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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>
    <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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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Investigating Crash Contributing Factors at Public Highway-Railroad Grade Crossings in Kentucky</title>
      <link>https://trid.trb.org/View/2562244</link>
      <description><![CDATA[Highway-railroad grade crossings (HRGCs) are intersections where transportation modes like trains, vehicles, and pedestrians converge. The US records over 2,000 crashes and 200 fatalities annually at HRGCs, with Kentucky showing an upward trend in severe crashes from 2021 to 2023. Considering the aforementioned statistics, this study evaluates crash contributory factors at Kentucky’s public HRGCs and recommends targeted safety improvements. This study analyzed 1,117 crashes at public HRGCs in Kentucky from 2014 to 2023 using data from the Kentucky Transportation Cabinet (KYTC). The contributing factors examined included crash-related factors (e.g., collision type and at-fault vehicle type), driver behaviors (e.g., aggressive driving), geometric features (e.g., presence of curves, grades, channelization, and track signalization), and environmental conditions (e.g., weather and crash timing). Statistical methods, including Chi-square test and odds ratio (OR), were applied. Additionally, police crash narratives were manually investigated in detail to identify the potential causes of HRGC-related crashes. The Chi-square test of independence showed that the manner of collision, at-fault vehicle type, speeding, presence of channelization nearby HRGCs, number of lanes, and time of crash significantly impacted the severity of crashes at HRGCs. Furthermore, the OR results indicated that the odds of severe crashes at HRGCs involving head-on collisions, motorcycles, higher speed limits (≥45 mph), presence of channelization, bi-directional traffic movement, more number of traffic lanes, and off-peak night/dawn were 10.37, 15.03, 2.355, 0.52, 2.6, 2.54, and 2.25, respectively. Additionally, the in-depth investigation of HRGC crash narratives indicated that driver behavior (lane changing and making left turns) significantly contributed to HRGC crashes. The study suggested installing channelizing islands, reflective road markings, and chevron signs with retroreflective strips before sharp horizontal curves leading to HRGCs to help reduce severe HRGC-related crashes.]]></description>
      <pubDate>Fri, 20 Feb 2026 15:28:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/2562244</guid>
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    <item>
      <title>A dynamic continuous flow intersection collaborative control framework based on virtual channelization in an intelligent connected environment</title>
      <link>https://trid.trb.org/View/2544112</link>
      <description><![CDATA[This study proposes a dynamic continuous flow intersection cooperative (DCFIC) control framework, integrating traditional continuous flow intersections with connected and automated vehicle technology. The challenge of adapting to traffic demand at conventional continuous flow intersections is addressed by incorporating virtual channelization, enabling real-time dynamic matching of road space resources to high traffic demand within brief time frames. A dynamic speed control method is introduced for exit vehicles to mitigate conflicts between these vehicles and left-turning vehicles. This method allows left-turning vehicles to change lanes without halting, actualizing continuous traffic flow. In addition, the authors have integrated all the methods into a unified control framework (DCFIC) for systematic control of intersection. The framework encompasses five primary modules: space layout optimization module, safety distance calculation module, left shift lane change condition Ⅰ determination module, left shift lane change condition Ⅱ determination module and exit vehicle platoon combination generation module. The DCFIC system activates different control modules in real-time based on the zone through which vehicles are navigating. Simulation results demonstrate that, under diverse traffic demand scenarios, DCFIC outperforms both traditional signal controls and continuous flow intersections. It exhibits pronounced adaptability, markedly reducing delays.]]></description>
      <pubDate>Thu, 26 Jun 2025 11:42:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/2544112</guid>
    </item>
    <item>
      <title>Marking the Approach-Ends of Channelization</title>
      <link>https://trid.trb.org/View/2559737</link>
