Civil & Environmental Engineering Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/2753
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Item IMPACT OF TRANSIT ORIENTED DEVELOPMENT ON MODE CHOICE WITH CONSIDERATION FOR SELF SELECTION AND MULTIMODAL ACCESSIBILITY(2015) Baghaei, Babak; Zhang, Lei; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The U.S Department of Transportation allocated $10 million in 2013 to provide funding to advance planning efforts that support Transit Oriented Development (TOD) associated with new fixed guideway and core capacity improvement projects. Transit Oriented Development (TOD) is generally considered to be a type of pedestrian-friendly community development around the major transit station that promotes transit ridership, increases non-motorized travel and encourages local economic development. This thesis is an effort to analyze the effect of TOD on travel mode choice in both Washington, DC, and Baltimore metropolitan areas using the MWCOG 2007 household travel survey. A relatively new method in the transportation field called "Propensity Score Matching" was used to address the self-selection, and statistical models were developed to evaluate the impact of TOD on mode choice. The results indicated that after controlling for self-selection, TOD has a significant impact on boosting transit ridership and increasing active mode of travel.Item Choice Modeling Perspectives on Social Networks, Social Influence, and Social Capital in Activity and Travel Behavior(2015) Maness, Michael; Cirillo, Cinzia; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Understanding the determinants of activities and travel is critical for transportation policymakers, planners, and engineers to design and manage transportation systems. These systems, and their externalities, are interwoven with social systems in communities, cities, regions, and societies. But discrete choice models - the predominant modeling tool for researching travel behavior and planning transportation systems - are grounded in theories of individual decision-making. This dissertation expands knowledge about the incorporation of social interactions into activity-travel choice models in the areas of social capital and social network indicators; social influence motivations and informational conformity; and misspecification errors from social network data collection. Incorporating social capital into activity choice models involves using social capital indicators from surveys. Using a position generator question type, the role of social network occupational diversity in activity participation was explored and the performance of models using name generator and position generator data was compared. Access to the resources embedded in diverse networks (extensity) was found to positively correlate with leisure activity participation. Compared to core network indicators from name generators, position generator indicators were typically better at predicting activity participation in a cross-validation study. Current models of social influence in travel do not account for varying motivations for social influence such as for accuracy, affiliation, and self-concept. To test for an accuracy motivation, a latent class discrete choice model was formulated that places individuals into classes based on information exposure. Contrasting with existing work, this model showed that "more informed" households are more likely to own bicycles due to preference changes causing less sensitivity to smaller home footprints and limited incomes. A Bayesian prediction procedure was used to derive distributions of local-level equilibria and social influence elasticity. The effect of errors in social network data collection using name and position generators is not fully understood for choice models. In a case study, the social network occupational diversity measure was robust to varying position generator lengths. Simulation experiments tested the implications of social network structure, misspecification, and small samples on social influence choice models where sample size, social influence strength, and degree of misspecification had the greatest impact.Item STRUCTURED PROJECT FINANCE FOR PUBLIC-PRIVATE PARTNERSHIPS IN THE U.S.: AN ENHANCED APPROACH TO BETTER ACHIEVE FINANCIAL AND POLICY OBJECTIVES(2014) Farajian, Morteza; Cui, Qingbin; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)As existing U.S. infrastructure ages, government entities are looking to the private sector and to alternative financing mechanisms, such as project finance, to help leverage traditional funding sources and pay for the increasing needs. As a result, the use of Public-Private Partnership (P3) delivery method in the U.S. has increased over the last two decades. The question is how the existing cases can be used to potentially enhance the current P3 model both in terms of bankability and overall procurement process maturity. This study is organized into three main parts. In the first section, project finance in general and the role of different credit enhancements in structured project finance in particular have been. In the second section, a QCA analysis has been perfumed to study and compare 18 P3 projects that have been procured in the U.S. over the last two decades. The goal is to identify logical patterns between project characteristics (i.e. capital value, term of contract, construction risk, traffic and revenue risk, and procurement competition level) and financial characteristics (i.e. equity IRR, interest rate on debt and leverage). The results are further analyzed to refine conclusions that to can provide a better understanding of how financing package of P3 projects may change based on project characteristics and policy objectives. In the third