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    <title>Transport Research International Documentation (TRID)</title>
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    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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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>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>AI-driven data mining for sustainable ship power system technologies</title>
      <link>https://trid.trb.org/View/2588398</link>
      <description><![CDATA[Shipping is pivotal for global supply chains, yet its predominance is made possible through a plethora of negative externalities that include extensive and very critical social, ethical, and environmental costs. The industry tries to power through the latter with a prime facilitator, which refers to maritime technology. Indeed, hope is placed in novel marine systems as they can foster a new age of sustainable shipping that will provide global mobility with high efficiency and utilization of clean, green, and minimized (if not zero) emissions technologies. As such, the domain of maritime technology that refers to ship power systems is of indicative importance, yet the literature is barren of a concise understanding of the trends and directions of contemporary research. Said gap in the body of knowledge is tackled by the present work. Through the utilization of artificial intelligence (AI), this work adopts a data mining approach that is executed in the body of research concerning ship power systems, and core trends along with dominant themes are extracted. The results of the current study summarize and highlight an array of current and future technological applications that can become integral parts of ships’ onboard systems, aiding the industry toward its sustainability endeavour and fostering resilient prosperity for the global society. Consequently, this work is a valuable instrument for maritime practitioners and policy makers in evaluating and distinguishing the most viable and readily applicable alternatives to foster environmental respect and entrepreneurial growth, simultaneously.]]></description>
      <pubDate>Mon, 22 Sep 2025 08:48:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/2588398</guid>
    </item>
    <item>
      <title>Adoption of Hydrogen in Railway Traction: Opportunities and Limits in the Case of Non-Electrified Railway Lines</title>
      <link>https://trid.trb.org/View/2571578</link>
      <description><![CDATA[Although rail transport is generally considered a sustainable transport system, and numerous research and design methods are based on considering rail transport as the backbone of public transport and/or sustainable mobility, it is necessary to highlight that in some cases railway lines are still based on the use of diesel-powered trains, since these railway lines are still non-electrified. Indeed, for instance, in Italy, compared to approximately 25,000 km of railway network, almost 19% consists of non-electrified railway lines. Moreover, the Italian National Recovery and Resilience Plan (included in the European Next Generation EU Programme) provides for the allocation of about €300M for the testing of hydrogen in rail transport. In this context, the objective of this paper is to provide an analysis of the opportunities and limits associated with the use of hydrogen-powered trains on non-electrified railway lines.]]></description>
      <pubDate>Tue, 02 Sep 2025 08:50:09 GMT</pubDate>
      <guid>https://trid.trb.org/View/2571578</guid>
    </item>
    <item>
      <title>Localized Analysis of Actual Road Carbon Emissions of Light Vehicles Based on Vehicle Specific Power</title>
      <link>https://trid.trb.org/View/2554023</link>
      <description><![CDATA[Against the backdrop of global advocacy for energy conservation and emission reduction, an understanding of the characteristics of vehicle carbon emissions can help to better formulate emission control strategies and lead the development of powertrain systems. This article reports on an investigation of the feasibility of carbon emission assessment based on both engine operating conditions and vehicle driving conditions. It was found that engine operating parameters can adapt well to CO2 emissions for fossil fuel powered vehicles. To modify a model of traditional vehicle specific power (VSP) correlated with CO2 emissions, two alternative parameters, VSP_air and VSP_fuel, have been proposed, which provide better prediction accuracy in linking tailpipe emissions to vehicle activities and engine operation parameters. Conversely, considering the complex geographical terrain of a city such as Chongqing, China, the correlation between VSP and vehicle carbon emissions rate will be significantly increased when the road gradient is coupled with the VSP formula. Moreover, the geospatial visualization of localized carbon emission during a real drive emission test was displayed based on a bubble map. As a result, the localized analysis of actual road carbon emissions of light vehicles based on the VSP method in this study facilitates the development of high-precision carbon accounting in traffic transportation.]]></description>
