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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>A Combined Model of Housing Location and Traffic Equilibrium Problems in a Continuous Transportation System</title>
      <link>https://trid.trb.org/View/758943</link>
      <description><![CDATA[This paper introduces a combined housing location and traffic equilibrium problem in a continuous transportation system.  The main objective has been to study the effects of congestion externality and housing rent in the disutility function on the choice of housing location in a city.  Two models are formulated to address the problem.  The first model is developed for a circular city with angular symmetrical properties, in which the problem is specified as an IVP for a system of ODEs, and specially designed but effective hierarchical line search (HLS) scheme is used to solve the problem.  The solution properties of this model are thoroughly investigated, and form the basis of the development of the second model, which is a generalized model for a city of arbitrary shape that does not have symmetrical properties.  The formulation of the generalized model is based on the Galerkin method in the weighted residual technique and the finite element method (FEM).  The problem is solved by the Newton-Raphson algorithm with a line search.  Two numerical examples are used to demonstrate the effectiveness of the methodology.  The first example is an angular symmetrical circular city, to which both the HLS and FEM are applied, with identical solutions being obtained.  The second example is of arbitrary shape, which shows the effectiveness of the generalized model in addressing the problem of irregular geometry and unsymmetrical propertied in practice.  Future research will include the evaluation of the economic aspects of the housing location problem, the formulation of a bi-level problem that maximizes the social benefit of housing distribution, and the investigation of polycentric urban forms.]]></description>
      <pubDate>Fri, 05 Aug 2005 14:15:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/758943</guid>
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    <item>
      <title>Comparison of Static Maximum Likelihood Origin-Destination Formulations</title>
      <link>https://trid.trb.org/View/758937</link>
      <description><![CDATA[Initially, the two basic formulations for estimating the most likely origin-destination (O-D) demand (as defined by the maximum entropy/minimum information) are presented and discussed in terms of logic behind each of the formulations.  These formulations include the maximum entropy/minimum information associated with the O-D matrix (termed the trip formulation) and the maximum entropy/minimum information associated with the link flows (termed the volume formulation).  These formulations are described in terms of how they are derived and any simplifying assumptions that were made in order to analytically solve the basic formulation.  After presenting the alternative formulations for solving the synthetic O-D problem and the associated simplifying assumptions, the following section investigates the consistency of the two formulations (trip and volume formulation) for two simple hypothetical networks, one that ensures a constant total demand and another that presents a variable total demand.  The reason for selecting these simple networks is to be able to enumerate the solution space in formulation.  Furthermore, the various formulations are tested for a number of cases including (1) the impact of seed O-D scaling on the final solution; (2) the impact of the seed O-D feasibility on the final O-D table estimate; and (3) the impact of the lack of flow continuity on the final solution.  This paper presented the various maximum likelihood static O-D estimation formulations.  The various formulations and solution algorithms for solving the synthetic O-D problem were compared considering the routes are know a priori under a number of conditions:  (1) when the total number of trips is constant versus variable; (2) when the seed matrix is feasible versus infeasible; and (3) when flow continuity is or is not satisfied, and finally conclusions are presented.]]></description>
      <pubDate>Fri, 05 Aug 2005 14:15:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/758937</guid>
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    <item>
      <title>A Sequential Experimental Approach for Analyzing Second-Best Road Pricing with Unknown Demand Functions</title>
      <link>https://trid.trb.org/View/758836</link>
      <description><![CDATA[This paper has described how, in recent years, road pricing as a way to reduce traffic congestion and raise revenues to fund transportation improvements has received substantial added interest.  Practical implementation has been progressing rapidly, for instance, electronic road pricing schemes have been proposed and implemented worldwide in places like Hong Kong, Singapore, California, and most recently in London.  With availability of new pricing technology and increasing concern over external cost, it is conceivable that there will be greater use of road pricing as an effective traffic management tool over the next few years.  This chapter has developed an encouraging procedure for trial-and-error implementation of the second best congestion pricing on a general road network with unknown demand functions.  The procedure involves sequential alternative solutions of the bi-level O-D demand estimation and bi-level toll optimization problems.  The technique presented here has the potential to allow a traffic planner to easily estimate the second-best link tolls from readily available traffic counts without resorting to the demand functions, and thus overcome the practical difficulty in designing a realistic second-best road pricing scheme.]]></description>
