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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>Microscopic evaluation of traffic operations on urban arterial roads: the case of Ongwediva, Namibia</title>
      <link>https://trid.trb.org/View/2571430</link>
      <description><![CDATA[This study aimed to assess traffic operations using micro-simulation (PTV VISSIM) techniques along Mandume Ndemufayo Street in Ongwediva during both morning and evening peak hours. Micro-simulation has been highlighted as a valuable tool for planning and assessing transportation strategies to enhance effectiveness and sustainability. Data collection involved parameters like traffic volume, vehicle composition, and turning proportions. Screen-line counts were executed at chosen intersections. The developed PTV VISSIM model was calibrated and validated to accurately reflect real traffic conditions, facilitating the evaluation of various intersection control scenarios. Simulation outcomes indicated a substantial reduction in vehicle delay and stoppage, ranging from 30 % to 87 %, upon the introduction of traffic signals. Additionally, the total and maximum queue lengths diminished by 2 % to 80% at selected intersections. Overall, traffic signal control proved instrumental in enhancing traffic operations and reducing emissions by 20 % to 40 %. The study recommendations offer a comprehensive approach to tackling traffic management and urban planning challenges in Ongwediva, potentially enhancing the overall quality of life, safety, and sustainability, and fostering economic growth and efficiency. This study assessed traffic congestion in Ongwediva, providing strategic interventions to reduce peak-hour delays. The findings could serve as a comparative reference for improving traffic management across Namibia, enhancing road network performance, and stimulating economic activities, including trade, agriculture, and tourism. Additionally, increased mobility will improve access to essential services. The research will also contribute to the empirical knowledge base, particularly in using micro-simulation modelling for traffic management in developing countries, with potential policy implications for Namibia. Furthermore, this research contributes to the existing body of knowledge by providing scarce empirical references on the application of micro-simulation in developing countries, notably Namibia. Future studies could delve into the intricacies of intermodal conditions and explore the utilisation of advanced digital tools like Artificial Intelligence in traffic management within the context of developing countries.]]></description>
      <pubDate>Tue, 23 Sep 2025 17:10:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/2571430</guid>
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    <item>
      <title>Investigation of Key Safety Measures for Pre and Post-Deployment of Connected and Automated Vehicles</title>
      <link>https://trid.trb.org/View/2582586</link>
      <description><![CDATA[In recent years, automated vehicles (AVs) are increasingly penetrating road networks with the main purpose of reducing driver error. Since around 94% of traffic crashes are due to driver errors, automated vehicles have the potential to enhance road safety by eliminating human drivers' tasks. Despite claims that these vehicles will increase road safety, their ability remains unclear. However, it is essential to address the safety effectiveness of these vehicles. To date, researchers have used surrogate safety measures, such as time-to-collision (TTC) to quantify the near-crash occurrence of vehicles, where 1.5 seconds is typically considered the critical TTC thresholds for both AVs and human-driven vehicles (HDVs). Although AVs can travel with shorter headway due to their enhanced safety features, studies continue to use the same threshold value in their analysis. This study aims to evaluate the safety effectiveness of AVs through accomplishing several phases. First, the reaction time of AVs, while they are traveling in car-following mode along freeway and arterial facilities, was measured through two different approaches, cross-correlation and visibility graph algorithm. In the next phase, multiple machine learning models were tested to model car-following behavior of AVs. Finally, a mixed environment simulation framework was developed to investigate the effects of different penetration rates of AVs on safety, using the derived reaction times for AVs. The results indicate that the mean reaction time of AVs is 0.95 seconds and 1.05 seconds on freeways and arterials, respectively. Considering these values as the critical TTC thresholds, this study found no incidents of potential conflicts for AVs in the dataset provided, which aligns with previous studies, proving the safety benefits of AVs. Furthermore, it is found that the Long Short-Term Memory (LSTM) algorithm outperforms other models in replicating AV behavior. Further research is needed to implement the proposed simulation framework within VISSIM to estimate the safety effects of AVs, considering the critical TTC thresholds based on the analysis.]]></description>
      <pubDate>Mon, 08 Sep 2025 14:53:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/2582586</guid>
    </item>
