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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
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    <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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      <link>https://trid.trb.org/</link>
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      <title>Modeling effects of roadway lighting photometric criteria on nighttime pedestrian crashes on roadway segments</title>
      <link>https://trid.trb.org/View/2233703</link>
      <description><![CDATA[Nighttime crashes account for 74% of pedestrian fatalities in the United States, and reduced visibility is a significant cause of nighttime pedestrian crashes. Maintaining sufficient and uniform roadway lighting is an effective countermeasure to improve pedestrian visibility and prevent nighttime pedestrian crashes and injuries. Previous studies have not quantified the safety effects of roadway photometric patterns (i.e., average lighting level and uniformity) on nighttime pedestrian crashes on roadway segments. This study investigated the association between two roadway photometric criteria (horizontal illuminance mean representing average lighting level and horizontal illuminance standard deviation representing lighting uniformity) and nighttime pedestrian crash occurrence in Florida roadway segments. The matched case-control method was used to decouple the confounding effects between the illuminance mean and standard deviation. Statistically-significant crash modification factors (CMFs) were developed to quantify the safety effects of the mean and standard deviation of horizontal illuminance on nighttime pedestrian crashes. The results show that if the average lighting level on a roadway segment is increased from a low illuminance mean (<0.2 foot-candle [fc]) to a medium illuminance mean [0.2 fc, 0.5 fc], a medium–high illuminance mean (0.5 fc, 1.0 fc], and a high illuminance mean (>1.0 fc), the relative likelihood of nighttime pedestrian crashes on midblock segments in Florida tends to be reduced by 77.5% (CMF = 0.225), 81.2% (CMF = 0.188), and 85.5% (CMF = 0.145), respectively. A poor uniformity (illuminance standard deviation ≥ 0.52 fc) is likely to increase the relative likelihood of nighttime pedestrian crashes on midblock segments in Florida by 80.3% (CMF = 1.803) compared to good uniformity (illuminance standard deviation < 0.52 fc).]]></description>
      <pubDate>Wed, 13 Sep 2023 10:23:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/2233703</guid>
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      <title>Evaluation and analysis of tunnel lighting service status based on driving safety</title>
      <link>https://trid.trb.org/View/2186162</link>
      <description><![CDATA[The service status of tunnel lighting has an important impact on driving safety. Existing research mainly discussed the impact of a single evaluation indicator of lighting service status on driving safety and paid less attention to the impact of multiple evaluation indicators on driving safety. In this research, field tests of tunnels in three speed scenarios and 52 service scenarios are completed. DIALux software was selected to simulate more intensive illuminance, which could be used to calculate U0, U1, qc, and C. Using U0, U1, qc, and C as explanatory variables, and applying the normalized visual recognition results as explained variables, ordinary least squares regression (OLS) was performed to calculate the influence weight of each explanatory variable on driving safety. The results show that the four independent variables occupied different weights under different working conditions. However, on the whole, U0 and U1 occupied a greater weight. The weight of C lies between qc and U0, and U1 and qc occupied the smallest weight in all scenarios. Locally, U0 was greater than U1, with the exception when the illumination attenuation value was 70%. The influence of the total uniformity of the road surface luminance and longitudinal uniformity of the road centerline luminance on driving safety was significantly greater than the influence of the contrast revealing coefficient and luminance contrast C on driving safety. When the luminous flux was attenuated to 70% or less and when the number of failed lamps was at least four, the lighting quality would be significantly reduced, which would substantially affect driving safety.]]></description>
      <pubDate>Wed, 21 Jun 2023 17:10:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/2186162</guid>
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    <item>
      <title>Lighting, Noise and Vibration Control, and Air Quality</title>
      <link>https://trid.trb.org/View/2006414</link>
      <description><![CDATA[Analyzing lighting, noise, and air quality programs early in the planning process is wise to identify who would be affected and address evident needs. Emerging techniques and technologies can assist the civil engineer in this regard. Design considerations for light, noise and vibration, and air quality previously dealt primarily with the finished product: the road, the building, or the neighborhood. This chapter explains ways to address economic, environmental, and social considerations. The Illuminating Engineering Society of North America (IES) has many guidance documents for roadway lighting design, including two ANSI standards: ANSI/IES RP-8-14 and RP-22-11. Guidelines for maximum noise levels allowed in various civil engineering contexts—on or alongside roads; in neighborhoods; and inside residential, commercial, and institutional buildings—are well established.]]></description>
