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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>
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    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
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    <item>
      <title>FUEL AND TIME IMPLICATIONS OF MERGING TRAFFIC AT FREEWAY ENTRANCES</title>
      <link>https://trid.trb.org/View/214841</link>
      <description><![CDATA[A microscopic traffic model is used to simulate the fuel and time penalties associated with merging traffic on a freeway system.  Merging traffic forces a merge with the inside lane freeway traffic through a series of individual vehicle interactions.  The model is validated both statistically and at an individual vehicle level by comparison of model results with speed time traces recorded in a research vehicle undergoing merging in Perth freeway traffic. Statistics of model parameters are calculated to estimate the overall penalties associated with merging on both a lane and system basis.  These illustrate the dependence of the merging penalty on traffic volumes in both the merging lane and the freeway.  The simulation results are compared with a simple Main Roads Department model based on observed delays at traffic signals and illustrate similar functional form but differing magnitudes.  (Author/TRRL)]]></description>
      <pubDate>Wed, 25 Aug 2004 01:42:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/214841</guid>
    </item>
    <item>
      <title>A DIGITAL SIMULATION PROGRAM OF A SECTION OF FREEWAY WITH ENTRANCE AND EXIT RAMPS</title>
      <link>https://trid.trb.org/View/117103</link>
      <description><![CDATA[A COMPUTER PROGRAM DEVELOPED FOR THE SIMULATION OF A SECTION OF FREEWAY, INCLUDING SEVERAL EXIT AND ENTRANCE RAMPS IS DESCRIBED. THE PROGRAM ALLOWS FOR THE SIMULATION OF THE TRAFFIC OPERATION UNDER DIFFERENT MODES OF ENTRANCE RAMP CONTROL: FIXED-RATE METERING, DEMAND-CAPACITY METERING, GAP- ACCEPTANCE CONTROL AND, OF COURSE, NO CONTROL. THE COMPUTER LOGIC AND SIMULATION TECHNIQUE ARE DISCUSSED IN DETAIL. LIMITED OUTPUT OF THE PROGRAM IS PRESENTED AS EVIDENCE OF THE FEASIBILITY AND REALISM OF THE SIMULATION MODEL. /AUTHOR/]]></description>
      <pubDate>Fri, 13 Aug 2004 18:56:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/117103</guid>
    </item>
    <item>
      <title>OPTIMIZATION OF SINGLE-LANE FREEWAY TRAFFIC FLOW BY SELECTIVE RAMP CLOSURE</title>
      <link>https://trid.trb.org/View/117056</link>
      <description><![CDATA[THE DIGITAL COMPUTER IS USED TO SIMULATE FREEWAY TRAFFIC FLOW AND THE EFFECT ON THIS FLOW OF THE INGRESS AND EGRESS OF TRAFFIC FROM THE FREEWAY RAMPS. IT WAS OBSERVED THAT SELECTIVE RAMP CLOSURE ON SINGLE-LANE FREEWAY TRAFFIC FLOW PROVIDES AN EFFECTIVE MEANS FOR ESTABLISHING A MINIMUM FREEWAY VELOCITY AND THUS MAXIMIZES TRAFFIC FLOW. /BPR/]]></description>
      <pubDate>Fri, 13 Aug 2004 18:56:04 GMT</pubDate>
      <guid>https://trid.trb.org/View/117056</guid>
    </item>
    <item>
      <title>A PROBABILISTIC APPROACH TO TRAFFIC PROBLEMS</title>
      <link>https://trid.trb.org/View/115196</link>
      <description><![CDATA[A SEVENTEEN-MONTH STUDY WAS CONDUCTED ON THE DEVELOPMENT OF THEORIES OF A PROBABILISTIC AND STATISTICAL NATURE THAT HAVE DIRECT APPLICATIONS FOR THE SOLUTION OF NETWORK FLOW, QUEUEING AND CONGESTION, SAFETY AND COST PROBLEMS. INVESTIGATIONS WERE MADE IN THE EXISTING LITERATURE ON TRAFFIC FLOW, APPLICATIONS OF VARIOUS STATISTICAL THEORIES AND IN THE THEORY OF QUEUES FOR VEHICLES AT TRAFFIC SIGNALS, AT STOP-SIGNAL INTERSECTIONS AND APPROACHING FREEWAYS FROM ON-RAMPS. FIVE TECHNICAL PAPERS WERE PREPARED AND INCLUDED IN THE FINAL REPORT. THESE PAPERS REFLECT RESEARCH ACCOMPLISHED IN THE THREE PROBLEM AREAS: TUNNEL PROBLEM, MERGING PROBLEM, AND THE NON-POISSON MODELS PROBLEM. THREE OF THE TECHNICAL PAPERS WERE WRITTEN IN THE TUNNEL PROBLEM AREA. THESE PAPERS ADVANCED RESPECTIVELY A SIMULATION MODEL, AN EXTREME VALUE DISTRIBUTION MODEL AND A QUEUEING MODEL. FOR THE MERGING PROBLEM, RENEWAL THEORY WAS APPLIED IN THE FORMULATIONS FOR MERGING PROBABILITIES AND EXISTENCE OF GAPS. IN THE NON-POISSON MODELS PROBLEM, A TECHNICAL REPORT WAS PREPARED THAT CONSIDERS THE MAJOR ASSUMPTIONS AND BASIC DEFINITIONS. IT THEN CONSIDERS THE DIFFERENTIAL-DIFFERENCE EQUATIONS APPROACH AND COMPARES THIS TO THE TRANSITION EQUATIONS APPROACH. RELATED TOPICS ARE FURTHER CONSIDERED. /BPR/]]></description>
      <pubDate>Fri, 13 Aug 2004 18:46:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/115196</guid>
    </item>
    <item>
      <title>CONSIDERATIONS IN THE APPLICATION OF COLLECTOR-DISTRIBUTOR DESIGNS FOR IMPROVING MAINLANE FREEWAY OPERATIONS. INTERIM REPORT</title>
      <link>https://trid.trb.org/View/374268</link>
