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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>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
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    <item>
      <title>Optical measurement method for large-scale surface defects on underwater bridge piers</title>
      <link>https://trid.trb.org/View/2645586</link>
      <description><![CDATA[The measurement of large-scale surface defects on underwater bridge piers faces challenges such as limited detection techniques, low accuracy, and inadequate coverage. To achieve high-precision measurement, this paper proposes an optical measurement method based on underwater multi-refraction correction, multi-point extrinsic calibration, and global cumulative error optimization. Specifically, a refraction plane parameter calibration method based on a three‑dimensional calibration object and coordinate transformation is developed to construct a multi‑refraction correction model that mitigates refraction-induced measurement errors. In addition, a multi‑point extrinsic calibration method leveraging overlapping region 2D-3D feature mapping, along with an error optimization approach for point cloud stitching based on feature point constraints, is introduced to overcome field of view limitations and system error accumulation. Experimental results demonstrate that the multi-refraction correction model achieves a chessboard corner measurement error of less than 1 % of the corner spacing in underwater conditions. Using the multi-point calibration method, the local seam size between consecutive measurement points remains below 1 mm, with a local axial error ratio of approximately 0.4 % and a global axial error ratio ranging from 1.33 % to 1.66 %. The multi-sequence point cloud stitching method effectively reduces stitching errors by 55.5 %. Additionally, the measurement error for large-scale appearance defects is less than 2 % in air and 3 % underwater. The proposed method demonstrates excellent scene adaptability, making it well-suited for widespread application in bridge structure defect detection.]]></description>
      <pubDate>Fri, 20 Mar 2026 08:41:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2645586</guid>
    </item>
    <item>
      <title>Multiple targets displacement response identification in bridges via an enhanced monocular vision-based method</title>
      <link>https://trid.trb.org/View/2576705</link>
      <description><![CDATA[Routine displacement measurement of bridge structures is essential for accurate evaluation of structural safety. Vision-based displacement measurement methods, as a representative of non-contact techniques, offer distinct advantages over traditional contact-based approaches However, existing vision-based methods face challenges such as limited target coverage, high time costs, and complex operational requirements. To address these issues, this study introduces a simplified multi-target displacement response identification (MTDRI) method. The MTDRI integrates a subpixel displacement extraction technique with a novel monocular vision-based displacement measurement method. It requires only a single setup and three external parameters of the camera, i.e., the nearest perpendicular distance (LH), pitch (θ), and yaw (β) angle, to directly and automatically calculate the physical displacement of all targets, enhancing its applicability to field bridges. Static crossover validation tests and three sets of dynamic tests were conducted to evaluate the performance of the proposed method. The results show that the maximum error in the static displacements was 2.55 %, while the dynamic displacement responses achieved an RMSE of 0.43 mm and an NRSEM of 2.02 %. These findings confirm that the MTDRI outperforms traditional vision-based measurement methods and can accurately identify multi-target displacement responses of bridge structures.]]></description>
      <pubDate>Thu, 16 Oct 2025 17:02:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/2576705</guid>
    </item>
    <item>
      <title>Could laser-based profile measurements be used in wheel/rail contact and vehicle dynamics simulations?</title>
      <link>https://trid.trb.org/View/2577198</link>
      <description><![CDATA[Contact-based profilometers have been the de facto standard in obtaining wheel and rail profiles for the purposes of vehicle-track and wheel-rail interaction studies. Still, they cannot collect profiles in large quantities. This paper explores the potential of laser-based profilometers for wheel and rail profile measurements in vehicle-track dynamic simulations. Comparisons between contact and laser-based profilometers were performed using sample rail profiles measured in the lab. Through contact simulations, contact preprocessing and multi-body dynamics simulations (MBD), differences in contact pressures, forces, and Y/Q were analyzed. The importance of data processing and profile smoothing is also discussed. Axle sum Y/Q showed the smallest differences between the two sets of profiles, with more than 80% of the MBD simulations having less than 10% difference. While far from perfect, the ability of wayside and vehicle-mounted laser profilometers can enable analyses to be performed at a much larger scale. The authors hope this work will lead to an open-minded approach to continue evaluating laser-based profiles in simulations.]]></description>
