Engineering Commons^™

Controlling Complex Dynamic Transportation Systems: Development And Adaptation Of A Novel Distributed Cooperative Multi-Agent Learning Technique, Russell Thomas Graves

Doctoral Dissertations

Intelligent transportation systems continue to increase complexity, scale, and scope as more devices contain embedded compute. Cooperation among vehicles, intersections, and other members of the greater traffic ecosystem at a system-of-systems level is critical to improving the efficiency of the multi-billion-dollar asset that is the U.S. roadway infrastructure. This work introduces a negotiations strategy among multi-agent reinforcement learning agents and applies this to both traffic signal control and supervisory control of vehicle platooning. The traffic signal control implementation builds off of many prior research thrusts, and was shown to improve vehicle throughput by an average of 671veh/hr over actuated traffic …

Drivers’ Hazard Avoidance During Vehicle Automation: Impact Of Mental Models And Implications For Training, Ganesh Pai Mangalore

Doctoral Dissertations

Advanced Driver Assistance Systems (ADAS) are vehicle automation systems that have become more accessible and prevalent in vehicles in recent years. But the introduction of such technologies introduces new human factors challenges. Past literature suggests that users of vehicle automation lack the necessary and appropriate knowledge about their automation system. This may play a negative role in their hazard avoidance abilities when driving with automation features. Improving mental models and knowledge could generally lead to safer interactions with vehicle automation systems, but any effort to develop hazard avoidance skills when driving with vehicle automation is impeded by the lack of …

Transportation System Performance And Traveler Behavior In The Context Of A Systemwide Shock: Applications Of Data Science Toward A Sustainable Future, A. Latif Patwary

Doctoral Dissertations

The COVID-19 pandemic, a systemwide shock, has left a long-lasting and significant impact on transportation systems. It has contributed to a shift in travel behavior, with many people turning to work from home (WFH) and online shopping. This shift has led to a reduction in vehicular travel. However, the pandemic witnessed increased crash fatalities despite a reduction in overall crashes, disproportionately affecting disadvantaged communities (DACs). The main question arising from these pandemic-related issues is what we can learn to improve transportation systems and shape future travel behavior. Therefore, this dissertation aims to investigate how the transportation system changed during COVID-19 …

Improving Mobility And Safety In Traditional And Intelligent Transportation Systems Using Computational And Mathematical Modeling, Shahrbanoo Rezaei

Doctoral Dissertations

In traditional transportation systems, park-and-ride (P&R) facilities have been introduced to mitigate the congestion problems and improve mobility. This study in the second chapter, develops a framework that integrates a demand model and an optimization model to study the optimal placement of P&R facilities. The results suggest that the optimal placement of P&R facilities has the potential to improve network performance, and reduce emission and vehicle kilometer traveled. In intelligent transportation systems, autonomous vehicles are expected to bring smart mobility to transportation systems, reduce traffic congestion, and improve safety of drivers and passengers by eliminating human errors. The safe operation …

Mining Crowdsourced Data For Pavement Maintenance, Incident Management, And Traffic Monitoring, Yangsong Gu

Doctoral Dissertations

Crowdsourcing has been a prevailing fashion of data acquisition thanks to the proliferation of smart devices and wireless communication techniques. In the transportation field, emerging crowdsourcing data could potentially facilitate traffic operation and management. A motiving example is Waze, which is a navigation app that allows Waze users (Wazers) to report different types of traffic incidents e.g., accidents, jams, potholes, disabled vehicles, and so on. Crowdsourced data has many advantages over existing fixed location sensors: cost-effective, extensive geographic coverage, high resolution, and real-time. Moreover, it assembles the human’s perception and judgment of traffic incidents, which is more straightforward compared to …

Evaluating Impacts Of Shared E-Scooters From The Lens Of Sustainable Transportation, Nitesh Shah

Doctoral Dissertations

As the popularity of shared micromobility is increasing worldwide, city governments are struggling to regulate and manage these innovative travel technologies that have several benefits, including increasing accessibility, reducing emissions, and providing affordable travel options. This dissertation evaluates the impacts of shared micromobility from the perspective of sustainable transportation to provide recommendations to decision-makers, planners, and engineers for improving these emerging travel technologies.