      <description><![CDATA[Collector-distributor roadways can be effective as a "buffer" facility with limited access interfacing between mainlanes and frontage road development.  However, both transverse and longitudinal space requirements are critical for acceptable implementation.  This report summarizes several key aspects of collector-distributor freeway system design considerations and features; and then presents a case study that demonstrates an evaluation methodology.]]></description>
      <pubDate>Fri, 07 Jun 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/374268</guid>
    </item>
    <item>
      <title>FREEWAY OPTIMIZATION UTILIZING RAMP METERING - AN IVHS TOOL</title>
      <link>https://trid.trb.org/View/457644</link>
      <description><![CDATA[This paper presents a discussion of a computer optimization program, which is used to optimize ramp metering and freeway flow by timing ramp signals to prevent excessive queuing on ramps while simultaneously minimizing delay on the freeway. The program can be used to design for a specified level of service and/or ramp queuing capacities based on the users constraints. This computer program was calibrated based on a specific section of the Milwaukee County Interstate Highway (IH) 94 freeway system. Data inputs to the program include freeway volumes, ramp volumes, distances between ramps, and ramp queuing capacities. The optimization program is a spreadsheet template so additional ramps can be easily added. Guidelines for application and further calibration with IVHS systems are discussed.]]></description>
      <pubDate>Thu, 31 Jan 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/457644</guid>
    </item>
    <item>
      <title>SPEED AND CRASHES: A CONTROVERSIAL TOPIC AND AN ELUSIVE RELATIONSHIP. APPENDIX B OF TRB SPECIAL REPORT 254</title>
      <link>https://trid.trb.org/View/542306</link>
      <description><![CDATA[This paper reviews studies relevant to the causal relationship between speeding and crashes.  The conclusions from this study are as follows:  (1) There is ample, but not unequivocal, evidence to indicate that, on a given road, crash involvement rates of individual vehicles rise with their speed of travel. (2) There are no convincing data to demonstrate that, across all roads, crash involvement rates rise with the average speed of traffic.  This is probably because the average traffic speed is highly correlated with the design speed of different road classes (and other conditions).  (3) The absolute speed deviation of crash-involved vehicles from the average traffic speed appears to be positively related to crash probability, especially for rural arterial highways and Interstate highways. (4) The principal factor that accounts for the effects of speed deviation is the requirement to slow down to make turns and to enter and exit high-speed roads.  Still, even when the effects of turning vehicles are removed from the data, some effects of speed deviation, especially at the extreme ends, remain.  (5) The disparities in speed of the traffic stream may be positively related to crash probability, especially on Interstate highways. However, the data are not very consistent, and more data are needed.  (6) On urban streets there appears to be a strong relationship between crash rates and the absolute speed of crash-involved vehicles.  (7) The data demonstrating the relevance of speed dispersion in the traffic stream and speed deviations of crash-involved vehicles are based on correlational effects and therefore cannot be used to indicate that if slow-moving drivers were to increase their speed, their crash probability would be reduced.  (8) There are unequivocal data to indicate that the risk of injuries and fatalities increases as a function of precrash speed or Delta-V.  This is true for all road types.  (9) The overall cost of speed-related crashes is much greater than the relationship between speed and crash probability indicates.  This is because high-speed crashes are associated with greater injury levels than are low-speed crashes.]]></description>
      <pubDate>Tue, 22 Dec 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/542306</guid>
    </item>
    <item>
      <title>CONSIDERATION OF BOLLARD TREATMENT AT EXIT GORE AREAS</title>
      <link>https://trid.trb.org/View/540864</link>