      <pubDate>Mon, 08 Sep 2025 14:54:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/2577198</guid>
    </item>
    <item>
      <title>Volume Accounting of Buildings and Premises and the Use of Mobile LIDAR Technology in the Cadastre</title>
      <link>https://trid.trb.org/View/2407965</link>
      <description><![CDATA[The article deals with the problems of state cadastral registration of buildings and premises. The article deals with the problems of state cadastral registration of buildings and premises. Research has established the need to take into account the volume of objects as the main characteristic to be entered in the Unified State Register of Immovable Property. The possibility of using mobile LiDAR technology to measure and prepare 2D and 3D floor plans has been revealed. It has been determined that the maximum effect of mobile LiDAR technology can be obtained in the cadastral registration of apartment buildings. The article provides illustrative examples to prove that the proposals can be applied.]]></description>
      <pubDate>Thu, 21 Aug 2025 09:19:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2407965</guid>
    </item>
    <item>
      <title>Measuring strain distributions in an asphalt pavement using fibre optic sensors under static loading by test vehicles</title>
      <link>https://trid.trb.org/View/2548851</link>
      <description><![CDATA[Understanding the in-situ structural behaviour of pavements plays an important role in road engineering. Hence, various measurement methods were developed in the past to get an insight into the response of roads to traffic loading. In the present study, distributed fibre optic strain sensors were embedded into a hot mix asphalt pavement. The sensors were used for strain measurements with high spatial resolution in order to assess its feasibility to gain the continuous strain distribution in the pavement under short-term static loading. In addition, the loading process was measured with high temporal resolution, indicating that – using shorter sensor lengths – vehicle passages could also be studied. The strain distributions gathered with this type of sensor were compared to the results of a simple finite element model and the effect of applying various sensor cables. In addition, new opportunities provided by distributed fibre optic sensors in road engineering are discussed.]]></description>
      <pubDate>Thu, 26 Jun 2025 11:42:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/2548851</guid>
    </item>
    <item>
      <title>Rapid measurement method for cable tension of cable-stayed bridges using terrestrial laser scanning</title>
      <link>https://trid.trb.org/View/2444808</link>
      <description><![CDATA[This study proposes a new method for the rapid and non-contact measurement of cable forces in cable-stayed bridges, including a cable force calculation method based on measured cable shapes and a batch acquisition method for the true shape of cables. First, a nonlinear regression model for estimating cable forces based on measured cable shapes is established, and a Gauss?Newton-based cable force solving method is proposed. Furthermore, terrestrial laser scanning technology is used to collect geometric data of the cables. Meanwhile, automatic segmentation, noise reduction, and centerline extraction algorithms for the cable point cloud are proposed to accurately and efficiently obtain the cable shape. The correctness of the proposed cable force calculation method is verified in a well-designed experiment, with the measurement error of cable forces for 15 test samples being less than 1%. Finally, the proposed point cloud automation processing algorithm and cable force measurement method are fully tested on a cable-stayed bridge with a span of 460 m. The measurement accuracy of the proposed method for actual bridge cable tension is comparable to that of the frequency method, but the detection efficiency on site is nine times higher than that of the traditional frequency method. Overall, this study provides a new measurement method for construction control, health monitoring, intelligent detection, and other fields of cable-stayed bridges.]]></description>
      <pubDate>Fri, 25 Oct 2024 09:29:04 GMT</pubDate>
      <guid>https://trid.trb.org/View/2444808</guid>
