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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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    <item>
      <title>Developing a Prototype System for Establishing Passing and No-Passing Zones of Two-Lane Highways</title>
      <link>https://trid.trb.org/View/2425084</link>
      <description><![CDATA[Two-lane highways comprise a considerable percentage of the nation's roads. A critical component required in the design of two-lane highways is the passing sight distance (PSD). In cases where it is inadequate, no-passing zones are established. There are multiple techniques employed for measuring the PSD in the field, and the Wyoming Department of Transportation (WYDOT) implements the two-vehicle method. However, WYDOT's apparatus used to implement the method is no longer functional. Hence, this project was aimed at proposing two state-of-the-art prototypes of the two-vehicle method and the first prototype, named Prototype 1, was replicated. The second prototype, Prototype 2, was designed to automate some of the functions of Prototype 1 by incorporating advanced intelligent transportation system devices. After the delivery of Prototype 1's units and that of the latter to WYDOT, the former's units were retrieved and upgraded such that their functionalities were similar to that of Prototype 2. As per the results of the testing of both prototypes, the equipment was not only efficient but also produced accurate results.]]></description>
      <pubDate>Fri, 06 Sep 2024 16:58:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/2425084</guid>
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    <item>
      <title>Developing a Prototype System for Establishing Passing and No-Passing Zones of Two-Lane Highways</title>
      <link>https://trid.trb.org/View/2301642</link>
      <description><![CDATA[Two-lane highways comprise a considerable percentage of the nation’s roads. A critical component required in the design of two-lane highways is the passing sight distance (PSD). In cases where it is inadequate, no-passing zones are established. There are multiple techniques that are employed for measuring the PSD in the field and the Wyoming Department of Transportation (WYDOT) implements the two-vehicle method. However, WYDOT’s apparatus that is used to implement the method is no longer functional. Hence, this project was aimed at proposing two state-of-the-art prototypes of the two-vehicle method and the first prototype, named Prototype 1, was replicated. The second prototype, Prototype 2, was designed to automate some of the functions of Prototype 1 by incorporating advanced intelligent transportation system devices. After the delivery of Prototype 1’s units and that of the latter to WYDOT, the former’s units were retrieved and upgraded such that their functionalities were similar to that of Prototype 2. As per the results of the testing of both prototypes, the equipment were not only efficient but also produced accurate results.]]></description>
      <pubDate>Mon, 11 Dec 2023 10:35:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2301642</guid>
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    <item>
      <title>Analysis of no-passing zones to assess the level of service on two-lane rural highways in Brazil</title>
      <link>https://trid.trb.org/View/1898854</link>
      <description><![CDATA[The highway capacity manual (HCM) is used to assess the level of service on two-lane rural highways in several countries, including Brazil. The 6th version of the HCM will address the capacity and level of service for two-lane highways based on follower density (FD). Studies have been conducted in Brazil to obtain a suitable method for calculating the level of service on two-lane highways. However, there are no studies that have determined the impact of no-passing zones involving FD, which is the main objective of this research. To achieve this goal, a set of traffic data was obtained from highway segments with the primary purpose of calibrating and validating the VISSIM traffic simulator used in this study. Using the simulator, traffic data were generated in hypothetical highway segments with a wide range of geometric and traffic characteristics. Traffic relationships for the simulation data were adjusted for the following conditions: (i) without no-passing zones, and (ii) with no-passing zones. The results of the analysis indicate that the models proposed in this study produce level of service and FD values close to values observed in the field.]]></description>
      <pubDate>Mon, 24 Jan 2022 10:49:13 GMT</pubDate>
      <guid>https://trid.trb.org/View/1898854</guid>
    </item>
    <item>
      <title>Introducing a New Apparatus for Designating Two-Lane Highway Passing and No-Passing Zones</title>
      <link>https://trid.trb.org/View/1770087</link>
