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Civil and Environmental Engineering Commons™
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- Hydrologic models (30)
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- Streamflow -- Forecasting (10)
- Soil liquefaction (9)
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- Hydrology -- Data processing (5)
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- Marine ecology (5)
- Oceanography -- Columbia River Estuary (Or. and Wash.) -- Mathematical models (5)
- Publication Year
Articles 331 - 360 of 424
Full-Text Articles in Civil and Environmental Engineering
Particle Resuspension In The Columbia River Plume Near Field, Emily Y. Spahn, Alexander R. Horner-Devine, Jonathan Nash, David A. Jay, Levi Kilcher
Particle Resuspension In The Columbia River Plume Near Field, Emily Y. Spahn, Alexander R. Horner-Devine, Jonathan Nash, David A. Jay, Levi Kilcher
Civil and Environmental Engineering Faculty Publications and Presentations
Measurements of suspended sediment concentration, velocity, salinity, and turbulent microscale shear in the near-field region of the Columbia River plume are used to investigate the mechanisms of sediment resuspension and entrainment into the plume. An east-west transect was occupied during spring and neap tide periods in August 2005 and May 2006, corresponding to low and high river discharge conditions, respectively. During the high-discharge period the plume is decoupled from the bottom, and fine sediment resuspended from the bottom does not leave the benthic boundary layer. The primary modes of sediment transport associated with the plume are advection of sediment from …
Seismic Vulnerability Of Oregon State Highway Bridges: Mitigation Strategies To Reduce Major Mobility Risks, Albert Nako, Craig Shike, Jan Six, Bruce Johnson, Peter Dusicka, Selamawit Tesfayesus Mehary
Seismic Vulnerability Of Oregon State Highway Bridges: Mitigation Strategies To Reduce Major Mobility Risks, Albert Nako, Craig Shike, Jan Six, Bruce Johnson, Peter Dusicka, Selamawit Tesfayesus Mehary
Civil and Environmental Engineering Faculty Publications and Presentations
The Oregon Department of Transportation and Portland State University evaluated the seismic vulnerability of state highway bridges in western Oregon. The study used a computer program called REDARS2 that simulated the damage to bridges within a transportation network. It predicted ground motions for a specific location and magnitude of earthquake, resulting bridge damage and the cost of the damage, as well as the cost to the public for traffic delays due to detours around damaged bridges. Estimated damage and delay costs were presented for major highways in the region.
An Overview Of The Odot Safety Investigations Manual, Christopher M. Monsere, Karen Dixon
An Overview Of The Odot Safety Investigations Manual, Christopher M. Monsere, Karen Dixon
Civil and Environmental Engineering Faculty Publications and Presentations
This presentation provides an overview of the ODOT Safety Investigations Manual. The objective of this manual is to function as a resource that will assist ODOT traffic investigators with highway safety project screening and evaluations.
A New Look At Richardson Number Mixing Schemes For Equatorial Ocean Modeling, Edward D. Zaron, James N. Moum
A New Look At Richardson Number Mixing Schemes For Equatorial Ocean Modeling, Edward D. Zaron, James N. Moum
Civil and Environmental Engineering Faculty Publications and Presentations
A reexamination of turbulence dissipation measurements from the equatorial Pacific shows that the turbulence diffusivities are not a simple function of the gradient Richardson number. A widely used mixing scheme, the K-profile parameterization, overpredicts the turbulent vertical heat flux by roughly a factor of 4 in the stably stratified region between the surface mixed layer and the Equatorial Undercurrent (EUC). Additionally, the heat flux divergence is of the incorrect sign in the upper 80 m. An alternative class of parameterizations is examined that expresses the mixing coefficients in terms of the large-scale kinetic energy, shear, and Richardson number. These representations …
Determining Azimuthal Variations In Frontal Froude Number From Sar Imagery, Jiayi Pan, David A. Jay, Hui Lin
Determining Azimuthal Variations In Frontal Froude Number From Sar Imagery, Jiayi Pan, David A. Jay, Hui Lin
Civil and Environmental Engineering Faculty Publications and Presentations