    </item>
    <item>
      <title>Real-time displacement measurement for long-span bridges using a compact vision-based system with speed-optimized template matching</title>
      <link>https://trid.trb.org/View/2388799</link>
      <description><![CDATA[This paper introduces a new accelerating algorithm, efficient match slimmer (EMS), specifically designed to lighten computational loads of sophisticated template matching algorithms, enabling these algorithms to be effectively run on single-board computers. Utilizing EMS in conjunction with a robust template matching algorithm, we have developed Raspberry Vision—a compact, cost-effective, and real-time vision-based system. Its compactness and portability facilitate a practical measurement strategy that not only minimizes the camera-to-target distance but also simplifies the camera calibration process in bridge displacement monitoring, thereby enhancing measurement accuracy. The performance of the system is estimated on two operational suspension bridges. The results demonstrate that Raspberry Vision, equipped with the measurement strategy, can significantly improve the measurement accuracy in the long-span bridge test and is also suitable for cross-sea bridge measurements.]]></description>
      <pubDate>Mon, 08 Jul 2024 09:08:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/2388799</guid>
    </item>
    <item>
      <title>Asphalt Concrete Characterization Using Digital Image Correlation: A Systematic Review of Best Practices, Applications, and Future Vision</title>
      <link>https://trid.trb.org/View/2350439</link>
      <description><![CDATA[Digital image correlation (DIC) is an optical technique that measures displacement and strain by tracking pattern movement in a sequence of captured images during testing. DIC has gained recognition in asphalt pavement engineering since the early 2000s. However, users often perceive the DIC technique as an out-of-box tool and lack a thorough understanding of its operational and measurement principles. This article presents a state-of-art review of DIC as a crucial tool for laboratory testing of asphalt concrete (AC), primarily focusing on the widely utilized two-dimensional DIC and three-dimensional DIC techniques. To address frequently asked questions from users, the review thoroughly examines the optimal methods for preparing speckle patterns, configuring single-camera or dual-camera imaging systems, conducting DIC analyses, and exploring various applications. Furthermore, emerging DIC methodologies such as digital volume correlation and deep-learning–based DIC are introduced, highlighting their potential for future applications in pavement engineering. The article also provides a comprehensive and reliable flowchart for implementing DIC in AC characterization. Finally, critical directions for future research are presented.]]></description>
      <pubDate>Fri, 29 Mar 2024 16:58:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/2350439</guid>
    </item>
    <item>
      <title>Visual measurement of lateral relative displacement of wheel-rail of high-speed train under earthquake</title>
      <link>https://trid.trb.org/View/2345127</link>
      <description><![CDATA[When an earthquake causes the wheel-rail detachment of a high-speed train, the derailment evaluation criteria based on wheel-rail force faces failure. At this time, the lateral relative displacement of the wheel-rail (LRDWR) is more intuitive and continuous to assess the running safety of a high-speed train. In the past, many experimental studies have been conducted on measuring the LRDWR of trains. However, there is still a lack of effective measurement methods to solve the problem of LRDWR measurement in complex texture and high-speed dynamic scenes. Therefore, a lateral relative wheel-rail displacement measurement method based on machine vision and the improved Hourglass network (LRWRDVH) is proposed in this paper to determine the LRDWR by predicting the pixel coordinates of a few wheel-rail keypoints. The scaled-down bridge running test of the high-speed train is designed for validation, and then the LRDWR measurement of high-speed train under earthquake is carried out using the LRWRDVH method to evaluate the running safety of high-speed train. The test results show that the LRWRDVH method is effective and accurate and can be further used to study the running safety of high-speed trains under earthquakes.]]></description>
      <pubDate>Fri, 29 Mar 2024 10:01:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/2345127</guid>
    </item>
    <item>
      <title>Considerations in LED Photometry</title>
      <link>https://trid.trb.org/View/1776851</link>