    <item>
      <title>Developing an Automated Microscopic Traffic Simulation Scenario Generation Tool</title>
      <link>https://trid.trb.org/View/2592067</link>
      <description><![CDATA[Traffic simulation is an effective tool for urban planners, traffic engineers, and researchers to study traffic. In particular, microscopic traffic simulation, which simulates individual vehicles’ movements within a transportation network, has demonstrated its importance in analyzing and managing transportation systems. However, integrating data from various sources, generating traffic scenarios, and importing information into traffic simulators to conduct microscopic simulations have always been a challenge. This paper presents a solution to overcome this challenge: RealTwin, a comprehensive tool for automated scenario generation for microscopic traffic simulation. Following a streamlined scenario generation and calibration workflow, RealTwin effectively bridges gaps between traffic data from various sources and traffic simulators, making microscopic traffic simulation more accessible for researchers and engineers across various levels of expertise. Using RealTwin to generate a real-world traffic scenario in Simulation of Urban Mobility (SUMO), VISSIM, and AIMSUN, RealTwin’s ability is demonstrated in the construction of realistic and consistent traffic scenarios in different simulators. Furthermore, this paper introduces and illustrates RealTwin’s capability for technology (e.g., autonomous vehicle) scenario generation. This feature can contribute to more comprehensive microscopic simulations, facilitating the analysis of potential effects of various technological innovations on mobility, energy efficiency, and safety. Finally, RealTwin is used to calibrate a simulation in SUMO. The calibration module enhances RealTwin’s ability to generate consistent simulations across different platforms and more realistic simulations that reflect real-world traffic operations.]]></description>
      <pubDate>Fri, 22 Aug 2025 13:42:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/2592067</guid>
    </item>
    <item>
      <title>Alteration in delay time considering different pedestrian's crossing characteristics in the era of autonomous vehicles</title>
      <link>https://trid.trb.org/View/2534387</link>
      <description><![CDATA[Delay is one of the most crucial factors for both pedestrians and car drivers around pedestrian crossings. Drivers often do not yield to pedestrians, which may result in both delay and impatient pedestrian behaviour. This tendency may alter after introducing autonomous vehicles as the vehicles will follow the traffic rules in all cases. This study aims to estimate the delay time alteration at a simple zebra crossing using on-site measures and simulation. Roadside video recordings were carried out in Budapest, Hungary, to obtain the crossing decisions of pedestrian groups based on the approaching vehicle distance. The authors have determined the accepted vehicle distance vales for pedestrian groups that served as input data for microsimulation modelling. The novelty of the study is that the simulation involved autonomous vehicles that hold preset headways from the leading vehicle. The simulation was designed based on the traffic share of autonomous vehicles and the headways they kept. The main findings are that the travel time and stopping time for cars are higher if the modal share of autonomous vehicles is high. For pedestrians, however, the authors found a slight decrease in both travel times and stopping times. Moreover, the authors have proposed modifications to the simulation software (Vissim) to handle distance-dependent pedestrian decisions and drivers' failure to give priority. The results can be useful for road operators to estimate the road capacity in the era of autonomous vehicles and for software developers to formulate the simulated and real driving mechanism for autonomous vehicles.]]></description>
      <pubDate>Wed, 28 May 2025 16:23:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/2534387</guid>
    </item>
    <item>
      <title>Headway Anomaly Detection for Lane-Based Queuing Status Classification Using Detector Presence Data: Comparative Study</title>
      <link>https://trid.trb.org/View/2554164</link>
      <description><![CDATA[The identification of queuing status in traffic streams is a pivotal task with implications for various applications, such as level of service estimation and signal timing optimization. This study presents a comparative approach for binary classification of vehicles into queuing and non-queuing statuses using machine learning techniques based on vehicle headway anomalies. The proposed models leverage features from vehicle movement data at the stopline as input and queuing status as output. Four machine learning methods, the support vector machine, random forest, logistics regression, and Gaussian mixture model, are used and compared in the proposed headway anomaly detection framework. To validate the models, a simulation environment is constructed in VISSIM 4.3 and calibrated using real-world data. Results indicate that the random forest exhibits superior classification performance, showcasing its effectiveness as an ensemble approach. Notably, the resilience of these models is tested against the missing detection rate, with the random forest showing robust performance across different missing detection rate levels. Furthermore, feature importance analysis within the random forest model reveals “acceleration” and “headway” as significant predictors for classifying queuing status. The results advocate for the efficacy of the random forest model as a method for queuing status detection, indicating its utility for traffic analysis and the optimization of transportation network operations.]]></description>