      <description><![CDATA[This report deals with a method of approach-end treatment to provide advance warning of physical barriers, such as channelizing islands and ramp terminals. The objectives of this approach-end treatment are "to provide, for approaching traffic, a maximum degree of warning of the presence of the island and a definite indication of the proper vehicle path or paths to be followed."' In other words, this approach-end treatment should guide the driver into the proper maneuver without physical restraints well in advance of the actual physical barrier. Tests were conducted to evaluate the visibility characteristics of the raised stripe method of approach-end treatment in comparison with the conventional paint line method.]]></description>
      <pubDate>Tue, 24 Jun 2025 17:13:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2559737</guid>
    </item>
    <item>
      <title>Pedestrian Safety and Accessibility Best Practices for Channelized Right-Turn Lanes</title>
      <link>https://trid.trb.org/View/2487312</link>
      <description><![CDATA[This research sought to identify best practices for channelized right-turn lanes (CRT) that better accommodate the safety and accessibility needs of all road users. This was accomplished through a comprehensive literature review, a state-of-the-practice survey of state and local roadway agencies (nationwide and within Minnesota), a review of agency policy and guidance materials (nationwide and Minnesota DOT), and a series of focus group meetings focused on vulnerable road users. Feedback received both from the survey of transportation agencies and the focus group sessions performed as a part of this research suggest that roadway agencies throughout the United States are moving toward proactive policies for the use of CRTs that emphasize safety and mobility for vulnerable road users. This movement is generally based on the concerns for the safety of vulnerable road users outlined in the prior section and commonly includes 1.) minimizing the use of CRTs at urban and suburban intersections and/or 2.) designing new CRT facilities or retrofitting existing facilities with mitigation strategies to improve the safety and accessibility for vulnerable road users. This information was synthesized along with the best practices found in the research literature and agency policy/guidance materials to develop implementation guidance, which is organized within the report as follows: 1.) guidance for use of CRTs based on the project scenario; 2.) traffic control recommendations for CRTs; 3.) recommended design features for CRTs; and 4.) recommended mitigation strategies intended to improve CRT safety and/or accessibility for vulnerable road users.]]></description>
      <pubDate>Tue, 28 Jan 2025 14:52:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/2487312</guid>
    </item>
    <item>
      <title>Exploring the Impact of Channelized Islands on the Driving Behavior of Right-Turning Vehicles at Intersections</title>
      <link>https://trid.trb.org/View/2475501</link>
      <description><![CDATA[As a key node where traffic conflicts are prone to occur on roads, it is of great significance to explore the influencing factors of vehicle driving behavior at intersections. However, the mechanism by which channelization islands affect the driving behavior of right-turning vehicles at intersections is not clear yet. In this study, the authors recruited 20 drivers and explored the impact of geometric factors on channelization islands on the average deviation and speed of right-turning vehicles through driving simulation experiments, including channelization island type, offset distance, end circular curve radius, length of two straight edges of channelization island, and the angle corresponding to the third curved side. The main influential factors for the average deviation and speed were selected through Spearman correlation test and stepwise regression method to establish the average deviation model of trajectory and the average velocity model of trajectories. The results could provide theoretical support for more accurate intersection simulation and right-turn channelization design.]]></description>
      <pubDate>Fri, 27 Dec 2024 15:27:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2475501</guid>
    </item>
    <item>
      <title>Analysis of driver behavior at grade-separated intersections to support design</title>
      <link>https://trid.trb.org/View/2368283</link>
      <description><![CDATA[Understanding driver behaviors in varied traffic scenarios is critical to the design of safe and efficient roadways and traffic control device. This research presents an analysis of driver cognitive workload, situation awareness (SA) and performance for three different scenarios, including a standard intersection and contraflow grade-separated intersections (C-GSI) and quadrant GSI (Q-GSI) with lane assignment sign manipulations. The study used a simulator-based driving experiment with application of the NASA Task Load Index and Situation Awareness Global Assessment Technique to assess the influence of the scenarios on driver behavioral responses. The findings reveal challenges for drivers navigating the C-GSI, characterized by diminished SA and elevated workload. These states were associated with behaviors such as delayed lane changes, missed opportunities for appropriate lane changes, heightened acceleration behavior