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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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    <language>en-us</language>
    <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>Distributed acoustic sensing-based real-time monitoring of far-field cracks in reinforced concrete bridge decks</title>
      <link>https://trid.trb.org/View/2667271</link>
      <description><![CDATA[Monitoring cracks is critical for the safety and efficiency of the construction and operation of civil infrastructure. Distributed fiber optic sensors offer advantages for crack monitoring, but their applications are largely limited to near-field cracks. This paper presents an approach for in situ, real-time monitoring of far-field cracks using distributed acoustic sensing. The approach is developed through multi-physics modeling of a representative concrete highway bridge. The influence of key configuration parameters, including gauge length, channel spacing, and sampling rate, is evaluated for crack detection and localization. Results show that cracks located up to 6 m from a fiber optic cable are detected and localized with an average error of 0.94 m across 60 tests with varying crack scenarios and configurations. A cost-benefit analysis compares the proposed approach with state-of-the-art methods based on acoustic emission and distributed fiber optic sensing, demonstrating its benefits for far-field crack monitoring.]]></description>
      <pubDate>Fri, 20 Feb 2026 14:15:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2667271</guid>
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    <item>
      <title>FHWA Traffic Noise Model Version 2.1 [supporting software]</title>
      <link>https://trid.trb.org/View/2666601</link>
      <description><![CDATA[The Traffic Noise Model is the Federal Highway Administration's (FHWA's) computer program for highway traffic noise prediction and analysis. TNM has been updated many times to add new content and capabilities, address different bugs, and include improved software and modeling methods. The FHWA TNM Version 2.1 includes over 20 enhancements to the FHWA TNM Graphical User Interface (GUI). Some enhancements include: Hide Rows function now fully operational. Directional arrow keys now fully active for panning views in Barrier Design. Clicking on a background window will bring it to the foreground. When importing Stamina files, FHWA TNM now fully supports shielding factors. Dollar amounts in costs are now rounded to the nearest whole dollar. Barrier Design Table enhanced. Calculations for L_dn and L_den modified to incorporate accurate time-duration percentages. Changing object names (receiver, roadway, roadway segment, barrier, barrier segment, important barrier, important barrier segment, tree zones, building rows, ground zones, contour zones) and receiver comments do not invalidate results. Object inputs all dynamically linked to their respective tables. Adjustment Factors function redesigned. Status bar enlarged and redesigned. Barrier Input Table column widths resized to allow all fields to be displayed without horizontal scrolling.]]></description>
      <pubDate>Thu, 19 Feb 2026 17:04:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/2666601</guid>
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      <title>FHWA Traffic Noise Model Version 1.0b [supporting software]</title>
      <link>https://trid.trb.org/View/2666599</link>
      <description><![CDATA[The Traffic Noise Model (TNM) is the Federal Highway Administration's (FHWA's) computer program for highway traffic noise prediction and analysis. TNM has been updated many times to add new content and capabilities, address different bugs, and include improved software and modeling methods. The FHWA TNM Version 1.0b is the latest update to the Version 1.0 release package. It requires the complete release package for use. This update is independent of the V1.0a update. It can be performed whether or not the V1.0a update has already been performed. This version includes the following: Addressed additional fatal floating-point error crashes. Implemented an error-catching mechanism. Implemented two small changes in the acoustics. Addressed data base (DB) errors. Implemented two new input error checks.]]></description>
      <pubDate>Thu, 19 Feb 2026 17:04:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/2666599</guid>
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    <item>
      <title>FHWA Traffic Noise Model Version 2.0 [supporting software]</title>
      <link>https://trid.trb.org/View/2666600</link>
      <description><![CDATA[The Traffic Noise Model is the Federal Highway Administration's (FHWA's) computer program for highway traffic noise prediction and analysis. TNM has been updated many times to add new content and capabilities, address different bugs, and include improved software and modeling methods. Owners of version 2.0 are also entitled to a free upgrade. The FHWA TNM Version 2.0 includes the following: Improvements to the 32-bit coding architecture. Improvements to DXF import functionality with compatibility to AutoCAD® 2000. Fixes to the comprehensive receiver input dialog. Fixes to the linkage to the NMPlot contour module. Fixes to the output tables printing functionality. Addressing of additional bug fixes.]]></description>
      <pubDate>Thu, 19 Feb 2026 17:04:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/2666600</guid>
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    <item>
      <title>FHWA Traffic Noise Model Version 3.2 [supporting software]</title>
      <link>https://trid.trb.org/View/2666604</link>
