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Search returned 18 reports containing keyword: 'modeling'
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Inouye,B. WA-RD 596.1 Seismic Analysis and Retrofit Study of the SR 99-Spokane Street Over-Crossing 2004 TRAC/UW
Abstract:
The SR99-Spokane Street Over-crossing is located in Seattle, Washington, and was built in the late 1950s. Its construction is mostly of reinforced concrete; the reinforcement detailing is poor by modern seismic standards, particularly with respect to confinement, and the underlying soils are also weak. Furthermore, the structure contains many "outrigger bents", in which columns are displaced from their ideal locations to accommodate passage of railroad tracks beneath the structure. These outrigger bents cause significant asymmetry in the structure that could lead to unusual and undesirable seismic response. In this study, the seismic response of the structure was evaluated analytically and seismic retrofit strategies were developed and evaluated. In a companion experimental study by Washington State University (WSU), the as-existing structure was investigated by testing scale models of representative bents, and one retrofit strategy was also tested. In this report, modeling approaches are discussed in detail, and the results of evaluations of the as-existing structure as well as the retrofit strategies are presented. Some components of the structure (e.g. the deck, the already-jacketed columns and the soil-foundation-structure system) were found to be critical to an accurate determination of response and were therefore modeled in some detail. Site-specific ground motions at three different hazard levels were used. The structure was found to be vulnerable, especially to the 72- and 475-year ground motions. The knee-joints that connect the outrigger beams and columns were found to be the most critical components, and their vulnerability was shown to be influenced by the type of retrofit performed on the outrigger column. Retrofit strategies included some designed to increase the strength and ductility of the components, and some intended to reduce the demands on them.

Authors:
Inouye,B., Lehman,D. E., Stanton,J. F., Kramer,S. L.

Keywords:
columns, concrete, construction, ductility, evaluation, experimental, hazard, ITS, knee-joints, modeling, models, outriggers, reinforced concrete, reinforcement, retrofit, seattle, seismic, seismic response, soil-structure interaction, strength, Washington, Washington state


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External Links:
http://www.wsdot.wa.gov/research/reports/fullreports/596.1.pdf http://wsdot.wa.gov/Research/Reports/500/596.1.htm
Waddell, P. UrbanSim: Development, Application and Integration with the Wasatch Front Regional Travel Model, Technical Report 2003 Center for Urban Simulation and Policy Analys
Abstract:
The objective of this report is to present the results of a project to evaluate the application of the UrbanSim land use model system and its integration with the Wasatch Front Regional council (WFRC) travel model system. The intent is to describe reasonably completely the entire process of developing and applying UrbanSim in the Greater Wasatch Front Region, including the development of the database, estimation and calibration of model parameters, integration with the WFRC travel model system , and validation of the model system through sensitivity analysis designed to explore the responsiveness of the model to major transportation system and land use policy changes.

Authors:
Waddell, P., Franklin, J., Britting, J.

Keywords:
UrbanSim, land use, modeling, planning


External Links:
https://www.academia.edu/50117617/UrbanSim_Development_Application_and_Integration_with_the_Wasatch_Front_Regional_Travel_Model
Chayanan,S. WA-RD 562.1 Interaction Between the Roadway and Roadside--An Econometric Analysis of Design and Environmental Factors Affecting Segm... 2003 TRAC/UW
Abstract:
The purpose of this research was to explore the relationship between roadway and roadside accidentrates for Washington State highways to improve the Washington State Department of Transportation's(WSDOT) process of modeling roadway and roadside accident rates and to arrive at possible improvements in the efficiency of WSDOT's safety project programming process.The project tested the use of the seemingly unrelated regression estimation (SURE) model to modelthe roadway and roadside simultaneously. The theoretical advantage of the SURE approach is that it does not impose any a priori assumptions on the explicit linkage between roadway and roadside accident rates, and there is no theoretical support for explicit linkage, either. The data used to derive this model were from a random sample of 500 one-mile sections from the Washington State highway system. Traffic dataincluded traffic volumes, truck compositions, AADT, traffic speeds, and other relevant information.Geometric data included lane, shoulder, median, curve, and intersection information. Historical weather data such as monthly precipitation and temperature were collected from the National Oceanic and Atmospheric Administration database.In comparing significant explanatory variables between the roadway accident rate and roadsideaccident rate models, very few variables were common. This confirms that it is preferable to specifyseparate functional forms for roadway and roadside accident rates. Empirical results indicated thatcorrelation between roadway and roadside accident rates was insignificant, indicating that efficiency gainsfrom the SURE model would be minimal. The important finding from a programming standpoint is thatjointly modeling the roadway and roadside simultaneously would not result in significant efficiencyimprovements in comparison to the current state-of-the-practice in Washington State.