within deceleration segments, and frequent speeding. In contrast, while drivers in the Q-GSI scenario faced elevated workloads, their SA remained steady, largely due to lane-specific signs facilitating early lane changes. Although the Q-GSI led to increased speed variability and slight increases in deceleration, the use of supplementary speed signage revealed a promising alternative to the S-intersection. Correlation analysis highlighted a significant relationship between mental workload and acceleration responses, indicating that increased acceleration was associated with higher mental workload. In addition, a significant negative correlation between driver perceived performance and absolute lane deviations indicated that drivers with higher self-assessed performance were more accurate in lane-keeping. The study underscores the need for GSIs and signage designs that support driver SA, manage cognitive workload to improve driver performance and increase road safety.]]></description>
      <pubDate>Thu, 23 May 2024 09:41:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2368283</guid>
    </item>
    <item>
      <title>Evaluation of the Severity of Deadlock at a Signalized Intersection with Auxiliary Lanes Using Trajectory Data</title>
      <link>https://trid.trb.org/View/2368203</link>
      <description><![CDATA[Intersection channelization and signal timing are important for mitigating traffic congestion in the urban transportation system. Most existing studies fail to quantitively evaluate the severity of deadlock caused by the mismatch between lane allocation and signal timing, especially at a channelized intersection with auxiliary lanes. This study proposes a new indicator —average unavailable time ratio (AUTR)—to quantitively evaluate the impacts of such deadlock on traffic operational efficiency at a channelized intersection with an auxiliary lane, based on trajectory data. Deadlock states are coded at the vehicle movement level and the state transition is analyzed with varying signal timings. They are classified into four types based on the evolution of queue length with different signal timings using discharging shockwaves. AUTR is calculated by constructing a spatiotemporal diagram using trajectory data, and simulation studies validate the effectiveness of the proposed indicator. The AUTR value has a strong positive correlation with vehicle travel time and queueing time caused by the deadlock and measures the severity of the deadlock. The storage length of the auxiliary lane has a greater impact on AUTR than the bay taper length. The impacts of lane allocation on the deadlock are affected by signal timings. This proposed method can effectively evaluate the rationality of lane allocation designs with auxiliary lanes given a signal timing scheme.]]></description>
      <pubDate>Sat, 20 Apr 2024 18:43:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2368203</guid>
    </item>
    <item>
      <title>Impact of “keep left” measure on pedestrians, cyclists and e-scooter riders at a crossing of a signalised junction</title>
      <link>https://trid.trb.org/View/2310788</link>
      <description><![CDATA[On a signalised crossing of a junction, large bidirectional flows of pedestrians, cyclists and e-scooter (ES) riders would converge and interact with each other in a confined space over a short time interval during each signal-enabled crossing stage. Such shared space interaction has hardly been researched. The authors experimented with a measure that encourages pedestrians’ “keep left” behaviour while promoting channelisation between pedestrians versus cyclists/ES riders. The impact of the treatment was examined by intercept perception survey and naturalistic observations of trajectory movements via video analysis. The findings showed that pedestrians adopted better keep-left discipline after the treatment, which consequently reduced their perceived conflict levels with other oncoming traffic agents on the crossing which increased their crossing speed. Cyclists and ES riders also indicated lower conflict levels when pedestrian movements on the crossing become more predictable.]]></description>
      <pubDate>Fri, 26 Jan 2024 10:02:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2310788</guid>
    </item>
    <item>
      <title>Channelization: The Design of Highway Intersections at Grade</title>
      <link>https://trid.trb.org/View/2226086</link>