      <pubDate>Mon, 19 May 2025 17:31:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2554164</guid>
    </item>
    <item>
      <title>Can Autonomous Vehicles Enhance Safety in Heterogeneous Disordered Traffic Conditions? A Simulation-based Exploratory Study</title>
      <link>https://trid.trb.org/View/2525349</link>
      <description><![CDATA[The emergence of autonomous vehicles (AVs) as a solution to various traffic externalities, including safety concerns such as crashes, has been promising. However, existing research primarily focuses on AVs plying in homogeneous traffic conditions prevalent in developed countries. Surprisingly, there is a significant lack of research exploring the impact of AVs on safety in heterogeneous disordered traffic (HDT) conditions, prevalent in developing countries like India. This study aims to fill this research void by conducting a comprehensive safety analysis of AVs on safety in HDT conditions. The safety analysis focuses on identifying crossing conflicts at intersections using post encroachment time as a surrogate measure. The study uses a simulation-based approach using the VISSIM software package to create various mixed traffic scenarios of AVs and other vehicles by adjusting the penetration rate of AVs. A total of 21 case scenarios were simulated and analyzed for crossing conflicts. The study's findings suggest that as the penetration rate of AVs increases, the number of conflicts decreases. Interestingly, solely replacing cars with AVs does not lead to substantial improvements in safety in HDT conditions.]]></description>
      <pubDate>Wed, 16 Apr 2025 11:24:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2525349</guid>
    </item>
    <item>
      <title>Identification of Simulation Calibration Parameters Using Urban Freeway Data</title>
      <link>https://trid.trb.org/View/2526713</link>
      <description><![CDATA[The reliability of a microsimulation model such as VISSIM depends on proper calibration and validation to accurately represent real-world traffic conditions. However, the VISSIM default values do not apply to local traffic conditions and need to be calibrated for local traffic conditions considering the higher number of car-following parameters. Hence, the present study determines TN-specific calibration parameters for PTV VISSIM microsimulation software using urban freeway data in TN. Field data were collected from the four majorly populated cities of TN namely Memphis, Nashville, Knoxville, and Chattanooga during the peak and off-peak hours of traffic using videography method. Trajectories were extracted using the YOLO-v8 computer vision techniques and the traffic flow variables were obtained from the microscopic trajectories. Wiedmann 99 carfollowing parameters were selected for the calibration of VISSIM. It was found that considering all the ten carfollowing parameters in the simulation model significantly reduces the error values between observed and simulated flow rates for the TN urban freeways.]]></description>
      <pubDate>Tue, 25 Mar 2025 09:30:53 GMT</pubDate>
      <guid>https://trid.trb.org/View/2526713</guid>
    </item>
    <item>
      <title>Examination of the Effects of Dynamic Speed Limit on Shock Waves with a Simulation Technique</title>
      <link>https://trid.trb.org/View/2475799</link>
      <description><![CDATA[The aim of motorway networks is to ensure smooth, high volume road traffic. The problem of anomalies in the system has been a longstanding concern for researchers, and with the widespread use of motorway networks a series of studies have been published on the subject. Speed limitation is one of the most important tools of mitigating disturbances. This study is looking for a solution to the problem known as the "shock wave effect". The research is based on a simulation method in a PTV VISSIM environment. The software can be used to examine certain traffic conditions, and then apply dynamic speed limitation based on these conditions. The Built Environment Information Platform (BENIP) is based on the idea that the built environment, the traffic, and the flow of information between them are closely related. The relevance of the study lies in the fact that a point-based notification of speed limits can be used for vehicles – a technology that is available in most cases at the infrastructure level on motorways – thus, improving road capacity and traffic safety.]]></description>
      <pubDate>Fri, 31 Jan 2025 11:38:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/2475799</guid>
    </item>
    <item>
      <title>Optimization of VISSIM Driver Behavior Parameter Values Using Genetic Algorithm</title>
      <link>https://trid.trb.org/View/2475736</link>
