<?xml version="1.0" encoding="utf-8"?><rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>TRB Publications Index</title><link>http://pubsindex.trb.org/</link><atom:link href="http://pubsindex.trb.org/common/TRIS Suite/feeds/rss.aspx?s=PHNlYXJjaD48cGFyYW1zPjxwYXJhbSBuYW1lPSJsb2NhdGlvbiIgdmFsdWU9IjIiIC8%2BPHBhcmFtIG5hbWU9InN1YmplY3Rsb2dpYyIgdmFsdWU9Im9yIiAvPjwvcGFyYW1zPjxmaWx0ZXJzIC8%2BPHJhbmdlcyAvPjxzb3J0cz48c29ydCBmaWVsZD0icHVibGlzaGVkZGF0ZSIgb3JkZXI9ImRlc2MiIC8%2BPC9zb3J0cz48cGVyc2lzdHM%2BPHBlcnNpc3QgbmFtZT0icmFuZ2V0eXBlIiB2YWx1ZT0icHVibGlzaGVkZGF0ZSIgLz48L3BlcnNpc3RzPjwvc2VhcmNoPg%3D%3D" rel="self" type="application/rss+xml" /><description></description><language>en-us</language><copyright>Copyright © 2015. 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>TRB Publications Index</title><url>http://pubsindex.trb.org/Images/PageHeader-wTitle.png</url><link>http://pubsindex.trb.org/</link></image><item><title>Cluster Modeling of Operating Speed for Improved Transferability on Large Road Networks</title><link>http://pubsindex.trb.org/view/2675946</link><description><![CDATA[There is consensus among researchers that the transfer of operating speed models is limited in geographical scope. This paper advances the argument that, even within a single region, the transferability of operating speed models can be problematic when applied to dissimilar road segments of a large road network. To address this issue, a novel methodology is introduced aimed at enhancing the transferability. This paper involves identifying similar road segments using landmark-based spectral clustering, based on attributes that prominently factor into speed models. Models are developed using data from select segments within a cluster, and their transferability to other segments is subsequently assessed on segments situated at a distance but belonging to the same cluster. To gauge this transferability, a multifaceted approach is employed, including conventional cross-validation methods, a transferability index, and covariance analysis. The results indicate an enhancement in the transferability of cluster-calibrated models. In addition, the nontransferability of the models from one cluster to an entirely different cluster within the same network is discussed.]]></description><pubDate>Wed, 04 Mar 2026 09:15:50 GMT</pubDate><guid>http://pubsindex.trb.org/view/2675946</guid></item><item><title>Public Acceptance of Autonomous Electric Vertical Take-Off and Landing Aircraft: Analysis Based on the Extended Technology Acceptance Model</title><link>http://pubsindex.trb.org/view/2675945</link><description><![CDATA[Urban air mobility (UAM) has been emerging as a promising direction in future transportation. The autonomous electric vertical take-off and landing (eVTOL) aircraft, as the core vehicle enabling urban air transportation, represents a promising technological trend because of its low operational costs and safety advantages. However, though public acceptance of UAM has been widely investigated, the potential users’ acceptance of autonomous eVTOL systems remains under-investigated. This research extends the technology acceptance model by incorporating perceived risk and trust factors and explores how it may explain variations in users’ acceptance of autonomous eVTOL aircraft. Thus, a survey study was conducted to guide the design and future deployment of autonomous eVTOL aircraft. Based on 412 responses from China, we analysed public acceptance of autonomous eVTOL aircraft using structural equation modeling. The study revealed that perceived usefulness was a primary determinant of potential users’ behavioral intention of using autonomous eVTOL aircraft. Further, trust demonstrates significant positive effects on perceived ease of use and perceived usefulness of autonomous eVTOL aircraft. Finally, respondents’ income and familiarity with eVTOL technologies can also moderate users’ psychological constructs and thus affect their willingness to use autonomous eVTOL aircraft. These insights provide valuable decision-making references for policymakers, eVTOL aircraft manufacturers, and service operators, contributing to both theoretical understanding of innovative transportation technology acceptance and practical implementation of autonomous eVTOL systems.]]></description><pubDate>Wed, 04 Mar 2026 09:15:50 GMT</pubDate><guid>http://pubsindex.trb.org/view/2675945</guid></item><item><title>Mechanical Performance of a Hot-Mix Asphalt Incorporating Rice-Husk-Biochar-Modified Binder</title><link>http://pubsindex.trb.org/view/2675944</link><description><![CDATA[Rice husk (RH), an abundant agricultural by-product, poses an environmental challenge if not properly managed. Through pyrolysis, this waste can be valorized into biochar (BC), a sustainable material with potential to modify asphalt binders. This study explored the use of RH-derived BC (RHB) as a modifier of an asphalt cement (AC) 60/70 asphalt binder to produce hot-mix asphalt (HMA) by the wet process and evaluate its mechanical performance. Initially, the physical and rheological properties of AC modified with 5%, 10%, 15%, and 