      <description><![CDATA[The efficiency of bollards - soft plastic post delineators which are installed at exit gore areas of some highways in Israel - is considered.  The devices are expected to contribute to better arrangement of traffic streams and to reduce erratic vehicle maneuvers at highway exits.  The treatment was examined in three ways:  (1) a review of current experience concerning delineation techniques and tools for safety enhancement at exit gore areas, (2) a detailed consideration of accidents occurring on freeways with emphasis on specifics relevant to exit area occurrences, and (3) field observations of driver behavior at exit areas before and after bollard installation.  The literature review showed that use of bollards for highway traffic arrangements has not been investigated closely, at least over the past 20 years. However, practice demonstrated that different kinds of delineation treatments did contribute to better traffic operations and decreased the number of erratic maneuvers at exit area approaches.  A detailed consideration of accidents for two highways revealed that the accidents occurring at "exit" and "on" areas are a major part of interchange area accidents (69%), while explicit "gore area crossing" maneuvers appear only in six cases (23% of exit accidents).  In total, a potential benefit of bollard application could be relevant to 11% of the accidents. Field observations of driver behavior were conducted for two sites.  The comparison proved a significant reduction in erratic maneuver rates after the treatment:  up to 60% in daytime and up to 65% at nighttime.  Finally, the bollard treatment was recommended for use at freeway exits.]]></description>
      <pubDate>Tue, 10 Nov 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/540864</guid>
    </item>
    <item>
      <title>TRAFFIC FLOW CONTROL IN CONGESTED MOTORWAY NETWORKS USING BUFFERS</title>
      <link>https://trid.trb.org/View/539269</link>
      <description><![CDATA[Around large urban areas, daily recurrent congestion in the form of queueing at bottlenecks is nowadays a normal pattern.  Apart from the congestion that directly follows from the capacity deficit at bottlenecks, more and more motorways are affected by a secondary congestion problem due to blocking of motorway exits and entries by long queues that build up upstream of bottlenecks, causing delay to travelers who are not going through the bottleneck.  A solution to avoid congestion-induced blockage is the construction of so-called buffer facilities. These are local widenings of the motorway by adding one or more lanes just before a bottleneck.  Buffers can shorten queues by an amount that is more than proportional to the number of added lanes.  In this way congestion-induced blockage can be avoided and total delay is reduced significantly.  Buffers are a cost-effective way to fight motorway congestion.  The principles and functioning of buffer facilities are explained.  Design elements and criteria as well as calculation of buffer dimensions are considered.  Attention is given to the control of traffic flow at the entrance and exit of buffers.  This is demonstrated with a case study from the Netherlands.]]></description>
      <pubDate>Wed, 30 Sep 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/539269</guid>
    </item>
    <item>
      <title>MODERN ROUNDABOUT INTERCHANGES COME TO AMERICA</title>
      <link>https://trid.trb.org/View/481598</link>
      <description><![CDATA[A modern roundabout interchange is a freeway-to-street interchange or street-to-street interchange which contains at least one modern roundabout. In addition to their cost advantage, modern roundabout interchanges usually cause less delay and fewer accidents than signalized interchanges. This may be why nearly all freeway-to-street interchanges in the U.K. are based on modern roundabouts. Signalized interchanges are rare in Britain, but a few do exist. Australia, Norway, France, and Sweden have also built modern roundabout interchanges in recent years. This paper describes the process and steps taken in the building of North America's first modern roundabout interchange in 1995 at I-70/Vail Road in Colorado.]]></description>
      <pubDate>Tue, 11 Mar 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/481598</guid>
    </item>
    <item>
      <title>QUEUING AND NATURAL DIVERSION AT SHORT-TERM FREEWAY WORK ZONE LANE CLOSURES</title>
      <link>https://trid.trb.org/View/465183</link>
      <description><![CDATA[Research conducted to explore the effects of natural diversion on traffic conditions and travel patterns upstream of temporary work zone lane closures on high-volume urban freeways in Texas is described.  Specific objectives were to explore how natural diversion affects traffic volumes at the exit and entrance ramps upstream of the lane closures and the interrelationships between the freeway and frontage road operating conditions that develop at a closure and the amount of natural diversion that occurs. The field studies showed that the rate of queue growth upstream of the short-term lane closures diminished significantly after the first hour at each site.  Eventually, the queues approached a balanced state in which the upstream end of the queue became almost stationary.  This stabilization was due to significant reductions in entrance ramp volumes both upstream of the freeway queue and within the limits of queuing, as well as to changes in exit ramp volumes within the queue.  As a result of these ramp volume changes the constrained flow rate within the queue increased as a function of the distance upstream of the actual lane closure.  Using the theory of shock waves in a traffic stream it was shown that the changes in ramp volumes and resulting impact on constrained freeway flow rates within the queue were consistent with the queue stabilization process observed at each site.]]></description>
