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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>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Impact of Autonomous-Vehicle-Only Lanes in Mixed Traffic Conditions</title>
      <link>https://trid.trb.org/View/1599467</link>
      <description><![CDATA[The introduction of autonomous vehicles (AVs) in the near future will have a significant impact on road traffic. AVs may have advantages in efficiency and convenience, but safety can be compromised in mixed operations of manual vehicles and AVs. To deal with the issues associated with mixed traffic and to avoid its negative effects, a special purpose lane reserved for AVs can be proposed to segregate AVs from manual vehicles. In this research, we analyze the effect on efficiency and safety of AVs in mixed traffic and in a situation where an AV-only lane is deployed. In the analysis, we investigate the average speed, the throughput, and the inverse time-to-collision (ITTC). We differentiate the behaviors of manual vehicles and AVs through the reaction time, desired speed, and car-following models. As a result, we observe that the efficiency is improved when the market penetration rate of AVs increases, especially when the highway throughput increases by up to 84% in the case of mixed traffic. However, safety worsens when the market penetration of AVs is under 40%. In this case, the average speed can be improved and the frequency of dangerous situations (ITTC > 0.49) can be reduced drastically in the merging section by making the innermost lane AV-only. Accordingly, we conclude that AV-only lanes can have a significant positive impact on efficiency and safety when the market penetration rate of AVs is low.]]></description>
      <pubDate>Mon, 13 May 2019 10:45:26 GMT</pubDate>
      <guid>https://trid.trb.org/View/1599467</guid>
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    <item>
      <title>Investigation of the Impact on Throughput of Connected Autonomous Vehicles with Headway Based on the Leading Vehicle Type</title>
      <link>https://trid.trb.org/View/1591354</link>
      <description><![CDATA[Although the future era of autonomous driving is seen as a solution for many of the current problems in traffic; the introductory phase, with low penetration rates of connected-autonomous vehicles (CAVs), might lead to lower capacities. This forecast is based on certain assumptions that the CAVs can operate more efficiently when communicating and cooperating—already proved in real tests—therefore in practice, they can keep smaller following headways. However, it is envisioned that they might keep larger headways to other conventional vehicles for safety reasons. Lower connected-autonomous vehicle (CAV) penetration rates lead to a reduction in the overall vehicle throughput, then with increasing penetration rates, throughput is recovered and eventually improved. Simulations demonstrate that the impact on vehicle throughput depends on the car following headway and penetration rate. Based on this potential reduction in the maximum throughput for low penetration rates, the aim of this paper is the mitigation of this phenomenon at urban intersections through a possible managing solution to sort CAVs and a pre-set green-time start. A microsimulation model has been calibrated using PTV Vissim to reflect this operating solution, using new possibilities as leading vehicle class dependent headway settings and formula-based routing for sorting vehicles at a two-lane intersection entry. This approach allows the formation of platoons at intersections and uses their effectiveness even at low CAV penetration rates. The tested scenario is simplified to through traffic without turnings maneuvers and the results show that the potential loss in throughput is canceled and reductions in the control delay can reach 17% for oversaturated conditions.]]></description>
      <pubDate>Mon, 15 Apr 2019 14:13:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/1591354</guid>
    </item>
    <item>
      <title>Methodology for justification of the place for applying a stop-line to secure safety of completion of travel through a signalled intersection</title>
      <link>https://trid.trb.org/View/1577501</link>
