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    <title>Transport Research International Documentation (TRID)</title>
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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>
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      <title>Transport Research International Documentation (TRID)</title>
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    <item>
      <title>A sustainable pavement coating with balanced cooling and adhesion for urban heat reduction</title>
      <link>https://trid.trb.org/View/2651724</link>
      <description><![CDATA[Urban heat islands intensify pavement distress and increase energy consumption. Heat-reflective coatings are widely used to reduce pavement temperature, but conventional designs often neglect durability, leading to frequent maintenance and additional resource consumption. In this study, a dual-objective optimization framework for cooling performance and bonding strength is established for road heat-reflective coatings. The film-forming material ratio is first optimized according to bonding strength, and the functional filler system is then designed to enhance solar reflectance and cooling capacity. Finally, the proportion between the film-forming matrix and functional fillers is adjusted to identify formulations that achieve a balanced combination of cooling performance and bonding strength. Field measurements on colored coatings show that the proposed formulations can reduce pavement surface temperature by up to about 10 °C under strong solar radiation. Indoor simulations indicate that high-temperature exposure duration is significantly shortened, suggesting a lower risk of rutting and thermal damage in asphalt layers. Combined abrasion and aging tests demonstrate that cooling performance and bonding strength gradually decrease under service-like loading, highlighting the need to consider durability in coating design. Outdoor experiments further reveal that coatings with effective pavement cooling also suppress the rise in near-surface air temperature, indicating potential environmental and economic benefits for urban heat island mitigation.]]></description>
      <pubDate>Mon, 30 Mar 2026 17:10:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/2651724</guid>
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    <item>
      <title>Overhead Guide Sign Visibility Factors, Volume II: Appendixes</title>
      <link>https://trid.trb.org/View/2658094</link>
      <description><![CDATA[The project discussed in this report concerned the night use of overhead guide signs, including button and reflectorized copy and all practical combinations of reflectorized and opaque backgrounds. This project was a follow-up effort to the literature review by Gordon.(l) Gordon's review found areas requiring further investigation, including the comparison of nonilluminated-nonretroreflectorized signs with both illuminated-nonretroreflectorized and retroreflectorized signs. The current project included the investigation of current signing practices throughout the country, development of a set of in-use luminance values for current overhead guide sign materials, development of life cycle costs for current signing materials and practices, and determination of driver response characteristics for these overhead guide sign systems. These goals were met through review of the literature, field testing, and static and dynamic laboratory testing. While the results of the tests are presented, no attempt has been made to draw conclusions from these data.]]></description>
      <pubDate>Thu, 12 Feb 2026 08:53:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2658094</guid>
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    <item>
      <title>A review of the near-infrared reflective coatings for cooling asphalt pavements in permafrost regions</title>
      <link>https://trid.trb.org/View/2609082</link>
      <description><![CDATA[Many highways with asphalt pavements were constructed in permafrost regions to provide convenience to local residents’ travel and to exploit abundant energy resources. The strong capacity of asphalt pavements to absorb intense solar irradiation and store heat significantly degrades the underlying permafrost, thereby inducing a series of severe thaw-related problems. This poses a great challenge to the design, construction, and maintenance of the safe operation of highways in permafrost regions. The near-infrared (NIR) reflective coatings, which absorbs solar radiation in visible region (400–700 nm, 46 %) while reflecting that in near-infrared region (700–2500 nm, 49 %), were proposed and applied to asphalt pavement to reduce the absorbed solar radiation while simultaneously ensure it presents a non-white color. To understand the research status and development direction of the NIR reflective coatings, the components, working mechanisms, influencing factors and applications of the NIR reflective coatings in permafrost regions were summarized and analyzed in detail. The challenges and development directions of the NIR reflective coatings for asphalt pavements were also presented. This review on the NIR reflective coatings is of great benefit to photo-thermal regulation of the asphalt pavement, and to thermal stability of the highway in permafrost regions.]]></description>