      <description><![CDATA[The Traffic Noise Model is the Federal Highway Administration's (FHWA's) computer program for highway traffic noise prediction and analysis. TNM has been updated many times to add new content and capabilities, address different bugs, and include improved software and modeling methods. TNM 3.2 now contains the necessary acoustics to compute both noise from normal use and operation of the roadway as well as noise from roadway construction activities and equipment. The roadway noise acoustics remain the same as in TNM 3.0 while the construction noise acoustics are based off of the results of the National Cooperative Highway Research Program (NCHRP) 25-49 project. This version also allows filtering and sorting more data tables, improved the error message information, and fixed segmentation bugs.]]></description>
      <pubDate>Thu, 19 Feb 2026 17:04:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/2666604</guid>
    </item>
    <item>
      <title>FHWA Traffic Noise Model Version 3.1 [supporting software]</title>
      <link>https://trid.trb.org/View/2666603</link>
      <description><![CDATA[The Traffic Noise Model is the Federal Highway Administration's (FHWA's) computer program for highway traffic noise prediction and analysis. TNM has been updated many times to add new content and capabilities, address different bugs, and include improved software and modeling methods. In addition to the architectural updates to make TNM more compatible with modern computers and operating systems, TNM 3.1 has many functional enhancements and maintains the improvements to the acoustical algorithms that were implemented with TNM 3.0.]]></description>
      <pubDate>Thu, 19 Feb 2026 17:04:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/2666603</guid>
    </item>
    <item>
      <title>Deterring Bats from Transportation Infrastructure: Methods and Results</title>
      <link>https://trid.trb.org/View/2666818</link>
      <description><![CDATA[Bat species in North America face many challenges including habitat loss and degradation, mortality at wind turbines, and disease (especially white-nose syndrome [WNS]). As U.S. bat populations decline, transportation structures such as bridges and culverts offer important opportunities for conservation. Across the U.S., Departments of Transportation (DOTs) manage hundreds of thousands of structures, inadvertently providing habitat for millions of bats. While most structures contain common species such as big brown (Eptesicus fuscus), Yuma (Myotis yumanensis) and Brazilian free-tailed (Tadarida brasiliensis) bats, some harbor rare species including the following federally endangered species: Indiana (Myotis sodalis), gray (M. grisescens), and northern long-eared (M. septentrionalis) bats, and a species proposed for listing, the tricolored bat (Perimyotis subflavus). The conservation value of transportation structures is well-established, but little-known outside of biologists working with DOTs. DOTs regularly remove bats from structures including bridges and culverts either 1) because bats pose a health or safety hazard to people or 2) to protect bats while a structure is repaired or demolished. Current studies highlight two approaches for DOTs to remove bats from structures. Exclusion refers to physically blocking access to structures or portions of structures via techniques such as applying filler materials. Alternatively, deterrents such as acoustic, light, or wind devices to discourage bat use of structures are also under consideration. Thus, DOTs require implementation of practices to either permanently or temporarily exclude bats from structures. However, detailed data regarding cost and efficacy of various exclusion/deterrent protocols are currently lacking. National Cooperative Highway Research Program (NCHRP) Project 25-63 facilitates current exclusion/deterrent protocol identification and evaluation through literature review, controlled field studies, and development of a guide to standardize DOT protocols including tools facilitating implementation of recommendations. This document describes the development of the project and the research undertaken.]]></description>
      <pubDate>Sat, 14 Feb 2026 19:11:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/2666818</guid>
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    <item>
      <title>Acoustic Sensors and Audio Signal Processing in Intelligent Transportation Systems: A Survey</title>
      <link>https://trid.trb.org/View/2617952</link>
      <description><![CDATA[The effectiveness of intelligent transportation systems (ITS) strongly relies on the quality of input data provided by traffic monitoring sensors. Conventional traffic sensors such as cameras and radar necessitate costly infrastructure and are limited in the types of data they can collect. In contrast, acoustic sensors emerge as an affordable alternative that provides a wide range of road-related data (e.g. vehicle count, speed estimation, etc.). This paper presents the first survey encompassing the applications of audio signal processing (ASP) and acoustic sensors within the domain of ITS. Through an extensive literature review, this study examines various tasks relevant to traffic sensors, characterizes frequent feature extraction methodologies, and evaluates ASP models. Moreover, the paper investigates recent trends in AI-based ASP applied in ITS, which have resulted in more sophisticated acoustic sensors. To furnish a pragmatic roadmap for future investigations in this domain, this survey conducts a comparative analysis of studies in the same class, categorized by each task assigned to acoustic traffic sensors, and illuminates their strengths and weaknesses. Lastly, the paper identifies the main research gaps and suggests future directions aimed at advancing ASP in ITS. In conclusion, this study provides insights and recommendations to guide future research on this subject and serves as a reference to the state-of-the-art of ASP for acoustic sensors deployed in ITS.]]></description>
