<?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?tc=NN%3AFmb%2A" 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>Cold-in-Place Recycling with 100% Recycled Asphalt Pavement Rejuvenated by Soybean Oil: Laboratory and Field Evaluation</title><link>http://pubsindex.trb.org/view/2709232</link><description><![CDATA[This study investigated the feasibility and performance of using soybean oil as a bio-based recycling agent in recycled asphalt pavement (RAP) for road reconstruction in cold regions. A comprehensive demonstration project was conducted on a 5-mile section of Old State Road in Clare County, Michigan, where a 100% RAP mixture modified with soybean oil was produced and placed using a conventional asphalt paver equipped with a screed. Laboratory evaluations included balanced mix design, rutting and cracking testing, and binder performance analysis. Field application processes, including mixing and compaction, were also documented and evaluated. The asphalt mixture tests included the Hamburg wheel-tracking test (HWTT) and the indirect tensile asphalt cracking test (IDEAL-CT), while the asphalt binder tests included dynamic shear rheometer (DSR), asphalt binder cracking device (ABCD), rotational viscometer (RV), linear amplitude sweep (LAS), Fourier transform infrared spectroscopy (FTIR), and CO2 emission analysis. An optimal soybean oil dosage of 1.0 wt.% (based on the total weight of the mix) significantly improved low-temperature cracking resistance and fatigue life while maintaining rutting resistance. Results showed that soybean oil improved compaction performance and exhibited a cracking temperature approximately 3.3°C lower than that of untreated RAP based on the ABCD test. Fatigue performance was also enhanced. Fourier transform infrared spectroscopy (FTIR) analysis confirmed the chemical compatibility and interaction between soybean oil and the RAP binder. On-site application was completed smoothly without workability issues, and the final pavement met all compaction and density requirements. In summary, using soybean oil as an RAP recycling agent provides a practical and environmentally friendly solution to improve the performance of recycled asphalt mixes, especially for low-volume roads in cold climates, while supporting the sustainability of Michigan’s pavement and the growth of the soybean market.]]></description><pubDate>Mon, 01 Jun 2026 16:52:46 GMT</pubDate><guid>http://pubsindex.trb.org/view/2709232</guid></item><item><title>A Multiobjective Optimization Method for Integrated Road Asset Management Considering Traffic Dynamics</title><link>http://pubsindex.trb.org/view/2701293</link><description><![CDATA[Traditional road asset management often operates in isolation, leading to suboptimal coordination. While integrated asset management enables multiasset maintenance and rehabilitation (M&amp;R) decisions on a unified platform, existing approaches typically do not systematically account for traffic redistribution effects. This study proposes a road M&amp;R planning method based on bilevel multiobjective optimization (MOO) that explicitly integrates user and environmental considerations with economic and performance objectives. The upper level optimizes network-level multiyear agency cost, network condition, user cost, and greenhouse gas (GHG) emissions. The lower level employs a traffic assignment model to address traffic dynamics caused by reduced link capacity during M&amp;R operations. The bilevel MOO model is solved using the Nondominated Sorting Genetic Algorithm III and Self-Regulated Method of Successful Averages to generate Pareto solutions, with an analytic hierarchy process-based weighted-sum method determining the final solution. A five-year case study on a road network in Liaoning Province, China, demonstrates the method’s effectiveness for pavement and bridge M&amp;R planning: 19.11% improvement in network condition, 9.07% reduction in GHG emissions, and 4.64% reduction in user costs, proving the method’s effectiveness for achieving cost-effective and sustainable M&amp;R decisions. Comparative analysis against a static traffic baseline reveals that explicitly modeling traffic redistribution reduces user costs by 99.39% and GHG emissions by 61.17%, demonstrating traffic dynamics alter optimal M&amp;R decisions. The methodology is validated for a regional network with asphalt pavements, reinforced concrete T-beam bridges, and passenger vehicle traffic under deterministic demand; extensions to heterogeneous vehicle types, elastic demand, and other infrastructures represent directions for future studies.]]