      <pubDate>Tue, 02 Dec 2025 09:56:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/2609082</guid>
    </item>
    <item>
      <title>Energy efficiency optimization for UAV-mounted IRS assisted ISAC systems under statistical CSI</title>
      <link>https://trid.trb.org/View/2573727</link>
      <description><![CDATA[Integrated Sensing and Communication (ISAC) systems are advantageous for enhancing both communication and sensing capabilities, but their performance is significantly impacted by signal blockages in dynamic vehicular environments. An Unmanned Aerial Vehicle (UAV)-mounted Intelligent Reflective Surface (IRS) for air-to-ground communication and sensing can significantly enhance coverage and deployment flexibility. However, the additional power consumption of the UAV-mounted IRS (UIRS) remains a challenge. To mitigate this, the authors propose a novel UIRS-assisted ISAC system that aims to maximize communication energy efficiency (EE) while meeting sensing quality-of-service (QoS) requirements by optimizing the UAV trajectory, IRS passive beamforming, and base station (BS) active beamforming. Due to the complex and dynamic nature of wireless channels, acquiring Channel State Information (CSI) is challenging, especially with the UAV's mobility and the passive mode of IRS. Therefore, statistical CSI is adopted in the proposed scheme. The optimization problem is reformulated into a tractable form and solved by decomposing it into three subproblems, which include using the Dinkelbach transformation for fractional programming in EE calculation, Successive Convex Approximation (SCA) for UAV trajectory optimization, and Semi-Definite Relaxation (SDR) for both active and passive beamforming designs. An alternating optimization (AO)-based framework iteratively solves all subproblems, with proven algorithm convergence and computational efficiency. Simulation results demonstrate that the proposed UIRS-assisted ISAC system significantly improves both communication and sensing performance compared to benchmark schemes.]]></description>
      <pubDate>Wed, 23 Jul 2025 09:15:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/2573727</guid>
    </item>
    <item>
      <title>Millimeter-wave vehicular collaborative communication assisted by intelligent reflecting surface</title>
      <link>https://trid.trb.org/View/2562351</link>
      <description><![CDATA[The combination of the intelligent reflecting surface (IRS) with reconfigurable wireless propagation environment and the millimeter-wave (mmWave) with abundant bandwidth resources can play a great advantage over the rate and delay in vehicular communications. Considering the problem of non-line-of-sight (NLOS) communication between the requesting nodes (RNs) and the service nodes (SNs) in the mmWave vehicular system in this paper, the authors propose an IRS-assisted multi-hop vehicle-to-vehicle (V2V) cooperative communication method to realize low-delay vehicular communication. Aiming to minimize the communication delay of RNs, an optimization problem is formulated by optimizing the link selection and reflection coefficient matrix of IRS. To tackle the optimization problem, an alternate optimization algorithm is proposed to decompose the original optimization problem into two subproblems for iterative optimization. First, they establish a link selection mechanism based on link quality and vehicle distance and propose a link selection algorithm based on the evaluation function to select communication links for each RN. Then, in particular, they derive the closed-form expression based on successive convex approximation (SCA) techniques for updating the reflection coefficient matrix of IRS. The simulation results show that the IRS-assisted mmWave vehicular cooperative communication scheme proposed in this paper can effectively reduce the communication delay and improve the performance of the mmWave vehicular network.]]></description>
      <pubDate>Thu, 26 Jun 2025 16:12:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/2562351</guid>
    </item>
    <item>
      <title>Läsbarhet och körbeteende vid vägmärket körfält upphör (F25) vid vägarbeten : en jämförande studie mellan lysande VMS och reflexfolie</title>
      <link>https://trid.trb.org/View/2491308</link>