      <pubDate>Mon, 26 Sep 2022 09:12:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/2006414</guid>
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    <item>
      <title>Safety evaluation of visual load at entrance and exit of extra-long expressway tunnel based on optimized support vector regression</title>
      <link>https://trid.trb.org/View/2006062</link>
      <description><![CDATA[The traffic environment of an extra-long expressway tunnel is more complex than that of a long tunnel, which increases the driving risk. The visual load of drivers can be used to evaluate driving safety and comfort. To reveal drivers’ visual load characteristics at the entrance and exit of extra-long tunnels on mountainous expressways, this study conducted vehicle tests with 12 drivers at Gonghe extra-long tunnel on the Yu-Xiang expressway in the Wulong District. An eye tracker, non-contact multifunctional velocimetry, illuminometer, and other test equipment were used to record drivers’ pupil areas, velocity, and illuminance when entering and leaving the tunnel. The change characteristics of drivers’ pupil areas were studied. The maximum transient velocity value (MTPA) of the pupil area was selected as an index to evaluate the visual load degree. Based on velocity and illuminance coupling, a visual load model was constructed using the optimized support vector machine (GA-SVM). The influence of velocity and illuminance on the MTPA in the tunnel’s approach, entrance, exit, and departure section was analyzed. The results show that drivers’ psychological tension order at the entrance and exit is entrance section ˜ exit section > departure section > approach section. In the approach section, the visual load is mainly affected by environmental illumination. In the entrance and exit sections, the visual load is positively correlated with velocity and negatively correlated with illuminance, and velocity has a greater impact on visual load. In the tunnel departure section, the two variables synergistically influence the driving visual load. The research results provide theoretical support for the safety design and management of extra-long tunnel entrances and exits.]]></description>
      <pubDate>Wed, 17 Aug 2022 09:33:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/2006062</guid>
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    <item>
      <title>LED Illumination for Commercial Vehicles</title>
      <link>https://trid.trb.org/View/1821948</link>
      <description><![CDATA[Light Emitting Diodes (LEDs) are commonly used for signaling and marking functions on commercial vehicles. Recent work on new LED modules will allow the use of LEDs for illumination functions.]]></description>
      <pubDate>Tue, 21 Jun 2022 14:26:21 GMT</pubDate>
      <guid>https://trid.trb.org/View/1821948</guid>
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    <item>
      <title>Challenges to Develop a Global Beam Pattern for ECE Markets Around the World</title>
      <link>https://trid.trb.org/View/1824353</link>
      <description><![CDATA[The vehicular illumination system has undergone considerable technological advances in recent decades such as the use of a Light Emitting Diode (LED) and HID (high intensity discharge) lamps. However, the challenges to develop a global beam pattern for ECE markets have been quite difficult due to different needs in different regions. Global programs have to deal with the differences among costumer needs and desires. This paper shows the challenges to understand the different needs and highlights the opportunities for the future to improve road illumination and the driver's safety adopting simulations and different road scenarios.]]></description>
      <pubDate>Fri, 17 Jun 2022 09:20:13 GMT</pubDate>
      <guid>https://trid.trb.org/View/1824353</guid>
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    <item>
      <title>Object Segmentation and Augmented Visualization Based on Panoramic Image Segmentation</title>
      <link>https://trid.trb.org/View/1847393</link>
      <description><![CDATA[Panoramic images can provide critical information for Advanced Driving Assistance Systems (ADAS), such as parking spaces and surrounding vehicles. However, the vehicle in the bird's-eye view image is severely distorted and incomplete, and the visual information becomes very blurred in some illumination insufficient environments. If the driver cannot see the surrounding environment information, the risk of collision will increase, especially during parking. To better percept the local environment with the help of panoramic images, the authors use panoramic image segmentation results to construct a virtual surround view monitoring system to provide drivers with clearer perception information. Firstly, a lightweight segmentation network is redesigned based on SegNet, which will improve the accuracy of the segmentation without increasing the model’s inference time. Secondly, the authors build an augment visualization around view monitor (AV-AVM) system with regards to the segmentation results. All necessary segmentation results will be presented as augmented visualization in AV-AVM systems, such as parking slots and road markings. Compared with the traditional panoramic system, the virtual panoramic surround view system the authors designed can provide the driver with more intuitive environmental perception information and can be further used to construct an automatic parking map.]]></description>
      <pubDate>Fri, 30 Jul 2021 17:50:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/1847393</guid>