River plume fronts are the locus of strong mixing between plume and ambient coastal waters, contribute to coastal productivity, and exert a major impact on coastal ecosystems. The frontal Froude number Fr is an important parameter characterizing the frontal status with respect to both propagation and vertical mixing. In this study, we examine azimuthal variations in Fr using a new remote sensing method. We derive Fr from SAR image data on the basis of the SAR imaging theory and the mechanism of internal wave fission at front. This method is applied to a SAR image showing a front off the …
Vertical Boil Propagation From A Submerged Estuarine Sill, C. Chris Chickadel, Alexander R. Horner-Devine, Stefan A. Talke, Andrew T. Jessup
Vertical Boil Propagation From A Submerged Estuarine Sill, C. Chris Chickadel, Alexander R. Horner-Devine, Stefan A. Talke, Andrew T. Jessup
Civil and Environmental Engineering Faculty Publications and Presentations
Surface disruptions by boils during strong tidal flows over a rocky sill were observed in thermal infrared imagery collected at the Snohomish River estuary in Washington State. Locations of boil disruptions and boil diameters at the surface were quantified and are used to test an idealized model of vertical boil propagation. The model is developed as a two-dimensional approximation of a three-dimensional vortex loop, and boil vorticity is derived from the flow shear over the sill. Predictions of boil disruption locations were determined from the modeled vertical velocity, the sill depth, and the over-sill velocity. Predictions by the vertical velocity …
Practical Approximations To Quantify The Impact Of Time Windows And Delivery Sizes On Vmt Multi-Stop Tours, Miguel A. Figliozzi
Practical Approximations To Quantify The Impact Of Time Windows And Delivery Sizes On Vmt Multi-Stop Tours, Miguel A. Figliozzi
Civil and Environmental Engineering Faculty Publications and Presentations
This paper studies approximations to the average length of Vehicle Routing Problems (VRP). The approximations are valuable for strategic and planning analysis of transportation and logistics problems. The research focus is on VRP with varying number of customers, demands, and locations. This modeling environment can be used in transport and logistics models that deal with a distribution center serving an area with daily variations in the demand. The routes are calculated daily based on what freight is available. New approximations and experimental settings are introduced. Average distance travelled is estimated as a function of the number of customers served and …
Evolution Of Tidal Amplitudes In The Eastern Pacific Ocean, David A. Jay
Evolution Of Tidal Amplitudes In The Eastern Pacific Ocean, David A. Jay
Civil and Environmental Engineering Faculty Publications and Presentations
Global sea level (GSL) rise is well documented. However, changes in high waters, including the tidal contribution, are sometimes more relevant than GSL rise. Analysis of 34 long tidal records from the Eastern Pacific Ocean shows that K1 and M2 amplitudes (∣K₁∣ and ∣M₂∣) are increasing, except for ∣M2∣ in the Gulf of Panama. North of 18°N, ∣K1∣ and ∣M2∣ are both growing at 2.2% century⁻¹. The mean increase in total tidal amplitude (0.59 mmyr⁻¹) is less than the present GSL rise (1.7 mmyr⁻¹). However, mean sea level is nearly constant in the NE Pacific, so tidal evolution plays a …
A Sequential Bayesian Approach For Hydrologic Model Selection And Prediction, Kuo-Lin Hsu, Hamid Moradkhani, Soroosh Sorooshian
A Sequential Bayesian Approach For Hydrologic Model Selection And Prediction, Kuo-Lin Hsu, Hamid Moradkhani, Soroosh Sorooshian
Civil and Environmental Engineering Faculty Publications and Presentations
When a single model is used for hydrologic prediction, it must be capable of estimating system behavior accurately at all times. Multiple-model approaches integrate several model behaviors and, when effective, they can provide better estimates than that of any single model alone. This paper discusses a sequential model fusion strategy that uses the Bayes rule. This approach calculates each model's transient posterior distribution at each time when a new observation is available and merges all model estimates on the basis of each model's posterior probability. This paper demonstrates the feasibility of this approach through case studies that fuse three hydrologic …