      <description><![CDATA[The paper considers security issues associated with the streets and road network (SRN) hub, which are directly related to the points of application of horizontal road marking line identified as 1.12 “Stop line”. It is established that application of the stop line with respect to the boundary of the intersected roadway is not regulated by GOST. This means that the stop line may be applied disregarding traffic safety requirements and efficient use of intersection area for maintaining optimum throughput capacity. A point for the stop line to be applied in many instances is selected proceeding from location of electrical illumination poles where traffic lights are mounted rather than from the safety principles. The most rational, from the point of view of maximum throughput capacity, is the option of traffic light unit operation that provides for switching the stop “red” light for vehicle traffic flow completing their movement through the intersection, while a green traffic light is turned on for the conflicting traffic flow starting to move. Under this approach, the vehicles completing their movement through intersection must pass through distant conflict point (DCP) before the moment when it is reached by the vehicles starting to move. Interrelation between the most rational, from the point of view of traffic safety and throughput capacity requirements, arrangement of stop lines for vehicles completing their movement through intersection, and application of stop lines for vehicles starting to move in the next phase to the green traffic light has been obtained. The obtained values of the relative position of the stop lines along conflicting movement directions of vehicles allow preventing intersection of traffic flows at the same point at the same time. Dependencies of arrangement of stop lines on the actual speed of the traffic flow crossing the intersection; degrees of influence of the speed of the vehicles entering intersection and degrees of influence of acceleration of the vehicles starting to move with the green traffic light on the traffic safety have been established.]]></description>
      <pubDate>Wed, 20 Feb 2019 12:28:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/1577501</guid>
    </item>
    <item>
      <title>Development of a signal-head-free intersection control logic in a fully connected and autonomous vehicle environment</title>
      <link>https://trid.trb.org/View/1515880</link>
      <description><![CDATA[Establishment of effective cooperation between vehicles and transportation infrastructure improves travel reliability in urban transportation networks. Lack of collaboration, however, exacerbates congestion due mainly to frequent stops at signalized intersections. It is beneficial to develop a control logic that collects basic safety message from approaching connected and autonomous vehicles and guarantees efficient intersection operations with safe and incident free vehicle maneuvers. In this paper, a signal-head-free intersection control logic is formulated into a dynamic programming model that aims to maximize the intersection throughput. A stochastic look-ahead technique is proposed based on Monte Carlo tree search algorithm to determine the near-optimal actions (i.e., acceleration rates) over time to prevent movement conflicts. The authors' numerical results confirm that the proposed technique can solve the problem efficiently and addresses the consequences of existing traffic signals. The proposed approach, while completely avoids incidents at intersections, significantly reduces travel time (ranging between 59.4% and 83.7% when compared to fixed-time and fully-actuated control strategies) at intersections under various demand patterns.]]></description>
      <pubDate>Fri, 29 Jun 2018 17:10:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/1515880</guid>
    </item>
    <item>
      <title>Evaluation of the Potential for Using Ramp Metering in the ATMS of the I-80 Showcase Corridor</title>
      <link>https://trid.trb.org/View/1492219</link>
      <description><![CDATA[Ramp metering was proven to be a viable form of freeway traffic control strategy, which could eliminate, or at least reduce, freeway congestion. In this study, general and technical requirements, ramp metering control strategies and models, and constraints (e.g., meter locations, ramp storage capacities, lower and upper bounds of ramp metering rates) were discussed in detail. Based on the collected geometric and traffic data, the CORSIM model was developed and used to simulate traffic operation of the study site. The pre-timed and demand/capacity metering control strategies were evaluated, while the potential metered ramps were determined. A dynamic multi-ramp metering control model with Simultaneous Perturbation Stochastic Approximation (SPSA) algorithm, which maximized the total throughput subject to a number of constraints, was developed and applied on single and multiple ramps of the study site. The potential benefit of the dynamic multi-ramp control model under time varying traffic demand was tested, simulated, and evaluated. The increased total throughput and reduced total delay were observed, while the traffic conditions suitable for implementing ramp metering control were suggested.]]></description>
      <pubDate>Thu, 28 Dec 2017 14:03:39 GMT</pubDate>
      <guid>https://trid.trb.org/View/1492219</guid>
    </item>
    <item>
      <title>Evaluation of the US 290 Changeable Lane Assignment System for Incident Management</title>
      <link>https://trid.trb.org/View/1429006</link>