      <description><![CDATA[Characteristics of light emitting diodes (LEDs), including physical size, flux levels, spectrum and spatial distribution, separate them from typical element sources, which are generally employed and measured for photometric and radiometric quantities. With an LED it is often difficult to achieve a high level of photometric or radiometric measurement accuracy, due to uncertainties within the measurement equipment and improper test setup. In addition, traditional photometers, because of their inability to simulate the response of the human eye at the ends of the visible spectrum, generate significantly flawed data when testing red, blue, and some styles of white LEDs.]]></description>
      <pubDate>Tue, 19 Dec 2023 09:14:04 GMT</pubDate>
      <guid>https://trid.trb.org/View/1776851</guid>
    </item>
    <item>
      <title>Flexible DIC System for Wind Tunnel Testing of Lightweight Structures</title>
      <link>https://trid.trb.org/View/2228297</link>
      <description><![CDATA[The authors propose an adjustable digital image correlation (DIC) system for the wind tunnel testing of small and large-scale aerospace and civil structures. A novel mounting rig with azimuth and pitch rotation fixtures was designed and developed for the DIC setup that can be installed from outside of the wind tunnel test section. The independent mounting rig makes the DIC system adjustable as per the shape and size of the test structure, which can reduce the installation and calibration efforts in wind tunnel testing. Telecentric lenses optimize the far-field optics of the DIC system. It allows the user to implement a rigorous calibration procedure to study magnification effects. They calibrated the DIC system at various fields of view and depths of field to ensure its suitability for wind tunnel experiments in which accuracy is a prime concern. The DIC measurements can be verified with the Euler transformation algorithm with a suitable combination of azimuth, pitch, and camera optical parameters. Case studies included a large-scale parachute model and a bioinspired flexible flapping wing to ensure the applicability of proposed system for both large- and small-scale structures. The inflated parachute diameter and the wing deformation fields were comparable to those predicted by the Euler transformation relationship. The DIC system can be coupled and synchronized with other measurement systems such as sting balances and particle image velocimetry for the real-time study of structural deformation, aerodynamic forces, and flow characteristics in the vicinity of structures.]]></description>
      <pubDate>Mon, 28 Aug 2023 09:19:08 GMT</pubDate>
      <guid>https://trid.trb.org/View/2228297</guid>
    </item>
    <item>
      <title>Acoustic roughness measurement of railway tracks: Implementation of an optical measurement approach &amp; possible improvements to the standard</title>
      <link>https://trid.trb.org/View/2047438</link>
      <description><![CDATA[The measure for assessing the acoustic quality of the rail surfaces, the acoustic roughness, is defined in the EN 15610 standard. It is shown that this standard contains gaps with regard to the applied procedures for processing the raw data to the quantity of acoustic roughness. Additions to the standard appear necessary to ensure better comparability of the results. A piece of rail tactilely measured by METAS (Swiss Federal Institute of Metrology) was used as a reference. Measurement data recorded by a laser triangulation sensor was used to quantify the adjustments to the standard. This paper provides an overview of the individual processing steps and systematically examines possible additions to the standard to improve the quality of the outcome. Special emphasis was given to a method for outlier removal, pre-filtering, spike removal, curvature correction and calculation of one-third octave bands. It becomes apparent that different implementations can have a significant impact on the final result. The filter used, the wavelength ranges, the methodology for removing outliers should be specified. The spike removal, curvature correction and the calculation of the one-third octave bands should be supplemented in detail to reduce ambiguities in the implementation.]]></description>
      <pubDate>Wed, 16 Nov 2022 11:36:30 GMT</pubDate>
      <guid>https://trid.trb.org/View/2047438</guid>
    </item>
    <item>
      <title>Global Vibration Comfort Evaluation of Footbridges Based on Computer Vision</title>
      <link>https://trid.trb.org/View/2027081</link>