20% RHB by weight were evaluated. Conventional tests were conducted, and the performance grade (PG) was determined at high and intermediate temperatures. Aging resistance was assessed, multiple stress creep recovery and linear amplitude sweep tests were performed, and scanning electron microscope visualizations were carried out. Based on the results obtained from this binder characterization phase, an asphalt binder modified with 10% RHB was chosen to produce the HMA. Marshall stability, indirect tensile strength (ITS), Cantabro, resilient modulus (RM), permanent deformation, and fatigue resistance tests were carried out on the control HMA (RHB/AC = 0%) and the modified HMA (HMA-RHB). The results show that RHB tends to increase the stiffness, aging resistance, and rutting resistance of the asphalt binder, while maintaining the PG at intermediate temperatures. As an AC modifier, it helped improve all the evaluated mechanical properties of HMA. Specifically, it increased strength under monotonic loading, ITS, and RM, and enhanced resistance to rutting, fatigue, and raveling, while moisture damage resistance showed a slight improvement but remained statistically unchanged.]]></description><pubDate>Wed, 04 Mar 2026 09:15:50 GMT</pubDate><guid>http://pubsindex.trb.org/view/2675944</guid></item><item><title>Air Quality Inside Buses</title><link>http://pubsindex.trb.org/view/2676946</link><description><![CDATA[In 2024, transit buses accounted for approximately 50.4% of total public transportation ridership in the United States, serving more than 3.86 billion riders. In-bus environmental quality plays a critical role in the health and safety of operators and passengers, as well as in overall system performance. Even on short trips, poor indoor air quality can cause discomfort and symptoms such as drowsiness, dizziness, nausea, and fatigue. TCRP Research Report 261: Air Quality Inside Buses presents research findings and practical approaches to air management in transit buses to help maintain a comfortable and safe environment for operators and passengers under normal and emergency conditions, including those involving airborne infectious diseases. The report also provides a comprehensive review of existing studies and current air management practices, with a focus on system configurations and their performance.]]></description><pubDate>Wed, 04 Mar 2026 08:56:10 GMT</pubDate><guid>http://pubsindex.trb.org/view/2676946</guid></item><item><title>Utilizing Drone Technology for Pavement Surface Condition Evaluation at Truck Weigh Stations: A Case Study from the State of Virginia</title><link>http://pubsindex.trb.org/view/2675891</link><description><![CDATA[Pavement management systems (PMS) are essential for optimizing maintenance budgets and scheduling effective treatments for pavement networks. Traditionally, PMS rely on manual pavement distress data collection, a process that is both costly and time-consuming. This study explores the use of unmanned aircraft systems (UAS), commonly known as drones, as an alternative for collecting pavement surface distress data. The study focused on 13 truck weigh stations managed by the Virginia Department of Transportation and the Virginia Department of Motor Vehicles in the U.S. A drone was utilized to capture detailed images of pavement sections, which were then analyzed using an artificial intelligence model to generate pavement surface evaluation and rating (PASER) scores. These drone-derived PASER scores were compared with those obtained through traditional manual inspections. The results demonstrate that the PASER values from drone imagery and manual surveys align closely, with statistical analyses showing no significant differences overall. However, discrepancies were noted for Portland cement concrete sections, where the drone technology analysis method missed certain distresses such as joint seal damage. This limitation highlights the need for improvements in drone imaging or additional technologies to fully capture and analyze all distress types. Moreover, challenges such as weather dependency, regulatory constraints, and site conditions must be addressed to optimize drone use in pavement management.]]></description><pubDate>Mon, 02 Mar 2026 13:29:09 GMT</pubDate><guid>http://pubsindex.trb.org/view/2675891</guid></item><item><title>Meta-Reinforcement Learning with Hypernetworks for Variable Speed Limit Control under Adverse Weather and Work Zones</title><link>http://pubsindex.trb.org/view/2675553</link><description><![CDATA[Variable speed limits (VSL) have been widely implemented to alleviate highway congestion and enhance operational efficiency. However, most existing studies focus on fixed traffic scenarios, making them inadequate when addressing uncertainties such as fluctuating traffic flows, extreme weather conditions, and construction-induced closures. Consequently, traditional VSL control strategies exhibit limited adaptability and generalization capability in unfamiliar scenarios. To overcome these limitations, this paper proposes a VSL control strategy based on Meta-Reinforcement Learning (Meta-RL) and