Engineering Commons^™

The Impact Of Freeway Traffic Conditions On In-Vehicle Exposure To Ultrafine Particulate Matter, Miguel A. Figliozzi, Alexander Y. Bigazzi

Civil and Environmental Engineering Faculty Publications and Presentations

There is evidence of adverse health impacts from human exposure to traffic-related ultrafine particulate matter pollution. As more commuters are spending a significant portion of their daily routine inside vehicles, it is increasingly relevant to study exposure levels to harmful pollutants inside the vehicle microenvironment. This study is one of the first research efforts to combine detailed freeway traffic data (at 20 s intervals) and in-vehicle ultrafine particulate (UFP) exposure data under varying vehicle ventilation conditions. Results show that due to negative correlation between traffic speed and density, traffic states have a small but significant impact on in-vehicle UFP concentrations, …

Evolution Of Ensemble Data Assimilation For Uncertainty Quantification Using The Particle Filter-Markov Chain Monte Carlo Method, Hamid Moradkhani, Caleb Matthew Dechant, Soroosh Sorooshian

Civil and Environmental Engineering Faculty Publications and Presentations

Particle filters (PFs) have become popular for assimilation of a wide range of hydrologic variables in recent years. With this increased use, it has become necessary to increase the applicability of this technique for use in complex hydrologic/land surface models and to make these methods more viable for operational probabilistic prediction. To make the PF a more suitable option in these scenarios, it is necessary to improve the reliability of these techniques. Improved reliability in the PF is achieved in this work through an improved parameter search, with the use of variable variance multipliers and Markov Chain Monte Carlo methods. …

Analysis Of Travel Time Reliability For Freight Corridors Connecting The Pacific Northwest, Miguel A. Figliozzi

Civil and Environmental Engineering Faculty Publications and Presentations

A new methodology and algorithms were developed to combine diverse data sources and to estimate the impacts of recurrent and non-recurrent congestion on freight movements’ reliability and delays, costs, and emissions. The results suggest that traditional traffic sensor data tend to underestimate the impacts of congestion on commercial vehicles travel times and variability. This research also shows that congestion is not only detrimental for carriers and shippers costs but also for the planet due to major increases in GHG emissions and for the local community due to large increases in NOx, PM, and other harmful pollutants.

The methodologies developed throughout …

Contextual Influences On Trip Generation, Kelly J. Clifton, Kristina Marie Currans, Christopher D. Muhs

Civil and Environmental Engineering Faculty Publications and Presentations

There is national interest in building data that expands upon the existing Institute of Transportation Engineers (ITE) trip generation rates to include sites located in a multi-modal context. Current ITE rates represent travel behavior for development in single lots and uses, primarily measured in low-density suburban areas. Despite evidence that a more compact urban form, access to transit and a greater mix of uses generates fewer and shorter vehicle trips, local governments are often compelled to use current ITE trip generation rates to evaluate transportation impacts and calculate transportation system development charges (TSDCs). This is due to: a) the expense …

Value Of Travel Time Reliability Part Ii: A Study Of Tradeoffs Between Travel Reliability, Congestion Mitigation Strategies And Emissions, Miguel A. Figliozzi, Alexander Y. Bigazzi

Civil and Environmental Engineering Faculty Publications and Presentations

Capacity, demand, and vehicle based emissions reduction strategies are compared for several pollutants employing aggregate US congestion and vehicle fleet condition data. We find that congestion mitigation does not inevitably lead to reduced emissions; the net effect of mitigation depends on the balance of induced travel demand and increased vehicle efficiency that in turn depend on the pollutant, congestion level, and fleet composition. In the long run, capacity-based congestion improvements within certain speed intervals can reasonably be expected to increase emissions of CO2e, CO, and NOx through increased vehicle travel volume. Better opportunities for emissions reductions exist for HC and …

Operational Guidance For Bicycle-Specific Traffic Signals In The United States, Christopher Monsere, Miguel A. Figliozzi, Sam Thompson, Kirk Paulsen