></description><pubDate>Wed, 13 May 2026 17:00:16 GMT</pubDate><guid>http://pubsindex.trb.org/view/2701293</guid></item><item><title>Testing and Microcracking Assessment of Cement-Treated Full-Depth Reclamation</title><link>http://pubsindex.trb.org/view/2695843</link><description><![CDATA[Full-depth reclamation (FDR) has gained increasing recognition as an efficient and cost-effective pavement rehabilitation method by recycling up to 100% of existing materials on-site, with Portland cement-stabilized FDR (FDR–PC) providing enhanced structural integrity. A comprehensive understanding of the mechanical properties of FDR–PC is essential to optimize its design and improve implementation efficiency. This study investigated the mechanical characteristics of FDR–PC, the interrelationships among various tests, and assessed the use of microcracking on constructed accelerated pavement test sections. Tests conducted included compressive strength (CS), flexural strength, elastic modulus, and shrinkage behavior in the laboratory, and deflection testing using a falling weight deflectometer. Four constructed FDR–PC pavement sections, including 3.25% and 5.5% cement content (by weight), both with and without induced microcracking, were built to study the shrinkage concerns observed during practice associated with FDR–PC. In addition, the influence of the microcracking technique was evaluated. The findings include: (1) a correlation factor of 1.46 to account for specimen-size effects in FDR–PC CS testing; (2) a slower loading rate than that specified in ASTM C469 may be more appropriate for characterizing FDR–PC; (3) the American Concrete Institute-based modulus predictions tend to overestimate FDR–PC stiffness; (4) the American Association of State Highway and Transportation Officials model provided the most accurate 7-day modulus of rupture (MoR) estimates; (5) length change test results were influenced by density and cement content; (6) strong correlations were observed among all evaluated mechanical properties; and (7) microcracked mixtures gained stiffness over time, with greater initial reduction in the lower-stiffness FDR–PC and significant stiffness recovery in the high-stiffness FDR–PC.]]></description><pubDate>Mon, 27 Apr 2026 15:00:16 GMT</pubDate><guid>http://pubsindex.trb.org/view/2695843</guid></item><item><title>Mechanisms and Remediation of Leakage at the Ring Beam in Operating Subway Tunnels</title><link>http://pubsindex.trb.org/view/2684234</link><description><![CDATA[As urban metro tunnels enter the middle-to-late operational stages, water leakage becomes a critical issue threatening structural safety and operational efficiency. Addressing challenges such as the short maintenance windows for operational tunnels and the unclear coupling mechanisms between seepage and structural interactions, this study systematically investigates leakage evolution mechanisms and rapid remediation methods for shield tunnel-ring beam joints in water-rich strata. Firstly, high-precision radar and total station instruments were employed to acquire leakage source data and structural deformation data. Subsequently, a seepage-structure coupling model was established using ABAQUS, revealing critical thresholds including the surface load critical effect (1.44 MPa) and strength degradation of the segment (0.8 times the original strength). Finally, an innovatively developed modified epoxy resin mortar material was applied for grouting remediation, demonstrating significant repair efficacy. The research achieves the first quantification of key leakage evolution parameters and establishes an integrated system encompassing leakage detection, mechanism analysis, and rapid remediation. These findings offer useful insights and a preliminary technical reference for leakage detection, mechanism understanding, and remediation in operational tunnels.]]></description><pubDate>Thu, 26 Mar 2026 13:38:05 GMT</pubDate><guid>http://pubsindex.trb.org/view/2684234</guid></item><item><title>Barriers to Winter Road Maintenance Policy Implementation and Coping Strategies Adopted by the Street-Level Bureaucrats: Evidence from Kashmir, India</title><link>http://pubsindex.trb.org/view/2666763</link><description><![CDATA[Winter road maintenance (WRM) is integral to economic continuity, freight logistics, environmental safety, and public well-being. The policy for WRM is laid down by the government in the form of Standard Operating Procedures (SOPs) and other guiding documents. This study employs qualitative analysis of data collected through in-depth interviews with snow clearance operators and managers at a snow control station in Tangmarg and Gulmarg, Kashmir. Through purposive sampling, the study revealed a host of factors (technological and human resource inadequacy, the non-availability of legal instruments and deterrents, and political nudges) responsible for increasing stress among snow clearance operators during the policy implementation phase causing deviations from SOPs and action plans. Street-level bureaucrats (SLBs) were left to use their discretion. The results emphasize