      <pubDate>Mon, 19 May 2025 16:38:38 GMT</pubDate>
      <guid>https://trid.trb.org/View/2554023</guid>
    </item>
    <item>
      <title>Individual Mathematical Modeling and Correction Based on a Combined Structure for Aircraft Engine</title>
      <link>https://trid.trb.org/View/2485205</link>
      <description><![CDATA[A combined structure for autoupdating rotating component characteristic maps is proposed for an individual aeroengine model. The designed combined structure, known as the Newton–Raphson (NR)-particle swarm optimization (PSO) method, mainly composed of three parts, namely the equilibrium equations design, stability improved strategy, and reduced optimization logics. The equilibrium equations are designed to ensure the accuracy of the modified model. However, in some scenarios, the optimization process has poor stability. Therefore, a stability improved strategy is designed through limiting the range of values of the optimal parameters. In addition, reduced optimization logic is designed to reduce the computing time of the optimization algorithm. The NR-PSO method uses the Newton–Raphson method to increase the accuracy of model outputs. Meanwhile, the time consumed for optimization and the number of equilibrium equations are decreased by particle swarm optimization. The suggested method for automatic model correction has higher model output accuracy, quicker optimization speed, and stronger algorithm stability than particle swarm optimization. The simulation results showed the proposed method can transform the average performance model into the individual model matching the actual rig test data of an individual engine, and the maximum error of outputs of individual model are less than 1.5%.]]></description>
      <pubDate>Wed, 29 Jan 2025 17:00:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2485205</guid>
    </item>
    <item>
      <title>Planning a zero-emission mixed-fleet public bus system with minimal life cycle cost</title>
      <link>https://trid.trb.org/View/2344617</link>
      <description><![CDATA[The variety of available technology options for the operation of zero-emission bus systems gives rise to the problem of finding an optimal technology decision for bus operators. Among others, overnight charging, opportunity charging and hydrogen-based technology options are frequently pursued technological solutions. As their operating conditions are strongly influenced by the urban context, an optimal technology decision is far from trivial. In this paper, we propose an Integer Linear Programming (ILP) based optimization model that is built upon a broad input database, which allows a customized adaption to local circumstances. The ultimate goal is to determine an optimal technology decision for each bus line, considering its combined effects on charging and vehicle scheduling as well as infrastructural design. To this end, we develop technology-specific network representations for five distinct technologies. These networks can be viewed individually or as a multi-layered graph, which represents the input for the optimal technology mix. The proposed optimization framework is applied to a real-world instance with more than 4.000 timetabled trips. To study the sensitivity of solutions, parameter changes are tested in a comprehensive scenario design. The subsequent analysis produces valuable managerial insights for the bus operator and highlights the decisive role of certain planning assumptions. The results of our computations reveal that the deployment of a mixed fleet can indeed lead to financial benefits. The comparison of single technology system solutions provides a further basis for decision making and demonstrates relative superiorities between different technologies.]]></description>
      <pubDate>Mon, 11 Mar 2024 09:10:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/2344617</guid>
    </item>
    <item>
      <title>Breaking barriers: An assessment of the feasibility of long-haul electric flights</title>
      <link>https://trid.trb.org/View/2326092</link>