      <description><![CDATA[Modeling effective vehicular traffic is a highly contested topic, especially in developing countries like Sri Lanka, which has a wide range of driving conditions. VISSIM microsimulation software is currently used by Road Development Authority (RDA) and relevant authorities to perform traffic management solutions in Sri Lanka. However, it is required to do modifications to the existing driver behavior parameter values to effectively reflect the realistic traffic conditions observed in the real-world in the simulated model. The main purpose of this study is to calibrate the VISSIM driver behavior parameter values using a genetic algorithm (GA). The methodology and results of the VISSIM model’s sensitivity analysis and calibration, which was developed for the Malabe three-legged signalized intersection, are presented in this study. A sensitivity analysis was used to find the most sensitive driver behavior parameters. Using the multi-objective GA optimization tool in the MATLAB software's optimization toolbox, the optimum driver behavior parameter values for these identified most sensitive driver behavior parameters were determined. The findings revealed that GA optimization is effective in reducing the difference between observed and simulated results.]]></description>
      <pubDate>Tue, 28 Jan 2025 09:18:26 GMT</pubDate>
      <guid>https://trid.trb.org/View/2475736</guid>
    </item>
    <item>
      <title>The Feasibility and Operational Performance of Implementation Median U-turn Intersections: A CRITIC Method</title>
      <link>https://trid.trb.org/View/2475771</link>
      <description><![CDATA[Currently, a growing number of cities are adopting the Median-U-Turn (MUT) intersection design to enhance road capacity and traffic efficiency. The critical question in selecting the right intersection design is how significantly the implementation of MUT can enhance intersection performance, focusing on three key aspects: intersection efficiency, capacity, and the environmental impact of the design. To address this question, an evaluation of operational performance under various prevailing conditions (roadway and control) was conducted using VISSIM, a microscopic simulation platform. This evaluation involved five scenarios: conventional intersections (with increased cycle length, grade separation with a signalized at-grade intersection, grade separation with a roundabout), MUT, and signalized crossover MUT at a dense urban arterial intersection in Amman, Jordan's capital. The performance was compared using several metrics: average control delay, number of stops, average travel speed and time, average stopped delay, Carbon Monoxide (CO) emissions, fuel consumption, and vehicle safety. The Criteria Importance Through Intercriteria Correlation (CRITIC) technique was subsequently used to select the optimal design. The findings indicate that the existing intersection configuration is the least effective, while the MUT with signals at the crossing U-turn points is the most efficient solution.]]></description>
      <pubDate>Wed, 08 Jan 2025 09:41:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/2475771</guid>
    </item>
    <item>
      <title>Emergency Evacuation in Urban Underground Loop Fire Scenarios: A Case Study</title>
      <link>https://trid.trb.org/View/2475484</link>
      <description><![CDATA[This study takes an urban underground loop in design stage as an example and proposes the evacuation control plans for underground loop fire scenarios based on the idea of hierarchical zoning and fire classification. The utilization rate of available safe evacuation time is proposed to represent the evacuation efficiency of different plans. VISSIM and Pathfinder software are used to construct simulation scenarios. The results show that the most effective evacuation strategy for different fire sizes is to keep all entrances and exits open. However, during a large-scale fire, it is not advisable to open the parking lot entrance near the fire source for vehicle access to prevent fire incidents in adjacent areas. Moreover, when a fire occurs in Area II, emergency evacuation is relatively convenient, while in Area IV, it is more challenging and requires careful monitoring. Strengthening the fire prevention capabilities in Area IV should be considered.]]></description>
      <pubDate>Fri, 27 Dec 2024 15:27:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/2475484</guid>
    </item>
    <item>
      <title>Optimal and Robust Control of Vehicle Platooning on Signalized Arterial With Significant Freight Traffic</title>
      <link>https://trid.trb.org/View/2464343</link>