Feedback Between Residual Circulations And Sediment Distribution In Highly Turbid Estuaries: An Analytical Model, Stefan A. Talke, Huib E. De Swart, H. M. Schuttelaars
Feedback Between Residual Circulations And Sediment Distribution In Highly Turbid Estuaries: An Analytical Model, Stefan A. Talke, Huib E. De Swart, H. M. Schuttelaars
Civil and Environmental Engineering Faculty Publications and Presentations
Motivated by field studies of the Ems estuary which show longitudinal gradients in bottom sediment concentration as high as O(0.01 kg/m4), we develop an analytical model for estuarine residual circulation based on currents from salinity gradients, turbidity gradients, and freshwater discharge. Salinity is assumed to be vertically well mixed, while the vertical concentration profile is assumed to result from a balance between a constant settling velocity and turbulent diffusive flux. Width and depth of the model estuary are held constant. Model results show that turbidity gradients enhance tidally averaged circulation upstream of the estuarine turbidity maximum (ETM), …
An Idealized Model And Systematic Process Study Of Oxygen Depletion In Highly Turbid Estuaries, Stefan A. Talke, Huib E. De Swart, Victor De Jonge
An Idealized Model And Systematic Process Study Of Oxygen Depletion In Highly Turbid Estuaries, Stefan A. Talke, Huib E. De Swart, Victor De Jonge
Civil and Environmental Engineering Faculty Publications and Presentations
The sensitivity of oxygen depletion in turbid estuaries to parameters like freshwater discharge, depth, and sediment availability is investigated using an idealized model. The model describes tidally averaged circulation and suspended sediment concentration (SSC), which are input into an advection–diffusion sink module of dissolved oxygen (DO). Based on the analysis of field data collected in the Ems estuary, the modeled oxygen depletion rates are proportional to SSC. The model is calibrated to the observed variation of DO with SSC and temperature. Modeled DO closely tracks changes to the estuarine turbidity zone (ETZ): increased channel depth, decreased freshwater discharge, and decreased …
The Potential Contribution Of Organic Salts To New Particle Growth, Kelley Barsanti, Peter H. Mcmurry, J. N. Smith
The Potential Contribution Of Organic Salts To New Particle Growth, Kelley Barsanti, Peter H. Mcmurry, J. N. Smith
Civil and Environmental Engineering Faculty Publications and Presentations
Field and lab measurements suggest that low-molecular weight (MW) organic acids and bases exist in accumulation and nucleation mode particles, despite their relatively high pure-liquid vapor pressures. The mechanism(s) by which such compounds contribute to the mass growth of existing aerosol particles and newly formed particles has not been thoroughly explored. One mechanism by which low- MW compounds may contribute to new particle growth is through the formation of organic salts. In this paper we use thermodynamic modeling to explore the potential for organic salt formation by atmospherically relevant organic acids and bases for two system types: one in which …
Using Archived Its Data To Measure The Operational Benefits Of A System-Wide Adaptive Ramp Metering System, Robert L. Bertini, Christopher Monsere, Oren Eshel, Soyoung Ahn
Using Archived Its Data To Measure The Operational Benefits Of A System-Wide Adaptive Ramp Metering System, Robert L. Bertini, Christopher Monsere, Oren Eshel, Soyoung Ahn
Civil and Environmental Engineering Faculty Publications and Presentations
A System-Wide Adaptive Ramp Metering (SWARM) system has been implemented in the Portland, Oregon metropolitan area, replacing the previous pre-timed ramp-metering system that had been in operation since 1981. SWARM has been deployed on six major corridors and operates during the morning and afternoon peak hours. This report presents results of a "before" and "after" evaluation of the performance of two freeway corridors as part of ongoing efforts to measure the benefits of the new SWARM system, as compared to the pre-timed system. The study benefited from using the existing regional data, surveillance and communications infrastructure in addition to a …
A Method For Processing Acoustic Doppler Current Profiler Velocity Data From Towed, Undulating Vehicles, David A. Jay, Jiayi Pan
A Method For Processing Acoustic Doppler Current Profiler Velocity Data From Towed, Undulating Vehicles, David A. Jay, Jiayi Pan
Civil and Environmental Engineering Faculty Publications and Presentations
