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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>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>NEW SYSTEMS REQUIREMENTS ANALYSIS PROGRAM. A PROCEDURE FOR LONG RANGE TRANSPORTATION (SKETCH) PLANNING</title>
      <link>https://trid.trb.org/View/89588</link>
      <description><![CDATA[THE PAPER PROVIDES AN OVERVIEW OF THE ENTIRE UTPS (URBAN TRANSPORTATION PLANNING SYSTEM) PACKAGE AND ITS DEVELOPMENT PLAN. IT CONTAINS A DETAILED DESCRIPTION OF THE SKETCH PLANNING PROCEDURE AS WELL AS OTHER UTPS MODULES USED WITH THE PROCEDURE DESIGNED TO AID PLANNERS AT ALL LEVELS OF TRANSPORTATION PLANNING. THE GOAL OF SKETCH PLANNING IS TO OVERCOME THE TRADITIONAL PROBLEMS OF HIGH COST IN SPECIFYING AND EVALUATING PLANNING ALTERNATIVES, AND THE INABILITY TO CONSIDER ALL MODES SIMULTANEOUSLY. THE PROCEDURE PROVIDES AN EFFICIENT MEANS OF DESCRIBING AND ANALYZING MANY ALTERNATIVE TRANSPORTATION NETWORKS, EACH COMPOSED OF A LARGE VARIETY OF MODES, AT A LEVEL OF DATA AGGREGATION APPROPRIATE TO LONG RANGE PLANNING AND TO REQUIRED POLICY DECISIONS. AMONG THE PROCEDURE'S UNIQUE CHARACTERISTICS ARE THE ABILITY TO CONSIDER SCORES OF NETWORK ALTERNATIVES EXPRESSED AS A BASIC NETWORK WITH APPENDED TREE-STRUCTURED SET OF MODIFICATIONS, ITS ALGORITHM FOR FINDING MULTIPLE PATHS THROUGH A MULTI-MODAL NETWORK, AND ITS ESTIMATION OF TRAVEL DEMAND USING A MULTI-MODAL MODEL. THE PROCEDURE WILL PROVIDE INTERACTIVE OPERATION USING A TIME-SHARED COMPUTER AND ON-LINE GRAPHICS FOR PHASED NETWORK MODIFICATION AND EVALUATION. INITIAL MODULES OF THE PROCEDURE WILL BE MADE AVAILABLE TO THE PUBLIC IN FALL 1973. /AUTHPR/]]></description>
      <pubDate>Thu, 15 May 2003 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/89588</guid>
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    <item>
      <title>USE OF A MULTIPLE ROUTING TECHNIQUE FOR ONE PASS CAPACITY RESTRAINT ASSIGNMENTS</title>
      <link>https://trid.trb.org/View/119993</link>
      <description><![CDATA[MULTIPLE ROUTING, AS PRESENTED HERE, ADDS THROUGH ITS STOCHASTIC PRINCIPLE A LONG-SOUGHT ELEMENT OF REALISM TO THE TRAFFIC ASSIGNMENT PROCESS. THIS PRINCIPLE ELIMINATES THE PROBLEM ASSOCIATED WITH THE MINIMUM PATH PROCEDURE, WHICH LEADS TO EXTREMELY UNBALANCED FLOWS WHERE MORE THAN ONE ACCEPTABLE ROUTE EXISTS BETWEEN PAIRS OF NODES. WITH THE MULTIPLE ROUTING PRINCIPLE AS ITS BASIC FRAMEWORK, A ONE-PASS INCREMENTAL CAPACITY RESTRAINT PROCEDURE IS PRESENTED, WHICH PROVIDES A FLEXIBLE AND ECONOMICAL TOOL FOR PRODUCING TRAFFIC ASSIGNMENTS WITH STABLE SPEED-FLOW RELATIONSHIPS. RESULTS OBTAINED WITH THIS PROCEDURE INDICATE A LEVEL OF ASSIGNMENT ACCURACY WHICH IS EQUIVALENT OR SUPERIOR TO THAT OBTAINED WITH FOUR ITERATIONS OF THE FREQUENTLY USED AVERAGING PROCEDURE. /AUTHOR/]]></description>
      <pubDate>Mon, 11 Jun 2001 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/119993</guid>
    </item>
    <item>
      <title>IDENTIFYING MULTIPLE AND REASONABLE PATHS IN TRANSPORTATION NETWORKS: A HEURISTIC APPROACH</title>
      <link>https://trid.trb.org/View/475171</link>
      <description><![CDATA[A fundamental component of many transportation engineering applications is the identification of the route between a given origin and destination.  Typically, some type of shortest-path algorithm is used for this task.  However, shortest-path algorithms are only applicable when a single criterion, such as minimizing travel time, is used for path selection.  When multiple criteria, such as the mean and variance of travel time, are used for path selection, then alternative-path identification methods must be found.  The present objective is to develop an algorithm that can identify multiple and reasonable routes in transportation networks so that multiple-criteria decision-making techniques can be used in route selection.  First, the definitions of single and multiple routes from a transportation engineering perspective are examined.  It is indicated that although the traditional k-shortest-path algorithms can find routes with similar route travel times, the routes may be too similar with respect to the links used and consequently are not appropriate for certain transportation applications.  