      <description><![CDATA[This study is a response to the current long-term policy effort aimed at reducing greenhouse gas emissions from aviation. It explores the short-term feasibility of servicing medium and long-haul commercial air routes with fully electric, zero-emission aircraft. The focus on long-haul flights reflects our understanding of the high levels of emissions associated with these routes. The analysis applies technical details of current electric aircraft development to the conditions faced by 183 long-haul over-water inter-city air routes. It also investigates the effect of future technical developments in battery power. Three scenarios of battery development illustrate how new electric aviation routes might evolve over time. Results show that, as expected, with current electric aircraft technology, most of the routes are more complex, slower, and more expensive than today's services. However, a significant number of simulated routes appear to be competitive in terms of fares with the current non-stop services. Furthermore, the simulations reflect conditions that existed in the early development of aviation and show that the expected evolution of batteries could increase the number of long-haul routes potentially served with electric aircraft. The study concludes that the immediate future of electric aviation might lie in selected, long-haul routes with low geophysical complexity and suggests that the methodology developed here could be used to evaluate proposals for services, some of which could be directed at smaller and remote locations.]]></description>
      <pubDate>Tue, 06 Feb 2024 15:03:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/2326092</guid>
    </item>
    <item>
      <title>Are urban mobility policies favoring the purchase of new vehicles?</title>
      <link>https://trid.trb.org/View/2291372</link>
      <description><![CDATA[This research aims to determine the extent to which citizens are uncertain about the mobility policies adopted by regulators and how the decision to purchase new vehicles may be motivated by doubts that individuals develop regarding the vehicle type to purchase. The automotive industry's technological innovations, promoted by governments, may not have the environmental impact desired in certain regions. To address this issue, a survey was conducted in the city of Madrid. An exploratory factor analysis, followed by a discriminant analysis, was used to validate the constructs and predict the decision-making. The results confirm that the policies adopted by regulators generate uncertainty among individuals regarding which vehicle to purchase. As such, the purchase of a new vehicle may be postponed. This has the opposite effect that is intended, since a delay in the decision to purchase a new vehicle increases the average age of the vehicle fleet, thus contributing to more pollution from the mobility environment. These results highlight the need for governments to work on policies that align environmental needs with the social and economic context in order to achieve the most efficient transition possible, and an global discussion on the technology and innovation applied to consolidate sustainable mobility.]]></description>
      <pubDate>Mon, 20 Nov 2023 17:10:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/2291372</guid>
    </item>
    <item>
      <title>Estimating Electrical Energy and Capacity Demand for Regional Electric Flight Operations at Two Mid-Size Airports in Washington, U.S</title>
      <link>https://trid.trb.org/View/2285032</link>
      <description><![CDATA[Advances in battery-powered electric motor systems, lightweight materials, and aircraft design have resulted in the development of new battery-electric aircraft that could gradually replace conventional fuel-powered aircraft for certain use cases in the coming years. In the face of tight climate action goals and large airport hubs facing capacity constraints, electric aircraft at regional airports could help respond to increased regional travel demands. Charging these aircraft may be a significant new load on the electric grid serving airports. In this paper, to understand these load impacts, we develop a framework for estimating future energy (annual MWh) and power (average and peak MW) demand for charging battery-electric aircraft at regional airports. We apply our modeling framework to two mid-size case study airports in Washington, U.S: Paine Field/Snohomish County Airport and Grant County International Airport. Our method has three parts: assumptions on flight operations growth, technical feasibility to serve these flights with electric aircraft, and actual adoption of electric aircraft to serve feasible trips. The results reveal that, while electricity demand could rise substantially over time, during the first decade of adoption utility companies are expected to be able to serve the energy and power needs of electric aviation with available capacity at existing substations close to the airports in our case studies.]]></description>
      <pubDate>Mon, 06 Nov 2023 14:49:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/2285032</guid>
    </item>
    <item>
      <title>A Novel Control Surface for Energy-Optimum Maneuver for Solar-Powered Aircraft</title>
      <link>https://trid.trb.org/View/2265702</link>