      <pubDate>Fri, 05 Aug 2005 14:15:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/758836</guid>
    </item>
    <item>
      <title>A Rolling Horizon Approach to the Optimal Dispatching of Taxis</title>
      <link>https://trid.trb.org/View/758931</link>
      <description><![CDATA[This paper describes how, in many towns and cities, taxis are requested by telephone and there is then a process by which each request is assigned.  The nature of the process depends on the structure of the industry, which varies from city to city.  For example, in some cases taxi drivers are self-employed, the call center offers the job to all drivers, and the driver who responds first is assigned to the job.  In other cases, the drivers work for a taxi company and a dispatcher in a control center assigns the job to the best placed taxi within the company.  In all cases, taxis are in radio contact with some form of call center from where information about each job (location of the request and any other relevant details) emanates.  Often in operations of this type, the jobs are queued on a display in front of the driver, with the driver reporting back to the control center upon completion of each job.  This paper assumes that the taxis are assigned jobs by a central dispatcher with the simple objective of minimizing passenger waiting time.  This objective can be regarded as synonymous with the maximization of fleet utilization.  However, dispatching the taxi that can reach a request first is at best a heuristic.  It is conceivable that the taxi that can reach the request first might actually be better assigned to a subsequent request.  A better heuristic might therefore compare the passenger waiting time incurred by assigning a taxi to the current request with the expected passenger waiting time if the taxi were instead assigned to the next request, and assign the taxi with the largest comparative advantage.]]></description>
      <pubDate>Fri, 05 Aug 2005 14:15:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/758931</guid>
    </item>
    <item>
      <title>First-Order Macroscopic Traffic Flow Models: Intersection Modeling, Network Modeling</title>
      <link>https://trid.trb.org/View/758861</link>
      <description><![CDATA[Based on the Bardos-LeReoux-Nedelec (BLN) boundary conditions, this paper proves that local traffic supply and demand define the boundary conditions for the Lighthill and Whitham Richards LWR model.  Based on the supply/demand concept and the Riemann problems for nodes, a rigorous methodology for intersection modeling within the LWR framework is proposed.  The invariance principle is shown to be necessary for intersection models to be consistent.  Two models, the equilibrium and the optimization model are introduced in order to satisfy the invariance principle.  Analytical solutions are given for the merge and diverge models, and in these special cases optimization and equilibrium models are shown to be equivalent and analytically tractable.  The merge model is shown to be compatible with experimental data, and to predict wide scatter of flow plots.  Finally, the analysis of the Riemann problem for the multi-commodity FIFO LWR model makes it possible to specify composition dynamics and boundary data.  Thus the intersection models, the boundary data and the flow models can be combined into a single network traffic flow model.  Future research should include modeling of heterogeneous traffic for non FIFO intersection modeling, as well as carrying out experimental tests for intersection models.]]></description>
      <pubDate>Fri, 05 Aug 2005 14:15:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/758861</guid>
    </item>
    <item>
      <title>An Empirical Assessment of Traffic Operations</title>
      <link>https://trid.trb.org/View/758840</link>
      <description><![CDATA[This paper describes how the California Freeway Performance Measurement System (PeMS) stores real-time data from 26,000 loop detectors that can be accessed via the internet.  It currently has 3 TB of data, growing at 2 GB/day.  PeMS extracts useful information from these data and displays it in graphical or tabular formats.  These data provide an unparalleled opportunity to assess freeway performance and suggests ways in order to improve freeway management.  Operational since 2001, PeMS receives real time data from the 26,000 loops grouped into 8,040 Vehicle Detector Stations (VDS) covering 3,000 directional miles of freeways in major California urban areas.  PeMS also collects incident data from the Traffic Accident Surveillance and Analysis System (TASAS) and the California Highway Patrol.  The principal objective of this paper is to examine congestion as a performance measure and demonstrate that data can be processed to reliably estimate the causes of congestion, and the gains from better ramp metering, incident management, and traveler information.  Each of the following sections in the paper addresses a different aspect of congestion. Some sections report on previous research by the PeMS Development Group.]]></description>
      <pubDate>Fri, 05 Aug 2005 14:15:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/758840</guid>
    </item>
    <item>
      <title>A Variational Formulation of Kinematic Waves: Bottleneck Properties and Examples</title>
      <link>https://trid.trb.org/View/758860</link>