A definition of a reasonable path is developed on the basis of transportation engineering rather than purely mathematical considerations.  Two k-reasonable-path algorithms are then illustrated.  These algorithms can be used to identify multiple and reasonable routes in transportation networks.  Lastly, the two heuristic algorithms were tested on a network from Bryan to College Station, Texas, and the results were compared with the results obtained with a traditional k-shortest-path algorithm.  It was found that the reasonable-path algorithms can identify routes that are similar in route travel time but significantly different in terms of the links used.]]></description>
      <pubDate>Wed, 07 Jan 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/475171</guid>
    </item>
    <item>
      <title>DESIGNING A SINGLE-VEHICLE AUTOMATED GUIDED VEHICLE SYSTEM WITH MULTIPLE LOAD CAPACITY</title>
      <link>https://trid.trb.org/View/469838</link>
      <description><![CDATA[Automated guided vehicle systems (AGVSs) play an important role in today's factories. When properly designed and controlled they can provide significant cost savings in material handling cost and work-in-process inventory. The authors introduce an analytical approach for the design of a single-vehicle AGVS with multiple load capacity operating under a simple "go-when-filled" dispatching rule. The AGVS supplements an existing non-automated material handling system. It delivers containers with raw material from a central depot to workcenters on the factory floor. The demand of the workcenters and the time until delivery are stochastic. The authors develop a non-linear binary integer program to determine which workcenters warrant automated guided vehicle delivery and the consequent path layout subject to constraints on maximum allowable mean waiting time for material delivery.]]></description>
      <pubDate>Mon, 03 Feb 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/469838</guid>
    </item>
    <item>
      <title>A GENERALIZED MULTIPLE DURATIONS PROPORTIONAL HAZARD MODEL WITH AN APPLICATION TO ACTIVITY BEHAVIOR DURING THE EVENING WORK-TO-HOME COMMUTE</title>
      <link>https://trid.trb.org/View/468297</link>
      <description><![CDATA[The model developed in this paper generalizes (in the context of multiple exit states from a duration spell) extant competing risk methods which tie the exit state of duration very tightly with the length of durations. In the current formulation, the exit state is modeled explicitly and jointly with duration models for each potential exit state. The model developed here, however, is much broader in its applicability than only to the competing risk situation; it is applicable to multiple durations arising from multiple entrance states, multiple exit states, or a combination of entrance and exit states. Multiple entrance states occur frequently in many situations, but have received little attention in the literature. Explicit consideration of the entrance state is important, even in single or multiple competing risk models in order to accommodate the sample selection in duration based on the no-entry/entry (to the duration spell) outcome. The generalized multiple durations model developed in the paper is applied to an empirical analysis of activity behavior during the return home from work.]]></description>
      <pubDate>Tue, 12 Nov 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/468297</guid>
    </item>
    <item>
      <title>THE AUTOMATICITY OF MULTIPLE ROAD INFORMATION SYSTEMS ON HIGHWAY IN JAPAN</title>
      <link>https://trid.trb.org/View/462132</link>
      <description><![CDATA[Over the last decade, road traffic on Japanese highways has increased significantly due to social demand for vehicle transportation.  A driver information system must be rapid and precise because of the increasing value of life time.  Man's ability to operate multiple road information systems simultaneouly, however, is limited.  Information must serve thousands of drivers on the road in spite of the fact that operators are few.  The proposed system supplies sufficient information to drivers accurately on several expressways simultaneously.  The newly developed system provides accurate information and makes the operator's job easier.]]></description>