The utility of the acoustic Doppler current profiler (ADCP) for sampling small time and space scales of coastal environments can be enhanced by mounting a high-frequency (1200 kHz) ADCP on an oscillating towed body. This approach requires both an external reference to convert the measured shears to velocities in the earth coordinates and a method to determine the towed body velocities. During the River Influence on the Shelf Ecosystems (RISE) project cruise, a high-frequency (1200 kHz) and narrowbeam ADCP with mode 12 sampling was mounted on a TRIAXUS oscillating towfish, which steers a 3D path behind the ship. This deployment …
The Inverse Ocean Modeling System. Part Ii: Applications, J. C. Muccino, H. G. Arango, Andrew F. Bennett, B. S. Chua, Julia Muccino Cornuelle, E. Di Lorenzo, Gary D. Egbert, D. Haidvogel, J. C. Levin, H. Luo, A. J. Miller, A. M. Moore, Edward D. Zaron
The Inverse Ocean Modeling System. Part Ii: Applications, J. C. Muccino, H. G. Arango, Andrew F. Bennett, B. S. Chua, Julia Muccino Cornuelle, E. Di Lorenzo, Gary D. Egbert, D. Haidvogel, J. C. Levin, H. Luo, A. J. Miller, A. M. Moore, Edward D. Zaron
Civil and Environmental Engineering Faculty Publications and Presentations
The Inverse Ocean Modeling (IOM) System is a modular system for constructing and running weak-constraint four-dimensional variational data assimilation (W4DVAR) for any linear or nonlinear functionally smooth dynamical model and observing array. The IOM has been applied to four ocean models with widely varying characteristics. The Primitive Equations Z-coordinate-Harmonic Analysis of Tides (PEZ-HAT) and the Regional Ocean Modeling System (ROMS) are three-dimensional, primitive equations models while the Advanced Circulation model in 2D (ADCIRC-2D) and Spectral Element Ocean Model in 2D (SEOM-2D) are shallow-water models belonging to the general finite-element family. These models, in conjunction with the IOM, have been used …
Effects Of Ambient Velocity Shear On Nonlinear Internal Wave Associated Mixing At The Columbia River Plume Front, Jiayi Pan, David A. Jay
Effects Of Ambient Velocity Shear On Nonlinear Internal Wave Associated Mixing At The Columbia River Plume Front, Jiayi Pan, David A. Jay
Civil and Environmental Engineering Faculty Publications and Presentations
Large-amplitude nonlinear internal waves (NLIWs) are frequently observed propagating away from Columbia River tidal plume fronts. They are generated because of the deceleration of the frontal bulge. During the River Influences on Shelf Ecosystems project cruises, the velocity, density structure and acoustic backscatter of the plume fronts and frontal NLIWs were observed using a towed vehicle, vessel-mounted instrumentation, and a vessel X band radar. These observations indicate that in the presence of strong ambient velocity shear, the NLIWs with maximum amplitudes occur well below the density interface and at a depth deeper than in the absence of shear. This deepening …
2007 Portland Metropolitan Region Transportation System Performance Report, Robert Bertini
2007 Portland Metropolitan Region Transportation System Performance Report, Robert Bertini
Civil and Environmental Engineering Faculty Publications and Presentations
Our transportation system is a key ingredient in the economy, quality of life and urban fabric of the Portland metropolitan area. It has been stated in the past that it is not possible to manage our transportation system tomorrow unless we understand how it is performing today. In this spirit, the Portland State University Center for Transportation Studies has been working with regional and statewide partners to develop new capabilities to measure, monitor and track the performance of the transportation system in real time and using archived data sources. We believe that it is possible to leverage these disparate data …
Hydrologic Remote Sensing And Land Surface Data Assimilation, Hamid Moradkhani
Hydrologic Remote Sensing And Land Surface Data Assimilation, Hamid Moradkhani
Civil and Environmental Engineering Faculty Publications and Presentations
Accurate, reliable and skillful forecasting of key environmental variables such as soil moisture and snow are of paramount importance due to their strong influence on many water resources applications including flood control, agricultural production and effective water resources management which collectively control the behavior of the climate system. Soil moisture is a key state variable in land surface?atmosphere interactions affecting surface energy fluxes, runoff and the radiation balance. Snow processes also have a large influence on land-atmosphere energy exchanges due to snow high albedo, low thermal conductivity and considerable spatial and temporal variability resulting in the dramatic change on surface …
