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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>
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    <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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      <title>Calibration of VISSIM for a Congested Freeway</title>
      <link>https://trid.trb.org/View/1158889</link>
      <description><![CDATA[A procedure for constructing and calibrating a detailed model of a freeway using VISSIM is presented and applied to a 15-mile stretch of I-210 West in Pasadena, California. This test site provides several challenges for microscopic modeling: an HOV lane with an intermittent barrier, a heavy freeway connector, 20 metered onramps with and without HOV bypass lanes, and three interacting bottlenecks. Field data used as input to the model was compiled from two separate sources: loop-detectors on the onramps and mainline (PeMS), and a manual survey of onramps and offramps. Gaps in both sources made it necessary to use a composite data set, constructed from several typical days. FREQ was used as an intermediate tool to generate a set of OD matrices from the assembled boundary flows. The model construction procedure consisted of: 1) identification of important geometric features, 2) collection and processing of traffic data, 3) analysis of the mainline data to identify recurring bottlenecks, 4) VISSIM coding, and 5) calibration based on observations from 3). A qualitative set of goals was established for the calibration. These were met with relatively few modifications to VISSIM's driver behavior parameters (CC-parameters). ]]></description>
      <pubDate>Thu, 23 Aug 2012 05:18:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/1158889</guid>
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    <item>
      <title>Improve FREQ Macroscopic Freeway Analysis Model</title>
      <link>https://trid.trb.org/View/1114542</link>
      <description><![CDATA[Several levels of FREQ model enhancements were undertaken as part of this freeway analysis project. Primary attention was given to enhance the modeling of the interaction between on-ramp and off ramp operations with mainline freeway operations. Two versions including this interaction were developed. Refinements in the ramp-freeway interaction module for off-ramp diverge analysis and on-ramp merge analysis are described.]]></description>
      <pubDate>Tue, 30 Aug 2011 07:28:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/1114542</guid>
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    <item>
      <title>Freeway Analysis Manual: Parts 1 and 2</title>
      <link>https://trid.trb.org/View/794769</link>
      <description><![CDATA[This Manual begins with a discussion on the fundamentals of freeway analysis using a demand-supply analytical framework. Emphasis is on estimating capacity and origin-destination demands. Included is a detailed example of the application of the demand-supply analytical framework for a typical freeway situation. The Manual next covers the study design and required traffic data for freeway analysis. Guidelines are given for establishing spatial and temporal limits of the freeway study area, selecting appropriate analytical tools, and identifying critical issues to be considered. The third part of the manual provides detailed guidance for using and applying FREQ, a macroscopic deterministic simulation model. Included is an overview and history of the model, as well as instructions for inputting data, checking and calibrating the model, and using the model in various applications. The last part of the manual provides a real-life application of the FREQ model to a 25-mil eastbound segment of the I-580 Freeway during the 5-hour afternoon peak period in the Pleasanton, Dublin, and Livermore area.]]></description>
      <pubDate>Fri, 29 Dec 2006 11:07:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/794769</guid>
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    <item>
      <title>Test of Simulation Models FREQ, KRONOS, Integration and VISSIM in Replicating Congested Freeway Flow</title>
      <link>https://trid.trb.org/View/794710</link>
      <description><![CDATA[The results from the application of two macroscopic (FREQ, KRONOS) and two microscopic (Integration, VISSIM) traffic simulation model on the same freeway network are presented. The data were collected contemporaneously on a heavily congestion 15-mile section of H-1 Freeway in Honolulu, Hawaii. The models were calibrated so that field-collected speeds at five cross sections were replicated adequately. The models were applied to evaluate a $50 million freeway widening project which was constructed between 2004 and 2006. Model predictions on the savings of the widening varied widely.]]></description>
      <pubDate>Fri, 29 Dec 2006 11:07:39 GMT</pubDate>
      <guid>https://trid.trb.org/View/794710</guid>
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    <item>
      <title>Derivation of Origin–Destination Distributions from Traffic Counts: Implications for Freeway Simulation</title>
      <link>https://trid.trb.org/View/794280</link>