      <description><![CDATA[On an arterial with significant freight traffic, traffic stability is a issue that can influence mobility. The stability functions of car-following models in mixed traffic have been extensively studied, but most of them focus on the feasible region of the parameters. Few studies use theory to control AV to improve traffic stability concerning the requirement of throughput at the same. With the development of connected and automated car (CAV) technology, vehicles can communicate information in real-time between the vehicle and the infrastructure to make decisions with less reaction time. Applying CAV technology, this project develops an adaptive headway method to ensure traffic stability and throughput in a mixed traffic environment of passenger cars and trucks. The relation between AV driving headway and stability is investigated under different AV market penetration rates and different truck percentages. According to the analysis, traffic can only be stable if the truck ratio is less than 80%. The proposed method is validated with a VISSIM simulation. The proposed method can reduce oscillations, reduce the delay by 23.19%, and increase average speed by 9.09% compared to the case of baseline where the desired head of AV is fixed. The results of the project will extend to the situation when the signal exists in the urban road in future work.]]></description>
      <pubDate>Tue, 17 Dec 2024 17:09:08 GMT</pubDate>
      <guid>https://trid.trb.org/View/2464343</guid>
    </item>
    <item>
      <title>Reduction of Vehicular Emission at Urban Road Junctions Through Traffic Interventions</title>
      <link>https://trid.trb.org/View/2407365</link>
      <description><![CDATA[The road transportation sector is one of the dominant sources of vehicular emission, which is causing very high levels of air pollution. Any technique to effectively control pollution is only possible by precisely estimating vehicle exhaust emissions. The objective of the research is to estimate vehicular emissions near the signalized intersection under the effect of traffic, control, vehicle, and road characteristics. This will enable to establish the link between emissions and the most likely influencing and measurable characteristics of Indian traffic conditions. The simulation results generated in VISSIM are imported into EnViVer to calculate the total emissions and emissions of individual vehicle classes. By simulating various combinations of vehicular, traffic, geometric, and control conditions at the intersection, the researcher will be able to arrive at the optimal combination that will result in minimal vehicular emission. The mathematical models that could be developed out of the research will be helpful to field practitioners in selecting the best strategy to tackle air pollution resulting from vehicular traffic. CO₂ emission reduces significantly by 45.79% by decreasing 2W (Two-wheeler) and cars in the traffic stream by 75% and substituting these with busses. Further, a reduction of pollution levels by 91.1% occurs when all conventional cars are replaced by electric vehicles. Hence, encouraging the use of public transportation and the adoption of electric-powered vehicles could be the right step to tackle the ever-increasing pollution levels on Indian roads.]]></description>
      <pubDate>Tue, 17 Dec 2024 17:09:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/2407365</guid>
    </item>
    <item>
      <title>Study on Benefit Analysis and Setting Condition of Signal Control Right-Turn Vehicles at Intersection</title>
      <link>https://trid.trb.org/View/2475418</link>
      <description><![CDATA[Based on the analysis of conflicts among non-motor vehicles, pedestrians crossing the street, right-turn vehicles traffic at a signalized intersection, and the signal control right-turn vehicles was proposed to alleviate the traffic conflicts. As an example, the intersection of Nanjing Road and Weijin Road in Tianjin is investigated. According to the real traffic flow characteristics of this intersection to set the exclusive right-turn phase, taking evaluation analysis on traffic benefit of signal control right-turn vehicle at intersection east entry and combining verification analysis with Vissim simulation, the results show that the countermeasures are reasonable and feasible. By changing the parameter value in the Vissim model building, it gets a signal control critical flow value to alleviate the conflict among the non-motor vehicles, pedestrians, and right-turn vehicles, which enables to improve the operation efficiency of the signalized intersection.]]></description>
      <pubDate>Thu, 12 Dec 2024 16:57:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/2475418</guid>
    </item>
    <item>
      <title>The Timing Optimization of One-Way Traffic Signal Intersection Based on Vissim Simulation</title>
      <link>https://trid.trb.org/View/2475414</link>
      <description><![CDATA[The signal timing plan plays a pivotal role in influencing the efficiency of one-way traffic operations. In this study, the authors focused on optimizing the performance of a one-way traffic intersection in Xi’an to alleviate urban traffic challenges. Firstly, the authors introduced a signal timing optimization scheme. Afterwards, the authors utilized Vissim simulation software to model and compare intersection performance before and after the optimization process. Three key evaluation metrics—travel time, queue length, and delay—were employed to assess the impact of the optimization. The results demonstrate that Vissim simulation proves an effective tool for optimizing one-way traffic signal timing, providing a clear basis for comparing outcomes before and after the optimization.]]></description>
      <pubDate>Thu, 12 Dec 2024 16:57:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/2475414</guid>
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