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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
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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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    <item>
      <title>Analysis of conflict between right-turning vehicles and pedestrians at urban intersections using random parameter Logit model</title>
      <link>https://trid.trb.org/View/2726598</link>
      <description><![CDATA[Pedestrians are prone to more dangerous conflicts with right-turning vehicles when crossing the street because of sharing phases with right-turning vehicles or their own violations. This paper aims to alleviate the frequent conflicts between right-turning vehicles and pedestrians and explores the significant influencing factors behind these conflicts. This study conducted field investigations at two representative signalized intersections in Guangzhou. During the research process, unmanned aerial vehicles (UAVs) were employed for oblique photography to collect data, which were then preprocessed using T-Analyst software. Based on this, intersection characteristics, characteristics of conflict participants, and unsafe crossing behaviors were extracted in detail, and this information was correlated with the behavioral trajectories of both parties involved in the traffic conflicts. In terms of conflict identification, the study utilized the time difference to collision (TDTC) method to identify 701 valid conflicts. In the data analysis phase, ordered Logit models, generalized ordered Logit models, and random parameter ordered Logit models were employed for modeling and analysis. Among them, the random coefficients ordered Logit model exhibited the best fit. The model results indicate that pedestrian pairing and the sequence in which conflict participants traverse the conflict point. Specifically, pedestrians crossing in pairs face a 13.9% higher risk of severe conflicts compared to those crossing alone, while the probability of minor conflicts decreases by 14.5%. Although vehicles passing first (VPF) through the conflict point reduce the occurrence of general and minor conflicts to some extent, they may trigger more severe conflicts. Furthermore, pedestrian and right-turning vehicle violations such as running red lights and failing to pay attention to oncoming traffic significantly increase the risk of severe conflicts. To mitigate conflicts between right-turning vehicles and pedestrians, it is recommended to appropriately adjust the length and width of pedestrian crossings and implement dynamic signal phase control strategies at intersections where significant temporal variations in pedestrian and vehicular traffic are observed, ensuring orderly traffic movement across all time periods. Additionally, surveillance equipment should be installed at intersections to conduct real-time monitoring and management of pedestrian and vehicular violations, thereby curbing the occurrence of unsafe behaviors.]]></description>
      <pubDate>Wed, 23 Sep 2026 15:55:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/2726598</guid>
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    <item>
      <title>Can you hear the collision risk? A VR study on beamforming warnings for cyclists at urban intersections</title>
      <link>https://trid.trb.org/View/2752379</link>
      <description><![CDATA[Right turns at urban intersections pose a significant risk to cyclists, but existing infrastructure-based warning systems often suffer from high false alarm rates and a lack of specificity. Following a PICO-based research design, this study addresses the research question of whether targeted acoustic warnings using beamforming technology can effectively warn cyclists (target) while simultaneously minimizing the disturbance for pedestrians and residents (non-targets). Using a fully immersive VR environment with spatial audio simulations and realistic traffic noise sounds, the study examined how cyclists, pedestrians, and residents perceive and accept these targeted signals. The experiment compared different warning sounds at varying distances from the intersection to determine their perceptibility and effectiveness. The results show that while all acoustic warnings were reliably perceived as relevant, verbal warnings proved to be the most effective, as speech is immediately understood regardless of the cyclist's distance from the intersection. In terms of environmental impact, the study found that beamforming can significantly minimize disturbance to pedestrians and residents, with narrow-beam signals perceived as the least disturbing. This work contributes to this field of research by demonstrating that spatially controlled acoustic systems offer a more specific and socially acceptable solution for protecting vulnerable cyclists than conventional omnidirectional or purely visual methods. By combining technical precision with intuitive communication, this approach effectively counteracts the “cry wolf” effect and improves overall road safety.]]></description>