      <description><![CDATA[The principal goal of this project was to evaluate the operational effectiveness of the Changeable Lane Assignment (CLAS) system as an incident management tool to optimize incident management operations in the US 290 Corridor. During incident management, the CLAS system provides for shared turn lane assignments and incident management signal timings at the intersections affected by the freeway mainlane incident. The incident management signal timing plans were developed as part of this project to provide time management by balancing the need to progress additional traffic along the westbound US 290 frontage road with the need to minimize delay along the corridor. Candidate incidents were documented by the video data collection system and reviewed to assess the impact of incidents on freeway and frontage road operations. Seven incidents (1 AM, 3 mid-day, and 3 PM) were evaluated using FREQ 11 to model freeway operations and Synchro to model frontage road operations. Comparisons were made between results for the actual incident conditions with simulated CLAS incident management conditions. Results indicated a reduction in total (freeway and frontage road network) delay for the three mid-day and three PM peak period incidents analyzed but resulted in increased total network delay during the one AM peak period incident analyzed. Other study measures of effectiveness documented in this report include delay per vehicle, frontage road and cross street levels of service, throughput, and lane use violations.]]></description>
      <pubDate>Wed, 09 Nov 2016 13:24:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/1429006</guid>
    </item>
    <item>
      <title>Influence of connected and autonomous vehicles on traffic flow stability and throughput</title>
      <link>https://trid.trb.org/View/1424411</link>
      <description><![CDATA[The introduction of connected and autonomous vehicles will bring changes to the highway driving environment. Connected vehicle technology provides real-time information about the surrounding traffic condition and the traffic management center’s decisions. Such information is expected to improve drivers’ efficiency, response, and comfort while enhancing safety and mobility. Connected vehicle technology can also further increase efficiency and reliability of autonomous vehicles, though these vehicles could be operated solely with their on-board sensors, without communication. While several studies have examined the possible effects of connected and autonomous vehicles on the driving environment, most of the modeling approaches in the literature do not distinguish between connectivity and automation, leaving many questions unanswered regarding the implications of different contemplated deployment scenarios. There is need for a comprehensive acceleration framework that distinguishes between these two technologies while modeling the new connected environment. This study presents a framework that utilizes different models with technology-appropriate assumptions to simulate different vehicle types with distinct communication capabilities. The stability analysis of the resulting traffic stream behavior using this framework is presented for different market penetration rates of connected and autonomous vehicles. The analysis reveals that connected and autonomous vehicles can improve string stability. Moreover, automation is found to be more effective in preventing shockwave formation and propagation under the model’s assumptions. In addition to stability, the effects of these technologies on throughput are explored, suggesting substantial potential throughput increases under certain penetration scenarios.]]></description>
      <pubDate>Fri, 21 Oct 2016 16:32:30 GMT</pubDate>
      <guid>https://trid.trb.org/View/1424411</guid>
    </item>
    <item>
      <title>Dynamic Pricing Algorithm with Embedded Controller for High Occupancy Toll Lanes</title>
      <link>https://trid.trb.org/View/1406385</link>
      <description><![CDATA[Today more and more Intelligent Transportation System (ITS) strategies are introduced nationwide to reduce congestion and maintain desired service levels on freeways. High Occupancy Toll (HOT) lanes (form of managed lanes) is one such ITS strategy. HOT lanes are intended to maintain certain level of service such as average speed, throughput, etc. One of the major challenges in achieving these objectives is the time delay (due to long stretches of HOT lanes) and the resulting uncertainty in the throughput calculated at the end of the HOT lanes. HOT lanes need to have pricing algorithms that control the traffic by considering this time delay between the checking point and the tollbooth. This paper introduces a proportional integral differential (PID) controller based pricing algorithm that addresses this need. A simulation model of I-95 is used to demonstrate the effectiveness of this approach.]]></description>
      <pubDate>Wed, 13 Jul 2016 11:41:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/1406385</guid>