      <pubDate>Wed, 12 Jun 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/462132</guid>
    </item>
    <item>
      <title>DISPERSION OF TRAFFIC FLOW THROUGH PROVISION OF TRAVEL-TIME INFORMATION ON MULTIPLE ROUTES</title>
      <link>https://trid.trb.org/View/462127</link>
      <description><![CDATA[A serious social problem in Japan is that the amount of traffic congestion and resulting traffic accidents are on the rise, along with traffic demand.  To deal with the traffic situation, systems were developed to provide travel-time information on two or more routes to drivers heading for the same destination, with a view to disperse traffic flow for more effective utilization of a limited number of roads.  In Osaka, the Prefectural Police Headquarters (HQ) have sought to expand and improve its system to provide road users with travel-time information on multiple routes.  In 1994, HQ developed such a system for three major roads running parallel to one another between Osaka and Kyoto, separated by a distance of approximately 10 km.  This system was the first to be operated for information provision covering such a wide area as between two large cities.  After system operation initiation, differences among the travel times of the three routes in the same time zone had decreased. Also, the average travel times of the three routes had been shortened on the whole.]]></description>
      <pubDate>Wed, 12 Jun 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/462127</guid>
    </item>
    <item>
      <title>A STRATEGY FOR SOLVING STATIC MULTIPLE-OPTIMAL-PATH TRANSIT NETWORK PROBLEMS</title>
      <link>https://trid.trb.org/View/459040</link>
      <description><![CDATA[Transit and private automobile trip making processes differ in their use of time schedules, walking paths, transfer stops, plus fares and safety issues.  Shortest path algorithms cannot always be applied due these factors.  The aim of this study is to develop an algorithm and strategy for transit providers to determine best alternatives for the user, and to demonstrate how geographic information systems can aid in development of transit advanced traveler information systems (TATIS) to address these needs.  The authors present a short introduction on TATIS, commonly used algorithms in determining the shortest and multiple paths, and a unique strategy unlike the standard network algorithms.  The major features of the proposed algorithm are: 1) handles multiple modes of transit; 2) provides paths that include walking distances from and to the transit path as well as between transfer points; and 3) offers multiple optimal paths to allow for user flexibility in choosing a path.]]></description>
      <pubDate>Fri, 03 May 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/459040</guid>
    </item>
    <item>
      <title>MULTILEVEL APPROACH TO THE DESIGN OF A FREEWAY CONTROL SYSTEM</title>
      <link>https://trid.trb.org/View/116711</link>
      <description><![CDATA[THE DEFINITION IS PRESENTED OF THE FUNCTIONAL AND OPERATIONAL REQUIREMENTS FOR FREEWAY CONTROL SYSTEMS AND THE ACTUAL DESIGN AND INSTALLATION OF A PROTOTYPE. THE SPECIFICATIONS PROPOSED FOR DESIGNING THE PROTOTYPE CONTROL SYSTEM ARE (1) THE OPTIMAL USE OF ACCEPTABLE FREEWAY GAPS BY MERGING RAMP VEHICLES AND (2) THE PREVENTION OF CONGESTION. THE UNDERLYING PHILOSOPHY IS THAT MINIMIZING INTER-VEHICULAR INTERFERENCE AT ENTRANCE RAMPS REDUCES THE PROBABILITY OF REAR-END COLLISIONS IN MERGING AREAS DUE TO FALSE STARTS REDUCES THE TENSION ON A MERGING DRIVER, AND PREVENTS SHOCK WAVES FROM DEVELOPING ON THE FREEWAY NEAR ENTRANCE RAMPS. THE THEORY BEHIND THIS IS BASED ON UTILIZING GAP AVAILABILITY AND GAP ACCEPTANCE MODELS. ANOTHER THEORY SUGGESTS THAT THE PREVENTION OF CONGESTION ULTIMATELY RESULTS IN MOVING MORE TRAFFIC FASTER. THEORETICALLY, CONGESTION IS PREVENTED IF DEMAND NEVER EXCEEDS SOME SERVICE VOLUME. THE APPROACH TAKEN IN THE DESIGN OF THE FREEWAY CONTROL SYSTEM PROTOTYPE IS BASED ON THE MULTI-LEVEL CONCEPT. THE FREEWAY IS VIEWED AS A SINGLE ENTITY WITH THE CONTROL LAW BEING SPLIT INTO SEVERAL DEGREES OF SOPHISTICATION OR LEVELS, WITH THE LOWER LEVELS DIRECTED TOWARD RECOGNIZING THE INFLUENCE OF SHORT-TERM FACTORS (GAP AVAILABILITY FOR MERGING RAMP VEHICLES) AND THE HIGHER LEVELS RESERVED FOR FACTORS THAT INFLUENCE PERFORMANCE ON A LONG-TERM BASIS (FREEWAY CAPACITY REDUCTIONS DUE TO ACCIDENTS, INCIDENTS, OR GEOMETRIC BOTTLENECKS). /AUTHOR/]]></description>