      <pubDate>Tue, 15 Sep 2026 09:53:08 GMT</pubDate>
      <guid>https://trid.trb.org/View/2752379</guid>
    </item>
    <item>
      <title>Domain Adaptation Framework for Turning Movement Count Estimation with Limited Data</title>
      <link>https://trid.trb.org/View/2772603</link>
      <description><![CDATA[Accurate turning movement counts (TMCs) at intersections are crucial for traffic signal control, congestion mitigation, and road safety. Recent advancements in machine learning and data-driven approaches have offered promising alternatives for estimating TMCs. However, traffic patterns can vary significantly across different intersections because of factors such as road geometry, traffic signal settings, and local driver behaviors. This domain discrepancy limits the generalizability and accuracy of machine learning models when applied to unseen intersections. To address these limitations, this research proposes a novel framework leveraging domain adaptation (DA) to estimate TMCs at intersections by using traffic-controller-event-based data, road infrastructure data, and point-of-interest data. Evaluated on 30 intersections in Tucson, Arizona, U.S., the proposed DA framework consistently outperformed state-of-the-art models, achieving the lowest error values across all movements. The framework obtained mean absolute error values of 12.29 for left turns, 34.39 for through movements, and 16.17 for right turns. A similar pattern was observed for root mean squared error, with the model achieving 15.73 for left turns, 43.90 for through movements, and 20.08 for right turns, outperforming all comparison methods.]]></description>
      <pubDate>Thu, 03 Sep 2026 09:08:04 GMT</pubDate>
      <guid>https://trid.trb.org/View/2772603</guid>
    </item>
    <item>
      <title>Graph interpretable planning for signal-free intersections: Optimizing lane-time coordination through solution space compression</title>
      <link>https://trid.trb.org/View/2701483</link>
      <description><![CDATA[In highly connected and automated traffic systems, conventional traffic signals suffer from significant efficiency limitations, making signal-free intersection control a promising alternative. To improve intersection efficiency while maintaining low computational cost, an Interpretable Graph Model (IGM) is proposed for vehicle trajectory planning at signal-free intersections. The model consists of two complementary modules. In the conflict zone, a trajectory warping graph encodes conflict-point occupation constraints and jointly determines entrance-lane assignment and vehicle passing order under an All-Direction Turn Lane (ADTL) configuration, thereby compressing the solution space and enabling efficient real-time planning. In the preparation zone, a trajectory planning hypergraph based on time-equative nodes explicitly models lane-changing and speed-adjustment processes to ensure feasible vehicle trajectories before entering the intersection. The IGM is evaluated against eight benchmark models, including reservation-based control, global conflict-free, subzone conflict-free, and fixed-lane configurations. Experimental results show that the proposed method achieves superior performance in efficiency, adaptability, and computational cost. The IGM achieves the highest throughput (around 5932 veh/h) and maintains low average delay, ranging from 0.01 s at 1000 veh/h to 6.25 s at 6000 veh/h. The results also highlight the importance of coordinating ADTL configurations with proactive entrance-lane assignment, as ADTL-based models without lane assignment may perform worse than fixed-lane strategies due to inefficient lane utilization. In addition, the IGM demonstrates strong adaptability to unbalanced turning distributions and maintains stable optimization time under increasing traffic demand, supporting real-time signal-free intersection control.]]></description>
      <pubDate>Thu, 27 Aug 2026 16:32:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2701483</guid>
    </item>
    <item>
      <title>Evaluation of Third-Party Turning-Movement-Count Data: A Kentucky Case Study</title>
      <link>https://trid.trb.org/View/2761635</link>