The dissertation focuses on four core aspects of shared micromobility as follows: 1) Safety: I evaluated police crash reports of motor vehicle involving e-scooter and bicycle crashes using the most recent PBCAT crash typology to provide a …

Fundamental Investigation Of Interaction Between Moisture And Asphalt-Aggregate Systems, Rui Xiao

Doctoral Dissertations

Moisture-induced damage is one of the most common forms of flexible pavement distress which directly causes or exacerbates pavement failure. The intrusion of moisture into the asphalt pavements reduces the overall mechanical properties of the locking structures and gives rise to one or more of the visible forms of distress such as raveling, stripping, permanent deformation and fatigue cracking. This doctoral study is aimed at understanding the detrimental action of water on the asphalt-aggregate systems and the damage mechanism by multi-technique investigation. A thermodynamics framework was considered to characterize the properties of asphalt mix ingredients as well as the engineering …

Emerging Trends In Bus Ridership In The United States, Abubakr Ziedan

Doctoral Dissertations

Public transit ridership in the United States was declining even before the COVID-19 pandemic. Many different factors affect transit ridership levels, and the recent declines in ridership across the country make it critical to assess which factors are causing declines and which may help to increase ridership. Therefore, this dissertation seeks to quantify the impact of three emerging factors on bus ridership: shared electric scooters (e-scooters), new fare payment technologies and policies, and the COVID-19 pandemic.

This dissertation analyzed the impacts of shared e-scooters on bus ridership. This was investigated at the route level in Louisville, KY, and Nashville, TN, …

A Study Of Readiness For Transportation Electrification And Automation Focusing On Safety And Future Adoption, Steve Lee

Doctoral Dissertations

Transportation electrification and automation are growing societal trends and considered promising pathways to enhance the safety, mobility, efficiency, and sustainability of the surface transportation system. At this early stage of transportation electrification and automation, one of the most critical issues is whether and to what extent people are willing to adopt electric vehicle (EV) and automated vehicle (AV) technologies in the future. Another critical issue, especially concerning transportation automation, is how to thoroughly ensure the safety of automated driving performance to resolve safety concerns about AVs, which is one of the key challenges to AV adoption. In this regard, the …

Optimizing Transportation Systems With Information Provision, Personalized Incentives And Driver Cooperation, Sayeeda Ayaz

Doctoral Dissertations

Poor performance of the transportation systems has many detrimental effects such as higher travel times, increased travel costs, higher energy consumption, and greenhouse gas emissions, etc. This thesis optimizes the transportation systems by addressing the traffic congestion problem and climate change impact resulting from the inefficient operation of these systems. I first focus on the key player of the transportation systems e.g., human being/traveler, and model travelers' route choice behavior with real-time information. In this study, I define looking-ahead behavior in route choice as a traveler's taking into account future diversion possibilities enabled by real-time information in a network with …

Using Heuristic Methods And Machine Learning To Enhance The Positional Accuracy Of Historical Geospatial Datasets, Pankaj Mani Dahal

Doctoral Dissertations

The recent availability of multiple geospatial datasets can be attributed to advancements in location-based technologies. The merging of various datasets, commonly known as conflation, is essential to strengthening the content of existing datasets by integrating information from various sources. However, complexities arise when these merged datasets contain distinct representations of the same real-world entities with differing accuracy, projections, data structure, and consideration of details. Although conflation has been an interest to researchers for a long time, the existing methods do not cater to the specific needs of some datasets. For example, historical datasets have lower resolution with richer attribute information, …

Analyzing Appropriate Policy Factors To Stimulate Zero Emission Vehicle (Zev) Population Growth In California To Achieve The State’S Overall Climate And Environmental Goals, Toks A. Omishakin

Doctoral Dissertations

The objective of this dissertation research is to assess critical policy factors that will need to be adjusted to stimulate significant increases in the adoption of Zero-Emission Vehicles (ZEV) in California to support the state's aggressive climate and environmental goals. Currently, California in comparison to the other 49 states has the United States' worst Greenhouse Gas Emissions (GHG) coming from its transportation sector. Also, within the state, transportation is ahead of all other economic sectors, including agriculture, electricity generation, and even industrial pollution in creating poor air quality. California in recent years has set aggressive targets to both decreases GHG’s …

