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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>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
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    <item>
      <title>Vehicle Specific Behaviour in Macroscopic Traffic Modelling through Stochastic Advection Invariant</title>
      <link>https://trid.trb.org/View/1370483</link>
      <description><![CDATA[In this contribution a new model to include stochastic vehicle specific behaviour and interaction in traffic flow modelling is presented. The First Order Model with Stochastic Advection (FOMSA) is presented as a first order macroscopic kinematic wave model in a platoon-based Lagrangian coordinate system. The use of Lagrangian coordinates allows characteristics of specific vehicles or vehicle-groups to propagate along with the traffic flow using a vehicle specific invariant. The invariant reflects how vehicle or platoon specific characteristics propagate with the vehicles and influence the local behaviour of a vehicle or platoon on a macroscopic level and in interaction with other surrounding vehicles. It represents a local vehicle specific adjustment to the critical density and makes use of two parameters: a stochastic boundary parameter and a transition parameter. These parameters indicate the extent of differences between vehicles or platoons. A case study is also presented in which a demonstration of the model is given and the face validity and sensitivity of the parameters are shown. Previously, similar approaches have made use of second order model descriptions. The formulation of this model as a first order model makes use of the advantages of first order models and also applies the improved accuracy of Lagrangian coordinates over the Eulerian coordinate system in time-stepping.]]></description>
      <pubDate>Wed, 07 Oct 2015 12:46:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/1370483</guid>
    </item>
    <item>
      <title>Outline of Diffusion Advection in Traffic Flow Modeling</title>
      <link>https://trid.trb.org/View/848067</link>
      <description><![CDATA[The quantity of data necessary in order to study traffic through a traffic network, and the large volume of information that is provided as a result renders the said model unmanageable in practice. A study of this kind is expensive and complex, with many sources of error connected to each step carried out. A simplification like the continuous medium is a reasonable approximation and, for certain dimensions of the actual problem, may be an alternative to be kept in mind. The hypotheses of the continuous model introduce errors comparable to those associated with geometric inaccuracies in the transport network, with the grouping of hundreds of streets in one same type of arc and therefore having the same functional characteristics, with the centralization of all journey departure points and destinations in discrete centroids, and with the uncertainly produced by a highly origin/destination matrix that is quickly phased out, etc. In the course of this work, a new model for characterizing traffic in dense network cities as a continuous medium, the diffusion/advection model, is put forward. The model is approached by means of the boundary element method that has the fundamental characteristic of only requiring the contour of the problem to be discretized, thereby reducing the complexity and need for information into one order. On the other hand, the boundary elements method tends to give a more complex mathematical formulation than that of other more diffuse methods. In order to validate the proposed technique, two examples in their fullest form are resolved with known analytic solution.]]></description>
      <pubDate>Wed, 21 May 2008 07:08:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/848067</guid>
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    <item>
      <title>Enhancement of a Tidal Model for the Loxahatchee River Estuary (Southeastern Florida)</title>
      <link>https://trid.trb.org/View/835424</link>
      <description><![CDATA[A two-dimensional, depth-integrated tidal model for the Loxahatchee River estuary (Southeastern Florida) is enhanced by examining its sensitivity to: 1) domain extent; 2) advection. The region of interest is modeled with three variations of an unstructured, finite element mesh, including a localized mesh with and without tidal flats, and an extended mesh describing the Atlantic Intracoastal Waterway (AIW). Phase and amplitude errors between model output and historical data are quantified at five locations within the Loxahatchee River estuary to assess the performance of the various computational meshes. While it is shown that the tidal flats provide some benefit to the numerical model, the hydrodynamics resulting from the extension of the AIW permit for a more significant improvement of the simulation results. In addition, globally computed velocity residuals reveal significantly different net circulation patterns within the Loxahatchee River estuary, depending on the spatial coverage of the AIW, and further demonstrate the importance of including the AIW in the numerical model. Finally, rotational residual flows generated offshore and within the Loxahatchee River estuary, for when the advective terms are considered, indicate that advection is a contributory factor in the long-term tidal circulation occurring within the estuarine, coastal, and continental shelf waters found along the east coast of Florida.]]></description>
      <pubDate>Fri, 05 Oct 2007 14:28:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/835424</guid>
    </item>
    <item>
      <title>FRACTIONAL KINETIC MODEL FOR FIRST FLUSH OF STORMWATER POLLUTANTS</title>
      <link>https://trid.trb.org/View/750181</link>