      <pubDate>Fri, 21 Oct 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/116711</guid>
    </item>
    <item>
      <title>THE APPLICATION OF PARALLEL PROCESSING TO TRAFFIC ASSIGNMENT FOR USE WITH ROUTE GUIDANCE</title>
      <link>https://trid.trb.org/View/365828</link>
      <description><![CDATA[The main objective of the work described in this paper was to investigate the potential for applying parallel processing to the traffic assignment process with special reference to its use with route guidance.  Existing traffic assignment methods and techniques are discussed.  Parallel processing is introduced and suggestions made for distributing the existing techniques as well as for developing new parallel methods.  Initial estimates of performances have been made for each, and preliminary recommendations made as to the best approach.]]></description>
      <pubDate>Sun, 31 May 1992 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/365828</guid>
    </item>
    <item>
      <title>A DYNAMIC MODEL OF MULTIPLE PATH TRAFFIC ASSIGNMENT</title>
      <link>https://trid.trb.org/View/360060</link>
      <description><![CDATA[A Random Shortest Path traffic assignment model and its algorithm are presented in this paper by simulating trip-makers' route-choice.  It is a multiple path assignment model which can be carried out by dynamic as well as by static method.  The model considers both the shortest path factor and the random factors in the route choice.  Both dynamic and static traffic assignment software has been developed which is particularly suited to large and medium-sized transportation networks.  (TRRL)]]></description>
      <pubDate>Sat, 30 Nov 1991 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/360060</guid>
    </item>
    <item>
      <title>MULTIPATH TRAFFIC ASSIGNMENT: A REVIEW OF THE LITERATURE. INTERIM REPORT</title>
      <link>https://trid.trb.org/View/351234</link>
      <description><![CDATA[Most multipath assignment techniques are generated based on either path enumeration or path diversion.  Path enumeration models primarily reiterate the assignment procedure with variable link impedance inputs.  Burrell's algorithm is a typical path enumeration model in which the link impedances are assumed to be randomly distributed to account for errors in the driver's perception in link travel time.  Path diversion models assign trips to alternate paths without repeating the assignment procedure.  The most noted path diversion model is Dial's algorithm.  Dial's technique originated from logit discrete choice theory in that each "reasonable" path between a particular O-D pair is assigned a portion of the trips according to a route-choice probability.  The literature review indicates that these multiple path algorithms can be incorporated into the capacity-restraint process, either iterative or incrementa. Burrell's algorithm can be implemented either in a single-pass procedure or with the capacity-restraint procedure.  Paths are enumerated by repeating simulations of link impedances for each origin zone (or a number of origin zones) in a single-pass procedure; paths are enumerated by repeating simulations of link impedances for each assignment stage when combined with the capacity-restraint procedure. In theory, Dial's algorithm can be implemented with the capacity-restraint procedure although his algorithm is a single-pass procedure.]]></description>
      <pubDate>Fri, 31 May 1991 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/351234</guid>
    </item>
    <item>
      <title>MULTIPATH CAPACITY-LIMITED TRANSIT ASSIGNMENT</title>
      <link>https://trid.trb.org/View/353978</link>