section, an enhanced P3 model has been proposed by using crowdfunding. A SWOT analysis has been conducted to explain how the proposed approach can improve current P3 model. The findings of this study can help P3 practitioners to better utilize available tools and also provides them with new tools to further enhance procurement of P3 projects. The case library provides a significant resource to practitioners as well as researchers and the proposed corwdfunding approach is a novel step toward taking P3 projects to a new maturity level.Item A MODEL SYSTEM TO EVALUATE THE IMPACTS OF VEHICLE-RELATED TAXATION POLICIES ON HOUSEHOLD GREENHOUSE GAS EMISSIONS(2014) LIU, YAN; Cirillo, Cinzia; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This thesis proposes a model system to forecast household-level greenhouse gas emissions (GHGEs) from private transportation and to evaluate effects of car-related taxation schemes on vehicle emissions. The system contains four sub-models which specifically capture households' vehicle type and vintage, quantity, usage, and greenhouse gas emissions rates for different vehicle types. An integrated discrete-continuous vehicle ownership model is successfully implemented, while MOVES2014 (Motor Vehicle Emission Simulator 2014) is utilized. The model system has been applied to the Washington D.C. Metropolitan Area. The 2009 National Household Travel Survey (NHTS) with supplementary data from the Consumer Reports, the American Fact Finder and the 2009 State Motor Vehicle Registrations (SMVR) are used for estimations and predictions. Three tax schemes, vehicle ownership tax, purchase tax and fuel tax, have been proposed and their impacts on vehicle GHGEs reduction are predicted. The proposed model system can be extended to other regions, counties, states and nations.Item LOCATING CHARGING STATIONS FOR ELECTRIC VEHICLES IN RURAL AND URBAN NETWORKS(2014) Roshan Zamir, Kiana; Haghani, Ali; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Using new alternative fuels for motorized transportation vehicles has become increasingly popular with the growing concerns on the limitation of fossil fuels and environmental degradation. Introduction of numerous models of electric vehicles in the 21 century raised hope for replacing conventional internal combustion engine vehicles with these vehicles; however several barriers has adversely impacted the widespread adoption of these vehicles. Providing adequate number of charging stations and planning the layout of their infrastructure will help overcome some of the existing challenges. In this thesis, two formulations are presented for the optimal layout of these stations in rural and urban networks and the models are applied on two networks. For the rural model, the results indicate the solution is highly sensitive to the assumptions about the range of vehicles for which we are designing the layout. In the urban context, the decision about number and location of chargers is highly dependent on the probability threshold we choose for satisfying the demand.Item An Integrated Bus-based Progression System for Arterials Having Heavy Transit Flows(2014) Cheng, Yao; Chang, Gang-Len; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Conventional Transit Signal Priority (TSP) controls often reach the limitation for arterials accommodating heavy bus flows since the priority control function can significantly increase the delay at minor streets. Under such conditions, a proper signal coordinated plan that aims to offer progression for buses is one potentially effective strategy. This study proposes a bus-based progression system to reduce the delay of buses on local arterials experiencing heavy bus volume. The proposed model is capable of providing bus-progression bands under various traffic conditions, which take into account the stochastic nature of bus dwell time and the capacity of bus stops. The trade-off between passenger-car and bus-based progression bands and the selection logic under different traffic compositions have been also investigated in this study. The results of extensive simulation experiments have confirmed the proposed model's effectiveness in reducing the bus passenger delay and the average passenger-car delays under various traffic conditions.Item Traffic Analysis on Cumulative Land Development and Transportation Related Policy Scenarios(2014) Zhu, Zheng; Zhang, Lei; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Numerous methods have been developed to evaluate the impact of land developments and transportation policies on transportation infrastructures. But traditional approaches are either limited to static performance or a lack of behavior foundation. With only a few activity-based land development models in practice, this thesis integrates dynamic traffic assignment (DTA) with agent-based positive travel behavior model as a feasible tool for land development and transportation policy analysis. The integrated model enhances the behavior realism of DTA as well as captures traffic dynamics. It provides a low-cost approach to conduct new traffic analysis which emphasis on not only regional/local system mobility, but also individual behaviors. A land development analysis and a flexible work schedule policy analysis are illustrated in this paper. Unlike traditional land development impact studies, a great deal of travel behavior shift is obtained via this integrated model, which creates a new way for land development and policy analysis.Item REAL-TIME CONTROL MODEL IN AIRLINE DELAY MANAGEMENT(2014) Dong, Han; Schonfeld, Paul M; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The real-time control in airport management can reduce delay cost and alleviate delay propagation in an airline network. In this study, a model is developed