      <description><![CDATA[The road sign F25 (Lane ends) is often used at road works, either as retroreflective sheeting or as an electronic variable message sign (VMS). Road authority documents often state that on larger roadsF25 must be of size large. When using a VMS there are however limitations concerning the size of the road sign, especially when there is an additional text board. Hence, it is important to know which dimensions and what text sizes are needed for the legibility of a VMS to not deteriorate compared to retroreflective sheeting. The overall aim of this project was to investigate which dimensions F25 needs to have when shown on an electronic VMS to have at least the same legibility as a retroreflective road sign of size large. The legibility of different text sizes on a text board of a VMS was also examined in relation to retroreflective sheeting. The project was divided into a literature review, a controlled legibility study and a verification study at actual road work conditions. The results showed that F25 of size large in a retroreflective sign can be replaced by a VMS of size 0,92×1,15 m or larger without deteriorated performance concerning legibility and driving behaviour. A VMS with black background and white symbol had at least as good legibility at night as a corresponding VMS with orange background and black symbol. In the verification study with road works on an urban expressway where the left lane ended, the speed profiles in the right lane were equal for the three different sign implementations. However, when F25 was implemented as a retroreflective sign, a larger share of lane changes was made closer to the road narrowing compared to VMS. The results from the project can be used as a basis for estimating requirements of dimensions of electronic VMS.]]></description>
      <pubDate>Fri, 17 Jan 2025 15:18:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/2491308</guid>
    </item>
    <item>
      <title>Application of Free Formed Surface Reflectors</title>
      <link>https://trid.trb.org/View/1787398</link>
      <description><![CDATA[In the 1992 SAE Technology Convention the authors reported a free formed surface reflector capable of sharp-cut illumination by adding a wavy shape to a paraparaboloid reflector consisting of different horizontal and vertical parabolas. Using this reflector, it has become possible to produce headlamps having inclined lens shapes and reduced lamp heights. However, headlamps are required to look more attractive and balanced with the vehicle body design, in addition to improving their photometric performance. In the present study, the authors investigated new free formed surface reflectors providing higher freedom in headlamp design to meet the recent market needs.]]></description>
      <pubDate>Mon, 23 Dec 2024 10:40:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/1787398</guid>
    </item>
    <item>
      <title>A survey of intelligent reflecting surfaces: Performance analysis, extensions, potential challenges, and open research issues</title>
      <link>https://trid.trb.org/View/2471004</link>
      <description><![CDATA[The rapid advancements in wireless communication have underscored the need for innovative solutions to enhance network performance, spectral efficiency, and energy savings. Intelligent Reflecting Surface (IRS) technology has emerged as a transformative approach that passively reconfigures wireless propagation environments, offering significant improvements without active power consumption. This survey provides a comprehensive analysis of IRS technology, covering its architecture, operational principles, and integration into next-generation wireless networks. The authors examine key performance metrics in various application scenarios, demonstrating IRS's potential to improve coverage, signal quality, and energy efficiency, with up to 40% higher spectral efficiency and substantial energy savings over traditional networks. The survey also explores the integration of IRS with advanced multiple access techniques such as Non-Orthogonal Multiple Access (NOMA) and Terahertz (THz) communication, positioning IRS as a critical enabler in future 6G networks. This survey contributes by offering an in-depth review of IRS design principles and operational mechanisms, presenting a performance analysis in various scenarios that highlights IRS's ability to improve network efficiency, and identifying practical challenges and open research areas, such as the need for robust channel estimation methods, effective interference management in dense networks, and IRS solutions scalable for urban and rural deployments. Additionally, they discuss the future trajectory of IRS standardization and the regulatory frameworks essential for large-scale deployment. By summarizing advancements and identifying key research directions, this survey aims to serve as a valuable reference for researchers and practitioners seeking to advance IRS technology in future wireless networks.]]></description>
      <pubDate>Mon, 23 Dec 2024 10:35:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/2471004</guid>
    </item>
    <item>
      <title>Performance optimization of novel wear-resistant reflective cooling coatings for asphalt pavement</title>
      <link>https://trid.trb.org/View/2454726</link>