      <description><![CDATA[At present most patronage predictions of transit systems are performed using UMTA Transportation Planning System (UTPS) package or some adaptation of it.  The transit assignment produced by a typical UTPS system can be classified as an all-or-nothing limited equilibrium assignment.  However, passenger loads assigned to a transit line can far exceed the line capacity.  In such a case line headway has to be reduced to provide enough capacity to accommodate transit demand.  If the increase in frequency is not accounted for by iterating again through the mode choice and assignment models, the equilibrium assumptions are violated.  If equilibrium between demand and supply is achieved, it might occur at a point that requires transit capacity much beyond economically feasible or engineering practical levels.  Thus the present transit assignment procedure suffers from two problems.  First, trips are assigned to transit lines without regard to their actual capacity.  Second, while some lines are assigned passenger loads beyond capacity, there might be other lines with just slightly longer travel times that are greatly underutilized.  A realistic assignment should take into account and not exceed the actual capacity of every transit line.  Furthermore, it should consider lines' capacities while rationally simulating people's travel behavior.  A transit assignment algorithm is presented that takes into account the actual capacity of transit lines and assigns trips to more than a single path when the shortest path reaches its capacity.  This procedure produces a practical Multipath Capacity-Limited Transit Assignment (McLAT).  The procedure was implemented on an IBM mainframe computer using the standard UTPS package with the addition of only one FORTRAN program.]]></description>
      <pubDate>Tue, 30 Apr 1991 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/353978</guid>
    </item>
    <item>
      <title>A MODIFICATION OF DIAL'S ALGORITHM BY REDEFINING PATH EFFICIENCY</title>
      <link>https://trid.trb.org/View/348809</link>
      <description><![CDATA[Dial's multipath assignment algorithm assumes that trips are only assigned onto efficient paths.  Hence the definition of efficient paths is a fundamental element of the algorithm. Dial has actually proposed two algorithms, each using a different definition of efficient paths.  Algorithm 1 defines an efficient path as one that always moves further away from the origin and closer to destination.  Algorithm 2 defines an efficient path as one that always moves further away from the origin.  This paper proposes a third definition and a third algorithm.  Algorithm 3 redefines an efficient path as one that either always moves further away from the origin or one that always moves closer to the destination.  A hypothetical grid network is used to illustrate the three different assignment algorithms.]]></description>
      <pubDate>Fri, 30 Nov 1990 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/348809</guid>
    </item>
    <item>
      <title>TRANSPORTATION-NETWORK DESIGN PROBLEM: APPLICATION OF A HIERARCHICAL SEARCH ALGORITHM</title>
      <link>https://trid.trb.org/View/309107</link>
      <description><![CDATA[Two variants of a network design problem are solved by application of the tree search method.  The first formulation aims to reduce a specified vehicle-minutes of traffic congestion at the least possible budget expenditure, and the second minimizes traffic congestion for a given budget.  Both involve system-optimizing traffic assignment models with multipath flows.  The solution method consists of network abstraction, tree search, and network disaggregation--collectively referred to as the "hierarchical search algorithm."  It is shown that such an algorithm reduces the search space by reducing the number of nodes and links and providing a tighter bound during the tree search.  It also groups detailed links according to the function they perform--whether it be access/egress, line-haul, bypass, or internal circulation.  However, the algorithm yields only a suboptimal solution, the quality of which is measured by an error function.  The metropolitan network of Taipei, Taiwan, Republic of China, is used as a case study to verify some of the algorithmic properties, confirming its role in real-world applications.  Finally, the performance of the algorithm, which is based on network abstraction, is favorably compared with a network-extraction network-design model.]]></description>
      <pubDate>Tue, 31 Jul 1990 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/309107</guid>
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