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    <title>Transport Research International Documentation (TRID)</title>
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    <language>en-us</language>
    <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>
    <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>A NEW APPROACH OF EVALUATION FOR ROAD NETWORK PLANNING IN HUNGARY</title>
      <link>https://trid.trb.org/View/269582</link>
      <description><![CDATA[This paper decribes a forecasting system and an evaluation method developed in Hungary for the development plan for the national highway network in Hungary.  The systems are used to: (1) select the optimum road network, based on multi-criteria evaluation.  This takes into account road operating costs, journey time, fuel consumption, vehicle running costs, accident costs, noise, air pollution, land use, tourism, and international connections.  A weighting system is used to assess the value of each parameter; (2) program road developments, to determine the order of priority of investments taking into account the constraints imposed by the available financial resources.  For this purpose a concised efficiency coefficient was derived in the form of a fraction.  Its numerator is the sum of the evaluation indices expressed in monetary terms (time value, vehicle running costs, accident costs, road operation costs) divided by all the investments; (3) estimate national economy losses caused by the drop out of the required investments.  The traffic forecast and multicriteria evaluation computer programs are edited in the program language PLIOPT and they are run in DOS/VS and DOS/VSE operation system on IBM 370/145 and IBM 4331 computers respectively.  For the covering abstract of the proceedings see TRIS 450538.]]></description>
      <pubDate>Fri, 27 Aug 2004 21:56:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/269582</guid>
    </item>
    <item>
      <title>THE PROBABILITY OF FOUNDATION SAFETY</title>
      <link>https://trid.trb.org/View/121896</link>
      <description><![CDATA[PROBABILITY ANALYSIS IS USED TO CALCULATE THE SAFETY OF FOUNDATIONS FOR A NUMBER OF LOADS AND STRENGTH DISTRIBUTIONS. THE APPLIED LOAD AND SOIL STRENGTH ARE CONSIDERED TO BE RANDOM VARIABLES. THE VARIOUS FACTORS THAT AFFECT THE PROBABILITY OF SAFETY ARE EXAMINED. THE APPROPRIATE PROBABILITY FUNCTION IS DETERMINED EMPIRICALLY BY FITTING TO THE EXPERIMENTAL DATA. THIS METHOD REPRESENTS A FIRST APPROXIMATION AND MAY BE CONSIDERED AS A STEP TOWARD THE OPTIMUM DESIGN OF STRUCTURES. /ASCE/]]></description>
      <pubDate>Sun, 15 Aug 2004 02:41:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/121896</guid>
    </item>
    <item>
      <title>SELECTION OF SOIL STRENGTH VALUES FOR THE DESIGN OF FLEXIBLE</title>
      <link>https://trid.trb.org/View/121411</link>
      <description><![CDATA[RECENT STUDIES OF QUALITY CONTROL, SOIL AND MATERIAL VARIANCE HAVE SHOWN THAT CONSIDERABLE VARIATION CAN EXIST IN A COMPLETED HIGHWAY PROJECT. THESE STUDIES HAVE SERVED TO POINT OUT THE NEED FOR DEVELOPING DESIGN TECHNIQUES WHICH TAKE INTO ACCOUNT THIS VARIATION. THIS PAPER PRESENTS A METHOD, BASED ON ECONOMICS, FOR SELECTING A DESIGN VALUE FROM AN ARRAY OF SOIL TEST DATA FOR A SOIL AREA. THIS ANALYSIS INDICATED THAT THE OPTIMUM DESIGN STRENGTH VALUE IS GENERALLY LESS THAN THE MEAN TEST VALUE AND THAT IT IS DEPENDENT UPON AMOUNT OF TRAFFIC, ENVIRONMENTAL CONDITIONS, SOIL VARIABILITY, COMPACTION VARAIBILITY AND PAVEMENT COSTS. PROCEDURES WERE DEVELOPED FOR SETTING UP A FIELD SAMPLING PROGRAM TO EVALUATE SOIL STRENGTH ON AN AREA BASIS. THESE CRITERIA ARE BASED ON TRAFFIC THAT WILL USE THE ROAD, ANTICIPATED MOISTURE CONDITIONS IN THE COMPLETED SUBGRADE, AND SOIL VARIANCE. GUIDELINES FOR SOIL SAMPLING AND SELECTION OF SOIL STRENGTH VALUES, BASED ON THE FACTORS OF TRAFFIC, ANTICIPATED DEGREE OF SATURATION AND SOIL VARIANCE, ARE PRESENTED. /AUTHOR/]]></description>
      <pubDate>Sun, 15 Aug 2004 02:39:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/121411</guid>
    </item>
    <item>
      <title>OPTIMAL DESIGN OF TRANSPORTATION NETWORKS WITH FLUCTUATING DEMANDS. A CASE IN MULTICOMMODITY NETWORKS FLOWS</title>
      <link>https://trid.trb.org/View/9749</link>
      <description><![CDATA[The problem of designing a transportation network that will best satisfy expected demand for travel among a given set of centers of activity is formulated by identifying for each origin-destination pair, called a commodity of the transportation network, all the alternative routes for travel that meet prespecified criteria and which constitute the set of feasible paths.  Modal choice is assumed to be a function of travel time and consequently the model generates expected demands for travel, over alternative routes of different length, from a probability distribution function of travel time associated with each origin-destination pair. (Modified author abstract)]]></description>
      <pubDate>Sat, 18 Oct 2003 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/9749</guid>
    </item>
    <item>
      <title>PLANNING OF TRAFFIC COUNTS</title>
      <link>https://trid.trb.org/View/63831</link>