Equitable Resource Allocation To Improve Safety: An Evaluation Based On Risk, Alyssa M. Ryan

Doctoral Dissertations

Transportation safety continues to be a serious issue throughout the world. Proven safety measures have been developed to increase the safety on all roadways, but have not been universally and equitably implemented due to lack of resources, inefficiencies, and understanding. Additionally, the relative level of mobility safety remains higher in certain environments than others, creating an inequitable landscape. In this dissertation, the efficiency of using local and statement resources to improve safety is investigated while controlling for level of safety risk in vulnerable environments and locations using a comprehensive approach. Several methodologies and techniques are employed and developed to examine …

Assessing The Impact Of Bicycle Treatments On Bicycle Safety: A Multi-Methods Approach, Aikaterini Deliali

Doctoral Dissertations

Compared to other modes, bicyclists are disproportionally affected by crashes considering their low mode share. There is evidence that crashes between bicyclists and motorized vehicle take place at road segments and signalized intersections where bicycle treatments (e.g., bike lanes) are present, urging for in-dept analysis of the safety impact of the various bicycle treatment types. Additionally, it is important to identify sensor types that have the potential to advance field data collection and traffic monitoring in multi-modal road environments. In this dissertation, three approaches, namely crash analysis, traffic conflict analysis, and analysis of driver speeding and glancing behavior, were implemented …

Exploring Potential Impacts Of Connected And Automated Vehicle Technologies, Iman Mahdinia

Doctoral Dissertations

Connected and automated vehicle technologies have the potential to significantly improve transportation system performance. In particular, advanced driver-assistance systems (ADAS), such as adaptive cruise control (ACC), cooperative adaptive cruise control (CACC), pedestrian crash prevention (PCP) system, and advanced automated collision notification (ACN) system may lead to substantial improvements in performance by decreasing driver inputs and taking over control of the vehicle. The main questions that might arise are 1) how we can quantify the potential environmental and safety impacts of these technologies and 2) what the potential for these technologies is to address some of the important transportation-related problems. Due …

A Multilevel Study Of Driving Behavior And System Performance- Harnessing Large-Scale Naturalistic Driving And Conventional Safety Data, Amin Mohammadnazar

Doctoral Dissertations

The performance of a transportation system highly depends on the drivers’ behavior because driving behavior is one of the main causes of traffic accidents and one of the key factors in fuel consumption and vehicle emissions studies. Specifically, the focus of this dissertation is on aggressive driving who not only put their selves and others at risk but also contribute more to greenhouse gas emissions. Recently, the development of advanced sensors, connected vehicles (CVs), location-based services (LBS) provided unprecedented access to new high-resolution microscopic-level data which can be used to evaluate and monitor instantaneous driving behavior and safety performance of …

Understanding The Safety Impacts Of Left-Turn Infrastructure On The Vulnerable Driving Population, Francis Tainter

Doctoral Dissertations

The severe impact of roadway fatalities has remained a significant concern for researchers in recent years. As of 2015, traffic fatalities were the leading cause of death for individuals between the ages of 15 and 20 years old and a significant safety concern for drivers over the age of 65 years old (otherwise known as the “vulnerable” driving population). Intersection-related crashes have also remained prevalent in these demographic categories. Through four primary crash data evaluations, this dissertation explores the safety implications on the “vulnerable” driving population in the Commonwealth of Massachusetts. Through the utilization of newly developed crash data linkage …

Optimization And Technology-Based Strategies To Improve Public Transit Performance Accounting For Demand Distribution, Charalampos Sipetas

Doctoral Dissertations

Public transit is important to societies worldwide. The operation of public transit systems is generally associated with great benefits for the users, but there are also cases in which these systems demonstrate inefficient performance. Quantifying transit performance is an important area of research over the last decades. This dissertation presents models to improve transit system performance through optimization techniques and new technologies, recognizing the effects of non-uniform distribution of demand over space and time. The contributions span fixed route transit services and on-demand transit, as well as models for flexible transit operations that lie in between. Regarding fixed route systems, …

Infrastructure Systems Modeling Using Data Visualization And Trend Extraction, Jacob Marshal Hale

Doctoral Dissertations

“Current infrastructure systems modeling literature lacks frameworks that integrate data visualization and trend extraction needed for complex systems decision making and planning. Critical infrastructures such as transportation and energy systems contain interdependencies that cannot be properly characterized without considering data visualization and trend extraction.