the importance of discretion, formal training, and political insulation to improve policy implementation. While the study highlights a perceived lack of enforceable legal instruments, this observation pertains more to the operational absence of specific and actionable deterrents than to any lack of legal provisions. The issue lies in the ineffective recognition and enforcement of existing laws. This reinforces the need for clearer alignment between road safety legislation and field-level enforcement. Furthermore, the study highlights the necessity of multilevel cooperation between governors, leaders, and frontline staff to reduce stress. Thematic analysis guided by street-level bureaucracy theory is used to detail coping mechanisms imposed by SLBs to ameliorate tough working conditions. Expanding the coping strategies employed by SLBs could enhance organizational resilience and performance.]]></description><pubDate>Tue, 10 Feb 2026 09:11:51 GMT</pubDate><guid>http://pubsindex.trb.org/view/2666763</guid></item><item><title>Comparative Evaluation of Flexural Strengthening and Bond Performance of Reinforced-Concrete Beams Strengthened with Near-Surface-Mounted Titanium-Alloy Straight Bars</title><link>http://pubsindex.trb.org/view/2646168</link><description><![CDATA[Strengthening reinforced-concrete (RC) members using near-surface-mounted (NSM) titanium-alloy bars (TiABs) has become an emerging method to extend the service life of RC structures. Current design and construction guidance for strengthening existing RC structures with this method is limited to the usage of TiAB with hooked ends, which can be challenging for structures where accommodating hooks is impractical. To evaluate an alternative mounting method, experimental work was performed in this study to investigate the flexural behavior of RC beams strengthened with NSM straight TiAB (without end hooks) and determine their bond strength for development length calculations. Five RC beams strengthened with NSM TiAB having TiAB bonded lengths were tested and compared against an unstrengthened control specimen. The test results indicate that beams strengthened with straight TiABs can achieve increased load capacity, provided that sufficient bond length is provided. Specimens with sufficient bond length demonstrated performance comparable to those strengthened with hooked TiABs, achieving yielding in both the steel reinforcement and the TiAB. An average bond strength of 0.5 ksi for straight TiABs is recommended when performing development length calculations. Additionally, this study presents guidelines and construction procedures for the practical application of NSM straight TiABs.]]></description><pubDate>Tue, 30 Dec 2025 08:56:41 GMT</pubDate><guid>http://pubsindex.trb.org/view/2646168</guid></item><item><title>Exploring the Correlation Between Winter Severity Indices and Winter Maintenance Costs: Insights and Comparative Analysis from Nationwide Practices</title><link>http://pubsindex.trb.org/view/2633003</link><description><![CDATA[Winter maintenance operations are essential for safe and efficient transportation, yet unpredictable weather introduces major challenges in cost and material planning. A single severe snowfall can deplete resources midway through the season, while milder-than-expected winters may result in unused surpluses. The Winter Severity Index (WSI) provides a standardized measure of winter intensity, offering a promising tool to address these challenges. This study explores the relationship between WSIs and winter maintenance costs through a nationwide survey of state DOTs and Clear Roads survey data. The Clear Roads survey analysis involves regression models, assessing the relationship between the Accumulated Winter Season Severity Index (AWSSI) and winter maintenance expenditures across different U.S. climate divisions. AWSSI was used not as a recommended tool for operations, but as a nationally available and consistent index to investigate whether winter severity is statistically associated with cost trends on a broad scale. The study also assessed nonlinear regression models, which yielded similar results to linear models; the linear model was, therefore, retained for its simplicity and interpretability. Results show significant correlation within various climate clusters, indicating that weather severity can explain cost variability. The study reveals that WSIs can improve winter maintenance budget management, but their effectiveness is regionally nuanced. Customized WSIs are essential to improve resource planning, as the findings indicate that AWSSI does not work optimally in all geographic contexts. The study also identified best practices by state departments of transportation (DOTs), such as integrating WSIs with real-time tools such as the Road Weather Information Service and the Maintenance Decision Support System, to enhance planning accuracy and responsiveness.]]