      <description><![CDATA[This paper has introduced recipes used to solve complex Kinematic Wave (KW) problems with precision and simplicity.  The techniques are especially useful for inhomogeneous KW problems with multiple moving bottlenecks.  They can be used even if the bottlenecks change the character of the road as they move through it.  The new methods are now being applied to complex real-life problems with combinations of gradual, moving, and time-dependent bottlenecks.  They can help improve hybrid (discrete/continuous) models of traffic flow, where trucks and other slow vehicles are modeled as underpowered discrete particles that can both generate queues and be slowed by them.  The hybrid models that include lane changing are currently being implemented and the initial tests with real data re very encouraging.  These models, for example, appear to explain the strange observations of moving bottlenecks, and the detailed merge bottleneck phenomena.  The new methods can also be used to simulate intermittent bus lanes and HOV lanes.]]></description>
      <pubDate>Fri, 05 Aug 2005 14:15:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/758860</guid>
    </item>
    <item>
      <title>Reliability of Freeway Traffic Flow: A Stochastic Concept of Capacity</title>
      <link>https://trid.trb.org/View/758841</link>
      <description><![CDATA[This paper describes how conventional measures of effectiveness for freeway facilities usually reflect travel time in the form of e.g. travel velocity or delay.  The paper describes how, it has recently been becoming more and more obvious that these parameters are not sufficient for freeway traffic performance assessments because they place great emphasis on smaller differences in travel time, whereas the more significant difference between flowing traffic and congestion is not adequately represented in the paper.  It addition, traditional quality assessment fails whenever demand exceeds capacity because it will simply attest a failure in this case.  However, temporary freeway overloads are quite common.  This is why quality assessments for different degrees of freeway congestion are required as well.  The capacity of a freeway is traditionally treated as a constant value in traffic engineering guidelines around the world, such as the HCM (2000).  Doubts about this nature of capacities as constant values were raised by Ponzlet (1996) who demonstrated that capacities vary according to external conditions like dry or wet road surfaces, daylight or darkness, and prevailing purpose of the freeway (long distance or metropolitan commuter traffic).]]></description>
      <pubDate>Fri, 05 Aug 2005 14:15:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/758841</guid>
    </item>
    <item>
      <title>Behavioral Dynamics in Activity Participation, Travel, and Information and Communications Technology</title>
      <link>https://trid.trb.org/View/758913</link>
      <description><![CDATA[The unique event of the rapid advance and growing adoption and popularity of Information and Communications Technology (ICT) offers an unprecedented opportunity to study behavioral dynamics.  This is unique for activity and travel behavior analysis because of the many claimed relationships between telecommunication and transportation.  For example, using telecommunication as a source of information to reach locations and procure goods we can alter our traditional limitations of accessibility and virtually eliminate spatial separation.  In addition, we may experience increases in schedule flexibility that may change our activity and travel patterns but may also alter our activity planning, location choice, and variety seeking behavior.  On one hand, these developments may increase variability of travel demand potentially decreasing regularity and predictability.  On the other hand, they also enable us to perform more interesting studies of travel behavior dynamics that may lead to better policy actions.  These claimed substantial impacts of ICT motivate the need for research on the present and future impacts of telecommunication on activity and travel behavior by studying change of behavior.  However, studying behavioral dynamics and change requires specific types of data such as panel survey data (i.e., repeated observation of essentially the same persons over time) and specific types of data analysis methods.]]></description>
      <pubDate>Fri, 05 Aug 2005 14:15:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/758913</guid>
    </item>
    <item>
      <title>A Behavioural Approach to Instability, Stop and Go Waves, Wide Jams and Capacity Drop</title>
      <link>https://trid.trb.org/View/758849</link>
      <description><![CDATA[This paper describes how congested traffic flow dynamics have attracted much interest over the last decade.  In order to explain congested traffic flow phenomena, some researchers have stressed the importance and validity of first order hydrodynamic models, while others point out the importance of second order phenomena (instability) for the formation of various congestion patterns, and of local perturbations initiating phase transitions.  A macroscopic traffic flow model is used in this paper in order to examine typical congestion related phenomena like traffic flow instability, stop-and-go waves, wide jams, hysteresis, and capacity drop, and the role of driver behavior.  The model related individual car-following behavior to macroscopic traffic flow dynamics, and accounts for the principal aspects of individual longitudinal behavior like:  finite reaction times, anticipation behavior to conditions downstream (i.e. non-locality and anisotropy), and finite, speed dependent space requirements of drivers.  Because of the strong relation with individual human driving behavior and gas-kinetic mathematics that underlies this model, it is called the human-kinetic traffic flow model.  Moreover, the parameters that govern the individual driver behavior in the human-kinetic model are not necessary constant in time, but may vary with traffic flow conditions, location, weather, and other conditions.  In this sense, the human kinetic traffic flow model is an experimental framework in which the role of variable individual longitudinal driver behavior in macroscopic traffic flow dynamics can be examined.]]></description>