Civil and Environmental Engineering Faculty Publications and Presentations

The research consisted of two phases: 1) a synthesis of practice and 2) and analysis of cyclist performance characteristics. The synthesis of current practice reviewed the literature, current engineering design and operational guidance documents, and surveyed the jurisdictions about their current deployments of bicyclespecific signals. This report summarizes research of cyclist behavior at signalized intersections in Portland, Eugene, Corvallis, Beaverton and Clackamas County, OR. These signals had both bicycle-specific indications and vehicle-only signals. A total of 4,673cyclists were observed. For each cyclist observed arriving on red, a set of descriptive variables were collected (e.g., age, sex, helmet use, presence of …

A Study Of Headway Maintenance For Bus Routes: Causes And Effects Of “Bus Bunching” In Extensive And Congested Service Areas, Miguel A. Figliozzi, Wu-Chi Feng, Gerardo Lafferriere, Wei Feng

Civil and Environmental Engineering Faculty Publications and Presentations

A healthy and efficient public transit system is indispensable to reduce congestion, emissions, energy consumption, and car dependency in urban areas. The objective of this research is to 1) develop methods to evaluate and visualize bus service reliability for transit agencies in various temporal and spatial aggregation levels; 2) identify the recurrent unreliability trends of bus routes (focusing on high-frequency service periods) and understand their characteristics, causes and effects; and 3) model service times using linear regression models.

This research utilized six months of archived automatic vehicle location (AVL) and automatic passenger count (APC) data from a low-performance route (Route …

Analyzing And Quantifying The Impact Of Congestion On Ltl Industry Costs And Performance In The Portland Metropolitan Region, Miguel A. Figliozzi

Civil and Environmental Engineering Faculty Publications and Presentations

Increased congestion during peak morning and afternoon periods in urban areas is increasing logistics costs. In addition, environmental, social, and political pressures to limit the impacts associated with CO2 emissions are mounting rapidly. A key challenge for transportation agencies and businesses is to improve the efficiency of urban freight and commercial vehicle movements while ensuring environmental quality, livable communities, and economic growth. However, research and policy efforts to analyze and quantify the impacts of congestion and freight public policies on carriers operations and CO2 emissions are hindered by the complexities of vehicle routing problems with time-dependent travel times and the …

Regional Models Of Internal Tides, Glenn S. Carter, Oliver B. Fringer, Edward D. Zaron

Civil and Environmental Engineering Faculty Publications and Presentations

Internal tides are ubiquitous in the ocean, and they play an important role in a range of ocean processes, for example, particle dispersal, acoustics, and vertical buoyancy flux. The wavelength of internal tides can be as much as 250 km in the open ocean, but as the generation of these tides depends on the angle between the depth-averaged current and the topography, there can be considerable local spatial variability. This range of scales makes it difficult to develop a comprehensive understanding of the processes involved from observations alone. Regional numerical modeling provides a way to study the generation and early …

Bus Fleet Type And Age Replacement Optimization: A Case Study Utilizing King County Metro Fleet Data, Wei Feng, Miguel A. Figliozzi

Civil and Environmental Engineering Faculty Publications and Presentations

Bus fleet data have consistently shown that vehicle operating and maintenance costs increase as vehicles age. A fleet manager has to deal with the tradeoff between the lower operating and maintenance costs of newer fleets and their higher initial capital costs as well as the tradeoff between conventional and fuel efficient bus technologies. This study formulates and implements a fleet replacement optimization framework that is applied to a case study that compares two bus types: a conventional diesel and a hybrid bus. Employing real-world bus fleet data from King County Metro (Washington State, USA) multiple scenarios are examined to account …

An Evaluation Of The Impacts Of An Adaptive Coordinated Traffic Signal System On Transit Performance: A Case Study On Powell Boulevard (Portland, Oregon), Courtney Natasha Slavin, Miguel A. Figliozzi, Wei Feng