      <description><![CDATA[This paper presents a new control surface, which the authors have named auxiron, that helps a solar-powered aircraft to orient itself according to the position of the sun in the sky to collect more solar power. The auxiron also enables an aircraft to land in crosswind conditions with no or reduced sideslip angle depending on the auxiron control power. The auxiron serves to produce the necessary side aerodynamic force for counterbalancing the horizontal component of the lift force. Its primary purpose is to eliminate the sideslip angle during flight with a nonzero bank angle. This results in a reduction in aerodynamic drag and power consumption required to maintain a straight-line flight with nonzero bank angles. By implementing this innovative control surface, an aircraft can now cruise straight without experiencing any sideslip angle, even with nonzero bank angles. The modified stability and control derivatives for the aircraft configuration with the auxiron are established, and these derivatives are incorporated into the aircraft dynamics. The 6-DoF simulation is carried out for the solar UAV, Maraal, which demonstrates the effectiveness of the auxiron.]]></description>
      <pubDate>Mon, 06 Nov 2023 08:39:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2265702</guid>
    </item>
    <item>
      <title>The effects of spacing to diameter ratio on mixing characteristics of circular and elliptical twin jets</title>
      <link>https://trid.trb.org/View/2240320</link>
      <description><![CDATA[Twin jets are encountered in many engineering and industrial applications, such as aircraft propulsion systems and combustors. Twin jets create a flow field that is more complex than a single jet due to its interaction with the individual jets. This paper investigates the effects of spacing to diameter (S/De) ratio and orientation on the mixing properties of circular and elliptical twin jets at four different S/De ratios of 1.25, 1.50, 1.75, and 2.0, respectively. The numerical simulations of twin jets are carried out with a jet Mach number of 0.8 using the Shear Stress Transport (SST) K-ω turbulence model. The results show that near the orifice exit, the twin jets are issuing into ambient conditions separately and resemble a free jet, leading to a potential core length independent of S/De. The merging and combined point locations change linearly from the exit with an increasing S/De ratio. The decay rate is higher for Twin Ellipse Minor than those in Twin Circle and Twin Ellipse Major, verified by a shorter converging region. In addition, near the jet exit, the spread rate is higher for Twin Ellipse Minor, which is consistent with the closer merging point location. The jet mixing is superior for twin minor elliptical configuration compared to twin circle and twin major elliptical jets at all S/De ratios.]]></description>
      <pubDate>Tue, 26 Sep 2023 16:05:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/2240320</guid>
    </item>
    <item>
      <title>Are green cars an optimal and efficient choice for motorists? Evidence from Italy</title>
      <link>https://trid.trb.org/View/2219573</link>
      <description><![CDATA[This study evaluates whether a motorist's choice over green cars (i.e., cars with featuring low CO2 emissions) and non-green cars (i.e., cars featuring high CO2 emissions) is efficient. To this end, the authors present a micro-founded model of motorist choice incorporating the impact of eco-incentives and taxation on CO2 emissions. Subsequently, they implement data envelopment analysis on a large database of new cars registered in 2019 to evaluate efficiency. The results show that the motorist's optimal choice (green car) does not coincide with the efficient choice. Moreover, motorist choice is mainly guided by the high price of green cars. On average, the efficient choice coincides with cars that end up in the dark area (they do not benefit from eco-incentives and do not pay the pollution tax), being the cheapest, the lightest, the least powerful (low Kw) and petrol fuelled. On average, these elements pertain to Italian motorists with respect to their tastes; most importantly, their budgets do not go well with the high costs of green cars.]]></description>
      <pubDate>Mon, 31 Jul 2023 08:45:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/2219573</guid>
    </item>
    <item>
      <title>Determination of the Quality Index of Cars</title>
      <link>https://trid.trb.org/View/2166454</link>
      <description><![CDATA[This article presents theoretical studies of methods for assessing car quality indicators in the operation stage. Important criteria for determining the quality indicators of cars during the operation phase are the following: functional stability, ecology, comfort, technical solutions, and traffic safety. The problem of converting a multicriteria quality assessment to a single criterion is proposed to be solved by the method of determining a quality index. The methodology for the practical and actual implementation of this research is based on the evaluation of the quality index established on the average vehicle speed then the basic methodological principles are formulated. The quality index of a car is significantly dependent on the operating conditions. This article presents the correction coefficients for the quality index of base, hybrid, and electric vehicles, depending on the operating conditions. The studies and the proposed car quality index provide timely information on the characteristics of operating conditions, creating the necessary conditions and opportunities for automakers to improve the design of cars, promote the image of car brands, and increase sales.]]></description>
