efficiency of ports are identified. Further ways of developing research in the field of assessing the forecasting of energy efficiency of port activities, which are based on the transition from purely statistical methods to computational and experimental methods, are considered.]]></description>
      <pubDate>Thu, 31 Jul 2025 13:58:09 GMT</pubDate>
      <guid>https://trid.trb.org/View/2407920</guid>
    </item>
    <item>
      <title>Enhancing urban sustainability through optimizing Distributed energy resources for electric vehicles’ fast charging</title>
      <link>https://trid.trb.org/View/2540057</link>
      <description><![CDATA[The rapid growth of the electric vehicles (EVs) market penetration rate and the resulting energy demand will impact the electricity supply-demand balance and stability in the electricity distribution network. These impacts could be mitigated by distributed energy resources (DERs) (i.e. second-life batteries (SLB), new batteries (NB), solar panels, and flywheels). To support the energy demand of EVs at fast-charging stations whilst minimizing the cost of the system, a mixed-integer optimization model is developed considering the spatiotemporal demand (existing demand and EV demand), the details of the electric grid distribution network, spatiotemporal power generation of solar panels, energy storage systems’ (ESSs’) charge/discharge schedule, and the capacity constraints. The case study (major cities in Michigan) shows sensitivity to the seasonal variation in the grid and solar conditions and the DER’s unit cost. Based on the result, providing the maximum area for solar panels leads to the maximum cost savings. Lithium-ion SLBs offer a cost-effective solution for energy storage, efficiently utilizing time-of-use electricity rates and intermittent solar energy. Depending on the existing and fast-charging energy demand, grid upgrades may be necessary at some locations.]]></description>
      <pubDate>Fri, 23 May 2025 15:35:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/2540057</guid>
    </item>
    <item>
      <title>Optimal Coal Transport Mode Choice for Near Plant Coal Mine by Using Integrated Fuzzy Analytical Hierarchical Process and Fuzzy Goal Programming Model</title>
      <link>https://trid.trb.org/View/2407364</link>
      <description><![CDATA[Transportation of coal is one of the critical attributes towards the overall cost of coal and requires both technical acumen and financial investments. Generally, coal transport constitutes approximately 40–50% of total coal; therefore, the study on optimizing coal transport becomes important and relevant. In this study, Integrated Fuzzy Analytical Hierarchical Process and Fuzzy Goal Programming Model have been proposed to find out the most suitable coal transportation mode among the available choice set. A total of five types of coal transportation modes were considered in the study duly incorporating seven criteria that may affect the selection of the best mode. The mode share obtained from the developed model for Belt Conveyor System is 45.05% and Railway is 21.42%. Belt Conveyor System was found the best mode in a scenario when a plant is closer to the coal mine. An attempt was made to prioritize various decision-making criteria. Per Unit Cost of Transportation Mode, Ore reserve, and Investment Cost of Transportation Mode were found to be the most important criteria for the selection of coal transportation mode. The results of the study would be useful for transportation planning and shall bring a new dimension to the transportation mode choice modeling domain.]]></description>
      <pubDate>Tue, 17 Dec 2024 17:09:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/2407364</guid>
    </item>
    <item>
      <title>Develop an Interactive Unit Price Estimation and Visualization Tool</title>
      <link>https://trid.trb.org/View/2256334</link>
      <description><![CDATA[The unit prices could be significantly different for various Texas Department of Transportation (TxDOT) districts considering several factors (e.g., soil conditions, weather conditions, urban vs. rural conditions, regional construction market conditions) impacting construction costs in these districts. The objectives of this project are to (1) conduct an overview analysis of factors affecting unit prices,  (2) identify factors affecting unit prices in Texas, (3) create a unit price estimation database, (4) create a geospatial statistical unit price estimation model considering the factors affecting unit prices, the interactions between factors, and the factors’ spatial variability, (5) develop the geographic information system (GIS)-based visualization tool with color-coded map, and automatic data updating function, and (6) implement, demonstrate, and validate the interactive unit price estimation and GIS-based visualization tool on five ongoing TxDOT projects (located in 5 different districts in North, South, East, West, and Center of Texas) to cover for different project-specific factors (e.g., urban vs. rural conditions, geotechnical site conditions, weather conditions) and external factors (e.g., regional construction market conditions). The deliverables will provide TxDOT with implementation details of the interactive unit price estimation and visualization tool, enabling their workforce to quickly and accurately estimate unit prices based on the estimation and visualization tool.]]></description>