      <description><![CDATA[Turning-movement counts (TMCs) are among the fundamental datasets in the transportation industry. This type of traffic count is regularly conducted and utilized as a core input to intersection design, signal timing, and more. However, traditional methods for collecting this data are expensive, labor-intensive, and time-consuming. Thus, the data collected from specific locations within short time periods does not necessarily capture all traffic variation. In recent years, advancements in tracking technologies have enabled third-party vendors to passively generate TMCs for different locations and time intervals. This study primarily focuses on evaluating TMCs estimated by a third-party vendor through comparison with ground-truth data. Actual TMCs are obtained from manually collected data for several planning studies across Kentucky between 2016 and 2024. Moreover, estimated counts are acquired from the StreetLight platform for these same locations. TMCs are evaluated across different functional classifications (FCs) and area types to assess their impact on the StreetLight data accuracy. The overall comparison of TMCs yields Pearson correlation coefficients greater than 0.75 and mean absolute percentage errors (MAPE) greater than 40%. When analyzed by area type and FC, urban intersections with higher functional importance show stronger agreement with observed counts than rural intersections show. The analysis suggests that variations in annual average daily traffic (AADT) had a measurable impact on estimation performance, with errors generally tending to decrease as AADT increases. Results of this study will help provide transportation agencies with a better understanding of the accuracy and utility of estimated data from third-party vendors, specifically TMCs.]]></description>
      <pubDate>Wed, 19 Aug 2026 09:25:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2761635</guid>
    </item>
    <item>
      <title>Understanding Bicycle Signal Operations and Leading Bicycle Interval (LBI) Implementations</title>
      <link>https://trid.trb.org/View/2736751</link>
      <description><![CDATA[Bicycles play a crucial role in sustainable transportation, easing congestion, lowering emissions, and promoting health. However, cyclists confront significant safety risks, especially in serious crashes. Florida has historically had the highest number of bicyclist fatalities nationwide, prompting the Florida Department of Transportation (FDOT) to prioritize reducing bicycle crashes. A significant number of bicyclist fatalities and injuries occur at intersections, especially during turning movements, highlighting the critical need to enhance safety at signalized intersections. This study focuses on optimizing bicycle signal operations, specifically Leading Bicycle Intervals (LBI), to mitigate conflicts between cyclists and turning vehicles. The research incorporates an extensive literature review and analysis of global case studies to inform strategies for FDOT’s broader implementation of bicycle signals. The findings seek to enhance bicyclist safety and promote cycling as a reliable transportation option throughout Florida and across the United States.]]></description>
      <pubDate>Fri, 14 Aug 2026 15:04:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/2736751</guid>
    </item>
    <item>
      <title>Effect of drum and disc brakes on roll stability of double-trailer trucks during braking-in-turn manoeuvers</title>
      <link>https://trid.trb.org/View/2697843</link>
      <description><![CDATA[This study compares the performance of drum and disc brakes in maintaining roll stability of long combination vehicles (LCV) using a multi-domain model integrating pneumatic brake dynamics in Simulink® and truck dynamics in TruckSim®. The LCV consists of a Class 8 tractor, two 33-ft trailers, and an A-dolly. While the tractor and dolly’s brakes remain unchanged, the trailers’ brakes changed from drum (baseline) to disc brakes. The multi-domain model is validated using straight-line braking test data. The validated model is used to evaluate and compare the straight-ahead stopping distance and roll stability in J-turns at various speeds and timing for brake initiation (TBI). Results indicate that disc brakes better mitigate the lateral accelerations of both front and rear trailers during braking-in-turn manoeuvers, lowering rollover risks. The disc brakes’ faster response time and larger braking torques yield larger speed reduction when the vehicle enters a turn at speeds higher than the vehicle rollover threshold. At an entry speed of 40 mph or higher, the disc brakes result in a higher TBI, allowing more time for the driver to initiate braking to prevent a rollover. The improvement increases with increasing entry speeds.]]></description>
      <pubDate>Fri, 31 Jul 2026 09:23:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/2697843</guid>
    </item>
    <item>
      <title>Pedestrian and Cyclist Safety: DOT Should Take Steps to Address Risks Related to Limited Driver Visibility</title>
      <link>https://trid.trb.org/View/2732352</link>