Authors:
Chayanan,S., Nebergall,M., Shankar,V., Juvva,N., Ouyang,Y.

Keywords:
roadway, roadside, accident rates, safety programming, research, Washington, Washington state, highway, transportation, WSDOT, modeling, safety, regression, linkage, data, traffic, traffic data, volume, truck, speed, median, temperature, database, models


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External Links:
http://www.wsdot.wa.gov/research/reports/fullreports/562.1.pdf http://wsdot.wa.gov/Research/Reports/500/562.1.htm
Rowland, E.R. WA-RD 545.1 Modeling Hydrology For Design Of Fish Passage Structures 50 2002 TRAC/WSU
Abstract:
An estimated 2,400 to 4,000 hydraulic structures are barriers to fish passage in Washington State. Many are culverts inadequately sized for fish Recently, the Washington Department of Fish and Wildlife established statewide guidelines to incorporate fish migration into culvert design by providing two approaches: stream simulation and hydraulic design. Stream simulation involves culverts to be wider than the natural channel under bank-full conditions. The hydraulic design option requires culverts to satisfy minimum depth and maximum hydraulic drop constraints ranging from 0.8 to 1.0 A and permissible velocities from 2.0 to 6.0 depending on species and culvert length. The permissible velocity criterion is to be met during fish passage design flow. A new model is presented for fish passage design flows at streams in Eastern Washington. The model is founded on two key concepts: a unique definition of fish passage design flow and an area based approach for estimating flow at ungaged streams. The fish design flow was developed by combining the concepts of allowable fish delay, established to be 3 days, with a consecutive day analysis. This design flow ensures that fish are not delayed for than 3 consecutive days during a water year. A fish passage design flow per area is assigned to previously delineated subwatersheds in Eastern Washington. Similarity relationships, derived basin characteristics, relate Geological Survey gaging stations to sub-watersheds in Eastern Washington. These relationships form the basis for a value of fish passage design flow per unit area to each sub-watershed in Eastern Washington. The percent standard error for this model was calculated as 36%. This is a significant improvement the 75% standard error calculated for the model that previously addressed fish passage design flows in Eastern Washington.

Authors:
Rowland, E.R., Hotchkiss, R.H., Barber, M E.

Keywords:
Analysis, barrier, barriers, Channel, condition, culvert, design, design flows, developed, Error, fish, fish passage, flow, hydrologic models, improvement, model, modeling, structural safety, structures, survey, velocity, Washington, Washington state, wildlife