></description><pubDate>Wed, 03 Dec 2025 09:19:38 GMT</pubDate><guid>http://pubsindex.trb.org/view/2633003</guid></item><item><title>Hierarchical Quantification of CO2 in Transportation Infrastructure Maintenance: Identifying Key Contributor and Targeting Reduction Department</title><link>http://pubsindex.trb.org/view/2619141</link><description><![CDATA[This paper introduces a hierarchical quantification framework based on process-based life cycle analysis for evaluating CO2 emissions from departments in transportation infrastructure maintenance. The method decomposes the maintenance process into a carbon responsibility chain consisting of “Maintenance Department–Maintenance Task–Maintenance Activity–Resource Utilization,” enabling a systematic mapping of CO2 emissions to the corresponding responsible departments. The method allows users to quantify the itemized CO2 emissions and identify high-emission activities and resources that are responsible by department, assisting in the development of targeted CO2 reduction strategies. Case studies of expressway, bridge and tunnel maintenance in Shanghai show that the road maintenance department for expressways, the structure maintenance department for bridges and tunnels contribute 70.2%, 69.7%, and 84.7% of emissions in their categories, with annual values of 32.69, 23.60, and 41.40 ton/single-lane kilometer, respectively. At the activity level, “Mechanical paving of SMA asphalt concrete,”“Manual paving of medium-graded asphalt concrete,” and “Tunnel segment joint sealing” are the primary high-emission activities in their respective categories, accounting for 29.4%, 13.2%, and 25.2% of their respective emissions. Accordingly, relevant government agencies and enterprises should prioritize targeted CO2 reduction strategies for them, such as warm-mix asphalt substitution, low-carbon material replacement, and engineering efficiency optimization. In the case studies, these measures are estimated to reduce CO2 emissions by 16.2% for expressway maintenance, 9.0% for bridge maintenance, and 3.8% for tunnel maintenance. The proposed framework offers a flexible and effective tool for reducing CO2 emissions in transportation infrastructure maintenance and provides valuable insights for policymakers and industry stakeholders.]]></description><pubDate>Thu, 06 Nov 2025 16:53:52 GMT</pubDate><guid>http://pubsindex.trb.org/view/2619141</guid></item><item><title>SHRP Goes to Dallas</title><link>http://pubsindex.trb.org/view/2608453</link><description><![CDATA[On September 18-20, 1985, some 500 individuals interested in highway research attended the SHRP National Workshop at the Amfac Hotel at Dallas-Fort Worth Airport to discuss the research plans being developed for the six technical areas in the Strategic Highway Research Program (SHRP). SHRP is the 5-year, $150-million research effort that has been initiated to address six highway research areas identified as those providing the greatest potential for improving the safety and productivity of the national highway program. Expertise and comments were offered on each of the six technical areas: asphalt, long-term pavement performance, maintenance cost-effectiveness, protection of concrete bridge components, cement and concrete in highway pavements and structures, and snow and ice control. The workshop was successful. Some of the technical plans were modified in significant ways as a result of the discussions. There can be no question that the level of awareness among those in attendance was raised significantly. Delegates identified several ways in which they and their organizations-domestic and foreign, public and private, large and small-can contribute to and benefit from the research to be undertaken by SHRP.]]></description><pubDate>Sat, 18 Oct 2025 18:52:54 GMT</pubDate><guid>http://pubsindex.trb.org/view/2608453</guid></item><item><title>Emergency Closure and Repair of the West Seattle High Rise Bridge</title><link>http://pubsindex.trb.org/view/2606571</link><description><![CDATA[The West Seattle High Rise Bridge was closed on March 23, 2020, under emergency circumstances because of excessive cracking of the primary concrete superstructure supporting the bridge. This paper describes the reasons for the closure and the work performed in the ensuing thirty months to reopen the bridge on September 17, 2022, with primary focus on: condition assessment and the use of structural health monitoring instrumentation, and discussion for context on the following topics: emergency response planning, return to service cost–benefit analysis, repair design and commissioning, and community engagement.]]