    </item>
    <item>
      <title>Evaluation of Current Practice for Illumination at Roundabouts: Safety and Illumination of Roundabouts (Phase I)</title>
      <link>https://trid.trb.org/View/1402150</link>
      <description><![CDATA[This report is for the first phase of a two-phase research program to develop recommended practices for Georgia Department of Transportation (GDOT) for lighting rural roundabouts. Phase I of the study was designed to improve understanding of the relationship between roundabout illumination and safety, particularly in rural areas. Such information is essential to developing a sound basis for determining if a rural roundabout should, or should not, be illuminated to the current Illuminating Engineering Society (IES) standard and, if not, whether safety objectives can be met with either unlit roundabouts or roundabouts illuminated at reduced levels. The report provides a summary of relevant literature; international practices for rural roundabout illumination, a safety analysis of nighttime roundabout crashes using data from Minnesota and Georgia and provides preliminary results regarding the cost effectiveness of unlit or partially lit roundabouts as rural safety treatments.]]></description>
      <pubDate>Fri, 22 Apr 2016 10:46:04 GMT</pubDate>
      <guid>https://trid.trb.org/View/1402150</guid>
    </item>
    <item>
      <title>Design of primary optics for LED chip array in road lighting application</title>
      <link>https://trid.trb.org/View/1118251</link>
      <description><![CDATA[The advantages of light-emitting diodes (LED) over conventional light sources are well known - monochromaticity, energy and space savings, reliability and longer service life. More LED chips must be integrated on a blase plate to achieve the various luminaries comparable to conventional light sources. This paper outlines research that uses LED chip array packaging (LCAP) modules to create luminaries that can be configuring for different lighting situations - bi-direction, three-lane major road, and so on. Computer modeling to simulating the different lighting environments was used to not only design and optimize the LCAP, but also to simulate different roadway lighting environments.]]></description>
      <pubDate>Fri, 21 Oct 2011 07:38:26 GMT</pubDate>
      <guid>https://trid.trb.org/View/1118251</guid>
    </item>
    <item>
      <title>Precast Concrete Parking Structure Lighting Study</title>
      <link>https://trid.trb.org/View/849105</link>
      <description><![CDATA[Among some members of the design community, there is a perception that lighting of precast concrete parking structures is not as efficient as lighting of posttensioned (PT) concrete parking structures. This perception occurs because it is assumed there is more light blockage from the closely spaced, precast concrete double-tee stems compared with wider spacing of beams in a PT concrete parking structure. This paper details a study performed to compare the lighting systems for precast concrete parking structures vs. PT concrete parking structures. The study indicates there is no difference in horizontal illuminance on the floor, or vertical illuminance on the perimeter walls, for identical lighting configurations in precast concrete and PT concrete parking structures. This conclusion requires that the bottom of each luminaire in the precast concrete parking structure is pendant-mounted and that the luminaires are no more than 6 in. above the bottom of the double-tee stem and centered between the 5 ft. double-tee stem spacing. The configuration of the 2 parking structures, the lighting configurations, the design methodology, and the results of the analysis are described.]]></description>
      <pubDate>Fri, 01 Feb 2008 08:18:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/849105</guid>
    </item>
    <item>
      <title>An Examination and Recommendation for Current Practices in Roundabout Lighting</title>
      <link>https://trid.trb.org/View/775440</link>
      <description><![CDATA[In 2000, the Federal Highway Administration (FHWA) and the American Association of State Highway and Transportation Officials (AASHTO) sponsored an international scan on the topic of roadway lighting. One of the topics covered in the international scan was roundabout lighting design practices. At the same time, the FHWA was actively promoting the use of roundabout intersections in the United States based on their safety and operational benefits. On return from the international scan, it was observed that there were a wide variety of practices with regard to roundabout lighting and that there was not a uniform understanding about what the recommended design practice should be. In response to this the Illuminating Engineering Society of North America (IESNA) Roadway Lighting Committee created a subcommittee to examine this issue and develop design guidelines for roundabout lighting. The authors of this paper are both members of the subcommittee. The current study was initiated in support of the IESNA effort in order gather information on the specific practices for lighting roundabouts in the United States and to obtain a better quantitative understanding of what constitutes a well lit roundabout in order to assist the IESNA in developing practical guidelines. The study evaluates the lighting at four roundabout sites with different levels of lighting and different lighting configurations. In addition to assessing general visibility criteria, the project examined overall roadway and pedestrian visibility. Various methods for collecting data are described and computer modeling results are presented.]]></description>
