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    <title>Transport Research International Documentation (TRID)</title>
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    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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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>NEW METHODOLOGY ESTIMATES INCIDENT IMPACTS</title>
      <link>https://trid.trb.org/View/541302</link>
      <description><![CDATA[The incorporation of incident-related information into the transportation planning process will be given a boost by a new sketch planning methodology under development by the Federal Highway Administration (FHWA).  The methodology requires data that are readily available from other planning functions.  Key features of the methodology that distinguish it from past methods and enhance its application to the planning process include the ability to account for temporal traffic variation, account for variation in incident characteristics, determine the impact of incident management programs in terms of reduced incident duration and reduced incident rates, determine the effect on incident delay of safety-related and capital improvements that reduce accident rates and provide usable shoulders, gauge the contribution of recurring and nonrecurring delay to total delay, and estimate the variability in total delay due to incidents. The methodology is derived from a stochastic queueing model, which simulates 24 hours of traffic on a test segment and allows for the growth and dissipation of queues that form throughout the day.]]></description>
      <pubDate>Tue, 01 Dec 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/541302</guid>
    </item>
    <item>
      <title>NEW ESTIMATION TECHNIQUE FOR VEHICLE-TYPE-SPECIFIC HEADWAY DISTRIBUTIONS</title>
      <link>https://trid.trb.org/View/540953</link>
      <description><![CDATA[Recently, a new statistical procedure was developed that enables fast, accurate, and robust estimation of composite headway distributions, such as Branston's generalized queueing model (GQM).  Until now, the new procedure had only been applied to aggregate vehicular flow.  In this paper, the estimation procedure is extended to headway observations segregated according to vehicle type and period of the day.  Consequently, the parameters of a new mixed-vehicle-type headway distribution model based on Branston's headway model can be estimated. Distinction of vehicle type and sample periods provides additional insight into the plausibility of the headway distributions and parameter values, as well as into the car-following behavior of the distinct vehicle classes varying across the different periods.  The estimation procedure was applied to traffic data collected on a two-lane rural road in the Netherlands.  Comparison of the estimated headway distributions with real-life data shows that headway distributions can be realistically replicated with the Pearson-III-based mixed-vehicle-type GQM.  Interpretable differences between the morning, noon, and evening sample periods and between passenger cars, unarticulated trucks, and articulated trucks are found.  In addition, passenger-car equivalents for both articulated trucks and unarticulated trucks were determined from the parameter estimates.]]></description>
      <pubDate>Wed, 18 Nov 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/540953</guid>
    </item>
    <item>
      <title>A COMBINED TRAVELER BEHAVIOR AND SYSTEM PERFORMANCE MODEL WITH ADVANCED TRAVELER INFORMATION SYSTEMS</title>
      <link>https://trid.trb.org/View/539982</link>
      <description><![CDATA[The goal of this paper is to develop a framework for evaluating the effect of Advanced Traveler Information Systems. The framework uses a composite traffic assignment model which combines a probabilistic traveler behavior model of route diversion and a queuing model to evaluate Advanced Traveler Information Systems impacts under incident conditions. The composite assignment model considers three types of travelers: those who are unequipped with electronic devices, i.e., they do not have Advanced Traveler Information Systems or radio in their vehicles; those who receive delay information from radio only; and those who access Advanced Traveler Information Systems only. Findings indicate that the overall system performance, measured by average travel time, improves marginally with increased market penetration of Advanced Traveler Information Systems.]]></description>
      <pubDate>Tue, 06 Oct 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/539982</guid>
    </item>
    <item>
      <title>SPEED AND DELAY PREDICTION MODELS FOR PLANNING APPLICATIONS</title>
      <link>https://trid.trb.org/View/487532</link>
      <description><![CDATA[Estimation of vehicle speed and delay is fundamental to many forms of transportation planning analyses, including air quality, long-range travel forecasting, major investment studies, and congestion management systems.  However, existing planning-level techniques do a poor job of estimating the duration and extent of congestion.  To improve the state of the practice, a simplified queuing-based model, QSIM, was developed.  QSIM incorporates several features, including the use of temporal distributions as a basis for developing hourly traffic estimates, for estimation of peak spreading, and for estimating delay rather than speed as the predictive variable.  Under congested conditions, the new procedure predicts substantially more delay than traditional methods.]]></description>