      <description><![CDATA[The Highway Research Board Committee on Channelization recognizes that the determination of operational performance and details of functional design of the various types of intersection channelization will require a considerable amount of study and research. Standards must be developed for measuring intersection performance and criteria established which will permit the practical comparison of possible designs. Such research and evaluation represent a long-range project. In the meantime, channelized intersections are being designed and constructed. The Committee believes that much value can be gained by presenting examples of channelized intersections which have received the test of performance under varying conditions of traffic. The report is not intended to establish principles of channelization design, but rather to present current design practice in the hope that highway and traffic engineers may profit by a review of the work of others. Cities and states were requested to furnish examples of channelized intersections for inclusion in the report. The report is presented in five parts: Part I - Definitions; Part II - Types of Intersections; Part III - Warrants for Channelization; Part IV - Principles of Channelization; and Part V - Examples of Channelization.]]></description>
      <pubDate>Sat, 12 Aug 2023 14:21:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/2226086</guid>
    </item>
    <item>
      <title>Pedestrian Safety and Accessibility Best Practices for Channelized Right Turn Lanes</title>
      <link>https://trid.trb.org/View/2213777</link>
      <description><![CDATA[Highway agencies throughout the United States often utilize channelized right-turn lanes to improve the operational performance of intersections across a variety of design settings. However, the impact of channelized right-turn lanes on safety performance is less clear. This proposed research intends to synthesize best practices in channelized right-turn lane design for pedestrians, including a specific focus on identifying both proven or emerging strategies to mitigate potential concerns for persons with vision impairments or other disabilities. This will be completed by aggregating the findings of a comprehensive literature review, a national survey of state and local highway agencies, as well as interviews with stakeholder groups. Guidance and recommendations will be provided regarding the preferred designs for right-turn channelization in order to meet the needs of all road users.]]></description>
      <pubDate>Tue, 18 Jul 2023 11:48:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2213777</guid>
    </item>
    <item>
      <title>Research on Traffic Channelization Optimization of Signalized Intersections Based on the Emission Analysis</title>
      <link>https://trid.trb.org/View/1990386</link>
      <description><![CDATA[This paper examines the problems of organizing traffic at urban road intersections and introduces improvement measures for urban road intersections in traffic engineering theory. The intersection at Xi’an Cuihua Road and Yucai Road is used as an example to study the signal timing program and channelization of signal control at an urban single point intersection. Investigation showed congestion in the intersection; therefore, an optimized channelization scheme was proposed and followed by Vissim software to calculate average delay and average queue length of each approach after optimization. This study also presents a combined emission evaluation index by analyzing (by synthesis) different emission factors. As a result, the average delay of each approach was reduced distinctly, and the comprehensive evaluation index of traffic emissions were also reduced. This study could show a relationship between traffic organization and traffic emission in urban intersections to optimize traffic organization.]]></description>
      <pubDate>Thu, 19 Jan 2023 11:23:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/1990386</guid>
    </item>
    <item>
      <title>Delay Model Revisited Considering Channelized Section Spillover</title>
      <link>https://trid.trb.org/View/1990327</link>
      <description><![CDATA[Delay is a key parameter in traffic signal optimization, and traditionally is calculated for directional movements. When channelized section spillover (CSS) occurs, turning flows interact with each other. If there are multiple potential spillover queues, the first spillover event will cut the flow off, and change the growth of other queues, further altering the evolution of the whole approach. Under such circumstances, the directional delays interrelate. A new delay model which can consider the CSS is necessary. This research identifies three components of extra delay caused by CSS: 1) delay due to spillover; 2) delay caused by the first-in-first-out (FIFO) principle; and 3) delay due to the saturation flow degradation. A numerical simulation is implemented to quantify the three components. It is found that delay when CSS occurs is a function of at least three groups of variables: 1) signal settings; 2) all directional flows; and 3) intersection approach attributes.]]></description>
      <pubDate>Fri, 23 Dec 2022 10:04:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/1990327</guid>
    </item>
    <item>
      <title>Optimization Design of Intersection Traffic Organization: A Case Study in Zhenjiang</title>
      <link>https://trid.trb.org/View/2019073</link>