      <description><![CDATA[Two-lane highways constitute a large proportion of the U.S. highways. An essential component needed in the design of safe two-lane highways is the passing sight distance (PSD). Otherwise, insufficient PSDs lead to passing-related crashes and, therefore, no-passing zones ought to be marked. This research involves the development of a new apparatus of the two-vehicle method, which is used for measuring the PSD in the field. That is to replace the defunct apparatus used by the Wyoming Department of Transportation (WYDOT). To the best of the authors’ knowledge, the introduced apparatus is the most up-to-date system and addresses shortcomings of previous research. The two-vehicle method involves two successive vehicles spaced at a gap, equivalent to PSD, and both vehicles travel at the speed limit. The driver of the rear vehicle operates a switch when the lead vehicle becomes invisible because of sight obstructions, such as vegetation, signaling the beginning point of the no-passing zone. Similarly, the switch is operated when the lead vehicle returns to view to designate the endpoint of the no-passing zone. The apparatus is composed of vehicle-to-vehicle radio communication devices, global positioning system devices, the switch and computers with graphical user interfaces to record and display the data. Testing was conducted on two two-lane highway segments. As per the results, overall discrepancies between WYDOT’s no-passing zone markings and those designated by the apparatus, developed, ranged from 1% to 7%. This research lays the foundation for a future study involving the development of a cutting-edge prototype.]]></description>
      <pubDate>Thu, 25 Feb 2021 10:14:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/1770087</guid>
    </item>
    <item>
      <title>A Streamlined and Automated Procedure for Identifying No-Passing Zones Using Existing Resources Available to the Nevada Department of Transportation</title>
      <link>https://trid.trb.org/View/1577688</link>
      <description><![CDATA[Computer aided design (CAD) and geographic information systems (GIS) software should make the identification of no-passing zones possible with the click of a button. However, most highways were built before the use of CAD and GIS software was standard practice in highway design. As a result, the identification of highway segments that require no-passing zone markings is often achieved by transportation agencies using the two-vehicle method field procedure. The two-vehicle method is inherently labor intensive and time-consuming, thus the need for streamlined procedures that can be adopted by transportation agencies. The Nevada DOT (NDOT) continuously conducts asset inventory surveys along highways using an instrumented data collection vehicle. An indirect result of the process includes an accurate dataset that describes the path followed by the data collection vehicle. Software that relies on the vehicle path dataset as input to create a model of the corresponding highway geometry was developed. Using the model, the software automates the identification of theoretical line of sight obstructions based on input from the user. Therefore, the software developed provides NDOT with a decision support system that allows identifying highway segments that are candidates for no-passing zones without the need for dedicated and labor-intensive field surveys.]]></description>
      <pubDate>Wed, 30 Jan 2019 10:17:13 GMT</pubDate>
      <guid>https://trid.trb.org/View/1577688</guid>
    </item>
    <item>
      <title>A Novel Real-time Visualization Algorithm for Computing Three-dimensional Sight Distance</title>
      <link>https://trid.trb.org/View/1494463</link>
      <description><![CDATA[A few models have been developed for computing the three-dimensional available sight distance (3D ASD), but nearly all of these existing models/algorithms have simplifications to the road environment, especially to the roadside obstructions. In this paper, a real-time visualization algorithm was proposed for determining the available 3D sight distance. The road environment was represented by the dense and organized 3D points along the spatial alignment while the crown slopes, superelevation, widening, etc. were all considered for the roadway and almost no simplification was made to the roadside obstacles. The driver’s dynamic vision along the highway was simulated and digitized with the sequential application of 3D coordinate transformation and perspective projection. A new concave hull algorithm was proposed to facilitate the process of searching for the sight obstacles. The result of the 3D sight distance and the instantaneous vision of the driver at a given position were outputted simultaneously. The new algorithm makes it possible to identify obstacles obstructing the line of sight, ensure the correctness of the sight distance, and provide basis for real-time safety applications. The algorithm can also be applied to undertake geometric consistency audits, road safety audits, and to determine passing or no-passing zones on two-lane highways. A case study was also presented to demonstrate the validity and superiority of the proposed algorithm over 2D models and other 3D models.]]></description>
      <pubDate>Mon, 26 Mar 2018 14:31:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/1494463</guid>
    </item>
    <item>
      <title>Improper Passing Related Crashes on Rural Roadways: Using Association Rules Negative Binomial Miner</title>
      <link>https://trid.trb.org/View/1439264</link>