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External Links:
http://www.wsdot.wa.gov/research/reports/fullreports/545.1.pdf http://wsdot.wa.gov/Research/Reports/500/545.1.htm
Holtz,R. D. WA-RD 532.1 Internal Stability Analyses of Geosynthetic Reinforced Retaining Walls 2002 TRAC/UW
Abstract:
This research project was an effort to improve our understanding of the internal stress-strain distribution in GRS retaining structures. Our numerical modelling techniques utilized a commercially available element program, FLAC (Fast Lagrangian Analysis of Continua). In this research, we investigated and appropriately considered the plane strain soil properties, the effect of low confining pressure on the soil dilation angle, and in-soil and low strain rate geosynthetic reinforcement properties.Modeling techniques that are able to predict both the internal and external performance of GRS walls simultaneously were developed. Instrumentation measurements such as wall deflection and reinforcement strain distributions of a number of selected case histories were successfully reproduced by our numerical modeling techniques. Moreover, these techniques were verified by successfully performing true "Class A" predictions of three large-scale experimental walls.An extensive parametric study that included more than 250 numerical models was then performed to investigate the influence of design factors such as soil properties, reinforcement stiffness, and reinforcement spacing on GRS wall performance. Moreover, effects of design options such as toe restraint and structural facing systems were examined. An alternative method for internal stress-strain analysis based on the stress-strain behavior of GRS as a composite material was also developed. Finally, the modeling results were used to develop a new technique for predicting GRS wall face deformations and to make recommendations for the internal stability design of GRS walls.

Authors:
Holtz,R. D., Lee,W. F.

Keywords:
analysis, behavior, design, experimental, FLAC, geosynthetic, geotechnical, materials, modeling, models, performance, prediction, pressure, program, reinforcement, research, retaining wall, retaining walls, stability, structures, systems, walls


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External Links:
http://www.wsdot.wa.gov/research/reports/fullreports/532.1.pdf http://wsdot.wa.gov/Research/Reports/500/532.1.htm
Dunston, P. S. Costs and Benefits of Constructibility Reviews 2001 Transportation Research Board, NCHRP
Abstract:
Together, NCHRP Report 390, \"Constructibility Review Process for Transportation Facilities,\" and NCHRP Report 391, \"Constructibility Review Process for Transportation Facilities--Workbook,\" provide rationale, explanation, and guidelines for a state highway agency (SHA) to implement its own constructibility review process (CRP). The American Association of State Highway Transportation Officials (AASHTO) Subcommittee on Construction has subsequently produced a more concise Constructibility Review Best Practices Guide to encourage wider CRP implementation among state highway agencies. This report follows the aforementioned in further addressing barriers to implementation and in developing procedures for measuring costs and benefits of CRP\'s. Critical elements that are emphasized for CRP implementation are (1) the institutionalization of a Constructibility Champion with responsibility to oversee CRP practice and an ongoing training program; (2) a resolution to acknowledge the shortcomings of a schedule-driven process or a quality-driven process; (3) a formal written policy on the timing, procedures, tools, and appropriate level of review; and (4) an industry-endorsed procedure for contactor involvement in the CRP. The benefit-cost model produced from this study emphasizes the impact of the CRP in reducing costs due to inefficiencies in the design process for transportation projects and constructibility oversights in the design.

Authors:
Dunston, P. S., McManus, J.F., Gambatese, J.A.

Keywords:
Constructability review, cost-benefit, modeling,


External Links:
http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=1466
Davids, W.G. WA-RD 455.1 Modeling of Rigid pavements: Joint Shear Transfer Mechanisms and Finite Element Solution Strategies 1998 TRAC/UW
Abstract:
This report documents the moldeling strategy and associated verification which permits analysis of multiple PCC plain jointed slabs. Several subbase/soil layers below the slabs and separation of the slab and base layer are considered. Load effects include those associated with both multiple tire and linear temperature gradients. A technique for modeling aggregate interlock shear transfer across PCC pavement joints is developed and verified. The overall development is contained in the computer program EverFE. The computer program uses a graphical user interface which aids its use.

Authors:
Davids, W.G., Turkiyyah, G.M., Mahoney, J.P.