      <pubDate>Thu, 25 May 2023 17:41:09 GMT</pubDate>
      <guid>https://trid.trb.org/View/2166454</guid>
    </item>
    <item>
      <title>Two-phase heat transfer devices for passive cooling of electric and hybrid aircraft onboard equipment</title>
      <link>https://trid.trb.org/View/2146009</link>
      <description><![CDATA[In connection with growing requirements for improving the environment, nowadays the world attaches importance to creation and enhancement of electric and hybrid airplanes, equipment of which is in need of effective cooling of its components heated by a passing current. The purpose of this work is to analyse the possibilities of using autonomous two-phase heat conductors (heat pipes, thermosyphons) and passive systems based on them for thermal control of equipment in electric and hybrid aircraft. The article discusses designs of heat pipes and thermosyphons, shows options for their use in electric and hybrid airplanes. The design and results of experimental studies of the kW-class loop thermosyphon with horizontal evaporator and condenser are presented. This thermosyphon has the right characteristics for use in thermal management systems: a high heat transfer capacity (up to 1.5 kW) and a short starting time.]]></description>
      <pubDate>Thu, 25 May 2023 17:41:09 GMT</pubDate>
      <guid>https://trid.trb.org/View/2146009</guid>
    </item>
    <item>
      <title>Challenges with the electrification of aircraft for a sustainable and greener aviation</title>
      <link>https://trid.trb.org/View/2082231</link>
      <description><![CDATA[Electric aircraft is a promising technological development in the aviation industry, and it will help reduce greenhouse gas emissions and fuel costs while increasing the efficiency of aircraft. There are also some challenges with electric aircraft, as in every new technology. These are storage technology, electric propulsion system comprising electric machine and power electronics converters, protection devices, wiring, thermal management of components, certification, and system/component integration. Electrification is once started with more electric aircraft, and ongoing research and development projects will light the way for the fully electric aircraft era in the future. This paper highlights the challenges of aircraft electrification and presents the current situation on electrification.]]></description>
      <pubDate>Tue, 25 Apr 2023 09:49:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/2082231</guid>
    </item>
    <item>
      <title>Aero-engine on-board model based on big Quick Access Recorder data</title>
      <link>https://trid.trb.org/View/2121544</link>
      <description><![CDATA[With the development of the Full Authority Digital Engine Controller (FADEC) technology, the aero-engine on-board model is widely used in Engine Health Management (EHM) and control. Due to the FADEC’s limited computational capability and storage capacity, the model should not be very intricate; consequently, the interpolation model is widely utilized. Although the interpolation model’s low precision precludes further development of on-board models for EHM and control. To address the trade-off between precision and complexity, a novel on-board modeling method is proposed based on the Nonlinear Autoregressive with Exogenous Inputs Backpropagation neural network (NARX-BPNN) trained using the mini-batch Levenberg–Marquardt (LM) algorithm on large Quick Access Recorder (QAR) data. The NARX model’s features and time delay are chosen by referring to the line interpolation model, which gives interpretability for feature selection. The combination of a shallow neural network and big data training can guarantee the on-board model’s real-time and storage requirements, as well as its generalizability. The mini-batch LM method can avoid both the local optimum problem in the shallow neural network and the storage difficulty associated with massive data while still achieving a rapid convergence rate due to the LM algorithm’s global view. The NARX-BPNN models are compared to an existing line interpolation model using 100 different aero-engines' QAR data. The results reveal that accuracy may be increased by approximately 30% while maintaining superior dynamic performance and anti-noise capacity compared to the line interpolation approach.]]></description>
      <pubDate>Tue, 21 Mar 2023 09:27:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2121544</guid>
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