      <description><![CDATA[Significant numbers of crashes end in rural roadways due to the lack of effective countermeasures to separate opposing traffic flows. As a result, a major concern involves vehicles crossing the centerline and ending in either sideswiping or head-on collisions on undivided roadways. At the same time, improper passing related crashes are also seen on divided roadways. Passing vehicles in either passing permitted or no passing zone requires complex interaction. For this task, a driver needs several judgments based on dynamic variables and allows little room for driver error yet can result in drastic consequences if performed improperly. By seeking to explore these types of crashes even further, researchers hope to gain knowledge that will contribute to reducing both the number of lives lost and severity of these types of crashes. This study used the second Strategic Highway Research Program’s (SHRP-2) Roadway Inventory Database (RID) crash data for Florida rural roadways to investigate improper passing related crashes. This study used an unsupervised data mining technique (known as association rules negative binomial (NB) miner) to extract the knowledge pattern of co-occurrence of the significant variables. The findings of this study would be beneficial for the safety practitioners and policy makers in decision making to reduce crashes due to improper passing.]]></description>
      <pubDate>Wed, 01 Mar 2017 16:08:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/1439264</guid>
    </item>
    <item>
      <title>No-Passing Zone System: User's Manual</title>
      <link>https://trid.trb.org/View/1420205</link>
      <description><![CDATA[This User’s Manual is intended for traffic engineers and technicians who will be either conducting passing sight distance measurement runs in the field or processing the collected data in the office. This User’s Manual includes: (1) A description of the individual hardware components of the system; (2) Instructions for connecting and powering hardware components for data collection; (3) Functional specifications of field data collection software; (4) Instructions for completing field data collection software set-up; (5) Instructions for completing a data collection run in the field; (6) Guidance for managing and storing field data; (7) Functional specifications and report descriptions for post-processing software; and (8) Instructions for generating and interpreting reports. For more information, see final report cmr 16-017 at http://library.modot.mo.gov/RDT/reports/TR201514/.]]></description>
      <pubDate>Mon, 29 Aug 2016 11:10:53 GMT</pubDate>
      <guid>https://trid.trb.org/View/1420205</guid>
    </item>
    <item>
      <title>Developing a System to Identify Passing and No Passing Zone Boundaries on Rural Two-Lane Highways</title>
      <link>https://trid.trb.org/View/1420185</link>
      <description><![CDATA[MRIGlobal developed an automated system to measure and display the distance between two instrumented vehicles traveling along a road. The system uses global positioning system (GPS) modules and radio modems to send location information between the vehicles five times per second. A field software was developed to calculate the distance between the vehicles based on this GPS data in real time and report it to the following driver. The field software is designed to allow the two vehicles to identify locations along a two-lane road where minimum passing sight distance is available. A post-processing software was also developed to produce a recommended striping plan, for both directions of travel along the route, based on the data recorded by the field data collection software. This system can be operated at near-highway speeds.]]></description>
      <pubDate>Mon, 29 Aug 2016 11:10:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/1420185</guid>
    </item>
    <item>
      <title>Operational Effects of Slow Vehicle Turnouts on a Rural Highway in Alaska</title>
      <link>https://trid.trb.org/View/1412402</link>
      <description><![CDATA[The Sterling Highway is a two-way, two-lane rural principal arterial located on the Kenai Peninsula of Alaska that connects Homer to Soldotna and areas north, including Anchorage. Annual average daily traffic (AADT) in 2013 varied from 5,300 vehicles per day to 2,400 vehicles per day throughout the 70-mile study corridor; however, there is significant seasonal variation in traffic volumes such that typical summer time traffic is 150% to 200% of AADT. The Sterling Highway carries significant levels of recreational vehicles or vehicles pulling a trailer. Twenty-two slow vehicle turnouts (SVTs) were constructed on the 70-mile section of the Sterling Highway between Homer and Soldotna in the summer of 2014. Prior to this, there were no passing lanes or designated SVTs within the project area. Speed, volume, and gap data were collected in the project area both before and after construction of the slow vehicle turnouts. Prior to construction, the expected operational benefit was calculated in terms of change in percent impeded dependent upon the percentage of leading vehicles using the turnouts. This paper reports on the actual change in percent impeded and makes conclusions about the efficacy of slow vehicle turnouts for operational improvements.]]></description>
      <pubDate>Tue, 28 Jun 2016 16:22:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/1412402</guid>
    </item>
    <item>
      <title>Algorithm for Analyzing Horizontal Sight Distance from Lane Centerline Coordinates</title>
      <link>https://trid.trb.org/View/1278373</link>