      <description><![CDATA[To enhance the wear resistance of traditional asphalt pavement reflective coatings and extend their cooling effect, this study employed Potassium Hexatitanate Whiskers (PHW) as a functional material to manufacture pavement reflective coatings. It was found that PHW exhibited excellent wear resistance though agglomeration resulted in adverse effects. Therefore, untreated PHW (U-PHW) underwent inorganic-organic surface modification to produce modified PHW (M-PHW). The results indicated that M-PHW exhibited excellent optical properties, with a reflectance of 78.9 %. M-PHW exhibited more uniform dispersion in the resin matrix, which significantly enhanced the coating reflectivity. Moreover, the interfacial bonding strength between M-PHW and the resin matrix was significantly improved, enhancing the wear resistance of the coating. Especially with a whisker content of 16 units, the tensile strength of the M-PHW coating reached 96.20 MPa, representing a 43.0 % increase compared to the U-PHW coating, while achieving a maximum outdoor cooling value of 5.6 °C.]]></description>
      <pubDate>Wed, 11 Dec 2024 10:39:04 GMT</pubDate>
      <guid>https://trid.trb.org/View/2454726</guid>
    </item>
    <item>
      <title>Bifunction HID Headlamp Systems - Reflection and Projection Type</title>
      <link>https://trid.trb.org/View/1787239</link>
      <description><![CDATA[For headlamps whose low beam function is equipped with High Intensity Discharge (HID) technology, a high beam counterpart of equal lighting performance is presented which fits in the constructional space available in modern cars. The new Bifunction HID system allows the use of HID technology for both low and high beam in the same reflector, utilizing the same bulb and electronic control unit. Bifunction HID technology on the basis of reflection as well as projection type systems will be presented in this paper. An overview of the regulation guidelines for world wide application of this new technology is given. The main aspects of the switching mechanisms and their effects on the light distributions are discussed and compared.]]></description>
      <pubDate>Sat, 30 Nov 2024 15:27:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/1787239</guid>
    </item>
    <item>
      <title>Impacts of Emergency Vehicle Marking Characteristics and Wearable Lights on Driver Responses</title>
      <link>https://trid.trb.org/View/2452717</link>
      <description><![CDATA[Retroreflective markings provide important visual information to drivers about emergency vehicles and the incidents at which they are working. A stationary outdoor field study to investigate the impacts of emergency vehicle marking color, retroreflectivity level, and spatial patterns on drivers’ ability to see nearby emergency responders was carried out. The study also examined the impacts of a wearable flashing light-emitting diode (LED) light. Based on the results, agencies should use materials with higher levels of retroreflectivity carefully, especially when they will be covering large-area vehicle surfaces. Limiting the maximum retroreflectivity level to no greater than American Society for Testing and Materials Type III may help lessen negative impacts of bright reflective materials on drivers’ ability to see emergency responders. As long as the average reflectivity of different color combinations is similar to that of red and yellow reflective markings, chevron patterns with those color combinations will not reduce emergency responder visibility. Outline patterns of reflective markings on vehicles performed similarly at night to patterns covering most of the vehicle surface. The effectiveness of using high-retroreflectivity materials in an outline pattern in combination with lower- (or non-) retroreflectivity materials elsewhere on the surface should be studied. Wearable flashing LED lights can make emergency responders easier to see at night, provided they do not increase glare to approaching drivers.]]></description>
      <pubDate>Fri, 15 Nov 2024 09:48:10 GMT</pubDate>
      <guid>https://trid.trb.org/View/2452717</guid>
    </item>
    <item>
      <title>The Influence of the Color of the Reflective Vest on the Visibility of the Cyclist at Night</title>
      <link>https://trid.trb.org/View/1971963</link>
      <description><![CDATA[Bicycle fatalities make up 8% of the total number of road accident fatalities in 2016 in the EU countries. In these countries, 2.015 people riding bicycles were killed in road accidents in 2016. During the night, the number of accidents involving cyclists is 26% higher than the number of accidents during the day. This work shows the influence of the reflective elements worn by cyclists on their visibility during the night. The tests were carried out on a public road, with cyclists wearing reflective vests of different colors (orange, yellow and white). The measurements were made using the low beam and the high beams for vehicles equipped with different types of bulbs.]]></description>
      <pubDate>Mon, 10 Jun 2024 17:08:38 GMT</pubDate>
      <guid>https://trid.trb.org/View/1971963</guid>
    </item>
    <item>
      <title>Measures to prevent and reduce the impact of collisions involving wildlife : potential of advanced driver assistance systems and ITSs in infrastructure</title>
      <link>https://trid.trb.org/View/2389092</link>