Keywords:
Aggregate, aggregate interlock, analysis, base, computer, computer program, developed, development, EverFE, finite element, Finite elements, ITS, Joints, joints load transfer, modeling, pavement, pavements, PCC, permits, program, rigid pavement, temperature, tire


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O'Donovan,T. WA-RD 305.3 Lateral-Load Response Of Two Reinforced Concrete Piers 1994 TRAC/UW
Abstract:
This study was part of a Washington State Department of Transportation (WSDOT) program to assess the vulnerability of multiple-span highway bridges built before 1984. During the first series of static tests (Phase I), discussed in a previous report, a three-span, reinforced concrete bridge was subjected to large lateral loads. In Phase II, described in this report, the researchers greatly reduced the resistance that the abutments provided so that they could evaluate the lateral-load resistance of the piers. The researchers then subjected the piers to large, transverse cyclic displacements with drift ratios of 0.5, 1.0, 2.0, and 3.0 percent.The piers resisted repeated loadings to a force equal to one third of the bridge's weight. The envelope to the pier's hysteretic response indicated that the system yielded at a drift ratio of 0.7 percent. Whereas the top of the columns spalled at large drift ratios, the damage to the bottom of the columns was limited to flexural cracks. The pier's measured response was compared to that calculated by the researchers, the California Department of Transportation, and the WSDOT. The calculated responses were found to be strongly sensitive to the assumed steel and soil properties. On the basis of the experience gained in performing the tests, the researchers made recommendations for those planning to perform future tests of large structures. In -addition, while acknowledging the limitations of a single series of static tests, the researchers concluded that (1) the tests should serve as a benchmark against which to evaluate proposed analytical models, (2) at an effective acceleration of 0.2g, the seismic damage to the isolated bridge would probably be minor, (3) at an effective acceleration of 0.4g, the piers would likely sustain heavy damage, and (4) the WSDOT should investigate the influence of soil properties on column damage to determine when geotechnical tests are warranted.

Authors:
O'Donovan,T., Eberhard,M. O., MacLardy,J. A., Marsh,M. L.

Keywords:
bridge, earthquake, piers, reinforced concrete, tests, modeling, lateral loads


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Muhunthan,B. WA-RD 350.1 Finite Element Study of the Rehabilitation of Faulted Portland Cement Concrete Pavements 1994 TRAC/WSU
Abstract:
The objective of the study was to determine the effectiveness of dowel bar retrofitting of faulted Z7 PCC pavements by (1) modeling FWD Test data for computer model development and verification, (2) evaluating long term effects by simulating material degradation of the rigid pavement system, and (3) determining and classifying deficiencies and trends of the parametric study.The results of the finite element analysis shows that remediation in the form of dowel bar retrofitting greatly reduces fault development. Use of a dowel bar significantly raised the stress concentration of the concrete at the dowel bar-concrete interface. However, these stresses are well below the levels that cause failure. Simulated degradation of the base course increased stresses in the dowel bar and concrete area. Pressure differentials in base course were reduced with use of a dowel bar. Recommendations for future analysis are also made.

Authors:
Muhunthan,B., Jennings,A.

Keywords:
pavement, faulting, modeling, dowel bar, retrofit


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Cofer, W.F. WA-RD 328.1 Analytical Modeling of Foundations for Seismic Analysis of Bridges 1994 TRAC/WSU
Abstract:
The response of bridges when subjected to seismic excitation may be significantly influenced by the dynamic properties of their foundations. With current design practice, foundation elements are typically considered as elastic springs without consideration of material and radiation damping. The objectives of this research were to identify general foundation models that are suitable for modeling soil-structure interaction in seismic bridge analysis, to modify an existing nonlinear seismic bridge analysis computer program to include a new element capable of representing such models, and to conduct a parametric study to assess the effect of the nacres energy dissipation mechanisms on the response of bridge substructures. For spread footing foundations, three different models were identified and applied to a typical two-column bridge bent. The seismic response for each model was compared with conventional elastic and fixed-base models. Several soil stiffness values and earthquake records were considered for analysis. Maximum values of displacement, plastic hinge rotation, and cumulative plastic hinge rotations were noted and compared. It was concluded that the use of the foundation models can produce an important change in the bridge response when compared to that of the fixed-based models, depending on the frequency and content of the earthquake and the stiffness of the soil. The effects of radiation damping were observed to be insignificant for foundations on stiff soil, but important for those on soft soil. In addition, the performance of the simpler damped foundation models was found to be quite similar to that of more complex models.