Civil and Environmental Engineering Faculty Publications and Presentations

Powell Boulevard is a prime example of a congested urban arterial; this roadway connects US-26 to downtown Portland, Oregon. This facility is one of the most congested arterial corridors in the Portland-metropolitan region. The City of Portland implemented the Sydney Coordinated Adaptive Traffic System (SCATS) in October 2011 in order to improve the operations of the corridor. SCATS has been implemented in a few US cities with mixed results so far. A properly calibrated system can have a significant positive impact on the performance of the traffic signals but its impact on transit performance has not been documented. This was …

Analysis Of The Impacts Of Transit Signal Priority On Bus Bunching And Performance, Eric Albright, Miguel Andres Figliozzi

Civil and Environmental Engineering Faculty Publications and Presentations

Efficient and reliable public transit systems provide opportunities to reduce congestion, emissions in urban areas and provide access and mobility to residents. Headway, or the time difference between departing or arriving vehicles, is a useful measure to gauge bus transit performance; because short headways can lead to bus bunching incidents that quickly degrade transit level of service. While Transit Signal Priority (TSP) has been shown to decrease travel time and delay experienced by buses, little work has shown how TSP may affect bus bunching. This research attempts to understand the characteristics of bus trips, especially TSP, that prevent or promote …

An Empirical Study Of Particulate Matter Exposure For Passengers Waiting At Bus Stop Shelters In Portland, Oregon, Usa, Adam Moore, Miguel A. Figliozzi, Christopher Michael Monsere

Civil and Environmental Engineering Faculty Publications and Presentations

Current guidelines for the location and design of bus stops do not take into account air quality or exposure considerations for waiting passengers. This paper compares the exposure of transit riders waiting at three-sided bus stop shelters that either: 1) face roadway traffic, or 2) face away from roadway traffic. Shelters were instrumented with devices to monitor particulate matter concentration inside and outside the shelter, wind speed and direction, and vehicle counts. Data were collected at three shelters during both the morning and afternoon peak periods. Bus shelter orientation is found to have a significant effect on the concentration of …

Exploratory Methods For Truck Re-Identification In A Statewide Network Based On Axle Weight And Axle Spacing Data To Enhance Freight Metrics: Phase Ii, Mecit Cetin, Christopher M. Monsere

Civil and Environmental Engineering Faculty Publications and Presentations

Vehicle re-identification methods can be used to anonymously match vehicles crossing two different locations based on vehicle attribute data. This research builds upon a previous study and investigates different methods for solving the re-identification problem and explores some of the factors that impact the accuracy of the results. To support this work, archived data from weigh-in-motion (WIM) stations in Oregon are used for developing, calibrating, and testing vehicle re-identification algorithms. In addition to the Bayesian approach developed by the researchers in the previous study, a neural network model is developed for solving the re-identification problem. The results from the testing …

Examining The Effectiveness And Robustness Of Sequential Data Assimilation Methods For Quantification Of Uncertainty In Hydrologic Forecasting, Caleb Matthew Dechant, Hamid Moradkhani

Civil and Environmental Engineering Faculty Publications and Presentations

In hydrologic modeling, state-parameter estimation using data assimilation techniques is increasing in popularity. Several studies, using both the ensemble Kalman filter (EnKF) and the particle filter (PF) to estimate both model states and parameters have been published in recent years. Though there is increasing interest and a growing literature in this area, relatively little research has been presented to examine the effectiveness and robustness of these methods to estimate uncertainty. This study suggests that state-parameter estimation studies need to provide a more rigorous testing of these techniques than has previously been presented. With this in mind, this paper presents a …

Toward Reduction Of Model Uncertainty: Integration Of Bayesian Model Averaging And Data Assimilation, Mark A. Parrish, Hamid Moradkhani, Caleb Matthew Dechant

Civil and Environmental Engineering Faculty Publications and Presentations

Multimodeling in hydrologic forecasting has proved to improve upon the systematic bias and general limitations of a single model. This is typically done by establishing a new model as a linear combination or a weighted average of several models with weights on the basis of individual model performance in previous time steps. The most commonly used multimodeling method, Bayesian model averaging (BMA), assumes a fixed probability distribution around individual models' forecast in establishing the prior and uses a calibration period to determine static weights for each individual model. More recent work has focused on a sequential Bayesian model selection technique …