      <description><![CDATA[The vibration comfort evaluation is a control standard other than strength and deflection, but the general comfort evaluation method only considers the response of the mid-span position and does not consider the difference in the vibration response of different positions at the same time. It is crucial to study how pedestrians actually feel when they walk on footbridges. The computer vision-based vibration comfort evaluation method is a novel method with advantages, such as noncontact and long-distance. In this study, a computer vision-based method was used to evaluate the global vibration comfort of footbridges under human-induced excitation. The improved Lucas–Kanade optical flow method is used for multitarget displacement identification of footbridges. Additionally, the YOLOv5 algorithm for pedestrian detection is used to obtain the position information of pedestrians on the footbridges. Then, according to the pedestrian position information, the structural responses of different pedestrian positions corresponding to time periods are extracted from the displacement responses of each point, and they are combined to obtain the structural global displacement. The global acceleration can be obtained by calculating the global displacement. The rms value can be calculated based on the global acceleration and compared with the standard for comfort evaluation. The global comfort evaluation method is validated by pedestrian walking experiments with different frequencies on a laboratory footbridge. The experimental results show that the computer vision-based global comfort evaluation method for footbridges is feasible and is a more specific and real-time comfort evaluation method.]]></description>
      <pubDate>Mon, 26 Sep 2022 16:44:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/2027081</guid>
    </item>
    <item>
      <title>Measurement of diesel particulate matter concentration by means of cavity ringdown spectroscopy</title>
      <link>https://trid.trb.org/View/1813664</link>
      <description><![CDATA[Aim of this article is to evaluate cavity ringdown spectroscopy (CRDS) as a suitable technique for the measurement of particulate matter concentration in diesel exhaust. The second harmonic of a Nd:YAG laser was used for pulsed cavity ringdown measurements of the optical extinction of diesel particulate matter. The investigation was carried out at the exhaust of a single cylinder prototype engine, derived from the Euro IV version of FIAT 1.9 JTD M-Jet 16V. Several steady state test points were investigated, corresponding to low and medium load conditions in the European emission test schedule for light duty cars. Unconventional diesel combustion regimes, aimed to get lower flame temperatures and overcome the NOₓ -soot trade off, have been also investigated. Optical measurements have been compared against two commercial devices: a standard smoke meter (AVL 415S) was used to measure the Particulate Matter (PM) concentration, while a photoacoustic soot sensor (AVL 483 Micro Soot Sensor) was used to infer the corresponding carbonaceous fraction.]]></description>
      <pubDate>Mon, 26 Sep 2022 09:12:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/1813664</guid>
    </item>
    <item>
      <title>Independent Component Analysis of Combustion Images in Optically Accessible Gasoline and Diesel Engines</title>
      <link>https://trid.trb.org/View/1828858</link>
      <description><![CDATA[Flame luminosity fields can nowadays be collected from optically accessible engines, with high spatial and temporal resolution, and constitute a very powerful investigation means for the transient combustion phenomena taking place in the engine chamber. Interpretation of the impressive amount of collected data can be quite challenging, mainly due to the variety of coupled phenomena involved. Application of Independent Component Analysis (ICA) aims here at separating spatial structures related to different combustion events, and is coupled with the analysis of the statistics of the coefficients of the independent components, and of the measured in-cylinder parameters. This paper reports on the comparison of the application of ICA to 2D images of combustion-related luminosity collected from two different optically accessible engines: Diesel and spark ignition. Independent components and their coefficients are first extracted from sets of luminosity images, and then used to identify leading structures and to study the transient behavior of the combustion process. The two components identified from the single Diesel cycle appear to be clearly related to early combustion along the fuel jets and later combustion near the bowl walls, respectively; quantitative analysis of coefficient statistics confirms the lower variability of the jet flames with respect to combustion near the chamber walls. The same can be said of the results of the analysis for SI combustion images, which are separated in early, median and final luminous combustion. The analysis is fast and reliable and can be prospectively applied to many different optical engine configurations.]]></description>
      <pubDate>Fri, 15 Apr 2022 17:16:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/1828858</guid>
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