      <description><![CDATA[By generalizing the urban ground as a fractal surface and revising the classical Fick's formula as a law of dispersion with a fractional-order derivative, a fractional kinetic model is developed for simulation of the first flush phenomenon of urban stormwater pollutants.  The model is comprised of:  (1) a fractional dispersion-advection equation (FADE); (2) the kinematic-wave overland flow equation; (3) methods for numerical solution of the equations.  A split-operator method is proposed for numerical solution of the FADE by means of a newly presented F.3 finite-difference scheme for fractional partial differential equations.  The kinematic-wave overland flow equation is solved using the Lax-Wendroff explicit scheme.  Under a constant rainstorm, the hydrograph displays an initial rising limb followed by a constant flow discharge.  The pollutograph exhibits a steep receding limb (the first flush), followed by a long stretched tail (heavy tail process).  The agreement between simulated and measured dispersion characteristics is found to be good, demonstrating that the fractional kinetic model is capable of accurately predicting the characteristics of the first flush phenomenon.]]></description>
      <pubDate>Tue, 01 Feb 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/750181</guid>
    </item>
    <item>
      <title>FRACTIONAL STEPS SCHEME OF FINITE ANALYTIC METHOD FOR ADVECTION-DIFFUSION EQUATION</title>
      <link>https://trid.trb.org/View/748517</link>
      <description><![CDATA[For simply finding local analytic solution, the time derivative in the traditional finite analytic (FA) method is generally replaced with a first-order finite difference approximation as a source term. However, this may induce excessive numerical diffusion, especially for advection-dominated transport problems. In this paper, a fractional steps scheme of the FA method without using the finite difference approximation to time derivative is proposed by applying the one-dimensional FA method whose local analytic solution is obtained from both spatial and time domains, together with the method of fractional steps. Four hypothetical examples, including two-dimensional and three-dimensional cases, are employed to investigate this newly proposed method as compared with the traditional FA method, the optimal unsteady FA method, and the alternating direction scheme of the hybrid FA method. The results show that the fractional steps scheme of the FA method can greatly diminish numerical diffusion and is superior to the other methods compared herein.]]></description>
      <pubDate>Tue, 18 Jan 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/748517</guid>
    </item>
    <item>
      <title>A REVIEW OF WATER MOVEMENT IN THE HIGHWAY ENVIRONMENT: IMPLICATIONS FOR RECYCLED MATERIALS USE</title>
      <link>https://trid.trb.org/View/698283</link>
      <description><![CDATA[Significant amounts of recycled materials are being used in structural components of highways such as base, subbase, portland cement and asphalt concrete, and embankments.  Past experience with recycled materials in highways has not shown a risk with respect to environmental impact and human health. However, environmental regulatory agencies frequently must assess risk to human health and the environment when conducting beneficial use determinations, particularly for new recycled materials.  Contaminant leaching and advective transport are believed to be the primary transport pathways and both of them depend on in situ moisture conditions.  The purpose of this study was to describe the state of the knowledge about water movement in the highway environment so that this knowledge may be incorporated into (1) practical leaching and preliminary impact assessments and (2) fate/transport models for use in risk assessment.  Measurement techniques for moisture content, pore water pressure, and rainfall were discussed.  For measuring in situ water content, time domain reflectometry (TDR) is a growing and promising technique.  However, there is not a universal agreement on a TDR calibration equation.  Laboratory techniques for measuring saturated hydraulic conductivity center on constant and falling head permeameter tests that should be conducted at low hydraulic gradients, and in addition, laminar and horizontal flow conditions.  Hydraulic conductivity data for asphalt concrete, portland cement concrete (PCC), and base/subbase layers displayed wide scatter due to high variability in mixture designs and in measurement techniques. Factors affecting hydraulic conductivity are shape, size, and interconnectivity of air voids, and in PCC, the curing temperature and the type and extent of chemical reactions during hardening.  Most of the evidence suggested that addition of recycled materials to PCC decreases the hydraulic conductivity after curing.  Water enters pavements despite efforts to prevent it, but the extent of pavement deterioration can be reduced by proper drainage and maintenance.  The major water ingress routes are infiltration through the pavement surfaces (through cracks and joints) and shoulders, melting of ice during the freezing/thawing cycles, capillary action, and seasonal changes in the water table.  Most important water pathways that are discussed in greater detail in the literature are infiltration through cracks, joints and shoulders and drainage through edge drains.  Groundwater level affects moisture conditions in the pavement and the subgrade if it is within approximately six meters from the surface.  There is also literature on water pumping, temperature variations, geotechnical properties of base/subbase and subgrade layers as they relate to the water movement in the highway environment.  Simplistic and more comprehensive approaches to modeling water movement in the highway environment were reviewed.  Among all models presented, none closely matched the purpose of the present study.]]></description>
      <pubDate>Wed, 23 Jun 2004 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/698283</guid>