An Iterative Route Construction And Improvement Algorithm For The Vehicle Routing Problem With Soft And Hard Time Windows, Miguel A. Figliozzi
An Iterative Route Construction And Improvement Algorithm For The Vehicle Routing Problem With Soft And Hard Time Windows, Miguel A. Figliozzi
Civil and Environmental Engineering Faculty Publications and Presentations
The joint solution of routing problems with soft and hard time windows has valuable practical applications. Simultaneous solution approaches to both types of problems are needed when: (a) the number of routes needed for hard time windows exceeds the number of available vehicles, (b) a study of cost-service tradeoffs is required or the dispatcher has qualitative information regarding the relative importance of hard time window constraints across customers. A new Iterative Route Construction and Improvement (IRCI) algorithm of average run time performance O(n2 ) is proposed to sequentially solve Vehicle Routing Problems with Soft Time Windows (VRPSTW) and Hard Time …
A Strategy For Reducing The Impact Of Driving Under Influence Of Intoxicants In Portland, Oregon, Christopher Monsere, Delia Chi
A Strategy For Reducing The Impact Of Driving Under Influence Of Intoxicants In Portland, Oregon, Christopher Monsere, Delia Chi
Civil and Environmental Engineering Faculty Publications and Presentations
Driving under the influence of intoxicants (DUII) applies to operating a vehicle under the influence of any substance that can impair driving performance. Nationally and locally there is a strong desire to reduce the societal impacts of this significant social problem. The trend in U.S. alcohol-related motor vehicle crashes was generally decreasing in the mid to late 1980’s but has remained fairly flat since the early 1990s. In 1982, approximately 60% of all US traffic fatalities were alcohol-related. By 1994, this had decreased to 43% but in the decade that followed it has changed little. In 2005, nearly 39% of …
New Insights Into The Controls And Mechanisms Of Plankton Productivity Along The Us West Coast, Raphael M. Kudela, Neil S. Banas, John A. Barth, Elizabeth R. Frame, David A. Jay, John L. Largier, Evelyn J. Lessard, Tawnya D. Peterson, Andrea J. Vander Woude
New Insights Into The Controls And Mechanisms Of Plankton Productivity Along The Us West Coast, Raphael M. Kudela, Neil S. Banas, John A. Barth, Elizabeth R. Frame, David A. Jay, John L. Largier, Evelyn J. Lessard, Tawnya D. Peterson, Andrea J. Vander Woude
Civil and Environmental Engineering Faculty Publications and Presentations
During the lifetime of the National Science Foundation's Coastal Ocean Processes program, four experiments were conducted on the US West Coast in the northern California Current System. Although each project had a unique scientific focus, all four addressed the mechanisms causing eastern boundary current systems in general, and the California Current System in particular, to be biologically rich, from phytoplankton to apex predators. Taken together, findings from these projects provide new insights into the canonical view that upwelling systems are simple wind-driven "conveyor belts," bringing cold, nutrient-rich waters to the well-lit surface ocean where biological organisms flourish. We highlight new …
Daily Forecasts Of Columbia River Plume Circulation: A Tale Of Spring/Summer Cruises, Yinglong J. Zhang, Antonio M. Baptista, Barbara M. Hickey, Byron C. Crump, David A. Jay, Michael Wilkin, Charles Seaton
Daily Forecasts Of Columbia River Plume Circulation: A Tale Of Spring/Summer Cruises, Yinglong J. Zhang, Antonio M. Baptista, Barbara M. Hickey, Byron C. Crump, David A. Jay, Michael Wilkin, Charles Seaton
Civil and Environmental Engineering Faculty Publications and Presentations