      <pubDate>Sat, 11 Jul 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/487532</guid>
    </item>
    <item>
      <title>MODELING VEHICULAR TRAFFIC FLOW USING M/G/C/C STATE DEPENDENT QUEUEING MODELS</title>
      <link>https://trid.trb.org/View/475301</link>
      <description><![CDATA[In this paper, M/G/C/C state dependent queueing models are proposed for modeling and analyzing vehicular traffic flows. Congestion aspects of traffic flow are represented by introducing state dependent service rates as a function of number of vehicles on each road link. Analytical models for unidirectional and multisource flows are presented. Finally, queueing models to analytically determine the optimal capacity and performance measures of the road links are incorporated into a series of software programs available from the authors.]]></description>
      <pubDate>Fri, 09 Jan 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/475301</guid>
    </item>
    <item>
      <title>MODELING AND ESTIMATION OF HEADWAY DISTRIBUTIONS</title>
      <link>https://trid.trb.org/View/474599</link>
      <description><![CDATA[A simple analysis to derive Branston's generalized queueing model for (time-) headway distributions is presented.  It is assumed that the total headway is the sum of two independent random variables:  the empty zone and the free-flowing headway. The parameters of the model can be used to examine various characteristics of both the road (e.g., capacity) and driver-vehicle combinations (e.g., following behavior). Furthermore, the model can be applied to vehicle generation in microscopic simulation models and to safety analysis.  To estimate the different parameters in the model, a new estimation method is proposed.  This method, which was developed on the basis of Fourier-series analysis, was successfully applied to measurements collected on two-lane rural roads.  The method was found to be both computationally less demanding and more robust than traditional parameter techniques procedures, such as maximum likelihood.  In addition, the method provides more accurate results.  Parameters in the model were examined with the developed estimation method.  Estimates of these parameters at a specific period and a specific measurement location were to some extent transferable to other periods and locations. Application of the method to road capacity estimation is discussed.]]></description>
      <pubDate>Mon, 29 Dec 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/474599</guid>
    </item>
    <item>
      <title>EVALUATING THE VALUE OF INFORMATION AVAILABLE IN ITS</title>
      <link>https://trid.trb.org/View/474013</link>
      <description><![CDATA[This paper is a survey of results by the author on an integration of predictive routing information available under an Intelligent Transportation System (ITS) with an Advance Traffic Management System (ATMS) scheme.  A contribution of this research is a suite of models which is currently being used in ITS evaluations including: the Lin-Sarkar-Statts (LS3) traffic simulator; a traffic signal timing algorithm which optimizes signal settings based on predictive routing information called the Predictive Routing Information Signal Timing INtEgration (PRISTINE) model; and an optimized Third Generation Control (3GC) signal timing model.  Both PRISTINE and 3GC integrate with LS3, allowing the signal settings within the simulation to be modified dynamically.  The first portion of this paper develops the theoretical basis for PRISTINE model.  PRISTINE explicitly uses the predictive routing information available under ITS as well as considering the effects of queuing and congestion and compensating for them in setting the traffic signal control plan.  The paper presents a new methodology for using spanning trees to determine the offsets in the network.  The paper shows a Queue Effects Model (QEM) that explicitly considers the effects of bulk arrivals on average delay and probability of stopping at an intersection.  The Queue Effects Model requires only the average arrival rate and the first two moments of platoon size, all of which can be collected using existing technology.  The Queue Effects and spanning tree models form the theoretical basis for PRISTINE.  The second portion of this paper describes the surge situation.  The surge situation arises when there is a sudden shift in traffic patterns or densities such as occur when a sporting event lets out or there is a traffic incident.  PRISTINE offers substantial savings as measured by average delay per vehicle in cases where there were either sudden shifts in traffic flow or dominant directions of flow in the network.]]></description>
      <pubDate>Wed, 24 Dec 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/474013</guid>
    </item>
    <item>
      <title>ESTIMATION OF TRAFFIC QUEUES AND DELAYS AT ROUNDABOUT ENTRIES</title>