    </item>
    <item>
      <title>On Using Perfect Signal Progression as the Basis for Arterial Design: A New Perspective</title>
      <link>https://trid.trb.org/View/1392597</link>
      <description><![CDATA[Many roadway agencies are interested in maximizing the throughput of existing roadways through the use of access management. Part of access management involves spacing intersections effectively so as to attempt to provide the maximum progression and bandwidth. However, an arterial often has intersections that are irregularly spaced, thereby not allowing for the maximum progression through traditional means. This paper proposes a new method of achieving perfect progression in both directions of an arterial roadway, by using signal progression itself as the design criterion for the arterial and its signalized intersections. First the green bands are established, and then the intersections are designed around them. What is important in the design of signal progression is to ensure that enough bandwidth is provided to handle the arterial’s through movements effectively. However, the most important parameter is a new parameter defined herein as the “bandwidth offset”, which is a measure of the amount of time in the cycle between the green bands in the two opposing directions of travel in a given location. Based upon these parameters, several principles for the design of intersections can be established. The hope with this theory is to be able to not just design a new corridor, but also to be able to retrofit an existing corridor, in order to guarantee perfect progression in both directions, minimizing the travel times along the corridor while also minimizing the long-term impacts on the surrounding community.]]></description>
      <pubDate>Wed, 24 Feb 2016 08:32:38 GMT</pubDate>
      <guid>https://trid.trb.org/View/1392597</guid>
    </item>
    <item>
      <title>Decentralized signal control for urban road networks</title>
      <link>https://trid.trb.org/View/1375395</link>
      <description><![CDATA[The authors propose in this paper a decentralized traffic signal control policy for urban road networks. Their policy is an adaptation of a so-called BackPressure scheme which has been widely recognized in data network as an optimal throughput control policy. The authors have formally proved that their proposed BackPressure scheme, with fixed cycle time and cyclic phases, stabilizes the network for any feasible traffic demands. Simulation has been conducted to compare the authors' BackPressure policy against other existing distributed control policies in various traffic and network scenarios. Numerical results suggest that the proposed policy can surpass other policies both in terms of network throughput and congestion.]]></description>
      <pubDate>Wed, 25 Nov 2015 16:37:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/1375395</guid>
    </item>
    <item>
      <title>An evaluation of departure throughputs before and after the implementation of wake vortex recategorization at Atlanta Hartsfield/Jackson International Airport: A Markov regime-switching approach</title>
      <link>https://trid.trb.org/View/1373763</link>
      <description><![CDATA[This paper utilizes a Markov regime-switching model to decompose airport departures into two regimes and to investigate the change in departure throughputs before and after implementing wake recat at ATL. Although analysts may not always know with certainty which regime prevails and how long it may last, they can compute the transition probabilities and expected duration of each regime. After the implementation, there was a 91% chance that departure throughputs would remain unconstrained (up from 86% before implementation) and a 37% chance that departure throughputs would become constrained (up from 35% before implementation).]]></description>
      <pubDate>Tue, 24 Nov 2015 09:29:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/1373763</guid>
    </item>
    <item>
      <title>Does traffic metering improve network performance efficiency?</title>
      <link>https://trid.trb.org/View/1354552</link>
      <description><![CDATA[Traffic metering at on-ramps in interstate highways has been widely used and led to desirable results. In urban transportation networks when demand reaches network capacity level, traffic metering may also increase network performance efficiency. In this paper, the authors apply different metering strategies to a case study network to see if they result in a different network operation and potentially a more efficient performance. To make sure if any observed differences in network performance efficiency are due to metering strategies and not due to an inappropriate signal timing, the authors determine near optimal signal timing of the network by using their Intelligent Dynamic Signal Timing Optimization Program (IDSTOP). IDSTOP incorporates Genetic Algorithms (GAs) with microscopic traffic