Development Of The Oregon Traffic Safety Data Archive: Phases 1 And 2, Christopher M. Monsere, Myenwoo Lim, Chengxin Dai, Xiaowei Wu

Civil and Environmental Engineering Faculty Publications and Presentations

This report describes the preliminary work to develop the Oregon Traffic Safety Data Archive (OrTSDA). The mission of OrTSDA is to "build the knowledge base of traffic safety data in Oregon". The archive hopes to become a valuable traffic safety data resource with researchers, practitioners, and community supporters. As envisioned, the archive will provide current and historical versions of related data, encompass complete documentation, and contain an online interface to the variety of traffic safety related data. Working with partner state agencies, the archive contains reported motor vehicle crashes statewide, population data, estimates of vehicle miles traveled, traffic crime, and …

Strength And Fatigue Of Three Glass Fiber Reinforced Composite Bridge Decks With Mechanical Deck To Stringer Connections, Andrew Gleason, Peter Dusicka

Civil and Environmental Engineering Faculty Publications and Presentations

Replacement of the steel grating deck on the lift span of the Morrison Bridge in Portland, OR, will utilize glass fiber reinforced polymer (FRP) panels to address ongoing maintenance issues of the deteriorated existing deck, improve driver safety and introduce bridge water runoff treatment. This report outlines the testing methods and results of an experimental program aimed primarily at evaluating a new open cell deck. While most FRP panels are connected via shear studs that are grouted within isolated pockets, the panels in this case were bolted directly to the steel stringers. Two different FRP deck options were evaluated for …

Climate Change Impact Assessment For Surface Transportation In The Pacific Northwest And Alaska, John Macarthur, Philip Mote, Miguel A. Figliozzi, Jason Ideker, Ming Lee

Civil and Environmental Engineering Faculty Publications and Presentations

The states in the Pacific Northwest and Alaska region share interconnected transportation networks for people, goods, and services that support the regional economy, mobility, and human safety. Regional weather has and will continue to affect the physical condition and serviceability of these networks, yet the nature of climate changes and their potential impacts on the regional transportation system and its use are very poorly understood. The world’s leading climate scientists, such as the Intergovernmental Panel for Climate Change, have reached consensus that global climate changes are being observed and will continue into the future, particularly increasing temperatures. Given this fact, …

Tsunami Hydrodynamics In The Columbia River, Harry Yeh, Elena Tolkova, David A. Jay, Stefan A. Talke, Hermann Fritz

Civil and Environmental Engineering Faculty Publications and Presentations

On 11 March 2011, the Tohoku Tsunami overtopped a weir and penetrated 49 km up the Kitakami River, the fourth largest river in Japan. Similarly, the 2010 Chile tsunami propagated at least 15 km up the Maule River. In the Pacific Northwest of the United States, large tsunamis have occurred along the Cascadia subduction zone, most recently the 'orphan tsunami' of 1700 (Atwater et al.). The expected future occurrence of a Cascadia tsunami and its penetration into the Lower Columbia River became the subject of “the Workshop on Tsunami Hydrodynamics in a Large River” held in Corvallis, Oregon, 2011. We …

Identification Of The Biogenic Compounds Responsible For Size-Dependent Nanoparticle Growth, Paul M. Winkler, John Ortega, Thomas Karl, Luca Cappellin, Hans R. Friedli, Kelley Barsanti, Peter H. Mcmurry, James N. Smith

Civil and Environmental Engineering Faculty Publications and Presentations

The probability that freshly nucleated nanoparticles can survive to become cloud condensation nuclei is highly sensitive to particle growth rates. Much of the growth of newly formed ambient nanoparticles can be attributed to oxidized organic vapors originating from biogenic precursor gases. In this study we investigated the chemical composition of size-selected biogenic nanoparticles in the size range from 10 to 40 nm. Particles were formed in a flow tube reactor by ozonolysis ofα-pinene and analyzed with a Thermal Desorption Chemical Ionization Mass Spectrometer. While we found similar composition in 10 and 20 nm particles, the relative amounts of …