      <description><![CDATA[Origin–destination (O-D) traffic flows are an essential element in several freeway and network traffic models. In general, it is impossible to identify a unique O-D matrix from volume counts alone. Several methods for deriving O-D data exist, and they vary in complexity, cost, and analysis time. O-D matrices were generated with five methods that were applied to the same set of volume data. The resulting O-D matrices were used as the only variable input component in traffic simulation with INTEGRATION. Traffic simulation output was used to assess the implications of the O-D distribution. The O-D data produced by the deterministic method were clearly different from those of the other four methods. The proportionate and QueensOD (with default seed) output were somewhat dissimilar. All other combinations were similar, and the proportionate and FREQ O-D output were statistically identical. The simulation output with the proportionate-method O-D data met the 10/75 speed criterion at all five of the cross-section locations [it was within 10 mph (16 km/h) of field speed for 75% of the time periods]. Pearson’s correlation of speeds at five locations indicated that all O-D methods except the deterministic one have a strong correlation with each other. A similar outcome was obtained with t-tests of the total travel time output.]]></description>
      <pubDate>Wed, 29 Nov 2006 11:38:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/794280</guid>
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    <item>
      <title>FREQ Model Improvements and Training</title>
      <link>https://trid.trb.org/View/789601</link>
      <description><![CDATA[The purpose of this Freeway Analysis Manual is to provide the reader with a basic understanding of freeway analysis techniques as well as to provide guidance on how to design and implement an analysis of freeway operations using FREQ, a macroscopic freeway simulation model. The third part of this five-part Manual is only partially completed, due to budgetary constraints. It will be completed under a new project. The FREQ model has been enhanced under this project to meet the needs of California Department of Transportation (Caltrans) District staff. Training and technical assistance have been provided to Caltrans District staff as they have applied the FREQ model to selected sites in their Districts.]]></description>
      <pubDate>Fri, 29 Sep 2006 10:36:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/789601</guid>
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      <title>F-R-E-Q M-O-D-E-L W-O-R-K-B-O-O-K : Caltrans workshop : a basic course on the FREQ and CALINK models : May 19-21, 1998, Sacramento, California</title>
      <link>https://trid.trb.org/View/761775</link>
      <description><![CDATA[This manual serves as a workbook  for a workshop on the CALINK and FREQ traffic simulation models. The FREQ model began with the development of FREQ1 in the late 1960s. This workshop serves as the introduction of the initial stage of the developing FREQ12 model. The workshop focused on the following objectives: 1) understand the demand-supply analytical framework; 2) perform freeway operations analysis; 3) code input using FREQ interface; 4) execute FREQ model; 5) interpret FREQ model output results; 6) undertake simulation model calibration; 7) apply FREQ model for design, incident, and growth investigations; 8) apply principles of entry control investigations; 9) apply principles of on-freeway HOV lanes; and, 10) understand the CALINK model.]]></description>
      <pubDate>Fri, 14 Oct 2005 07:46:53 GMT</pubDate>
      <guid>https://trid.trb.org/View/761775</guid>
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    <item>
      <title>APPLICATION OF FREEWAY SIMULATION MODELS TO URBAN CORRIDORS. VOLUME 1: FINAL REPORT</title>
      <link>https://trid.trb.org/View/691722</link>
      <description><![CDATA[Freeway simulation is gaining increasing acceptance and popularity as a tool for evaluating freeway improvement alternatives and refining freeway designs.  The evaluation of individual sections one at a time is frequently inadequate to fully consider the implications of traffic flow on freeway design and operations.  As the need to evaluate the interaction among sections and facilities increases, so too will the need to employ these more sophisticated analytical techniques.  Several freeway simulation models now operate on microcomputers, simplifying the use of the models and opening up opportunities to many engineers previously unable to take advantage of the analysis power these models afford.  The purpose of this research contract, entitled "Analysis of Complex Congested Corridor Locations," was to apply three freeway simulation models and the procedures in the 1985 Highway Capacity Manual to real-world situations.  Each of the models was applied in five case study sites: Seattle; Minneapolis; Milwaukee; Columbus, Ohio; and New York City.  The Application of the models provided the opportunity to compare their strengths and weaknesses, to suggest possible enhancements to the models evaluated.  These included FREFLO, a macroscopic simulation model developed under Federal Highway Administration (FHWA) contract; FREQ, a macroscopic model developed by the University of California at Berkeley; and FRESIM, a microscopic model developed under FHWA contract.  This report is directed toward existing and potential users of freeway simulation models, with an emphasis on guidelines for model selection and application.]]></description>
      <pubDate>Wed, 28 Nov 2001 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/691722</guid>
    </item>
    <item>
      <title>EVALUATION OF SIMULATION MODELS FOR CONGESTED DALLAS FREEWAYS</title>
      <link>https://trid.trb.org/View/673452</link>