      <description><![CDATA[In 2024, about 9,200 pedestrians and cyclists were killed on U.S. roadways— an increase of about 65 percent since 2010. A range of factors can contribute to increased pedestrian and cyclist fatalities, including larger vehicles, which make up an increasing share of vehicles on U.S. roadways and may limit driver visibility. The U.S. Government Accountability Office (GAO) was asked to review issues related to driver visibility. This report examines (1) what studies and federal data show about the relationship between vehicle characteristics, driver visibility, and pedestrian and cyclist fatalities; (2) actions selected auto and truck manufacturers have taken related to driver visibility; (3) approaches selected foreign jurisdictions have used to reduce driver visibility–related risks to pedestrians and cyclists; and (4) the extent to which the U.S. Department of Transportation (DOT) has analyzed and responded to potential driver visibility– related risks to pedestrians and cyclists. GAO reviewed selected studies published from 2015 to 2025, analyzed DOT pedestrian fatality data, and selected and interviewed five auto and five truck manufacturers. GAO also reviewed driver visibility standards adopted by the EU and London and interviewed officials about their approaches. Finally, GAO reviewed DOT studies and planning documents and interviewed DOT officials. GAO is recommending that DOT (1) determine a method to measure driver visibility, and (2) fully analyze risks that limited driver visibility poses to pedestrians and cyclists and develop responses to those risks. DOT concurred with the first recommendation and did not concur with the second. GAO continues to believe DOT should fully implement both recommendations, as discussed in the report.]]></description>
      <pubDate>Mon, 27 Jul 2026 09:06:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2732352</guid>
    </item>
    <item>
      <title>Design evaluation of bus cross-traffic turn priority box</title>
      <link>https://trid.trb.org/View/2724868</link>
      <description><![CDATA[Cross-traffic turns (left turns in right-hand traffic) significantly delay buses at intersections, reducing transit reliability. This study introduces the Bus Cross-Traffic Turn Priority Box, a design that allows buses to bypass turn queues by using through lanes and enables the pre-acceleration of turning traffic when no bus is present. Microscopic simulations conducted at three intersections (a stylized three-way intersection, a stylized four-way intersection and a real-world intersection using observed traffic data) demonstrate substantial delay reductions for buses and minor improvements for general traffic. Unlike traditional bus priority measures, this approach requires minimal infrastructure changes and enhances overall intersection efficiency, supporting its adoption in space-constrained urban settings to improve public transport performance without adversely affecting other road users.]]></description>
      <pubDate>Mon, 13 Jul 2026 10:46:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/2724868</guid>
    </item>
    <item>
      <title>Effects of driver direct visibility in passenger vehicles on the risk of turning crashes with pedestrians</title>
      <link>https://trid.trb.org/View/2709661</link>
      <description><![CDATA[This study examined if characteristics of direct visibility metrics in passenger vehicles, such as large blind zones, corresponded with higher risk of turning crashes with pedestrians aged 16 years and older. It also evaluated effects of vehicle front structures on some direct visibility metrics.  Single-passenger vehicle, single-pedestrian crashes in seven states were included. Direct visibility metrics included driver- and passenger-side blind zone sizes, front nearest visible point (NVP) distance, and front field of view (FOV) width; measurements were taken on 168 combinations of vehicle make, series, and redesign years. Logistic regression analyses evaluated effects of visibility metrics and other factors on the odds of a left- or right-turning pedestrian crash, relative to straight-moving. Linear regression analyses examined effects of front structures on blind zone sizes and front NVP distances.  For left-turning pedestrian crashes, large (> 30%) and medium (> 20% and ≤ 30%) driver-side blind zones were, respectively, associated with a significant 75.3% and 62.4% increase in the odds, compared with a small size (≤ 20%). A narrow front FOV (≤ 85°) was associated with a significant 49.6% increase in the odds, compared with a wide FOV (> 90°). A long front NVP distance (> 9 m) was associated with a significant 35.3% increase in the odds, compared with a short distance (≤ 6 m). No significant associations were found between visibility metrics and right-turning pedestrian crashes.  Larger driver-side blind zones, longer front NVP distances, and narrower front FOVs increased risk of left-turning pedestrian crashes. Effects of A-pillars, side mirrors, hoods, and windshields on blind zone sizes and front NVP distances were also validated. Findings could help automakers improve safety for road users outside vehicles with changes in vehicle design to enhance drivers’ direct vision and improvements to AEB technology to address vehicle-turning conflicts.]]></description>
      <pubDate>Thu, 18 Jun 2026 16:34:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/2709661</guid>
    </item>
    <item>