This dissertation presents two case analyses to showcase the effectiveness and improvements that can be made using these techniques. Case one examines flood management and mitigation of disruption impacts using geospatial characteristics as part of data visualization. Case two incorporates trend analysis and sustainability assessment into energy portfolio transitions.

Four distinct contributions are made in this …

Application Of Crowdsourced Data In Transportation Operations And Safety, Nima Hoseinzadeh

Doctoral Dissertations

Crowdsourcing refers to the acquisition of data from users who contribute their information via smartphone, social media, or the internet. In transportation systems, crowdsourcing turns users into real-time sensors, providing data on traffic speed, travel time, mile traveled, incidents, roadway conditions, weather severity, irregularities in traffic patterns, and hazards. These data can be collected actively or passively in quantitative or qualitative forms. With the emergence of smartphones and navigation apps, crowdsourced data are gaining increased attention in transportation. Crowdsourced data have advantages over traditional fixed-location sensors and camera monitoring: low implementation costs, extended geographic coverage, high resolution, real-time application, increased …

Exploring The Potentials Of Using Crowdsourced Waze Data In Traffic Management: Characteristics And Reliability, Zhihua Zhang

Doctoral Dissertations

Real-time traffic information is essential to a variety of practical applications. To obtain traffic data, various traffic monitoring devices, such as loop detectors, infrastructure-mounted sensors, and cameras, have been installed on road networks. However, transportation agencies have sought alternative data sources to monitor traffic, due to the high installation and maintenance cost of conventional data collecting methods. Recently, crowdsourced traffic data has become available and is widely considered to have great potential in intelligent transportation systems. Waze is a crowdsourcing traffic application that enables users to share real-time traffic information. Waze data, including passively collected speed data and actively reported …

Seismic Behavior Of Composite Bridge Columns, Mohanad M. Abdulazeez

Doctoral Dissertations

“This study investigates experimentally and numerically the seismic behavior of large-scale hollow-core fiber-reinforced polymer-concrete-steel (HC-FCS) innovative bridge columns as a sustainable approach to endure and rapidly recover from natural disasters such as earthquakes. The HC-FCS column consisted of a concrete shell sandwiched between an outer fiber-reinforced polymer (GFRP) tube and an inner steel tube to provided continuous confinement for the concrete shell along with the height of the column. The columns have a slender inner steel tube with diameter-to-thickness (D_s/t_s) ratios ranged between 85 to 254. Each steel tube was embedded into the footing, while the …

Equity And Efficiency In Multi-Modal Transportation Systems, Nicholas M. Fournier

Doctoral Dissertations

The land-use pattern for many cities is a central business district surrounded by sprawling suburbs. This pattern can lead to an inefficient and congestion-prone transportation system due to a reliance on automobiles, because high-capacity transit is not efficient in low-density areas where insufficient travelers can access transit. This also poses an equity concern as the monetary cost of faster and more expensive travel disproportionately burdens low income travelers. This dissertation presents a deterministic approximation of a discrete choice model for mixed access and mainline transportation modes, meaning that travelers may use different modes to access a mainline system, such as …

Modeling And Optimizing Routing Decisions For Travelers And On-Demand Service Providers, Xinlian Yu

Doctoral Dissertations

This thesis investigates the dynamic routing decisions for individual travelers and on-demand service providers (e.g., regular taxis, Uber, Lyft, etc). For individual travelers, this thesis models and predicts route choice at two time-scales: the day-to-day and within-day. For day-to-day route choice, methodological development and empirical evidences are presented to understand the roles of learning, inertia and real-time travel information on route choices in a highly disrupted network based on data from a laboratory competitive route choice game. The learning of routing policies instead of simple paths is modeled when real-time travel information is available, where a routing policy is defined …