      <description><![CDATA[Recent and continuing growth has resulted in increased demand for travel on urban freeways throughout Texas.  Many freeways are operating under congested conditions throughout much of the day.  However, proposed operational improvements for congested freeways are difficult to evaluate or to simulate accurately because under congestion there is increased effect of vehicle interactions and impact of design elements on traffic flow. There have been improvements in recent years in traffic models that offer promise in the simulation of congested freeways or freeway elements including ramps, merges, weaving areas, and basic freeway sections.  The more promising models include simulation of vehicle interactions, lane changing, car following and vehicle rerouting, accommodate origin-destination information, and in general try to model driver behavior. However, there is no universally accepted model for simulating congested conditions and thus arises the need for a project to determine which models produce the best results under different congested conditions.  The objectives of this project are to select appropriate models for simulating congested freeways, test the calibration and validation performance of those models using data collected on Dallas freeways, and provide recommendations on the use of the best model for congested freeways in Texas.  The CORSIM (FRESIM component), FREQ, and INTEGRATION models were selected for project based on the literature review.  Three different freeway sections with bottlenecks that caused recurrent congestion were selected to test and evaluate model performance.  Before and after operational data (i.e., speeds and volumes) at each of the sites were used in the attempt to calibrate and validate the chosen models.  The research team determined that all of the models performed relatively well for uncongested conditions; however, the performance became sporadic and mostly unreliable for congested conditions.  None of the models was successfully calibrated and validated for all of the test sites.  The CORSIM model had the best overall performance in this project, but it was effective only on the simplest test site.]]></description>
      <pubDate>Thu, 26 Apr 2001 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/673452</guid>
    </item>
    <item>
      <title>VALIDATION RESULTS FOR FOUR MODELS OF OVERSATURATED FREEWAY FACILITIES</title>
      <link>https://trid.trb.org/View/670635</link>
      <description><![CDATA[Some researchers have noted that the current procedures in the "Highway Capacity Manual" (HCM) may not be appropriate for analyzing complex or oversaturated freeway facilities.  The results of a comparison of an HCM-based procedure with field data from six such freeway sites are reported.  Because simulation has often been suggested as an alternative to the HCM for oversaturated freeway facilities, three simulation models (CORSIM, FREQ, and INTEGRATION) were also used to analyze these same six sites.  The results suggest that the HCM-based procedures do as well as the three simulation models in reproducing the average speeds across the freeway facilities.]]></description>
      <pubDate>Wed, 29 Nov 2000 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/670635</guid>
    </item>
    <item>
      <title>Simulation Modeling of the Santa Monica Freeway
</title>
      <link>https://trid.trb.org/View/640919</link>
      <description><![CDATA[As part of a project investigating the benefits of Intelligent Vehicle Highway Systems (IVHS) technology using simulation, two models of the Santa Monica Freeway in Los Angeles were developed.  This report describes the work performed to create, test, and apply these simulations.  Two independent simulations were coded, using FREQ and INTEGRATION models, from the available data.  The report describes the strategies, limitations, and assumptions needed to code the Santa Monica Freeway using the two simulation tools.  After coding the models, calibrating the output to match traffic performance from a typical day was needed to insure that the simulations would be useful for IVHS investigations.  Three representative studies using the FREQ model of the freeway to perform initial investigations are described. These investigations (considering future demand growth, ramp metering and HOV lanes) are representative of the potential for study using simulation.  The report ends with individual evaluations of the two models for freeway simulations and suggestions for future research.]]></description>
      <pubDate>Fri, 17 Nov 2000 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/640919</guid>
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    <item>
      <title>TEXAS WORKSHOP: A BASIC COURSE IN FREQ10.</title>
      <link>https://trid.trb.org/View/532985</link>
      <description><![CDATA[No abstract provided.]]></description>
      <pubDate>Wed, 28 Sep 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/532985</guid>
    </item>
    <item>
      <title>AN EDUCATIONAL PROGRAM FOR FREEWAY OPERATIONS ANALYSIS</title>
      <link>https://trid.trb.org/View/325525</link>
      <description><![CDATA[No abstract provided.]]></description>
      <pubDate>Sun, 30 Sep 1990 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/325525</guid>
    </item>
    <item>
      <title>COMPUTER DEMONSTRATION: THE FREQ10PC PROGRAM</title>
      <link>https://trid.trb.org/View/312493</link>
      <description><![CDATA[No abstract provided.]]></description>
      <pubDate>Mon, 31 Jul 1989 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/312493</guid>
    </item>
    <item>
      <title>DEVELOPMENT AND DESIGN OF A FREEWAY SURVEILLANCE AND INCIDENT MANAGEMENT SCHEME FOR THE TAIWAN FREEWAY</title>
      <link>https://trid.trb.org/View/261781</link>
      <description><![CDATA[No abstract provided.]]></description>
      <pubDate>Tue, 31 Jan 1989 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/261781</guid>
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