      <link>https://trid.trb.org/View/577778</link>
      <description><![CDATA[Queue lengths and delays at entry points are the important indices for measuring the performance of roundabouts.  The object of this study is to find out suitable methods for estimating these indices.  Several formulae for estimating average queue length and delay at roundabout entries have been developed.  The well-known formulae are those developed by Kimber and Hollis. Field observations on queue lengths and delays at roudabout entries indicate Kimber's formulae provide reasonable predictions for under-saturated traffic conditions. New formulae, based on Kimber's formulae, are derived by introducing two new parameters, one for adjusting the deterministic equation and the other for increasing the approaching speed.  The parameters used in this new formulae are determined on the basis of the average simulation data for oversaturated conditions.  A computer program was developed to apply the research results in practice.]]></description>
      <pubDate>Wed, 05 Nov 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/577778</guid>
    </item>
    <item>
      <title>QUEUEING AT UNSIGNALIZED INTERSECTIONS</title>
      <link>https://trid.trb.org/View/482149</link>
      <description><![CDATA[A general queueing theory model for traffic flow at unsignalized intersections is described and analyzed which contains most of the mathematical models developed in the literature as special cases. Thus a consistent approach is presented for obtaining these models from a general viewpoint. Included are green-red models which are based on an analogy to traffic signals. Critical gaps and merging times or move-up times are allowed to be stochastically dependent. Inconsistent and consistent driver behavior is considered. Platooning of the major road traffic with random intra-bunch headways is included. The results focus on the distributions of queue lengths and delays and, in particular, on capacities. A general capacity formula is developed and it is shown how the various capacity formulas from the literature come out as special cases.]]></description>
      <pubDate>Mon, 21 Apr 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/482149</guid>
    </item>
    <item>
      <title>A CONTINUUM THEORY OF TRAFFIC DYNAMICS FOR FREEWAYS WITH SPECIAL LANES</title>
      <link>https://trid.trb.org/View/482140</link>
      <description><![CDATA[This paper presents a generalized theory of kinematic waves for freeways with two vehicle types and a set of lanes reserved for one of the vehicle classes. The theory is not restricted to freeways on which the special lanes are clearly identified by signs and pavement markings; e.g. for high occupancy vehicles. It may also apply if the restrictions are self-imposed, such as would occur on a freeway segment upstream of a busy off-ramp where the existing traffic naturally avoids the 'far-side' lanes. Of particular interest are oversaturated time periods because the original theory of kinematic waves proposed by Lighthill and Whitham [Proceedings Royal Society, A 229, 281-345 (1955)] and Richards (1956) does not recognize that different traffic conditions (queues and speeds) may arise on the two sets of lanes, and that these may affect the two vehicle classes in different ways. The model is attractive because the nature of its solution can be described in complete physical detail by means of simple intuitive diagrams that show how the simple kinematic wave model is improved.]]></description>
      <pubDate>Thu, 17 Apr 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/482140</guid>
    </item>
    <item>
      <title>OPTIMAL ROAD TOLLS UNDER CONDITIONS OF QUEUEING AND CONGESTION</title>
      <link>https://trid.trb.org/View/464866</link>
      <description><![CDATA[In this paper, the authors present a bi-level programming approach for determination of road toll patterns. The lower-level problem represents a queueing network equilibrium model that describes user's route choice behavior under conditions of both queueing and congestion. The upper-level problem is to determine road tolls to optimize a given system's performance while considering users' route choice behavior. Sensitivity analysis is also performed for the queueing network equilibrium problem to obtain the derivatives of equilibrium link flows with respect to link tolls. This derivative information is then applied to the evaluation of alternative road pricing policies and to the development of heuristic algorithms for the bi-level road pricing problem.]]></description>
      <pubDate>Fri, 25 Oct 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/464866</guid>
    </item>
    <item>
      <title>ON THE USE OF NEURAL NETWORKS TECHNIQUES FOR TRAFFIC FLOW MODELING</title>
      <link>https://trid.trb.org/View/463428</link>