Semi-operational daily forecasts of circulation from an observatory for the Columbia River estuary-plume-shelf system routinely support oceanographic cruises, by providing 24h-ahead estimates of plume location and structure for planning purposes and for near real-time interpretation of observations. This paper analyzes forecast skill during spring/summer cruises in 2004-2007. Assessment addresses both qualitative descriptions of major plume trends and features and quantitative representation of data from (primarily) vessel-based flow-through, cast and towed systems. Forecasts emerge as robust predictors of plume location and variability, with skill that has grown over time, at least in part due to improvements in model algorithms. When the …
Seasonal Variability And Estuary-Shelf Interactions In Circulation Dynamics Of A River-Dominated Estuary, Arun Chawla, David A. Jay, Antonio M. Baptista, Michael Wilkin, Charles Seaton
Seasonal Variability And Estuary-Shelf Interactions In Circulation Dynamics Of A River-Dominated Estuary, Arun Chawla, David A. Jay, Antonio M. Baptista, Michael Wilkin, Charles Seaton
Civil and Environmental Engineering Faculty Publications and Presentations
The long-term response of circulation processes to external forcing has been quantified for the Columbia River estuary using in situ data from an existing coastal observatory. Circulation patterns were determined from four Acoustic Doppler Profilers (ADP) and several conductivity-temperature sensors placed in the two main channels. Because of the very strong river discharge, baroclinic processes play a crucial role in the circulation dynamics, and the interaction of the tidal and subtidal baroclinic pressure gradients plays a major role in structuring the velocity field. The input of river flow and the resulting low-frequency flow dynamics in the two channels are quite …
Combining Climate, Crash, And Highway Data For Improved Ranking Of Speed And Winter-Weather Related Crash Locations In Oregon, Christopher M. Monsere, Peter G. Bosa, Robert L. Bertini
Combining Climate, Crash, And Highway Data For Improved Ranking Of Speed And Winter-Weather Related Crash Locations In Oregon, Christopher M. Monsere, Peter G. Bosa, Robert L. Bertini
Civil and Environmental Engineering Faculty Publications and Presentations
In recent years, the techniques for screening transportation networks to identify high crash locations have become more sophisticated. Many transportation agencies, however, lack sufficient data, either in timeliness, completeness, or accuracy to implement many of the recent advances. This paper presents the results of an empirical analysis of screening and ranking for specific crash type (speed and ice related crashes) on rural 1.6 km (1 mi) highway sections of Oregon highways. The analysis includes data generated with the extensive use of spatial techniques and incorporates climate data to enhance environmental considerations. The paper compares the results of five ranking methods—critical …
Suspended Sediment Fluxes At An Intertidal Flat: The Shifting Influence Of Wave, Wind, Tidal, And Freshwater Forcing, Stefan A. Talke, Mark T. Stacey
Suspended Sediment Fluxes At An Intertidal Flat: The Shifting Influence Of Wave, Wind, Tidal, And Freshwater Forcing, Stefan A. Talke, Mark T. Stacey
Civil and Environmental Engineering Faculty Publications and Presentations
Using in situ, continuous, high frequency (8–16 Hz) measurements of velocity, suspended sediment concentration (SSC), and salinity, we investigate the factors affecting near-bed sediment flux during and after a meteorological event (cold front) on an intertidal flat in central San Francisco Bay. Hydrodynamic forcing occurs over many frequency bands including wind wave, ocean swell, seiching (500–1000 s), tidal, and infra-tidal frequencies, and varies greatly over the time scale of hours and days. Sediment fluxes occur primarily due to variations in flow and SSC at three different scales: residual (tidally averaged), tidal, and seiching. During the meteorological event, sediment fluxes are …
New Particle Formation In The Front Range Of The Colorado Rocky Mountains, Micahel Boy, Thomas Karl, Andrew Turnipseed, Roy Lee Mauldin, Edward Kosciuch, James Greenberg, Jeff Rathbone, James Smith, Andreas Held, Kelley Barsanti, Alex Guenther
New Particle Formation In The Front Range Of The Colorado Rocky Mountains, Micahel Boy, Thomas Karl, Andrew Turnipseed, Roy Lee Mauldin, Edward Kosciuch, James Greenberg, Jeff Rathbone, James Smith, Andreas Held, Kelley Barsanti, Alex Guenther
Civil and Environmental Engineering Faculty Publications and Presentations