Multi-Agent Proximal Policy Optimization (MAPPO) (Meta-MAPPO). This method leverages the meta-learning mechanism of Meta-RL and integrates a Hypernetwork module to dynamically adjust the network parameters of the control policy. By doing so, it adapts to diverse traffic scenarios and environmental disturbances, facilitating rapid policy transfer across scenarios and enhancing control performance. The training results demonstrate that Meta-MAPPO achieves faster convergence and superior model performance than MAPPO and Meta Multi-Agent Soft Actor-Critic (Meta-MASAC). Simulation experiments reveal that, compared with traditional feedback control methods and conventional multi-agent RL approaches, Meta-MAPPO exhibits significant advantages in unseen scenarios: it effectively mitigates traffic congestion and substantially reduces total travel time. The findings provide a more applicable solution for the practical implementation of VSL and offer valuable insights for further exploration of multi-agent methodologies in intelligent transportation systems.]]></description><pubDate>Mon, 02 Mar 2026 13:29:09 GMT</pubDate><guid>http://pubsindex.trb.org/view/2675553</guid></item><item><title>Systematic Analysis of Quality Management for Highway Projects Delivered Using Alternative Contracting Methods</title><link>http://pubsindex.trb.org/view/2675178</link><description><![CDATA[Quality control (QC) and quality assurance (QA) processes are essential to the success of highway infrastructure projects but vary between alternative contracting methods (ACMs), including design-build (D-B), construction manager/general contractor (CM/GC), public–private partnership (P3), and progressive design-build (P-D-B). State departments of transportation (DOTs) tailor QA and QC processes to individual ACM projects, yet these documents and processes are frequently scattered and unassessed. Specifically, there is little research examining how variations in QA and QC processes across ACMs affect project outcomes. In this study, trends and lessons learned from QA and QC implementation of individual highway design and construction projects are evaluated through a systematic review and content analysis. Data were collected from solicitation and contract documents of 91 ACM projects (51 D-B, 15 CM/GC, 13 P3, 12 P-D-B) from 27 states and 21 manuals, guidance, and research reports, including requests for proposals, requests for qualification, contracts, and statement of qualification checklists. The frequency and context of key terms related to quality management revealed patterns in how QA and QC requirements are defined and implemented across project types and delivery methods. It is found that a structured QA and QC process is essential for enhancing the success and reliability of highway projects delivered using four ACMs (D-B, CM/GC, P-D-B, P3). Additionally, for P-D-B projects, combining qualifications-based shortlisting and best-value determination is effective for selecting highly qualified teams and can be applied for less-mature state DOTs adopting P-D-B. This approach is valuable for state DOTs with less experience in implementing ACMs, as it offers a practical pathway for ensuring project quality and team capability early in the quality management process. These findings contribute to advancing QA and QC practices in ACMs by offering actionable insights that support more informed decision-making, standardization efforts, and the development of tailored quality management strategies aligned with agency experience levels.]]></description><pubDate>Sat, 28 Feb 2026 17:17:58 GMT</pubDate><guid>http://pubsindex.trb.org/view/2675178</guid></item><item><title>Reforming the Coast Guard's Certificate of Compliance Program for Liquefied Gas Carriers: Promoting Efficient Implementation and Safety Effectiveness</title><link>http://pubsindex.trb.org/view/2672508</link><description><![CDATA[As liquefied gas exports from U.S. ports have grown rapidly in recent years, reforms are needed to a U.S. Coast Guard program that examines liquefied gas carriers (LGCs). Going forward, this growth in LGC exports and arrivals is likely to increase the demand for gas carrier exams by Coast Guard marine inspectors, of which there is a chronic shortage. This Special Report was requested by Congress out of concern for the Coast Guard's ability to examine the increasing number of foreign tank ships that load liquefied gas for transport overseas. The National Academies' committee concluded that the time is right for Congress to revisit the Certificate of Compliance program's requirements mandating the frequency of exams and to allow the Coast Guard greater flexibility to decide when and how to examine individual LGCs using indicators of risk.]]