></description><pubDate>Wed, 08 Oct 2025 09:29:42 GMT</pubDate><guid>http://pubsindex.trb.org/view/2606571</guid></item><item><title>Road Diets and Vehicle Positioning: A Before-and-After Case Study of Retrofitted Cycleways in Christchurch, New Zealand</title><link>http://pubsindex.trb.org/view/2596606</link><description><![CDATA[The New Zealand (NZ) government has promoted road diet programs to improve the quality and quantity of bicycle infrastructure. Numerous cycleways have been retrofitted onto existing roadways as the public good generally outweighs the cost. This paper examines vehicle positioning changes when retrofitting separated cycleways onto existing roads in Christchurch, NZ. Two reconstructed roads were selected for this study. An Internet of Things (IoT) prototype was used to collect vehicle lateral positioning before and after the reconstruction projects. Although retrofitting cycleways onto existing roads brings several well-researched benefits for cyclists and society, the results from this study showed that as vehicle lanes became narrower to accommodate the new facilities, it presents new challenges for motorists to navigate, with very high centerline encroachment rates. Whereas the separated cycleway effectively prevented vehicle encroachment on cycleways and increased cyclist safety, the results showed that a road diet can significantly narrow the vehicle wheel paths. This effect has traditionally not been accounted for when implementing cycleways on existing roads in NZ and its impact on aspects of pavement maintenance needs to be further investigated. The results also showed that chip-seal contractors should recalibrate the variable bitumen sprayer to accommodate the new location and narrower wheel paths after a road diet to improve maintenance practices. These findings provide valuable insights for planning. Future research in this area could be aided by IoT-based approaches, as demonstrated by this case study.]]></description><pubDate>Wed, 10 Sep 2025 17:05:47 GMT</pubDate><guid>http://pubsindex.trb.org/view/2596606</guid></item><item><title>Effects of Improved Density Techniques on the Field Performance of Asphalt Pavements</title><link>http://pubsindex.trb.org/view/2586811</link><description><![CDATA[The in-place density of asphalt pavements significantly influences their long-term performance and service life. This study assessed the impact of increased in-place density techniques on field performance by analyzing two field projects. Field project 1 included three test sections: Evotherm warm-mix asphalt (WMA), increased asphalt content (Plus AC), and a control section. Field project 2 evaluated four asphalt rehabilitation routes, categorized into two sections: control and temperature-segregated sections. Across both projects, 13.95 lane miles were evaluated. The control sections in field project 2 were areas with temperature differentials less than 14°C from the specified compaction temperature, whereas the temperature-segregated sections were colder areas with temperature differentials exceeding 14°C. Structural capacity data was collected from field project 1 using a falling-weight deflectometer. Field performance data from both projects was used to assess the impact of increased in-place density techniques on pavement performance. The results showed that pavement sections with enhanced density techniques exhibited significantly better structural capacity than the control section. Generally, Evotherm WMA and Plus AC increased-density techniques caused a significant improvement in rutting resistance after 5?years in service. Additionally, these sections exhibited transverse-, longitudinal-, and alligator-cracking performances similar to or better than their corresponding control sections. The Evotherm WMA and Plus AC techniques effectively improved the pavement condition index (PCI) rating from “good” to “very good.” Furthermore, the temperature-segregation phenomenon negatively affected the PCI rating of two sections in field project 2, reducing it from “very good” to “good” compared with their corresponding control sections.]]></description><pubDate>Mon, 11 Aug 2025 09:14:37 GMT</pubDate><guid>http://pubsindex.trb.org/view/2586811</guid></item><item><title>Practices to Enhance Resiliency of Existing Roadway and Embankment Culverts</title><link>http://pubsindex.trb.org/view/2582401</link><description><![CDATA[Culverts are buried drainage structures underneath roadways or embankments that are open at both ends and used to convey and transport water. Culverts were frequently identified as vulnerable components to extreme weather events and climate change during a 2013–2015 pilot study (FHWA-HEP-16-079), and many culverts under the jurisdiction of state departments of transportation (DOTs) were designed and installed well before the effects of climate change were understood or realized. Existing culverts must be able to handle the increasing frequency and severity of extreme weather events [National Oceanic and