New particle formation is of interest because of its influence on the properties of aerosol population, and due to the possible contribution of newly formed particles to cloud condensation nuclei. Currently no conclusive evidence exists as to the mechanism or mechanisms of nucleation and subsequent particle growth. However, nucleation rates exhibit a clear dependence on ambient sulphuric acid concentrations and particle growth is often attributed to the condensation of organic vapours. A detailed study of new particle formation in the Front Range of the Colorado Rocky Mountains is presented here. Gas and particle measurement data for 32 days was analyzed …
Optimal Bus Stop Spacing For Minimizing Transit Operation Cost, Huan Li, Robert L. Bertini
Optimal Bus Stop Spacing For Minimizing Transit Operation Cost, Huan Li, Robert L. Bertini
Civil and Environmental Engineering Faculty Publications and Presentations
With the increasing attention to finance issues relative to transit operation, a bus stop spacing model is generated with the aim at minimizing the operation cost without impact on transit accessibility. Two cost functions are considered in the model including passenger access cost and in-vehicle passenger stopping cost aiming at minimizing total cost. A bus route in Portland, Oregon, USA is examined as an example using Archived Bus Dispatch System (BDS) data provided by TriMet, the regional transit provider for the Portland, Oregon metropolitan area. Based on the optimization model, the theoretical optimized bus stop spacing is 930 feet comparing …
The Impacts Of Congestion On Commercial Vehicle Tours Characteristics And Costs, Miguel A. Figliozzi
The Impacts Of Congestion On Commercial Vehicle Tours Characteristics And Costs, Miguel A. Figliozzi
Civil and Environmental Engineering Faculty Publications and Presentations
Congestion is a common phenomenon in all major cities of the world. Increased travel time and uncertainty brought about by congestion impacts the efficiency of logistics operations. Recent studies indicate that a significant proportion of commercial vehicle kilometers traveled (VKT) and vehicle hours traveled (VHT) are generated by trip-chains or multi-stop tours. This paper presents research demonstrating the impact of congestion on multi-stop tours in urban areas. An analytical model, numerical experiments, and real-world tour data are used to understand the impact of congestion on tour characteristics, carriers? costs, VKT, and VHT. This research shows that travel time/distance between customer …
Analysis Of Freight Tours In A Congested Urban Area Using Disaggregated Data: Characteristics And Data Collection Challenges, Miguel Andres Figliozzi, Lynsey Kingdon, Andrea Wilkitzki
Analysis Of Freight Tours In A Congested Urban Area Using Disaggregated Data: Characteristics And Data Collection Challenges, Miguel Andres Figliozzi, Lynsey Kingdon, Andrea Wilkitzki
Civil and Environmental Engineering Faculty Publications and Presentations
Confidentiality issues are usually an insurmountable barrier that precludes the collection of detailed and complete freight data. However, when detailed disaggregated truck activity data is available, the analysis of commercial vehicle routes and trip chain structures can provide insightful information about urban commercial vehicle tours, travel patterns, and congestion levels. Where truck data is usually aggregated and cross-sectional, this research analyzes several months of detailed truck activity records in a congested urban area and thus contributes a level of investigation unavailable with aggregated data. To the best of the author's knowledge, there is no published research regarding the analysis of …
A Comparison Of Five Models For Estimating Clear-Sky Solar Radiation, Robert Leslie Annear, Scott A. Wells
A Comparison Of Five Models For Estimating Clear-Sky Solar Radiation, Robert Leslie Annear, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
Many agencies in the USA are developing management approaches to address water quality concerns and threatened and endangered species habitat requirements in water bodies. Many of these water bodies are water quality limited for temperature. Factors influencing stream temperature include: streamside vegetation, topographic shading, inflows and outflows, stream width, stream depth, light extinction and solar radiation. One of the key driving factors in estimating a water body heat budget is calculating the amount of solar radiation incident on the water surface. Even though it is preferable to measure clear-sky solar radiation, many temperature models rely on theoretical estimates of clear-sky …