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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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      <title>Safety Evaluation of Red-Light Indicator Lights (RLILs)</title>
      <link>https://trid.trb.org/View/1489840</link>
      <description><![CDATA[This document is a technical summary of the Federal Highway Administration (FHWA) report "Safety Evaluation of Red-Light Indicator Lights (RLILs) at Intersections" (FHWA-HRT-17-077). The FHWA established the Development of Crash Modification Factors (DCMF) program in 2012 to address highway safety research needs for evaluating new and innovative safety strategies (improvements) by developing reliable quantitative estimates of their effectiveness in reducing crashes. The goal of the DCMF program is to save lives by identifying new safety strategies that effectively reduce crashes and promote those strategies for nationwide implementation by providing measures of their safety effectiveness and benefit–cost (B/C) ratios through research. State transportation departments and other transportation agencies need to have objective measures for safety effectiveness and B/C ratios before investing in broad applications of new strategies for safety improvements. Forty State transportation departments provide technical feedback on safety improvements to the DCMF program and implement new safety improvements to facilitate evaluations. These States are members of the Evaluation of Low-Cost Safety Improvements Pooled Fund Study, which functions under the DCMF program. This study investigated the safety effectiveness of red-light indicator lights (RLILs). This effort was intended to reduce the frequency of crashes resulting from drivers disobeying traffic signals by providing a safer and more efficient means for police to enforce the red interval and educate drivers about the existence and purpose of RLILs. Few studies have explored the safety effectiveness of RLILs; specifically, studies have not shown the crash-based safety effectiveness for four-legged intersections. This study sought to fill this knowledge gap.]]></description>
      <pubDate>Sat, 02 Dec 2017 17:49:38 GMT</pubDate>
      <guid>https://trid.trb.org/View/1489840</guid>
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      <title>Safety Evaluation of Red-Light Indicator Lights (RLILs) at Intersections</title>
      <link>https://trid.trb.org/View/1489837</link>
      <description><![CDATA[The Development of Crash Modification Factors program conducted the safety evaluation of red-light indicator lights (RLILs) at intersections for the Evaluation of Low-Cost Safety Improvements Pooled Fund Study. This study evaluated safety effectiveness of RLILs. RLILs are auxiliary lights mounted on signal heads, mast arms, or poles that are directly connected to a traffic-control signal. The RLIL activates at the onset of the red phase and allows an enforcement officer to observe red-light running from downstream of the intersection. This strategy is intended to reduce the frequency of crashes resulting from drivers disobeying traffic signals by providing a safer and more efficient means for police to enforce the red interval. Geometric, traffic, and crash data were obtained at treated four-legged signalized intersections in Florida. To account for potential selection bias and regression-to-the-mean, an empirical Bayes before–after analysis was conducted using reference groups of untreated four-legged signalized intersections with characteristics similar to those of the treated sites. The analysis also controlled for changes in traffic volumes over time and time trends in crash counts unrelated to the treatment. Results indicate statistically significant crash reductions for most crash types. Disobeyed signal crashes had an estimated crash modification factor (CMF) of 0.71. Total crashes, fatal and injury crashes, right-angle, and left-turn crashes had estimated CMFs of 0.94, 0.86, 0.91, and 0.60, respectively. The benefit-cost ratio estimated with conservative cost and service life assumptions was 92:1 for four-legged signalized intersections. The results suggest that the treatment, even with conservative assumptions on cost, service life, and the value of a statistical life, can be cost effective. In addition to the crash-related benefits, RLILs can improve the efficiency and safety of red-light running enforcement efforts. While this study did not evaluate the efficiency and safety impacts with respect to enforcement, it should be noted that RLILs do allow police to observe violators from a downstream position, eliminating the need for a second observer (upstream) and the need to pursue a violator through the red light.]]></description>
      <pubDate>Sat, 02 Dec 2017 17:49:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/1489837</guid>
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      <title>A STATE-OF-THE-ART SURVEY OF THE DEVELOPMENT OF TAXIWAY GUIDANCE AND CONTROL SYSTEMS</title>
      <link>https://trid.trb.org/View/177499</link>
      <description><![CDATA[This study consisted of a review and analysis of the historical background of taxiway lighting and marking, its functions and development. The study emphasized the block control system used at Heathrow, the problems associated with manual and automated control of stop, hold and clearance bars, and the problems associated with automated surface movement control. The study provides the present status of developments and recommendations for future research endeavors. (Author)]]></description>
      <pubDate>Sun, 30 Nov 2003 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/177499</guid>
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      <title>ESTABLISHMENT CRITERIA FOR VISUAL APPROACH SLOPE INDICATOR (VASI)</title>
      <link>https://trid.trb.org/View/56640</link>