      <description><![CDATA[Despite measures to reduce the number of wildlife-vehicle collisions (WVCs) in Sweden, the trend is pointing in the wrong direction. The number of WVCs has increased by 37% between 2010 and 2021. Besides the fluctuating numbers of wildlife, the increase in the number of WVCs on Swedish roads is due to an increase in traffic, as well as high speeds on the parts of the road network where wildlife is common. More than half of WVCs occur on roads used by 4,000 or more vehicles per day and with speed limits above 80 km/h. For wild boar, fallow deer and red deer, increased distribution in Sweden and growing populations are also contributing to the increase in WVCs. Speed is a crucial factor in the occurrence of WVCs and their effects. Detection of wildlife, advanced driver support systems in vehicles and infrastructural Intelligent Transport System (ITS) measures such as warnings indicating wild animals and variable speed limits at strategically riskful locations are important enablers to reduce the number of WVCs. Research and technology development regarding the design of roadside areas, animal behaviour and ecology, and so forth, is therefore necessary. The purpose of this prestudy is to identify both existing and new driver support systems and systems in infrastructure that can help to prevent or reduce the impact of WVCs on parts of the road network where the proportion of WVCs per road user is high and where physical measures cannot be justified. Knowledge from authorities, industry and the academic community has been gathered with a view to identifying opportunities for solutions that could reduce the number of WVCs.]]></description>
      <pubDate>Mon, 10 Jun 2024 14:06:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/2389092</guid>
    </item>
    <item>
      <title>Deep Learning Enabled IRS for 6G Intelligent Transportation Systems: A Comprehensive Study</title>
      <link>https://trid.trb.org/View/2307043</link>
      <description><![CDATA[Intelligent Transportation Systems (ITS) play an increasingly significant role in our life, where safe and effective vehicular networks supported by sixth-generation (6G) communication technologies are the essence of ITS. Vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications need to be studied to implement ITS in a secure, robust, and efficient manner, allowing massive connectivity in vehicular communications networks. Besides, with the rapid growth of different types of autonomous vehicles, it becomes challenging to facilitate the heterogeneous requirements of ITS. To meet the above needs, intelligent reflecting surfaces (IRS) are introduced to vehicular communications and ITS, containing the reflecting elements that can intelligently configure incident signals from and to vehicles. As a novel vehicular communication paradigm at its infancy, it is key to understand the latest research efforts on applying IRS to 6G ITS as well as the fundamental differences with other existing alternatives and the new challenges brought by implementing IRS in 6G ITS. In this paper, the authors provide a big picture of deep learning enabled IRS for 6G ITS and appraise most of the important literature in this field. By appraising and summarizing the existing literature, they also point out the challenges and worthwhile research directions related to IRS aided 6G ITS.]]></description>
      <pubDate>Mon, 11 Mar 2024 09:10:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/2307043</guid>
    </item>
    <item>
      <title>Experimental development and evaluation of a fiber bragg grating-based outside air temperature sensor for aircraft applications</title>
      <link>https://trid.trb.org/View/2286588</link>
      <description><![CDATA[This study presents the development and rigorous evaluation of a Fiber Bragg Grating (FBG)-based Outside Air Temperature (OAT) sensor designed for aircraft applications. Employing a Design of Experiments (DoE) approach, the research optimized the sensor's performance for reliability, accuracy, and durability in aviation environments. Experimental assessment covered detailed installation of the FBG sensor on an aircraft, considering influential parameters such as outside dimensions and varying temperature. The OAT sensor's design focused on robustness and precision for accurate real-time temperature recording, vital for operational efficiency and safety. Extensive statistical analysis assessed the sensor's performance under differing conditions, providing valuable insights into operational capabilities and overall efficacy. Thermo-climatic chamber tests simulated extreme environmental conditions to validate the sensor's durability and function under potential aircraft operational scenarios. This research enhances understanding of FBG-based OAT sensors for aircraft applications, demonstrating their superior robustness and performance capabilities, thereby contributing to aviation safety, operational efficiency, and data precision.© 2017 Elsevier Inc. All rights reserved.]]></description>
      <pubDate>Tue, 28 Nov 2023 10:25:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/2286588</guid>
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