      <pubDate>Tue, 15 Oct 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/465183</guid>
    </item>
    <item>
      <title>SOME GENERAL RESULTS ON THE OPTIMAL RAMP CONTROL PROBLEM</title>
      <link>https://trid.trb.org/View/464160</link>
      <description><![CDATA[In this paper, the authors consider a freeway system comprised of a freeway section and its entry/exit ramps, and formulate the ramp control problem as a dynamic optimal process to minimize the total time spent in this system. Within this framework, they are able to show when ramp metering is beneficial to the system in terms of total time savings, and when it is not, under the restriction that the controlled freeway has to serve all of its ramp demand, and the traffic flow process follows the rules prescribed by the LWR theory with a triangular flow-density relationship. They also provide solution techniques to the problem and present some preliminary numerical results and empirical validation.]]></description>
      <pubDate>Mon, 16 Sep 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/464160</guid>
    </item>
    <item>
      <title>MODELING PERSPECTIVES FOR THE AUTOMATED HIGHWAY</title>
      <link>https://trid.trb.org/View/459048</link>
      <description><![CDATA[An automated highway system (AHS) is one in which specially equipped vehicles operate on guideways under automatic control. Recent studies reveal that deployment of automated vehicles has a positive impact on travel time when separate facilities are provided for these vehicles.  This article examines the concept of a separate AHS facility constructed using existing traditional vehicle lanes.  Vehicle and roadway enhancements are analyzed and the transition stages of the AHS are considered.  Two representative system configurations (RSC) are studied:  1) low-level RSC, which provides access and egress links directly between the AHS lane and the traditional freeway lane; and 2) high-level RSC, which requires significant new road construction for the AHS lanes and their connections to other facilities leaving them totally separate from the traditional freeway system.  AHS operation is simulated and several case studies are presented that compare existing freeway operations at different levels of utilization with an AHS scenario with the same levels of utilization.]]></description>
      <pubDate>Tue, 07 May 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/459048</guid>
    </item>
    <item>
      <title>COMMUNICATING FREEWAY EXIT LANE DROPS TO MOTORISTS</title>
      <link>https://trid.trb.org/View/457665</link>
      <description><![CDATA[This project determined how motorists interpret or respond to various sign and pavement marking alternatives they may or may not have experienced before. Motorist interpretation of signs and markings were obtained through surveys, while field observations were used to determine driver behavior at exit lane drops and to measure motorist responses to pavement markings.]]></description>
      <pubDate>Mon, 05 Feb 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/457665</guid>
    </item>
    <item>
      <title>IMPROVEMENTS TO HOV SAFETY AND ENFORCEMENT</title>
      <link>https://trid.trb.org/View/451405</link>
      <description><![CDATA[The Washington State Department of Transportation (WSDOT) conducted a comprehensive analysis in the Puget Sound Region to improve the access into and out of High Occupancy Vehicle (HOV) lanes, and to make them safer to operate and enforce. First, the study was to identify improvements to freeway HOV lanes which make the freeway safer for both HOV and general purpose (GP) travelers. Second, the study recommended, for further study by the WSDOT, measures to improve the enforceability of HOV lane restrictions. Safety and enforcement improvements ranged from sing;e-site signing issues to systemwide geometric design revisions, but generally did not include large capital projects. This paper summarizes the safety and enforcement study process along with key technical and policy recommendations.]]></description>
      <pubDate>Thu, 26 Oct 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/451405</guid>
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