    </item>
    <item>
      <title>NUMERICAL SIMULATION OF ADVECTED THERMAL USING GAUSSIAN-VORTEX MODEL</title>
      <link>https://trid.trb.org/View/669079</link>
      <description><![CDATA[Buoyant jets are the essential form of release of many types of wastes into the oceans or the atmosphere.  The Gaussian-vortex integral model is applied to laboratory data on an advected thermal and field experimental data for a single submerged sewage outfall.  The Gaussian-vortex integral model is distinguished from other conventional jet integral models that do not consider vortex-pair formation effects on the behavior of a buoyant jet in the buoyancy- and ambient-dominated regions.  The experimental data relative to an advected thermal, measured by a laser-induced fluorescence technique were used for verifications of the numerical model.  With the incorporation of vortex-pair formation effects, the simulated results on the bulk characteristics of an advected thermal were in good agreement with the laboratory data, and for applications the simulated surface minimum dilutions also show fairly good agreement with field experimental data. Finally, the numerical model is applied to a horizontal buoyant jet in cross-flow to demonstrate the capability of the numerical model for the buoyant jet that has three-dimensional characteristics.]]></description>
      <pubDate>Fri, 13 Oct 2000 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/669079</guid>
    </item>
    <item>
      <title>PREDICTION OF OZONE FORMATION BASED ON NEURAL NETWORK</title>
      <link>https://trid.trb.org/View/657726</link>
      <description><![CDATA[The atmospheric ozone concentration in Seoul, Korea, was forecasted using an artificial neural network (ANN) and spatiotemporal analysis.  The ANN was trained by using hourly pollutant and meteorological data that resulted in complex patterns of ozone formation.  The finite-volume method was employed in the spatiotemporal analysis in order to take into account the effects of wind.  Time horizons in the forecasts were 1-6 hours and 16-21 hours.  The resulting predictions of ozone formation were compared with measured data.  From the comparison, it was found that the ANN method gave reliable accuracy within a limited prediction.]]></description>
      <pubDate>Tue, 01 Aug 2000 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/657726</guid>
    </item>
    <item>
      <title>CENTRIFUGE MODELING OF MOISTURE MIGRATION IN SILTY SOILS. TECHNICAL NOTE</title>
      <link>https://trid.trb.org/View/657711</link>
      <description><![CDATA[An effort has been made to demonstrate use of a small geotechnical centrifuge as a research tool to understand moisture migration in a silty soil.  Such a basic study is essential for understanding the much more complex phenomenon of solute transport through a soil, where the physical, chemical, and biological properties of the soil-solute system play an important role.  This study indicates that the advection in soils is dependent on the state of the soil and, in particular, on its degree of saturation.  The effect of pore structure on the advection process has also been demonstrated.  The trends of experimental data indicate that modeling of models may be valid only for saturated soils.]]></description>
      <pubDate>Mon, 31 Jul 2000 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/657711</guid>
    </item>
    <item>
      <title>ANALYSIS OF FINE-GRAINED SEDIMENT MOVEMENT IN SMALL CANALS</title>
      <link>https://trid.trb.org/View/482326</link>
      <description><![CDATA[The author presents a one-dimensional model for quantification of fine-grained sediment movement in small canals.  The time-dependent, advection-dispersion equation is the basis of the proposed model.  The model represents the effects of deposition and erosion through appropriate sink and source expressions.  The rates of deposition and erosion are represented by a linear relation and an exponential function, respectively.  Selective settling and consolidation effects are incorporated via the depositional and erosional expressions.  The governing equation is solved by a finite integral transformation that reduces the original PDE into a Sturm-Liouville ODE.  Closed-form solutions are provided in terms of eigenseries for various boundary and initial conditions.  Depending on the circumstances, the eigenfunctions and eigenvalues are derived by analysis or estimated by employing the Kramers-Wentzel-Brillouin (KWB) approximation.  Comparison of model results with experimental data reveal good agreement.]]></description>
      <pubDate>Sun, 20 Apr 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/482326</guid>
    </item>
    <item>
      <title>THERMALLY DRIVEN ELECTRICAL COUPLING EFFECTS AND PORE WATER ADVECTION IN SOILS</title>
      <link>https://trid.trb.org/View/354005</link>
      <description><![CDATA[Measurements of near-surface temperature fluctuations during a period of night frost were used in conjunction with a surrogate measure of soil water ion concentration to attempt to trace inflections in these time series to soil water advection effects.  Major inflections in the ion concentration time series were traceable to water and water vapor processes as a freeze-thaw front propagated vertically through a soil profile at shallow depths.  Relative ion concentration was related to the electrical potential measured between a probe at different depths of interest and a ground spike.  The field probe electric circuit was modeled as an electrolytic cell without transference.  Field time series data illustrated that effects of water migration toward near-surface evaporation/freezing fronts, solute expulsion from a freezing region, internal evaporation, and clean melt water release could be detected by variations in the electric potential or its surrogate, the relative ion concentration index.  The spatial/temporal pattern of temperature and relative ion concentration helps to explain interactions or coupling between induced hydraulic, osmotic, and electrical gradients during the propagation of a thermal disturbance through a soil.]]></description>