      <description><![CDATA[Today, most large cities in industrialized countries are confronted with chronic traffic congestion.  To cope with this problem, traffic management in urban areas seems to be a necessity.  The most recently designed urban traffic control systems are fully adaptive, in the sense that they modify the signal states on the basis of a control law to respond to variation of the traffic conditions.  Their policy is to evaluate the consequences of the application of a particular set of commutations on traffic evolution.  Only the use of a traffic flow model makes this projection in the future possible.  No unified theory of traffic flow exists, rather there are several theoretical approaches to describe this phenomenon.  The traffic flow models, most widely applied, are analytic models, based on the laws of physics and mathematics.  Usually, they require preliminary knowledge about traffic flow.  Moreover, due to the limitations of the hypotheses they are built on, they are inaccurate to represent the traffic dynamics under some circumstances.  To overcome these difficulties, a traffic flow model based on neural networks is proposed.  Neural nets are introduced here to model the queue length on a link whose output is controlled by signals.  They are nonlinear data driven models, capable of inferring, from data that are relevant to the computation of the queue length, the queue length function.  The purpose of this paper is to present the results of the investigations on the potential of neural networks to model traffic flow.  The first part is dedicated to an overall presentation of adaptive real time UTC systems.  The second part presents the limits of conventional modeling techniques used in such systems.  Then, neural networks are further detailed.  In the fourth part, their abilities to approximate the queue length function are underlined.  The benefits of their use over more conventional techniques are clear.  Finally, based on numerical simulations, their effectiveness to queue modeling is discussed.]]></description>
      <pubDate>Wed, 07 Aug 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/463428</guid>
    </item>
    <item>
      <title>TRAFFIC PREDICTION FOR REAL TIME TRAFFIC MANAGEMENT</title>
      <link>https://trid.trb.org/View/461684</link>
      <description><![CDATA[A real-time traffic model is developed for operation as the kernel unit in a traffic management system, supplying the system with necessary short-term predictions.  Online real-time tests are performed.  Traffic is estimated and predicted for three different time worlds; one is used internally for fast feedback of predictions.  High frequency response from sensors are filtered for different frequency domains, and then special methods are applied giving the best possible prediction of traffic flow and corresponding travel time.  The new knowledge about real-time traffic processes is utilized in a queue model to handle direction and prediction of the queue growth process in real time.  The automatic incident detection function is developed using advanced constant false alarm ratio.  The real-time traffic theory is not only the basis for the traffic model, but also serves as the basis for design of traffic management systems and precalculation of system performance.]]></description>
      <pubDate>Wed, 22 May 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/461684</guid>
    </item>
    <item>
      <title>DESIGNING EFFICIENT TOLL PLAZAS USING IQPAC</title>
      <link>https://trid.trb.org/View/452983</link>
      <description><![CDATA[The Integrated Queue Analysis Package (IQPAC) was developed after several years of research and design for toll plaza operations conducted by the author. While designing toll plazas throughout Florida, the need for a flexible design tool became evident -- one that could model lane configurations of several types including those using Automatic Vehicle Identification (AVI) technology. Several agencies were contacted for procuring a tool which would help model toll plaza operations, but no such tool was found. Thus, development of IQPAC began. The rest of this article describes general concepts of toll plaza design, the use of analytical and microscopic simulation models, IQPAC software applications, sample problems, and a discussion of the suitability of the models for particular design situations.]]></description>
      <pubDate>Thu, 25 Jan 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/452983</guid>
    </item>
    <item>
      <title>PREDICTING TRAFFIC IMPACTS AT TWO-LANE HIGHWAY WORK ZONES. FINAL REPORT</title>
      <link>https://trid.trb.org/View/423067</link>
      <description><![CDATA[Maintenance or reconstruction activity on a two-lane highway often requires a lane closure.  The implementation of "one-way traffic control", required to maintain traffic flow throughout the work zone, typically produces significant motorist delay. This report describes the adaptation and application of queueing models, originally derived for intersections controlled by vehicle-actuated traffic signals, to estimate delay at two-lane highway work zones.  The models estimate expected delay as a function of directional traffic demand rates, work zone physical length and observed traffic measures.  Validation efforts using simulation suggest that the models accurately predict the impacts of two-lane highway lane closures.]]></description>
      <pubDate>Fri, 11 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/423067</guid>
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