      <pubDate>Mon, 27 Feb 2006 08:54:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/775440</guid>
    </item>
    <item>
      <title>Iowa's High-Mast Lighting Towers: A Proactive Approach to a Problem</title>
      <link>https://trid.trb.org/View/760357</link>
      <description><![CDATA[The Iowa DOT owns 233 high-mast lighting towers, ranging from 100 to 180 feet tall. These structures are typically located at the intersection of major highways and interstates and provide broad illumination to the traveling public. In 2000, a statewide inspection was conducted of the 193 towers in the inventory at that time. A 140-foot tower located near Sioux City collapsed in 2003 due to the development of a large fatigue crack at the welded connection at the base plate. Subsequently, cracks were found in 20 other towers.  In all cases, the cracked structures were taken out of service.  This paper will present forensic information about the collapsed and cracked towers and describe the instrumentation and long-term monitoring of Iowa towers. Preliminary findings of the monitoring will be included. The goal of the testing is to determine the types of vibration and stress ranges that the towers are experiencing. This testing will provide a better understanding of the ways the towers in Iowa will perform over time and will help develop policy for long-term inspection and maintenance of these structures.]]></description>
      <pubDate>Fri, 30 Sep 2005 08:12:02 GMT</pubDate>
      <guid>https://trid.trb.org/View/760357</guid>
    </item>
    <item>
      <title>Roadway Lighting</title>
      <link>https://trid.trb.org/View/759183</link>
      <description><![CDATA[This chapter describes how the ability to see is essential for the safe and efficient flow of traffic on highways.   However, in many instances, limitations of the human eye prevent vehicle headlights alone from completely satisfying visual nighttime driving requirements.  Fixed roadway lighting supplements vehicle headlights by extending the visibility range both longitudinally and laterally, thus aid the driver by providing earlier warning of hazards on or near the roadway.  Previous research has shown that the nighttime accident rate can be reduced by the provision of adequate lighting.  Lighting defines the roadway geometrics, such as the edge of pavement, curves, dead ends, and illuminates obstructions in or near the roadway, including channelization islands, bridge piers, and parked cars.  Lighting allows the drive to see a pedestrian in the roadway beyond the headlight beam and even before the pedestrian enters the road.  It also aids pedestrians by illuminating obstacles on the sidewalk and roadway in their vicinity.  Lighting raises the surrounding brightness level to which the driver’s eyes adapt and it also increases the drivers contrast sensitivity, which results in an overall improvement in the driver’s ability to see.  Fixed roadway lighting also contributes to a more pleasant and comfortable night driving environment, which in turn, reduces driver fatigue and improves driver efficiency.  Lighting is also an aid to police surveillance, and a reduction in street crimes may be experienced following installation of improved street illumination.]]></description>
      <pubDate>Thu, 11 Aug 2005 13:36:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/759183</guid>
    </item>
    <item>
      <title>Concerning Lamps and Static Bend Lighting - Performance Aspects and Technical Comparison in AFS-Systems</title>
      <link>https://trid.trb.org/View/751030</link>
      <description><![CDATA[This paper describes how one of the most important features of a headlamp with adaptive light distribution is the improved side illumination for driving situations in towns, at intersections and in small radius curves.  Pending legal requirements will allow the use of bending light realized by side illumination from either a part of the low beam or a separate cornering lamp.  The first part of this paper compares the legal requirements of both SAE and ECE regulations for bend lighting and cornering lamps.  The second part discusses the performance of different lamps developed on the basis of these regulations and they are compared with respect of technical and performance aspects.]]></description>
      <pubDate>Thu, 05 May 2005 12:22:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/751030</guid>
    </item>
    <item>
      <title>REDUCED FREEWAY LIGHTING</title>
      <link>https://trid.trb.org/View/269828</link>
      <description><![CDATA[The paper discusses various systems that have been employed to reduce roadway lighting, their costs, benefits, and potential legal problems that must be addressed.  Two general types of systems were identified: 1) older and oil-embargo related systems, such as extinguishing the lighting on all or part of specified roadways during various time periods and 2) modern systems that are controlled by special ballasts, electronic sensors and controls, and computers.  It is concluded that under both the common law and state Tort Claims Acts, the specter of liability is present for a municipal entity which seeks to reduce or eliminate lighting on its highways during periods of low traffic density.  Any municipal agency which undertakes such a program will be well advised to do so only after extensive scientific research and study.]]></description>
      <pubDate>Fri, 27 Aug 2004 21:56:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/269828</guid>
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