      <description><![CDATA[This report describes an approach to the problem of optimum design in connection with traffic counts for estimation of parameters in traffic models. The case with only one parameter (zero-intercept regression) is dealt with in some detail. Examples are given of two selection procedures. These procedures have a lot in common with the forward and stepwise techniques used in linear regression to select independent variables in an open model. The procedures are demonstrated by a short example. /TRRL/]]></description>
      <pubDate>Sat, 20 Sep 2003 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/63831</guid>
    </item>
    <item>
      <title>DEVELOPMENT OF A 100-KM/H REUSABLE HIGH-MOLECULAR WEIGHT/HIGH-DENSITY POLYETHYLENE TRUCK-MOUNTED ATTENUATOR</title>
      <link>https://trid.trb.org/View/541989</link>
      <description><![CDATA[A reusable truck-mounted attenuator has been developed that dissipates kinetic energy through the lateral deformation of a nested cluster of high-molecular weight/high-density polyethylene cylinders.  This 100-km/h impact attenuation device, called the Vanderbilt truck-mounted attenuator (VTMA), satisfies the crash testing requirements of National Cooperative Highway Research Program (NCHRP) Report 350.  It has been approved by the Federal Highway Administration for use on the national highway system under these NCHRP Report 350 guidelines. Most impact attenuation devices currently employed require the replacement of damaged structural components and spent-energy-dissipating elements following an impact event. Until these repairs and refurbishments are carried out, these safety devices are largely ineffective because they are unable to dissipate kinetic energy in a subsequent impact in an acceptable manner such that relevant occupant risk parameters are within prescribed limits.  The VTMA is a reusable and self-restorative truck-mounted attenuator.  It can dissipate large amounts of kinetic energy, undergo significant deformations and strains without fracturing, and then, essentially, regain its original shape and energy-dissipation potential on removal of the load.  The VTMA design was optimized through finite-element modeling using DYNA3D.  This inexpensive modeling tool resulted in a reduction in the number of expensive full-scale crash tests required to develop the system.  Computer modeling can optimize the probability for success of a given full-scale crash test, removing trial-and-error approach to appurtenance design.]]></description>
      <pubDate>Tue, 15 Dec 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/541989</guid>
    </item>
    <item>
      <title>DESIGN OF TRUSSES UNDER UNCERTAIN LOADS USING CONVEX MODELS</title>
      <link>https://trid.trb.org/View/477581</link>
      <description><![CDATA[The optimal design of trusses subjected to loads considered to be uncertain in both magnitude and direction is investigated.  A nonprobabilistic ellipsoidal convex model is established for considering the uncertainties using three different criteria. The convex model is described as a set of constraints on the upper and lower limits of the load magnitudes and directions. The optimal design of the trusses is performed using two different optimization objectives.  The first objective function to be minimized is the structural volume; constraints are imposed on the stresses and buckling loads of the members and on the joint displacements.  Another objective function to be minimized is a selected displacement; constraints are implemented on the stresses and buckling loads of the members and on the structural volume.  The presented method yields optimal designs that violate stress, displacement, and buckling constraints with less frequency than the assumed worst load condition.  This method offers an alternative to formal probabilistic methods.]]></description>
      <pubDate>Thu, 16 Apr 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/477581</guid>
    </item>
    <item>
      <title>SELECTING AN OPTIMUM CONFIGURATION OF ONE-WAY AND TWO-WAY ROUTES</title>
      <link>https://trid.trb.org/View/475306</link>
      <description><![CDATA[This paper considers a network with established transportation flows between nodes which take place along shortest paths. Links on the network may be one-way or two-way. One-way links, although lengthening some shortest paths, are faster, effectively reducing the travel time in the permitted direction. The objective is to select the optimum configuration of one-way and two-way routes to minimize the total flow-weighted transportation time (distance) in the system.]]></description>
      <pubDate>Fri, 09 Jan 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/475306</guid>
    </item>
    <item>
      <title>LINEARIZED OPTIMIZATION MODEL FOR RELIABILITY-BASED DESIGN OF WATER SYSTEMS</title>
      <link>https://trid.trb.org/View/474805</link>