></description><pubDate>Thu, 26 Feb 2026 09:15:16 GMT</pubDate><guid>http://pubsindex.trb.org/view/2672508</guid></item><item><title>Funding for Maintenance of Complete Streets: A Synthesis of Highway Practice</title><link>http://pubsindex.trb.org/view/2674678</link><description><![CDATA[As state departments of transportation (DOTs) expand active transportation infrastructure through Complete Streets programs, new challenges have emerged in maintaining these facilities. Roadway maintenance equipment is often incompatible with bicycle and pedestrian facilities, and additional funding for dedicated maintenance is limited. This synthesis examines how state DOTs manage the maintenance and funding of Complete Streets projects. The report explores maintenance policies and operations for active transportation facilities; cost-sharing approaches and funding models involving local governments and other partners; the role of local and tribal governments in maintenance agreements; and strategies for training, staffing, and equipment procurement to support Complete Streets maintenance. Contents include: (1) objectives, scope, and methodology; (2) literature review of Complete Streets policies and maintenance provisions; (3) summary of survey responses and current maintenance practices across state DOTS; (4) case examples of Complete Streets maintenance practices and challenges from five state DOTs; and (5) summary of key findings and recommendations for future research.]]></description><pubDate>Thu, 26 Feb 2026 09:15:16 GMT</pubDate><guid>http://pubsindex.trb.org/view/2674678</guid></item><item><title>Implementation of a Guide to Computation and Use of System-Level Valuation of Transportation Assets</title><link>http://pubsindex.trb.org/view/2674639</link><description><![CDATA[Transportation agencies need to determine the current value of their physical assets to prepare financial reports and to support a range of transportation asset management (TAM) applications. Once an agency has calculated the value of its assets, that information can help describe its asset management program, demonstrate the impact of investments, and address key TAM questions. Asset values summarize the quantity of assets an agency owns or maintains, while changes in value indicate trends in asset condition and whether an agency’s inventory is improving or deteriorating. Depending on how it is calculated, asset value can also support decisions about how best to invest in assets—or whether an investment is justified. This report describes the development and dissemination of outreach materials that provide an overview of the Asset Valuation Guide through case studies, as well as supplemental tools and worksheets. The results of this project were incorporated into the web-based version of the Asset Valuation Guide (NCHRP Web-Only Document 335), which is maintained by the American Association of State Highway and Transportation Officials.]]></description><pubDate>Thu, 26 Feb 2026 09:15:16 GMT</pubDate><guid>http://pubsindex.trb.org/view/2674639</guid></item><item><title>Low-Impact Frog Design Primer and Research Roadmap</title><link>http://pubsindex.trb.org/view/2672509</link><description><![CDATA[The frog is a component of special trackwork where one rail crosses another. Openings called flangeways in standard frogs let wheel flanges pass through. When a wheel passes through the flangeway at the frog point, contact between the wheel tread and frog wing rail creates high-impact forces, noise, and vibration. Low-impact frog designs can reduce these effects, but little public data exist on their effectiveness, longevity, or maintainability. This Transit Cooperative Research Program (TCRP) Research Report serves as a guide for transit agencies in selecting appropriate frog designs for noise and vibration mitigation and in maintaining effective noise and vibration performance through proper maintenance practices. It also offers a research roadmap for the rail transit community to focus its efforts to foster, support, monitor, disseminate, and implement research on frog system design.]]></description><pubDate>Thu, 26 Feb 2026 09:15:16 GMT</pubDate><guid>http://pubsindex.trb.org/view/2672509</guid></item><item><title>Analytic Framework for Imbalanced Traffic Crash Type Classification and Management Using a Hybrid Tabular Transformer Approach</title><link>http://pubsindex.trb.org/view/2672768</link><description><![CDATA[Traffic crashes, especially rear-end collisions, fixed-object crashes, and rollovers, are common and severe, highlighting the need for comprehensive classification and management. However, research on classifying and managing imbalanced traffic crash data is limited. Therefore, this study proposes an analytic framework for imbalanced traffic crash type classification and management using a hybrid tabular transformer approach. The central idea is to analyze data using feature selection, multi-crash type classification, single-crash type clustering, and targeted safety recommendations. First, the multinomial logit model is used for feature selection, removing features with low correlation. Second, the Feature Tokenizer Transformer (FT-Transformer) with the Synthetic Minority Over-Sampling Technique (SMOTE) at varying ratios to perform multiclass crash classification is used. Third, mini-batch K-means clusters crash types based on key features are used. Finally, targeted safety recommendations for each cluster are developed. This study used 5,515 real-world traffic crash records from Anhui Province, China. The results show that: (1) the FT-Transformer model, with SMOTE at a 1:2:4 ratio, outperformed other machine learning models; and (2) rear-end, fixed-object, and rollovers were clustered into three, three, and five categories, respectively. Safety recommendations focus on traffic management (e.g., real time traffic updates), driver behavior (e.g., driving education), and road infrastructure (e.g., reinforced road markings).]]