      <title>Anticipatory vibrotactile cues about upcoming turns reduce motion sickness: A study with car passengers on public roads</title>
      <link>https://trid.trb.org/View/2681473</link>
      <description><![CDATA[The introduction of automated driving brings improvements towards comfort and enables all passengers to use their time more efficiently. However, the more the occupant engages in tasks unrelated to driving, the risk of massive discomfort caused by motion sickness or more specifically carsickness, increases. The development of carsickness includes symptoms such as dizziness or nausea and depends, among other factors, on the occupants’ ability to anticipate upcoming vehicle movements. The present study investigated whether anticipatory vibrotactile cues, focused exclusively on lateral maneuvers (turns) and tested in real-world driving conditions, can reduce passengers' carsickness. In a counterbalanced within-subjects design, 40 participants experienced two 30-min rides on public roads. During the ride, all participants watched a movie and were asked every minute about their current subjective carsickness level, using the Fast Motion Sickness Scale (FMS). In the intervention condition, upcoming right and left turns were announced 1 s in advance by cues via a vibrotactile belt. In the control condition, passengers merely wore the belt but did not receive such cues. We found that anticipatory vibrotactile cues about upcoming right and left turns have a mitigating effect on the level of carsickness.]]></description>
      <pubDate>Thu, 18 Jun 2026 08:54:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/2681473</guid>
    </item>
    <item>
      <title>Evaluation of Expanded Uses of Residential Driveway Temporary Signals (RDTS): Turn Lane Volumes and Storage</title>
      <link>https://trid.trb.org/View/2712243</link>
      <description><![CDATA[Traffic management for work zones in rural two-lane two-way highways can be challenging as these segments often intersect with low volume side streets and access points. Residential Driveway Temporary Signal devices (RDTS) (formerly Driveway Assistance Device (DAD)) have provided a solution to improve mobility for traffic entering a one-lane, two-way work zone. These devices have been implemented for several years under experimental evaluations by numerous state and local agencies across the United States. In January 2025, the optional use of RDTS was approved by the Federal Highway Administration (FHWA) under Interim Approval (IA) 23. However, whereas prior experimental use of the DAD allowed the device to be deployed at minor cross-streets and commercial driveways, IA-23 only allows for the RDTS to be used at residential driveways. To that end, this proposed research project will assess the operational effects of RDTS when used at non-residential access points to develop guidance that will inform future policy-making related to the device. The proposed project objectives build upon the work already performed with RDTS/DAD and other temporary work zone signal systems by considering their use at uncontrolled rural low-volume side streets and access points. Of particular interest is the ability of RDTSs to handle traffic on low volume side streets and access points with a focus on turning volumes related specifically to the designed turn lane storage capacity (i.e., the amount of left and right turn storage). The results will include implementation guidance that will delineate appropriate usage cases of the RDTS, including appropriate mainline and access point exiting volumes based on storage capacity of the turn lane(s) departing the access point. Guidance related to future Manual on Uniform Traffic Control Devices (MUTCD) language will also be provided where applicable and appropriate.]]></description>
      <pubDate>Tue, 09 Jun 2026 12:32:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/2712243</guid>
    </item>
    <item>
      <title>Two-Lane to Three-Lane Roadway Conversions: Active Transportation Safety Implications</title>
      <link>https://trid.trb.org/View/2712207</link>
      <description><![CDATA[Land development patterns often shift two-lane collector roadways from serving primarily through traffic to accommodate a greater mix of through and local access traffic. In other cases, local destinations remain while downstream development increases through-traffic demand. In both scenarios, turning movements and through traffic increasingly conflict with each other. Where no alternative corridor options exist, through traffic remains on the road along with increased traffic volumes generated by new land uses. Prior to development, these roads may have included paved shoulders occasionally used by pedestrians, though active transportation activity was generally limited because fewer nearby destinations existed. As development intensifies, pedestrian activity increases alongside turning conflicts, creating pressure on agencies to widen the roadway cross-section by adding center turn lanes or sidewalks.