      <description><![CDATA[Optimal network design constrained by reliability is an improvement over the traditional methods for water-distribution system analysis.  But the large computer time for reliability-optimization restricts its practical use for design. In this paper, a new technique is developed that applies a linear programming algorithm to optimal design constrained by reliability.  The objective function and constraints are expressed by a first-order Taylor series expansion, and three submodels (a steady-state simulation model, a reliability model, and a linear optimization model) are linked in the algorithm. The optimal search is done in two steps.  The first step is to search for an optimal solution and then the reliability and pressure heads, evaluated on this configuration, are compared with the constraint values.  If there still exists a possibility that the cost of the system can be further decreased, a new iteration is repeated.  The computing burden is significantly decreased and, therefore, the proposed reliability-optimization technique can be used in planning large networks.]]></description>
      <pubDate>Wed, 03 Dec 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/474805</guid>
    </item>
    <item>
      <title>RELIABILITY-BASED OPTIMIZATION DESIGN METHOD OF STRUCTURAL SYSTEM USING INFORMATION INTEGRATION METHOD</title>
      <link>https://trid.trb.org/View/483080</link>
      <description><![CDATA[In this study, an optimization method of a structural system is proposed using the Information Integration Model (IIM) and Genetic Algorithm (GA).  Structural design should be performed so that the structural system satisfies various requirements, for example, safety, economic and social requirements, etc. Therefore, the general design problem of a structural system should be formulated as a multi-objective optimum design problem with multi-constraint conditions.  In such a design problem, evaluation of the system with respect to various evaluation items is necessary.  However, the formulation and calculation of such evaluations are difficult, because each of the evaluation results corresponding to various evaluation items has other dimensions.  To overcome these difficulties, this study uses the IIM to evaluate at what level the system satisfies all the evaluation items.  The IIM is a powerful calculation method of system evaluation.  Moreover, formulation and calculation are easy by making use of the IIM.  Therefore, simple mathematical programming techniques can be used for system optimization.  This study uses the GA as an optimization method.  For a numerical example, an optimum design problem of a highway bridge girder is considered.  Results obtained by this method are compared with those of the present design method, and then the efficiency of this method is demonstrated.]]></description>
      <pubDate>Tue, 20 May 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/483080</guid>
    </item>
    <item>
      <title>SELECTION OF HIGHWAY DESIGN PARAMETERS IN THE PRESENCE OF UNCERTAINTY</title>
      <link>https://trid.trb.org/View/452675</link>
      <description><![CDATA[AASHTO guidelines on highway design have drawn criticism for their inability to deal with the uncertainty of traffic operations, costs, and physical constraints.  Some analysts believe that in light of changing economic and socio-environmental values, new procedures are needed to better address uncertainties and to justify engineering decisions.  An analytical model that could be used to determine the optimal design curvature for horizontal curves on two-lane highways is presented.  The optimal curvature results in the minimum total cost, defined as the sum of construction, maintenance, and expected user costs.  The expected user cost is the sum of expected accident, travel time, and vehicle operating costs.  It is shown that:  (a) optimal design curvature is highly sensitive to the skewness of the probability distribution of the required curvature; (b) when the mean operating speed is high, optimal design curvature does not change significantly with the changes of standard deviation of speeds compared with the low mean operating speed; and (c) when the mean operating speed is low, the polynomial model best represents the relationship between optimal design curvature and the standard deviation of the operating speeds.  When the mean operating speed is high, the linear model best represents the relationship between optimal design curvature and the standard deviation of the operating speeds.  The application of the model and sensitivity of the optimum to model parameters are illustrated using numerical examples.]]></description>
      <pubDate>Wed, 20 Dec 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/452675</guid>
    </item>
    <item>
      <title>MOTOR VEHICLE HEADLIGHTING: A CLASSIC PROBLEM IN ERGONOMICS</title>
      <link>https://trid.trb.org/View/289575</link>