      <description><![CDATA[An algorithm for analyzing the availability of horizontal sight distance on two-lane highways to establish the location of no-passing zones is described. The intent was to incorporate the algorithm into a computer model that could use coordinates of a lane centerline as the input and evaluate the availability of horizontal sight distances. The algorithm was applied to develop a method for locating no-passing zones that was more efficient, accurate, and safe than the current methods that require field measurements. The algorithm uses vector product calculations to derive the geometry of the roadway centerline from spatial coordinates of available data points that represent the center of the travel lane. From the roadway centerline definition, the algorithm defines the location of visual clear zone boundaries on both sides of the roadway. Finally, the algorithm uses the roadway centerline and visual clear zone boundary information to determine whether sufficient passing sight distance exists at each point along the centerline.]]></description>
      <pubDate>Mon, 25 Nov 2013 10:46:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/1278373</guid>
    </item>
    <item>
      <title>Highway Safety Requirements for Low-Volume Rural Roads</title>
      <link>https://trid.trb.org/View/1262976</link>
      <description><![CDATA[No abstract.]]></description>
      <pubDate>Fri, 27 Sep 2013 15:04:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/1262976</guid>
    </item>
    <item>
      <title>Using GPS to Locate No-Passing Zones on Straight Sections of Two-Lane Highways</title>
      <link>https://trid.trb.org/View/1251109</link>
      <description><![CDATA[This article describes a method of using global positioning system (GPS) coordinates to identify the location of no-passing zones in vertical curves. It details a new application of a mathematical technique to smooth GPS data and obtain a geometric model of the roadway, then describes an analytical algorithm for analyzing the availability of sight distance along the vertical profiles of two-lane highways. The algorithm is incorporated into a computer model that can use GPS data as the input and produce a more efficient, accurate, and safe method of locating no-passing zones compared with the current field measurement methods, which place crews on highways in the presence of moving traffic. The automated system processes GPS coordinates and converts them into easting and northing values, smooths GPS data, and evaluates road profiles for possible sight restrictions, which indicate where no-passing zones should be located according to the vertical alignment. In a comparison of these results with existing pavement markings, the model shows potential for evaluating available sight distance and locating no-passing zones.]]></description>
      <pubDate>Tue, 28 May 2013 09:36:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/1251109</guid>
    </item>
    <item>
      <title>Criteria for No-Passing Zones : Technical Paper</title>
      <link>https://trid.trb.org/View/1219077</link>
      <description><![CDATA[The concept presently used by most states for establishing and marking no-passing zones on two-lane highways legally prohibits motorists from driving on the left side of a yellow line throughout the length of a no-passing zone. The shortcomings of this concept, called the short zone concept, are well known. It is physically impossible for motorists to always complete a passing maneuver without crossing the yellow line because of the limited visibility of no-passing zone signs and pavement markings. Furthermore, the crossing of a yellow line to complete a passing maneuver begun prior to the beginning of a no-passing zone is not an unsafe practice. An alternative to the short zone concept is a concept that allows the yellow line to be crossed for the purpose of completing a passing maneuver. This concept, called the long zone concept, prohibits the beginning of a passing maneuver in a marked no-passing zone. The purpose of this study was to determine which no-passing zone concept should be adopted to assure maximum safety and comfort for the motoring public, and to determine appropriate criteria and legislation to implement the recommended concept. The results of the research indicate that the long zone concept, which legally allows the completion of a passing maneuver within a no-passing zone, should be adopted. Criteria for marking no-passing zones and a model law required to implement the concept were developed.]]></description>
      <pubDate>Wed, 19 Dec 2012 09:01:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/1219077</guid>
    </item>
    <item>
      <title>Automating the Process for Locating No-Passing Zones Using Georeferencing Data</title>
      <link>https://trid.trb.org/View/1222615</link>
      <description><![CDATA[This research created a method of using global positioning system (GPS) coordinates to identify the location of no-passing zones in two-lane highways. Analytical algorithms were developed for analyzing the availability of sight distance along the alignments of two-lane highways. The main algorithm was incorporated into a computer model that uses GPS data as the input and produces a method for locating no-passing zones. The resulting automated system processes GPS coordinates and converts them into easting and northing values, smoothes GPS data, and evaluates roadway alignment for possible sight restrictions that indicate where no-passing zones should be located.]]></description>
      <pubDate>Fri, 30 Nov 2012 08:56:10 GMT</pubDate>
      <guid>https://trid.trb.org/View/1222615</guid>
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