      <pubDate>Wed, 27 Sep 2023 17:35:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/2256334</guid>
    </item>
    <item>
      <title>Inbound replenishment and outbound dispatch decisions under hybrid shipment consolidation policies: An analytical model and comparison</title>
      <link>https://trid.trb.org/View/2173902</link>
      <description><![CDATA[The authors investigate operational decisions in a distribution warehouse facing stochastic demand and incurring fixed and linear transportation costs for the inbound inventory replenishment and outbound dispatch decisions. In order to realize scale economies associated with transportation both on the outbound and inbound sides, dispatch schedules and replenishment decisions at the warehouse must be synchronized over time. Immediate delivery policies on the outbound side are not financially viable because outbound dispatch operations will benefit from temporal shipment consolidation. Their focus in this setting is the analytical modeling of hybrid shipment consolidation policies and their comparison to the time-based and quantity-based counterparts. To this end, they propose analytical (exact and approximate) methods to compute and compare the cost under hybrid policies relative to its alternatives. Since shipment consolidation impacts customer waiting and inventory holding, they also investigate the average delay per order and average inventory per time unit as two important metrics of the distribution operation’s performance, along with the annual cost. They compare these metrics among the alternative under hybrid, time-based, and quantity-based policies. The comparison then allows us to offer an explicit analytical comparison of long-run average cost under these three policies without needing to solve the corresponding optimization problems. Notably, their results offer an analytical characterization of relative cost performance (vis-a-vis the numerical comparison available in the literature) and demonstrate the implications of alternative shipment consolidation policies regardless of the values of model parameters. The results are of practical value in the context of the design and operation of an integrated framework for inventory-transportation systems.]]></description>
      <pubDate>Thu, 01 Jun 2023 09:34:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2173902</guid>
    </item>
    <item>
      <title>Highway Performance Monitoring System: Case Study Procedural Manual - Highway Improvement Unit Costs</title>
      <link>https://trid.trb.org/View/2121051</link>
      <description><![CDATA[Proper planning for highway improvement programs requires that alternative improvement strategies be evaluated in terms of the performance and benefits expected to be received relative to the amount of capital expenditures proposed. This is important at the national level as well as at the State and local levels. Capital improvement cost data are a necessary input to this evaluation process. The Federal Highway Administration (FHWA) is continually making such evaluations for its internal planning needs, and to provide information to other Federal agencies and to the Congress. The biennial highway needs report to Congress includes results from this type of analysis. There are many uses for highway improvement unit cost information. Highway needs analysis models require improvement cost data as input. Investment - Performance models, which relate the level of highway capital investment to future highway performance, also must have this type of data as input. These models that estimate future highway performance based on a series of alternative levels of capital investment in highway facilities, or that relate future performance to the types of improvements proposed, are becoming more important as the funds for highway investment reach critically low levels in many jurisdictions.]]></description>
      <pubDate>Wed, 15 Mar 2023 12:25:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/2121051</guid>
    </item>
    <item>
      <title>A Reliability Model for Road Construction Unit Cost</title>
      <link>https://trid.trb.org/View/2015314</link>
      <description><![CDATA[Investment in road infrastructure development remains a priority for governments, and it is therefore imperative that governments are equipped with obligatory analytical explanation justifying such immense spending of the taxpayers’ monies as part of their budgets. For this, as well as for cost management of the budgeted outlay, establishing a unit cost is often that what road agencies are tasked with. However, very often average unit costs (i.e., cost per km, obtained by using historical data of executed projects) show wide variations and thereby puzzling the agencies on what should be the ideal unit cost. Further, with such inherent variations such unit cost fails to serve as a yardstick for sustainable design considerations. It is appreciated that instead of margins (factor of safety, FOS, that designers traditionally look for while concluding on recommended designs for construction) based on central value as a measure of risk, risk measured in the term of the probability of failure allows accounting for randomness of