      <pubDate>Tue, 30 Apr 1991 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/354005</guid>
    </item>
    <item>
      <title>SIMULATION OF OIL SLICK TRANSPORT IN GREAT LAKES CONNECTING CHANNELS: THEORY AND MODEL FORMULATION</title>
      <link>https://trid.trb.org/View/344116</link>
      <description><![CDATA[The growing concern over the impacts of oil spills on aquatic environments has led to the development of many computer models for simulating the transport and spreading of oil slicks in surface water.  Almost all of these models were developed for coastal environments.  In this study, two computer models, named as ROSS and LROSS, were developed for simulating oil slick transport in rivers and lakes, respectively.  The oil slick transformation processes considered in these models include advection, spreading, evaporation and dissolution.  These models can be used for slicks of any shape originated from instantaneous or continuous spills in rivers and lakes with or without ice covers.  Although the study was originated by U.S. Army Corps of Engineers, Detroit District in relation to the Great Lakes limited navigation season extension study, these models can be used for any river and lake.]]></description>
      <pubDate>Wed, 31 Oct 1990 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/344116</guid>
    </item>
    <item>
      <title>LABORATORY DETERMINATION OF DIFFUSION AND DISTRIBUTION COEFFICIENTS OF CONTAMINANTS USING UNDISTURBED CLAYEY SOIL</title>
      <link>https://trid.trb.org/View/282518</link>
      <description><![CDATA[This paper describes a technique for determining the diffusion coefficient and the distribution coefficient for contaminants using saturated, intact (undisturbed) clayey soil samples.  The technique is illustrated with reference to a number of laboratory tests involving advective-diffusive migration of potential contaminants through an intact clayey soil from Sarnia, Ontario.  An important aspect of the proposed technique is that the mass of contaminant in the system is kept constant and so significant decrease in source leachate concentration occurs during each test.  A simple theoretical model is used to analyze this case and it is shown that this phenomenon can be used to deduce both the diffusion coefficient and the distribution/partitioning coefficient from a single test. Parameters are deduced for a number of salt solutions passing through the clay from the Sarnia area.  On the basis of these tests it is suggested that for the Sarnia soil and advective velocities up to the maximum examined (0.035 m/a), mechanical dispersion does not measurably affect the magnitude of the "coefficient of hydrodynamic dispersion" (i.e., there is no significant dispersion).  It is also suggested that the effective porosity corresponds to that deduced from the water content of the soil.]]></description>
      <pubDate>Thu, 30 Jun 1988 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/282518</guid>
    </item>
    <item>
      <title>CENTRIFUGE MODELING OF TRANSPORT PROCESSES FOR POLLUTANTS IN SOILS</title>
      <link>https://trid.trb.org/View/278297</link>
      <description><![CDATA[The physico-chemical processes of advection, dispersion, adsorption, and degradation that control pollutant transport processes in groundwater are described.  Dimensional analysis is presented, and the scaling requirements for centrifuge modeling of these processes is developed.  The validity of these scaling laws is examined by conducting modeling of models tests using several types of soils in idealized models of one-dimensional flow situations.  The importance of scaling gravity (by using a centrifuge) is highlighted.  The centrifuge permits simulation of prototype stress levels and thus makes it possible to obtain identical soil properties such as permeability in a small-scale model as compared to a full-scale soil deposit. Simulation of capillary effects and a phreatic surface is also possible in a centrifuge model, but not in a 1-g scale model.  It is concluded that the scaling laws are valid for adsorption and advection in the reported model tests, but in coarse-grained soils where the Peclet number is often greater than one, the dispersion process cannot be directly scaled from model to prototype.  Even if direct scaling is not possible, the centrifuge is a useful tool for providing data to test or verify numerical models, since full-scale test data are not abundant, and the full-scale boundary and site conditions are poorly defined.]]></description>
      <pubDate>Mon, 29 Feb 1988 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/278297</guid>
    </item>
    <item>
      <title>LABORATORY MEASUREMENT OF FINE-GRAINED SOIL FLUID CONDUCTIVITY</title>
      <link>https://trid.trb.org/View/270198</link>
      <description><![CDATA[Advective fluid flow, which depends directly on hydraulic conductivity, controls contaminant migration through soils in many cases.  The state of practice in laboratory measurements of hydraulic conductivity of soils was reviewed and found to be extremely variable, with the result that measurements on a given soil material often give variations of several orders of magnitude.  An experimental program was completed using compacted clay soils to study several facets of laboratory testing practice, and a suitable test procedure from consistent results was developed. Recommendations on several important aspects of procedure are presented.  (Author/TRRL)]]></description>
      <pubDate>Sat, 31 May 1986 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/270198</guid>
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