      <description><![CDATA[This report develops revised establishment and discontinuance criteria for Visual Approach Slope Indicator (VASI) which provide Visual Flight Rules (VFR) guidance only. Criteria are based upon detailed benefit/cost methodology. This approach takes into account the number of aircraft landings by user class with variations depending upon whether or not the runway is equipped with an Instrument Landing System. Benefits derived from a VASI were principally in the area of safety which are obtained by improved guidance during final VFR approaches. Revised criteria require that a ratio value be computed for each of the three types of operations (air carrier, air taxi, and general aviation including military). The three ratios are then added to obtain a total ratio value, and this is multiplied by the runway utilization to obtain a net ratio value. If this net ratio value is equal to 1 or greater, then the runway is a candidate for a VASI. In the short term, it is estimated that 590 runways now without a VASI will qualify. Over the next ten years, an additional 388 runways are expected to qualify for a VASI. (Author)]]></description>
      <pubDate>Tue, 29 Oct 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/56640</guid>
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      <title>VORTEX ADVISORY SYSTEM. VOLUME I. EFFECTIVENESS FOR SELECTED AIRPORTS</title>
      <link>https://trid.trb.org/View/155858</link>
      <description><![CDATA[The Vortex Advisory System (VAS) is based on wind criterion--when the wind near the runway end is outside of the criterion, all interarrival Instrument Flight Rules (IFR) aircraft separations can be set at 3 nautical miles. Five years of wind data have been obtained for 20 airports. By comparing the VAS wind criterion to the 5 years of wind data, the percentages of time that interarrival separations can be reduced at the 20 airports have been found. The percentages are given on an hourly and a monthly basis. Volume II (to be published at a later date) will examine the VAS effectiveness at Chicago O'Hare (ORD) with respect to the length of the intervals during which reduced separations might have been used. (Author)]]></description>
      <pubDate>Sun, 27 Oct 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/155858</guid>
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      <title>CONSPICUITY OF THE FRONT DIRECTION INDICATOR IN COMBINATION WITH A D1 HEADLAMP</title>
      <link>https://trid.trb.org/View/460505</link>
      <description><![CDATA[In the frame of the European research project VEDILIS (VEhicle DIscharge LIghting System) the conspicuity of the front direction indicator in combination with a D1 headlamp was studied by simulation in the laboratory.  The conspicuity was measured by determining the maximum angle between the line of sight and direction indicator, at which the indicator was perceptible.  Rectangular lamps were studied, at 25 m distance. The distance between the headlamp and the direction indicator (separation) was varied between 0 and 40 cm.  Three headlamp sizes (3x6, 6x12, 12x24 cm) and three corresponding indicator sizes (3x6, 6x8, 12x8 cm) were used.  In addition three intensity ratios were studied, low (0.028), medium (0.31), and high (3.44).  In the laboratory experiments this situation was scaled down a factor five.  In the unfavorable condition with a low intensity ratio, the conspicuity of the direction indicator was strongly affected by the separation.  In this condition the mean conspicuity angle at separations of 0 and 40 cm was, respectively, 10 and 65 deg.  For medium and high intensity ratios the conspicuity was high, and practically independent of the separation.  Conspicuity angles larger than 70 deg were found in these conditions.  An affect of lamp size was only found for the low intensity ratio.  A factor four increase of lamp area, with a constant luminous intensity, caused 6 deg increase of conspicuity angle of the direction indicator.]]></description>
      <pubDate>Tue, 13 Aug 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/460505</guid>
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      <title>KOERRIKTNINGSVISARE PA MOPED - EN UNDERSOEKNING (DIRECTION INDICATORS ON MOPEDS - A SURVEY)</title>
      <link>https://trid.trb.org/View/169067</link>
      <description><![CDATA[This report describes a study of direction indicators for mopeds. The purpose of the study was to give a basis for a decision on a possible change of the Swedish law regarding direction indicators and also a basis for the work on ECE regulations.]]></description>
      <pubDate>Sat, 15 Aug 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/169067</guid>
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      <title>SURVEY OF DRIVER AID DEVICES FOR IMPROVED FUEL ECONOMY</title>
      <link>https://trid.trb.org/View/47900</link>
      <description><![CDATA[This report presents a brief summarization of available information pertaining to devices offered to aid the driver in improving his driving habits in order to reduce fuel consumption. Principal emphasis is placed on characterizing the available devices in terms of their features and operating principles. When appropriate, possible side effects (e.g., safety considerations) occasioned by the use of such devices are examined. The available fuel economy test data for drivers who had received training only (no auxiliary or aid devices) are reviewed for comparison purposes.]]></description>
      <pubDate>Wed, 11 May 1977 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/47900</guid>
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      <title>STUDIES OF SUBMINIATURE LAMPS USED FOR INDICATING PURPOSES IN THE SYSTEM MAINTENANCE MONITOR CONSOLE</title>
      <link>https://trid.trb.org/View/30010</link>
      <description><![CDATA[Under subprogram 121-101, one of the tasks was to investigate alternate lamps to replace the type 247 subminiature lamps which are currently used in the projection readout indicators of the system maintenance monitor console. This report discusses the various tests that were conducted in the process of this investigation. The results of these tests are intended to provide assistance in bringing about the replacement of the existing lamp in an orderly and expeditious manner.]]></description>
      <pubDate>Wed, 29 Dec 1976 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/30010</guid>
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