      <description><![CDATA[Intersections play an important role in the road network. The traffic organization of the intersections may affect the safety and efficiency of the entire road network. This paper takes the intersection of Tanshan Road-Longmai Road in Zhenjiang City as an example to study the optimization design of intersection traffic organization. First, traffic survey is conducted to analyze the current situation of the chosen intersection. The traffic organization issues of the intersection are summarized based on the traffic survey results. Second, by combining several specific methods such as intersection channelization, a complete optimization scheme is proposed to improve the traffic service of the intersection. Finally, VISSIM is used to simulate the traffic flow of the intersection before and after the optimization. The simulation results show that the optimization scheme reduces the average vehicle delay and maximum queue length. Besides, the delay time of the optimized intersection is shortened by 7 s.]]></description>
      <pubDate>Thu, 17 Nov 2022 10:15:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/2019073</guid>
    </item>
    <item>
      <title>Impact of Right-Turn Channelization on Pedestrian Safety at Signalized Intersections</title>
      <link>https://trid.trb.org/View/1675742</link>
      <description><![CDATA[Channelized right turns or slip lanes have been widely implemented as an effective countermeasure of reducing traffic delay and number of conflicts between vehicles at signalized intersections. However, only a few studies have investigated the impact of channelized right turns (in left-hand driving countries) on pedestrian safety. Channelized right turns may increase the risks for pedestrians since they bring pedestrian-vehicle interactions in a fully non-signalized environment. Furthermore, the increased turning radius at channelized lanes can lead to higher vehicle speeds. This paper investigates the impact of channelized right turns on pedestrian safety based on surrogate safety and behavior measures. Video data were collected from twelve signalized intersections in the city of Zunyi, China, involving three main types of right-turn designs: 1) non-channelized right-only lanes, 2) non-channelized right-through lanes, and 3) channelized right-turn lanes. Different measures are used, including interaction and behavior measures based on a recent-proposed Distance-Velocity model, the PET measurement, speed measurements, and observations of failures in interactions (pedestrian retreats and evasive maneuvers from pedestrians or vehicles). Results indicate that the design of channelized right-turn lane increases pedestrian risks at signalized intersections from different dimensions of safety. The impact of the nighttime condition on pedestrian safety was also compared. Pedestrians are safer at nighttime at non-channelized locations, while the impact of nighttime conditions on pedestrian safety at channelized intersections was not ascertained. Consequently, cities should be cautious to install channelized intersections as a safety countermeasure. Treatments are needed to improve pedestrian safety if channelized right turns are implemented.]]></description>
      <pubDate>Thu, 30 Jan 2020 11:08:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/1675742</guid>
    </item>
    <item>
      <title>Feasibility of Using a Single Traffic Signal Controller to Accommodate Adjacent Intersections</title>
      <link>https://trid.trb.org/View/1653654</link>
      <description><![CDATA[The operation cost of signalized intersections is usually higher than unsignalized intersections, not only because of the expenses on hardware devices but also due to the device maintenance as well as software upgrading. Moreover, at a signalized corridor, the coordination between signals is also considered to be necessary, which requires additional labor and maintenance costs. With these considerations, this paper aimed to investigate the feasibility of using a single signal controller to control two or multiple adjacent intersections. This study developed a procedure to decide when to use one-controller strategy and evaluated the operation of two real-world cases in Reno, Nevada, where the previous two-controller strategy has just replaced by a one-controller strategy. Based on microsimulation study, it was concluded that the Level-of-Service (LOS), delay, and the average number of stops under one controller strategy maintained a similar condition in comparison with the previous two-controller strategy, indicating that the proposed one-controller strategy would be a feasible alternative to reduce the operation costs of adjacent intersections. It is expected that reducing the number of signal controllers will not only reduce the infrastructure cost, but also lead to notable operation benefits, such as it facilitates the development of signal coordination plans, and the implementation of future adaptive signal control in a connected vehicle environment, since it reduced the number of communication nodes within the arterial system.]]></description>
      <pubDate>Mon, 28 Oct 2019 10:29:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/1653654</guid>
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