Authors:
Cofer, W.F., McLean, D.I., McGuire, J.W.

Keywords:
Structures, seismic, bridge, earthquake, soil-structure interaction, foundation, analysis, modeling


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Cofer,W. F. WA-RD 328.2/NTIS No. PB940181799 Analytical Modeling of Foundations for Seismic Analysis of Bridges 1994 TRAC/WSU
Abstract:
The response of bridges when subjected to seismic excitation may be significantly influenced by the dynamic properties of their foundations. With current design practice, foundation elements are typically considered as elastic springs without consideration of material and radiation damping. The objectives of this research were to identify general foundation models that are suitable for modeling soil-structure interaction in seismic bridge analysis, to modify an existing nonlinear seismic bridge analysis computer program to include a new element capable of representing such models, and to conduct a parametric study to assess the effect of the increased energy dissipation mechanisms on the response of bridge substructures. For spread footing foundations, three different models were identified and applied to a typical two-column bridge bent. The seismic response for each model was compared with conventional elastic and fixed-base models. Several soil stiffness values and earthquake records were considered for analysis. Maximum values of displacement, plastic hinge rotation, and cumulative plastic hinge rotations were noted and compared. It was concluded that the use of the foundation models can produce an important change in the bridge response when compared to that of the fixed -based models, depending on the frequency and content of the earthquake and the stiffness of the soil. The effects of radiation damping were observed to be insignificant for foundations on stiff soil, but important for those on soft soil. In addition, the performance of the simpler damped foundation models was found to be quite similar to that of more complex models.

Authors:
Cofer,W. F., McLean,D. I., McGuire,J. W.

Keywords:
bridge, earthquake, soil-structure interaction, foundation, analysis, modeling


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Eberhard, M.O. WA-RD 305.1 Lateral-Load Response of a Reinforced Concrete Bridge: Final Report 1993 TRAC/UW
Abstract:
This study was part of a WSDOT program to assess the vulnerability of highway bridges built before 1984. Researchers applied slowly varying transverse loads to a three-span, reinforced concrete bridge, including the superstructure, piers, and abutments. The purpose of the tests was to measure the transverse stiffness of the bridge and to estimate each support\'s contributions to stiffness. The researchers also evaluated analytical models by comparing the calculated and observed responses. The researchers concluded that (1) the tests can serve as a valuable benchmark against which to evaluate proposed seismic-evaluation procedures and models, (2) bridges that are similar to the test bridge are not highly vulnerable to transverse motions, (3) complex soil modeling is not justified if soil test data are not available, and (4) nonlinear analysis was necessary to reproduce the details of the observed response.

Authors:
Eberhard, M.O., MacLardy, J.A., Marsh, M.L., Hjartarson, G.

Keywords:
Bridge , earthquakes, reinforced concrete, tests, modeling, lateral loads