Atmospheric Administration (NOAA) 2023; Pluimer 2023], which can accelerate failure mechanisms and shorten culvert expected design lifetimes. Accelerated deterioration of culverts can lead to a suite of unplanned repairs, rehabilitation projects, or full replacements, all of which are financially burdensome and present issues of staffing or sourcing of work to state DOTs. The needs of state DOTs to improve resilience are common, but practices may be diverse due to variability in climate, weather events, seismic susceptibility, slope and embankment stability, watershed characteristics, and challenges due to urban development and land usage. The objective of this synthesis is to document management and maintenance practices used by state DOTs to enhance resiliency of existing roadway and embankment culverts. Information for this study was gathered through a literature review, a survey of state DOTs, and follow-up interviews with selected DOTs. Case examples of five state DOTs provide additional information related to their maintenance practices for wide cracks and joints in flexible and composite pavements.]]></description><pubDate>Thu, 31 Jul 2025 15:26:17 GMT</pubDate><guid>http://pubsindex.trb.org/view/2582401</guid></item><item><title>Limiting Damage to Flexible and Composite Pavements due to the Presence of Water: Guidelines</title><link>http://pubsindex.trb.org/view/2576325</link><description><![CDATA[Recognizing that there is no single source of information that addresses issues and techniques for limiting pavement damage caused by water, NCHRP Project 01-54, “Guidelines for Limiting Damage to Flexible and Composite Pavements Due to the Presence of Water,” was initiated with the following objectives: Develop guidelines detailing strategies to limit damage to flexible and composite pavements due to the presence of water; Assemble a 1-day training course for practicing engineers on the use of the guidelines; Develop a stand-alone web-based application to provide easy access to the guidelines content; and Prepare a webinar covering the project content. This Guidelines document presents a broad set of topics related to drainage evaluation, assessment, and improvement. This stand-alone document also contains several key appendixes, including standard drainage plans, specifications, and selected agency fact sheets. The recommendations in the Guidelines document are neither new nor unique. The value of the document lies in the fact that in a single source they present successful practices that have been used by highway agencies nationwide in minimizing the adverse effects of moisture on flexible and composite pavement structures at all of the stages of a pavement’s life, from design to construction, maintenance and preservation, and rehabilitation.]]></description><pubDate>Mon, 21 Jul 2025 09:59:53 GMT</pubDate><guid>http://pubsindex.trb.org/view/2576325</guid></item><item><title>Inequity-Averse Pavement Maintenance and Rehabilitation Budget Allocation Incorporating Gini Index and Social Vulnerability</title><link>http://pubsindex.trb.org/view/2572387</link><description><![CDATA[Highway authorities create and implement pavement maintenance and rehabilitation (M&amp;R) programs to keep pavement conditions at a suitable level. Highway agencies generally face financial uncertainty for initiatives involving pavement repair and restoration because of limited resources and fluctuating government policies. Furthermore, natural and manufactured hazards, as well as rising concerns about inequity and ecology in the face of limited resources, make maintaining the pavement network at user-satisfactory standards significantly more difficult. In addition, recent research has found evidence of inequity and social injustice in tranportation policy and decision making. In this paper, a pavement M&amp;R scheduling and budget allocation model is explored, with consideration in the formulation gives to maximization of average network condition, minimization of a horizontal equity measure (Gini index), and prioritization of pavement M&amp;R based on social vulnerability. The uncertainty of available budget is modeled as a chance-constrained optimization problem. The proposed model provides an M&amp;R program for the pavement network that achieves certain levels of equity vertically and horizontally. A case study examining the pavement network from Rockwall, Texas is conducted. The solutions for different chances of budget constraint are presented. Also, the value of the system to the decision maker is discussed. The results show that the proposed model is a practical and flexible way to include equity considerations in the management of pavement maintenance at the network level.]]></description><pubDate>Fri, 11 Jul 2025 08:39:01 GMT</pubDate><guid>http://pubsindex.trb.org/view/2572387</guid></item></channel></rss>