      <pubDate>Fri, 05 Aug 2005 14:15:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/758849</guid>
    </item>
    <item>
      <title>Modeling Commercial Vehicle Empty Trips: Theory and Application</title>
      <link>https://trid.trb.org/View/758929</link>
      <description><![CDATA[This paper attempts to provide a comprehensive discussion of the theoretical developments pertaining to commercial vehicle empty trip models, the corresponding estimation procedures, empirical evidence, and practical implications of modeling empty trips.  The paper also describes new mathematical formulations to model commercial vehicle empty trips.  In doing so, it expands and synthesizes the previous research on the subject.]]></description>
      <pubDate>Fri, 05 Aug 2005 14:15:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/758929</guid>
    </item>
    <item>
      <title>Doubly Dynamic Equilibrium Distribution Approximation Model for Dynamic Traffic Assignment</title>
      <link>https://trid.trb.org/View/758942</link>
      <description><![CDATA[This paper has successfully made the first step in linking together the fields of network equilibrium theory, whole-link dynamic travel time models, and stochastic process models of the within- and between-day evolution of traffic flows over a network.  In making this link, the paper has devised a computational procedure for estimating the equilibrium distribution of such a doubly dynamic stochastic process model, utilizing information form a conventional stochastic user equilibrium model.  A key element of the approximation is the computation of the Jacobian of the whole-link travel time mapping that may have many applications beyond those discussed in this paper.  This research opens up many avenues for further research, including analysis of the stability of the dynamical process, application of the method to alternative forms of whole-link travel time model, and travel behavior research investigating the impacts of the various learning and decision parameters on the network flows.]]></description>
      <pubDate>Fri, 05 Aug 2005 14:15:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/758942</guid>
    </item>
    <item>
      <title>Calibration and Validation of Dynamic Traffic Assignment Systems</title>
      <link>https://trid.trb.org/View/758898</link>
      <description><![CDATA[Intelligent Transportation Systems (ITS) have the potential to improve traffic conditions and reduce travel delays by facilitating better utilization of available capacity.  Such systems are quite complex, and employ sophisticated algorithms to achieve their objectives.  Several simulation-based dynamic traffic assignment (DTA) systems have been developed for a wide range of ITS applications.  These systems target more realistic approaches to short-term transportation planning such as special events and work zones and address the growing importance of real-time applications such as incident management, route guidance and emergency response.]]></description>
      <pubDate>Fri, 05 Aug 2005 14:15:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/758898</guid>
    </item>
    <item>
      <title>A Simulation Model for Motorway Merging Behaviour</title>
      <link>https://trid.trb.org/View/758855</link>
      <description><![CDATA[This paper presents a model of motorway traffic merging behavior that tries to capture both the acceleration and the gap-acceptance behavior of the merging traffic, and also the cooperative behavior of the motorway traffic.  The paper presents the model formulation, sensitivity analysis of some of the key model parameters, initial simulation tests on a standard merging section, and their comparison with observations.]]></description>
      <pubDate>Fri, 05 Aug 2005 14:15:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/758855</guid>
    </item>
    <item>
      <title>Freeway Ramp Merging Process Observed in Congested Traffic: Lag Vehicle Acceleration Model</title>
      <link>https://trid.trb.org/View/758856</link>
      <description><![CDATA[This paper is the second of a pair of papers that discuss the modeling of freeway ramp merging behavior under congested traffic conditions.  The fist paper focused on the modeling of the merged vehicle (from the ramp) and was presented in the 15th ISTT, while this paper develops a model for the lag vehicle (approaching the ramp area from the freeway) in order to provide a complete picture of driver interaction behaviors at the time of merging.  A four year extensive study that has been undertaken to investigate traffic behavior and characteristics during the traffic merging processes under congested traffic flow in order to design a safer and less congested merging points.  The acceleration and merging process from an entrance ramp to freeway lanes constitutes an important aspect of freeway traffic operations and ramp junction geometric design.  Competing traffic demands for space influence this process regarding both the ramp freeway junction and the upstream freeway lanes.  A merging driver must make a series of decisions and carry out control tasks, all within the driver capability to process the roadway and traffic information and interpret it into speed and position control responses.  This paper presents a methodology for collecting field data, analyzing freeway merging behavior data and developing a freeway lag vehicle acceleration model.]]></description>
      <pubDate>Fri, 05 Aug 2005 14:15:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/758856</guid>
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