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Eberhard,M. O. WA-RD 305.2 Lateral-Load Response of a Reinforced Concrete Bridge 1993 TRAC/UW
Abstract:
This study was part of a Washington State Department of Transportation (WSDOT) program to assess the vulnerability of highway bridges built before 1984. Researchers applied slowly-varying transverse loads to a three-span, reinforced concrete bridge, including the superstructure, piers, and abutments. The purpose of the test was to measure the transverse stiffness of the bridge and to estimate each support's contribution to stiffness. The researchers also evaluated analytical models by comparing the calculated and observed responses. The bridge was extremely stiff and strong. In two cycles to a load equal to 45 percent of the bridge's weight, the maximum bridge displacement was 0.15 inch. During these cycles damage was minimal. At a load equal to 65 percent of the bridge's weight, the pier displacement was 0.30 inch. After the bridge had been excavated, the stiffness decreased to 15 percent of its original stiffness. The stiffness further decreased to 8 percent of the initial stiffness after the superstructure had been isolated from the abutments. The University of Washington (UW), California Department of Transportation (CALTRANS) and WSDOT models underestimated the stiffness of the bridge in its initial state. The UW model probably overestimated the resistance of the polystyrene at the abutments and underestimated the stiffness of the soil at the wingwalls. The CALTRANS model was too flexible because it neglected the resistance of the bearing pads and polysterene, and underestimated the soil stiffness. The researchers concluded that (1) the test can serve as a valuable benchmark against which to evaluate proposed seismic-evaluation procedures and models, (2) bridges that are similar to the test bridge are not highly vulnerable to transverse motions, (3) complex soil modeling is not justified if soil test data are not available, and (4) nonlinear analysis was necessary to reproduce the details of the observed response.

Authors:
Eberhard,M. O., MacLardy,J. A., Marsh,M. L., Hjartarson,G.

Keywords:
bridge and construction, bridge, earthquake, reinforced concrete, tests, modeling, lateral loads


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Hayes, P. S. WA-RD 231.1 Prediction of Precipitation in Western Washington State 1991 WSDOT
Abstract:
This research adapted an orthographic precipitation model developed during previous WSDOT project (Report No. WA-RD 91.1) to run efficiently on an operational basis on a 386 personal computer, and made numerous model improvements. The precipitation model is being used operationally at the Northwest Avalanche Center in Seattle. Although the model is a two-dimensional and employs simple precipitation parameterizations, it reproduced observed precipitation for two case studies remarkably well. The model should provide forecasters with useful guidance, especially during flow patterns that exhibit relatively two-dimensional characteristics.

Authors:
Hayes, P. S.

Keywords:
Precipitation, modeling


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Hallenbeck, M.E. Freeway Management Working Paper: Current Development of Traffic Models 1988 TRAC/UW
Abstract:
This paper provides an overview of traffic models that are available for use by WSDOT. It is intended to provide a general review of modeling capabilities that exist today, and present a future vision of what these capabilities will be in the near future. The information collected for this paper was used to select models to be tested for improving the departments ability to manage traffic during construction projects as well as during normal operation. Material presented in this document is based primarily on an extensive literature search, supplemented by the review of the documentation for a limited number of models, and the experience of project staff. Many of the models reviewed are still undergoing modification and refinement and many of these changes are not addressed in the literature. Thus, the reader should be aware that some models discussed within have capabilities not mentioned.

Authors:
Hallenbeck, M.E., Lin, C.

Keywords:
Traffic, management, modeling, construction,

Khisty, C.J. WA-RD 125.1 Inexpensive Travel Demand Techniques 1987 TRAC/WSU
Abstract:
Conventional urban travel demand models, which are data-hungry, costly and mainly meant for large cities and metropolitan areas are not suitable for small urban areas with a population of 50,000 or less. These small urban areas generally lack the staff, expertise and budget to operate the conventional models. This report examines the applicability of simplified travel demand models suitable for small urban areas. The scope of this research is limited to simplified travel demand forecasting techniques that make use of routinely collected traffic ground counts. A total of thirteen methods are examined, of which four are discussed in detail, by applying them in a common setting. Their input requirements and usability are examined. Contacts with selected MPOs, COGs, Planning Commissions in the State of Washington reveal that such methods will be useful in small urban areas considering the staff, expertise, and budget limitation available. Currently, these small urban areas use unproven heuristic methods. The use of methods described in this report will considerably help small urban areas to forecast travel demands using traffic ground counts and socioeconomic data.

Authors:
Khisty, C.J., Rahi, M.Y.