></description><pubDate>Mon, 23 Feb 2026 16:30:15 GMT</pubDate><guid>http://pubsindex.trb.org/view/2672768</guid></item><item><title>Mental Health, Suicide Prevention, and Addiction Mitigation in Construction and Maintenance</title><link>http://pubsindex.trb.org/view/2672716</link><description><![CDATA[This report presents the state of practice of state departments of transportation (DOTs) on addressing mental health issues, suicide, and substance misuse in construction and maintenance workforces. The synthesis includes information on trends in these workplace issues and initiatives in use by state DOTs and industry partners to address them. Under NCHRP Synthesis Project 20-05/Topic 56-04, “Practices on Mental Health, Suicide Prevention, and Addiction Mitigation in Construction and Maintenance,” Colorado State University was asked to synthesize information to document state DOT practices on education and promotion of mental health, suicide prevention, and addiction mitigation for highway workers. Information used in this study was obtained through a literature review, a survey of state DOTs, and interviews to develop in-depth case examples. Chapter 4 provides five case examples that highlight policies, workforce awareness of programs, deployed mental health programs, performance measures, and organizational dynamics.]]></description><pubDate>Sun, 22 Feb 2026 14:57:19 GMT</pubDate><guid>http://pubsindex.trb.org/view/2672716</guid></item><item><title>Total Rewards for Airport Sponsor Employees</title><link>http://pubsindex.trb.org/view/2672717</link><description><![CDATA[This report presents the state of practice regarding airport total rewards programs that help recruit and retain individuals who are essential to keeping an airport running, with a focus on frontline and supervisory staff. This synthesis includes information on challenges and opportunities that airports have found when developing or revising total rewards, and information on ways airports recruit and retain frontline and supervisory employees using total rewards. Total rewards include health benefits, well-being programs, learning and development, and recognition programs, as well as compensation. Under ACRP Project 11-03/Topic S06-09, “Total Rewards for Airport Sponsor Employees,” Embry-Riddle Aeronautical University was asked to synthesize information to describe total rewards that airport sponsors use to attract and retain frontline and supervisory employees. Information used in this study was obtained through a literature review, a survey of airports, and interviews to develop case examples. Chapter 4 provides six case examples that highlight total rewards programs from airports with different governance structures, including airports governed by a port authority, airport authority, city, and county.]]></description><pubDate>Sun, 22 Feb 2026 14:57:19 GMT</pubDate><guid>http://pubsindex.trb.org/view/2672717</guid></item><item><title>Microscopic Simulation for Coordinated Ramp Metering in Antwerp Ring Road: Combined Feedback Linearization and Model Predictive Control Approach</title><link>http://pubsindex.trb.org/view/2672678</link><description><![CDATA[In this paper, an innovative real time coordinated ramp metering based on combined feedback linearization and model predictive control (FLMPC) is implemented and evaluated in a microscopic simulation. The controller employs METANET as a macroscopic traffic flow model to predict the future states of traffic flow. Then, a linear model predictive control (MPC) is designed based on the feedback linearized representation of the METANET model to provide coordinated ramp metering. With the Antwerp, Belgium, ring road as a case study, the controller is applied in a microscopic simulation. This paper presents how this connection was made and used to implement ramp metering in a microscopic simulation. In highway systems, the controllers may create sharp fluctuations in ramp metering signals. Therefore, this paper investigates an improved FLMPC approach to tackle this drawback and evaluates its effectiveness via the microsimulation of the Antwerp, Belgium, ring road. Analyzing the simulation results reveals that FLMPC can generate substantial reductions in congestion, with a small computational cost that enables real time implementation. In addition, the effectiveness of the controller in smoothing the control signals is demonstrated without increasing the delay experienced by drivers or causing excessively long computational time.]]></description><pubDate>Sun, 22 Feb 2026 14:57:19 GMT</pubDate><guid>http://pubsindex.trb.org/view/2672678</guid></item></channel></rss>