to determine holding decisions and departure policies to the ready departure flights, which have transfer passengers from late arrival flights. Optimization with downstream coordination (ODC) and optimization without downstream coordination (ONDC) are presented in the model. The results show that ODC and ONDC could reduce system total cost when flights are delayed, and ODC performs better than ONDC. The sensitivity analysis of the total cost to various inputs is also discussed. The results show that the system total cost varies with holding time, slack time, number of transfer passengers and headway.Item EQUITABLE AND PROGRESSIVE DISTANCE-BASED USER CHARGE: DESIGN AND EVALUATION OF INCOME-BASED MILEAGE FEES IN MARYLAND(2014) Yang, Di; Zhang, Lei; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Due to the declining purchasing power of fuel tax revenue, the Highway Trust Fund is insufficient to operate and maintain the surface transportation system in the U.S. Alternative sources of revenue, other than the fuel tax, should be considered to address the insolvency of the funding system. Mileage fees and value pricing have long been attractive options to researchers and decision-makers, but they often raise equity concerns. This paper aims to design and evaluate equitable and progressive distance-based user charge policies, and focuses specifically on income-based fee rate structures. Three variable-rate vehicle-miles traveled (VMT) fee scenarios with respect to income are introduced and all policy scenarios are tested with a statewide transportation model in Maryland. Results show that income-based VMT fees can well protect lower-income households while generating more revenue. However, a standard fee structure based on Ramsey pricing does not work as well as the fixed-percentage incremental fee structure. The latter is progressive across all income groups while ensuring that equity and revenue goals are met.Item ACTIVE RELOCATION AND DISPATCHING OF HETEROGENEOUS EMERGENCY VEHICLES(2014) Sharifi, Elham; Haghani, Ali; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)An emergency is a situation that causes an immediate risk to the property, health, or lives of civilians and can assume a variety of forms such as traffic accidents, fires, personal medical emergencies, terrorist attacks, robberies, natural disasters, etc. Emergency response services (ERSs) such as police, fire, and medical services play crucial roles in all communities and can minimize the adverse effects of emergency incidents by decreasing the response time. Response time is not only related to the dispatching system, but also has a very close relationship to the coverage of the whole network by emergency vehicles. The goal of this dissertation is to develop a model for an Emergency Management System. This model will dynamically relocate the emergency vehicles to provide better coverage for the whole system. Also, when an emergency happens in the system the model will consider dispatching and relocation problem simultaneously. In addition, it will provide real-time route guidance for emergency vehicles. In summary, this model will consider three problems simultaneously: area coverage, vehicle deployment, and vehicle routing. This model is event-based and will be solved whenever there is an event in the system. These events can be: occurrence of an emergency, change in the status of vehicles, change in the traffic data, and change in the likelihood of an emergency happening in the demand nodes. Three categories of emergency vehicle types are considered in the system: police cars, ambulances, and fire vehicles. The police department is assumed to have a homogeneous fleet, but ambulances and fire vehicles are heterogeneous. Advanced Life Support (ALS) and Basic Life Support (BLS) ambulances are considered, along with Fire Engines, Fire Trucks, and Fire Quints in the fire vehicle category. This research attempts to provide double coverage for demand nodes by non-homogenous fleet while increasing the equity of coverage of different demand nodes. Also, the model is capable of considering the partial coverage in the heterogeneous vehicle categories. Two kinds of demand nodes are considered, ordinary nodes and critical nodes. Node demands may vary over time, so the model is capable of relocating the emergency fleet to cover the points with highest demand. In addition, an attempt is made to maintain work load balance between different vehicles in the system. Real-world issues, such as the fact that vehicles prefer to stay at their home stations instead of being relocated to other stations and should be back at their home depots at the end of the work shift, are taken into account. This is a unique and complex model; so far, no study in the literature has addressed these problems sufficiently. A mathematical formulation is developed for the proposed model, and numerical examples are designed to demonstrate its capabilities. Xpress 7.1 is used to run this model on the numerical examples. Commercial software like Xpress can be used to solve the proposed model on small-size problems, but for large-size and real-world problems, an appropriate heuristic is needed. A heuristic method that can find good solutions in reasonable time for this problem is developed and tested on several cases. Also, the model is applied to a real-world case study to test its performance. To investigate the model's behavior on a real-world problem, a very sophisticated simulation model that can see most of the details in the system has been developed and the real case study data has been used to calibrate the model. The results show that the proposed model is performing very well and efficient and it can greatly improve the performance of emergency management centers.