      <pubDate>Mon, 09 Feb 2026 08:53:26 GMT</pubDate>
      <guid>https://trid.trb.org/View/2617952</guid>
    </item>
    <item>
      <title>Strategies for Deterring Bats from Transportation Infrastructure</title>
      <link>https://trid.trb.org/View/2666718</link>
      <description><![CDATA[This report presents a guide to select and implement methods to temporarily deter and/or exclude bats from transportation structures ahead of and during construction and maintenance activities. The guide describes methods that are both sensitive to the biological needs of bats and effective for a range of geographical locations, project types, and site conditions. The guide was developed following a series of field evaluations, with a focus on nonlethal ultrasonic acoustic devices used alone and in combination with other methods. The findings of this research effort will prove useful to staff at state departments of transportation (DOTs) in balancing efficient project delivery with the need for responsible bat population stewardship.]]></description>
      <pubDate>Sat, 07 Feb 2026 12:17:08 GMT</pubDate>
      <guid>https://trid.trb.org/View/2666718</guid>
    </item>
    <item>
      <title>Acoustic optimization design for the laying schemes on the composite roof structure of high-speed train</title>
      <link>https://trid.trb.org/View/2613678</link>
      <description><![CDATA[If the weak sound insulation in the roof during high-speed train travel through tunnels can be addressed by adjusting the order of materials, this will meet design requirements for both economy and lightweight construction. This paper studies this problem. First, a prediction model for sound transmission loss (STL) of the roof was established to investigate the impact of different material placement schemes and optimize their arrangement. Then, the optimal placement schemes between the roof and floor were compared using STL tests. Finally, this study also examined how an optimal scheme mitigates power radiation from the roof into the train interior under typical mechanical excitations. The results indicate that the optimal laying scheme for the roof differs from that of the floor. By placing sound absorption materials on the inner side of aluminium extrusion and sound insulation materials on decorative plate, it effectively enhances vibro-acoustic characteristics of the roof.]]></description>
      <pubDate>Tue, 30 Dec 2025 09:46:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/2613678</guid>
    </item>
    <item>
      <title>Aero-Acoustic Characterization of a Commercial Vehicle Configuration Using CFD</title>
      <link>https://trid.trb.org/View/2623805</link>
      <description><![CDATA[Noise pollution from automotive vehicles is a significant concern in urban areas, emphasizing the need for improved vehicle engineering of automotive vehicles to reduce noise levels. The necessity for automotive vehicles to have a low acoustic signature may further be emphasized by local regulatory requirements, such as the EU's regulation 540/2014, which sets sound level limits for commercial vehicles at 82 dB(A). In addition to this the external noise may propagate inside the cabin affecting the overall wellbeing of the driver. To address the issue vehicles are observed to measure noise levels at various locations, including inside and outside the cabin. These testing facilitate noise source identification and categorization of noise into structure-borne noise and air-borne noise. The air-borne noise, which can be either broadband or tonal in nature, is particularly discomforting and may require mitigation. To analyze these complex aero-acoustic behavior of the vehicle, CFD can be used to complement experimental observation. Although studies have been conducted on actual vehicle configurations, most of them focus solely on capturing broadband noise levels rather than tonal noise behavior. This study explores the phenomenon of external tonal noise generation caused by aero components, such as the A-pillar turning vane (APTV) on a commercial vehicle configuration using both the compressible and incompressible transient CFD approaches. The results are compared with critical tonal frequencies in previous observation for similar vehicle configurations. The comparison reveals that CFD tends to overpredict the critical tonal frequency although the overall deviation within 5% of the expected Strouhal no. frequency data. The source of sound is identified as the coherent vortex shedding from the APTV which exhibits a dipole acoustic behavior. The developed method can be further refined for accuracy and integrated with a Vibro-acoustics tool to propagate the noise inside the cabin.]]></description>
      <pubDate>Thu, 18 Dec 2025 15:37:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2623805</guid>
    </item>
    <item>
      <title>Acoustic characteristics of wall jets in the developing regime</title>
      <link>https://trid.trb.org/View/2617155</link>