parameters that drive unit costs of road constructions. This paper outlines a possible approach for establishing unit costs from a conventional reliability analysis perspective, using efficient spreadsheet algorithm for first order reliability method (FORM). The performance function (limit state function) considered for FORM uses a FOS applied to the central value measure (of historical data on cost per km) to have the resistance (R). As the load (Q) it considers a set of parameters which are perceived as basic cost drivers for road construction projects. A sensitivity analysis then allows determining the influence of various random parameters (perceived cost drivers) on the reliability of assessed unit cost. Employing such cost drivers to derive reliable unit cost lends a better acceptability (to governments and policy makers deciding on investment priorities, who may even choose to extend them to carry out a benchmarking exercise with costs in neighbouring countries to allay a possible perception of a prevailing higher unit cost in a specific country) besides making such unit cost a sustainable design outcome criteria. This paper further employs the kernel density regression to finally show how a identified more sensitive cost driver (its bid-price, price per unit quantity) is driven by other contributing variables, namely its unit-quantity (quantity/km), which can thus be used as important criteria in the agencies procurement framework, besides controls for design engineers.]]></description>
      <pubDate>Mon, 03 Oct 2022 09:16:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2015314</guid>
    </item>
    <item>
      <title>Assessment of the Unit Costs of Capital Expenditure for Investment Projects in Road Transport: Annex N—Handbook of the RoDUCT</title>
      <link>https://trid.trb.org/View/1869686</link>
      <description><![CDATA[The aim of this document is to support the user of the REGIO Road Unit Cost Tool - hereunder referred to as Tool or RoDUCT - in filling out the required inputs and in the correct understanding of the provided output. Simplifying to the extent feasible, the Tool has been designed to perform statistical elaboration over a set of observations and derive cost range distributions. The set of observations to be included in the analyses is automatically selected by the Tool on the basis of a filtering process which matches inputs provided by the user with historical data on projects included in the RoDUCT database. The RoDUCT database has been compiled during the large majority of the study in order to include the information on a wide and reliable sample of road investment projects in the EU in the last 20 years.]]></description>
      <pubDate>Thu, 30 Sep 2021 17:14:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/1869686</guid>
    </item>
    <item>
      <title>Assessment of the Unit Costs of Capital Expenditure for Investment Projects in Road Transport: Annex G—Case Study on Bridges and Viaducts</title>
      <link>https://trid.trb.org/View/1869685</link>
      <description><![CDATA[Bridges and viaducts, together with tunnels, are among the most relevant civil structures in road infrastructures. Due to their complexity, bridges have a significant impact on the overall construction cost of road infrastructures. Considering the wide variety of sizes, designs and complexities having a significant impact on bridges construction cost, it is difficult to identify a data sample large enough to perform statistical analysis and evaluate a standard-unit construction cost for bridges. To this aim, a case study has been tailored to investigate technical parameters and external factors having a major impact on bridge costs. The analysis is based on a set of diverse road bridges built in Europe in different regions and conditions, and also leverages the results and the experience of a wide range of studies and researches made in the past about this topic.]]></description>
      <pubDate>Thu, 30 Sep 2021 09:33:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/1869685</guid>
    </item>
    <item>
      <title>Assessment of the Unit Costs of Capital Expenditure for Investment Projects in Road Transport: Annex J— Case Study on Smart Roads</title>
      <link>https://trid.trb.org/View/1869684</link>
      <description><![CDATA[The goal of the Smart Road is to implement a technological environment that favours interoperability among infrastructure and new generation vehicles. The study is structured in this way: in the first sections a general overview of the subject and the definition (both in terms of technology and legal framework) of Smart roads are provided, then the main areas of application of such technologies are presented (i.e. road safety, traffic management and infrastructure management). Following, a focus on Cooperative Intelligent Transport Systems, i.e. the process of data exchanging between different actors in the transport system (e.g. vehicles and road infrastructure) is introduced. In conclusion several examples of successful projects related to the implementation of ICT solutions in the road infrastructure sector are presented.]]></description>
      <pubDate>Thu, 30 Sep 2021 09:33:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/1869684</guid>
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