      <description><![CDATA[The optimum beam pattern remains an elusive design concept. The reasons why there is so much difficulty can be summed up briefly by pointing out that there are a great number of criteria to be considered in headlight design, many of which are in conflict.  Unfortunately, there is no agreement as to how to weigh criteria that are in conflict.  For example, almost anything that can be done to improve visibility down the road will increase glare to some degree, under at least some conditions.  In order to decide whether the increase in visibility represents a system improvement, it is necessary to determine whether that benefit outweighs the negative aspects of increased glare.  The problems in making such a decision are compounded by the fact that there is generallly no way to quantify the glare effect or determine how often or under what conditions it will occur.  Progress toward a solution of this dilemma has been made in recent years, however, through the creation of a computer model that affords a comprehensive evaluation of headlamp beam patterns.  Clearly, it is necessary to consider combined effects, something that has rarely been done to date.]]></description>
      <pubDate>Thu, 30 Nov 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/289575</guid>
    </item>
    <item>
      <title>IMPROVING DESIGN AND FABRICATION OF BRIDGES USING KNOWLEDGE BASE</title>
      <link>https://trid.trb.org/View/426364</link>
      <description><![CDATA[Bridge designers and fabricators in Japan often reduce the steel weight of bridges because total cost is estimated by price per unit weight.  This results in increasing the number of weld lines and cross-section variations.  A shortage of technicians and increasing labor costs, though, are making it necessary to simplify and accelerate the fabrication process to get a more rational and near optimal design.  Knowledge-based systems can be combined with actual design data of available bridges to facilitate decisionmaking and improve design and fabrication. This paper describes the creation of a knowledge base that includes data on previously designed plate-girder bridges, and its application in simplifying design to determine the cost of bridges.  The steps followed to create and process the knowledge base is explained, and then, the knowledge base is applied to several bridges to explore design alternatives.  Recommendations for more rational designs are offered based on previous design information.]]></description>
      <pubDate>Mon, 17 Jul 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/426364</guid>
    </item>
    <item>
      <title>RELIABILITY-BASED STRUCTURAL DESIGN WITH MARKOV DECISION PROCESSES</title>
      <link>https://trid.trb.org/View/425911</link>
      <description><![CDATA[An optimal structural design can be described as the synthesis of the initial structural design and its maintenance/management policy over the design lifetime.  By using a Markov decision process (MDP) model and structural reliability theory, a designer at the initial design stage can incorporate a reliability-based model of the lifetime process of the structure.  The MDP systematically characterizes the process, including decisions, costs, and system performance.  In addition, it provides a solution of this dynamic problem through a static method, thus retaining computational tractability.  A long-term maintenance policy based on minimum expected lifetime cost can be generated, with respect to the chosen initial design, and used to select an optimum initial design to minimize cost and maintain acceptable reliability.  For existing structures, the MDP gives decisionmakers future maintenance policy, which leads to identification of the minimum discounted expected future cost of the structure, based on its present condition, and maintains acceptable reliability.]]></description>
      <pubDate>Sun, 04 Jun 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/425911</guid>
    </item>
    <item>
      <title>OPTIMIZATION OF ROLLER-COMPACTED CONCRETE FOR LOCAL APPLICATION</title>
      <link>https://trid.trb.org/View/424758</link>
      <description><![CDATA[Recently constructed asphalt pavements in Saudi Arabia are experiencing a high level of wheel track rutting, which is mainly attributed to the high ambient pavement temperature, the high volume of loaded trucks, and the viscoelastic behavior of the asphalt pavement.  One proposed solution is to use reinforced concrete rigid pavement.  Because of corrosion of the reinforcement bars, a common problem in Saudi Arabia, it is better to use roller-compacted concrete (RCC) pavements.  A comprehensive and rational design of RCC mixes, such as conventional concrete, is extremely complex, because it is influenced by numerous factors that depend on the sources of materials and their properties; methods of preparation, placement, compaction, and curing; and, most important, prevailing environmental conditions.  Incorporation of all these factors into RCC mix design not only requires the arduous selection of appropriate proportions of the ingredients, but also inaccuracies occur in the required properties of RCC that are usually rectified by trial-and-error procedures.  Effects of variation of the water to cement ratio, coarse-to-fine aggregate ratio, and total aggregate to cement ratio, on rollability, density, and strength of RCC are investigated for three compactive efforts.  The main objective is to find optimum mix design proportions for locally available materials by varying the mentioned variables and to develop a model to predict the flexural strength of local mixes.]]></description>
      <pubDate>Fri, 28 Apr 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/424758</guid>
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