      <description><![CDATA[The present study is an experimental investigation of the acoustic characteristics of developing wall jets in the jet Reynolds number in the range 2.5 × 10⁴ ≤ Re ≤ 7.6 × 10⁴. The length of the wall jet is varied in the range of 5 ≤ L/h ≤ 20, and acoustic measurements are taken at different streamwise locations of the wall jet. The acoustic spectra of L/h = 5 and 10 show a higher noise level at a Strouhal number (Stₕ) of 0.18. In the mid-frequency range, the noise levels are higher for larger plates (L/h = 20) due to the mixing of inner and outer shear layers of the wall jet. This is confirmed by the scaling of acoustic spectra in 0.2 ≤ Stₕ ≤ 0.6 using inner layer thickness (yₘ) and maximum jet velocity (Uₘ). An increase in noise level up to 5 dB is obtained within 1.5 ≤ Stₕ ≤ 3 due to the higher turbulence of flow structures in the inner layer, which is depicted by the scaling of acoustic spectra using the inner layer half-width (y1/2)ᵢₙ and streamwise velocity of 0.5Uₘ. Further, the high-frequency acoustic spectra are scaled with friction velocity (uₜ) and wall shear stress (τᵥᵥ). In addition, the autocorrelation and probability density function of wall jets demonstrate the behaviour of flow structures in the potential core and developing regimes on noise generation.]]></description>
      <pubDate>Tue, 02 Dec 2025 09:58:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/2617155</guid>
    </item>
    <item>
      <title>Aeroacoustic behavior of edgewise propeller under upstream wing wake</title>
      <link>https://trid.trb.org/View/2617153</link>
      <description><![CDATA[This study investigates the influence of an upstream wing on the far-field aeroacoustic characteristics and aerodynamic performance of a propeller in edgewise inflow conditions. Experiments were conducted using a two-bladed APC 7″ × 4″ propeller operating at rotational speeds of 9500 and 12,500 rpm, with an upstream wing placed at varying angles of attack. Far-field acoustic measurements and propeller thrust and torque data were acquired. The presence of the wing led to a reduction in thrust and torque coefficients relative to the no-wing case. Tonal noise at the fundamental blade passage frequency (BPF) was significantly suppressed in the presence of the wing. In contrast, high-frequency broadband noise levels increased due to wake-induced inflow disturbances, with a clear dependence on the angle of attack of the wing. Time-frequency analysis further revealed amplitude modulation and intermittency in the BPF tonal peak, as well as increased broadband noise levels due to turbulence ingestion from the wing wake.]]></description>
      <pubDate>Tue, 02 Dec 2025 09:58:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/2617153</guid>
    </item>
    <item>
      <title>Flow and acoustics of supersonic cruciform jet</title>
      <link>https://trid.trb.org/View/2617145</link>
      <description><![CDATA[The experimental article focuses on the flow characteristics and acoustic features of a jet issuing from a Convergent Divergent (C-D) nozzle with a cruciform (cross-shaped) cross-section. The design Mach number is 1.5. The cruciform nozzle has an equivalent exit diameter of 5.42 mm, and its features are compared with the equivalent circular and square nozzles. The operating Nozzle Pressure Ratio (NPR) is varied from 2 to 6. The pitot probe and microphone, in conjunction with data acquisition instruments, provide the total pressure and acoustic measurements of the jet flow. The cruciform jet exhibits a shorter supersonic core length compared to both the circular and square jets for all operating NPRs. Compared to circular and square jets, the cruciform jet has a maximum Overall Sound Pressure Level (OASPL) reduction of 7.06 dB and 7.73 dB at NPR 5. The screech is suppressed and is only discernible at NPR 5 in the cruciform jets, whereas it exists from NPR 3 to 6 in the other two jets. The higher screech amplitudes are localized to lower emission angles from 45° to 75°. Together, the OASPL, and screech are suppressed in cruciform jets.]]></description>
      <pubDate>Tue, 02 Dec 2025 09:58:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/2617145</guid>
    </item>
    <item>
      <title>Prediction of splash noise in a rectangular tank under longitudinal periodic excitation</title>
      <link>https://trid.trb.org/View/2617116</link>
      <description><![CDATA[Sloshing phenomena within fuel tanks have emerged as a significant contributor to noise in hybrid and high-end vehicles, particularly as other sources of noise, such as those from the engine and transmission system, minimized. The manifestation of noise during sloshing results from the dynamic interplay between the fluid within the tank and both its surrounding structures and the fluid itself. “Splash noise” is an acoustic phenomenon which arises due to pressure fluctuations induced by fluid-fluid interactions during sloshing. Thus, the generation of splash noise encompasses a multi-physics process involving fluid flow and acoustic radiation. Accurate prediction of splash noise is crucial for implementing measures to mitigate it during the design phase. The current paper proposes a hybrid approach for predicting splash noise within a rectangular tank. The first step in the methodology is to predict the flow field within the tank, from which acoustic sources are computed. These sources are then utilized to calculate the sound propagation based on the acoustic analogy. To emulate a regime dominated by fluid-fluid interactions, periodic longitudinal excitations are imposed on the rectangular tank, both with and without baffles. Parameters such as fluid free-surface profile, tank wall pressures, and radiated sound pressure levels are systematically calculated and subsequently validated against experimental results available in the existing literature.]]></description>
      <pubDate>Tue, 02 Dec 2025 09:58:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/2617116</guid>
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