 The objective of this research is to evaluate and compare the safety performance of two-lane roadway cross-sections without dedicated turn lanes and three-lane cross-sections with center two-way left-turn lanes along corridors that include treatments or countermeasures to protect vulnerable road users. The research will identify the traffic, land use, and operational conditions under which each cross-section is more effective at improving safety for motorists and vulnerable road users while balancing multimodal operational performance.

 A secondary objective is to develop a guide with evidence-based recommendations, design considerations, and implementation strategies for improving multimodal safety along suburban and urbanizing corridors with current or projected high through-motorist travel and left-turn motorist demand.]]></description>
      <pubDate>Wed, 10 Jun 2026 11:36:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/2712207</guid>
    </item>
    <item>
      <title>Guidance for Selecting Pedestrian Safety Treatments at Signalized Intersections to Address Permitted Turn Conflicts</title>
      <link>https://trid.trb.org/View/2712202</link>
      <description><![CDATA[State departments of transportation (DOTs) and local agencies work to improve pedestrian safety at signalized intersections while maintaining efficient vehicle operations. Traditional signal timing practices often allow pedestrians to cross concurrently with permitted turning vehicles, which can create unsafe or stressful conditions for pedestrians, particularly at intersections with high turning volumes and speed or complex geometries. Agencies have implemented treatments such as leading pedestrian intervals (LPIs), delayed-turn strategies, and protected-only turn phases, but these applications are often applied without nationally consistent, data-driven guidance.

Existing resources identify available pedestrian safety treatments but provide limited guidance on when specific strategies are most appropriate. This can lead to inconsistent practices and difficulty balancing pedestrian safety improvements with operational impacts to vehicles.

The objective of this research is to develop a data-driven guide for selecting pedestrian safety treatments at signalized intersections to address conflicts with permitted turning vehicles. Using field-collected data, the research will evaluate treatments under varying traffic, geometric, and signal timing conditions, with results to help agencies identify appropriate strategies.]]></description>
      <pubDate>Wed, 10 Jun 2026 11:11:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/2712202</guid>
    </item>
    <item>
      <title>Use of Bicycle Signal Faces in Applications with Concurrent Turning Traffic</title>
      <link>https://trid.trb.org/View/2709246</link>
      <description><![CDATA[Bicycle infrastructure is expanding rapidly across the United States. Conflict involving bicyclists and other users at urban intersections is a growing safety concern. Various signalization strategies have been employed to govern bicycle and turning-vehicle movements, but the use of the bicycle signals has been restricted to locations where bicycle movement is phase-separated from turning traffic.

Because dedicated bicycle phases can substantially reduce green time for both cyclists and turning vehicles, the added delay may reduce red-signal compliance or encourage cyclists to use less-protected routes or ride in mixed traffic.

Research is needed to better understand the safety and operational effects of bicycle signals. This includes evaluating tradeoffs for cyclists and drivers when phase separation is required; documenting current methods that allow cyclists to proceed concurrently with turning vehicles, with or without bicycle signal indications; and comparing compliance and crash outcomes associated with different signalization strategies.

OBJECTIVE: The objective of this research is to explore the feasibility and implications of configuring bicycle signals to permit bicycles to move concurrently with turning traffic.]]></description>
      <pubDate>Tue, 02 Jun 2026 14:44:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/2709246</guid>
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