Applications Of Machine Learning Methods In Macroscopic Crash Analysis For Transportation Safety Management, Somaye Garmroudi Dovirani

Doctoral Dissertations

Transportation Safety Planning (TSP) is a statewide-scale tool and combines transportation planning processes with safety aims to increase safety and reduce transportation fatalities and injuries. Traffic safety, which continues to remain a critical issue worldwide, has led to a myriad of modeling techniques to improve analytical capabilities with respect to crash modeling and prediction. State and metropolitan transportation planning processes must be consistent with Strategic Highway Safety Plans. This research aims to identify models and methods to improve the ability to capture variables that have the most significant impact on traffic safety through crash prediction modeling. In order to achieve …

Intersection Signal Control And Design For Improved Person Mobility And Air Quality In Urban Multimodal Transportation Systems, Farnoush Khalighi

Doctoral Dissertations

Alternative geometric designs (e.g. roundabouts) and multi-objective signal control strategies are promising measures to improve sustainability of traffic networks. However, roundabouts are mostly used because of their safety and operational advantages. There has been less attention to the environmental performance of roundabouts. Also, the existing studies have been mostly used through field measurements and current simulation models, which need high calibration efforts and they are not inclusive in terms of considering all influencing factors on vehicular emissions at roundabouts. Furthermore, the existing real-time signal control strategies do not account for the emission rates of different vehicle types (e.g. cars and …

Modeling Performance, Cost, Delivery, And Trip Distribution Of Demand Responsive Transit Systems With Zoning, Mahour Rahimi

Doctoral Dissertations

Demand responsive transit (DRT) services are expensive to operate, so it is crucial to understand the factors that drive the agency costs and be able to investigate and predict the effect of possible changes in specific operating parameters as well as demand and service coverage areas on total costs. In this research, we adopt the concept of the analytical model proposed by Daganzo (1978) to present continuum approximation (CA) models that can estimate important service related factors. As the first step, we propose three analytical models to approximate the operation related variables of DRT services; Fleet Size, Vehicle Hours Traveled …

Physical Information Incorporated Clustering Techniques And Their Applications In Transportation Information System, Yang Zhang

Doctoral Dissertations

Massive data from different sources are becoming available in transportation field, and spurring new research on utilizing these data to nurture new intelligent transportation information systems. Clustering algorithms are among the methods that are being applied to the domain but facing challenges. Classical clustering algorithms work fine with \point" based data, which are homogeneous and have no extra constraints. Data in transportation are sometimes involved with specific geometric shapes, have underlying constraints, and can be heterogeneous. There has been no clustering algorithm dedicated to these situations.

In this dissertation, we re-examine the mathematical foundation and underlying philosophy of hierarchical, density …

Evaluation Of Increased Targeted Enforcement And Community-Based Outreach And Education Programs To Increase Nighttime Seatbelt Use In East Tennessee, Kwaku Frimpong Boakye

Doctoral Dissertations

According to the National Highway Traffic Safety Administration (NHTSA), motor vehicle crashes are the leading cause of death among people aged 1-54 in the United Sates. In 2015, the number of motor-vehicle deaths on U.S. roadways totaled 35,092, a 7% increase from 2014 (32,744). Though lower gas prices and increased vehicle mileage combined with risky driving behaviors (e.g. speeding, driving while texting) account for the increased fatality rate, seatbelt non-use has been a significant contributory factor. It is estimated that nearly half (48%) of passenger vehicle occupants involved in fatal crashes each year are unrestrained.

In a recent 2014 report …

An Evaluation Of Traffic Control Devices And Driver Distraction On Driver Behavior At Railway-Highway Grade Crossings, Radhameris A. Gomez Gabriel

Doctoral Dissertations

At-grade crossings (grade crossings) are those crossings in which any part of a roadway intersects with railroad tracks. Safety at these railroad-highway grade crossings is a major concern, with traffic control warning devices serving as the main mechanisms for improving safety. There are three factors that influence a driver’s behavior at a given crossing. First, traffic control devices, including warning devices at the railroad-highway grade crossings, provide the driver with information whose impact will depend in part on the likelihood that the driver knows whether to glance in the direction of the device based on prior experience, and in part …