simulation to find near-optimal signal timing parameters of the network. The authors' results showed that letting all traffic enter the network or metering a large portion of the traffic are not the best options. Instead metering around 20% of the traffic resulted in the best network performance in terms of average delay (16% reduction compared to no metering and 17% reduction compared to extremely heavy metering strategies), network throughput (18% increase compared to heavy metering), and average travel time (14% reduction compared to no metering and 10% reduction compared to heavy metering). The authors' findings suggested that in an urban network, there is an optimal point that sending more vehicles into the network than that deteriorates network performance efficiency.]]></description>
      <pubDate>Mon, 08 Jun 2015 16:00:38 GMT</pubDate>
      <guid>https://trid.trb.org/View/1354552</guid>
    </item>
    <item>
      <title>Microscopic dynamic traffic management: Simulation of two typical situations</title>
      <link>https://trid.trb.org/View/1354504</link>
      <description><![CDATA[This paper presents an evaluation of two typical situations of Microscopic Dynamic Traffic Management. Where Dynamic Traffic Management aims to more efficiently use existing road capacity by generic measures, Microscopic Dynamic Traffic Management anticipates suboptimal use of the available infrastructure by disturbing behavior of one or a few drivers. Using simulation, anticipation of slow predecessors in the same lane and anticipation of slow merging vehicles from an on-ramp are assessed on throughput, average travel time loss and traffic flow stability. The simulation results show positive effects, mainly on traffic flow stability, but also on throughput and travel time in the case of anticipating slow merging vehicles.]]></description>
      <pubDate>Tue, 02 Jun 2015 17:14:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/1354504</guid>
    </item>
    <item>
      <title>Using Dynamic Flashing Yellow for Traffic Signal Control Under Emergency Evacuation</title>
      <link>https://trid.trb.org/View/1338095</link>
      <description><![CDATA[Effective signal timing plans for emergency evacuation are crucial for public safety. Two conflicting objectives of emergency evacuation in a corridor are to increase throughput on the main street (evacuation route) and to decrease delay on the side streets. Previous studies have proved the effectiveness of using the static flashing yellow signal timing plan in evacuating a high number of vehicles. However, the static flashing yellow plan also yields extremely high delay on side streets. This study investigates a variant of the static flashing yellow plan called the dynamic flashing yellow (DFY) signal timing plan under a few reasonable assumptions. The DFY plan consists of two signal phases. Phase 1 is flashing yellow on the main street and flashing red on the side street, whereas Phase 2 is a red signal on the main street and a green signal on the side street. Three types of DFY plans are proposed, including fixed DFY, actuated DFY, and actuated and coordinated DFY. This study demonstrates that the DFY provides a high volume of evacuated vehicles with relatively lower delay to the side street traffic. Moreover, the DFY is adjustable to favor different weights between network throughput and average delay. To compare the DFY with the static flashing yellow and other plans, VISSIM is implemented to model a 4.1-mi corridor in Buffalo, New York. The DFY plan is further analyzed by method and cycle length. According to the Pareto frontier, the actuated and coordinated DFY with cycle lengths of 60 s and 120 s produces more desirable results (Pareto nondominated solutions) than other plans.]]></description>
      <pubDate>Sat, 28 Mar 2015 12:49:02 GMT</pubDate>
      <guid>https://trid.trb.org/View/1338095</guid>
    </item>
    <item>
      <title>Multivariant Forecasting Mode of Guangdong Province Port throughput with Genetic Algorithms and Back Propagation Neural Network</title>
      <link>https://trid.trb.org/View/1280494</link>
      <description><![CDATA[For better accurate forecasting of port throughput, a back propagation (BP) neural network model with genetic algorithms is proposed. By means of analysis of influence factors for port throughput, the structure of the (BP) neural network model is determined. Then the connection weight matrix of the BP network is designed for chromosomes of genetic algorithms (GA), which is proved to optimize BP network. The port throughput of Guangdong province in China is used for verification, and the result of the experiment shows that GA-BP neural network model has better accuracy, but consumes more time than a traditional BP network model does.]]></description>
      <pubDate>Fri, 21 Feb 2014 15:16:31 GMT</pubDate>
      <guid>https://trid.trb.org/View/1280494</guid>
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