Keywords:
Travel demand, modeling


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Rossano, A.T. WA-RD 012.1 A Critical Review Of Mathematical Diffusion Modeling Techniques For Predicting Air Quality With Relation To Motor Vehicl... 1973 UW
Abstract:
Federal and State laws require highway departments to prepare statements assessing the impact that proposed highway improvements or construction may have on the environment. An important consideration in the preparation of an impact statement is the anticipated effect the proposed activity will have on air quality since highway transportation is a source of several major air pollutants: particulate matter, nitrogen oxides, carbon monoxide, hydrocarbons, and photochemical oxidants which are formed in the atmosphere in the presence of sunlight. Comprehensive physical studies to predict the air quality impact at proposed sites are generally prohibitive due to the time required to obtain suitable data, the cost of such studies and the number of impact statements that must be considered by most highway departments.Methods have been developed to predict the air quality impact of new highway construction through the use of mathematical atmospheric diffusion models. Once they are properly calibrated these models can be used to test alternative locations and designs. Basically models use meteorological conditions and emission rates to predict downwind concentrations as illustrated in Figure 1.The principal objective of this research project has been to conduct a search of the literature to identify state-of-the-art air quality predictive schemes applicable to motor vehicle transportation. The available models have been analyzed in detail and evaluated in terms of selected characteristics that serve to describe the predictive capabilities of each. Limitations in the models have also been noted where appropriate.Section 2.0 o f this report describes the methods used in conducting the research. Sections 3.0 and 4.0 present the models analyzed and a general discussion of applicability, in both narrative and tabular form. Section 5.0 summarizes the study and presents the recommendations for future consideration.

Authors:
Rossano, A.T., Lamb, D.V., Badgley, F.

Keywords:
Air quality, Alternative, carbon monoxide, Concentrations, condition, construction, cost, data, design, environment, highway, highway construction, Highways, hydrocarbons, impact, model, modeling, models, nitrogen, particulate matter, Pollutants, quality, research, state-of-the-art, transportation, Washington, Washington state


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Rossano, A.T. WA-RD 012.3 Acoustic Radar and Its Applicability to Highway Air Pollution Studies 1977 UW
Abstract:
At the request of the Washington Department of Highways two studies have been conducted by a team of specialists at the University of Washington Air Resources Program to determine the applicability of the Acoustic Radar to air quality modeling to mobile sources.At the request of the Washington Department of Highways two studies have been conducted by a team of specialists at the University of Washington Air Resources Program to determine the applicability of the Acoustic Radar to air quality modeling of mobile sources. Following an exploratory investigation, a comprehensive study was undertaken in which the atmospheric structure was measured by a modified Monostatic Acoustic Radar and the derived stability conditions were compared with the commonly used Pasquill-Turner stability classes, which are based on empirical data. This comprehensive study was performed over a three month period in the fall of 1976, when an unusually persistent air stagnation existed in the study area caused by a stationary high pressure system over the entire Northwest.The Evergreen Point Floating Bridge Toll Plaza in Bellevue, Washington was selected for test location.The carbon monoxide (CO) concentrations were measured at six strategically located sampling points and then compared with the computer model predictions utilizing atmospheric stability data derived by both the Pasquill-Turner and the Radar echo methods. The results indicated that the Acoustic Radar method of determining D & E stability classes is a more realistic approach than that of the Pasquill-Turner Method. Furthermore, the Radar method can also provide continuous remote sensing and recordings of atmospheric parameters. The variation of the inversion height, as measured by the Radar echoes has shown a reasonably good correlation with the variation of the measured CO concentration.

Authors:
Rossano, A.T., Badgley, F.I., Juhasz, P.C., Bang, G., Carsey, F.

Keywords:
Acoustic Radar, air pollution, air quality, Air Quality Modeling, bridge, carbon monoxide, Carbon Monoxide Perdictions, computer, Concentrations, condition, data, floating bridge, highway, Highways, ITS, model, modeling, prediction, pressure, program, quality, remote sensing, Remote Sensing Atmospheric Structur, sampling, stability, Transportation Pollutio, Washington


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