Doctor of Philosophy

dissertationTraffic congestion is an increasing problem in most urban areas in the United States. One of the sources of this problem is the automobile-oriented development that encourages automobile use and suppresses other transportation modes. A good transit system can satisfy most of the requirements of a transportation system user. A transit system must be efficient, safe, comfortable, and competitive to private cars in order to attract more riders. Transit Signal Priority (TSP) is an operational strategy that facilitates transit vehicles at signalized intersections. It improves transit efficiency and helps transit offer travel times competitive to private cars. A lot of studies conducted in the past 40 years show the major possibilities and benefits of TSP. The goal of this research is to develop a simulation-based methodology for the evaluation and improvement of TSP strategies. The objectives consist of evaluating existing and future TSP systems, and developing field-ready algorithms that provide adaptive ways for achieving different levels of TSP and improving its operation. The focus of the research is on using traffic microsimulation to evaluate and improve TSP, but it also looks into some field-based implementations and evaluations for additional support. The analysis of different TSP strategies is performed on existing and future rapid transit mode implementations, namely Bus Rapid Transit (BRT) and Light Rail Transit (LRT). The results from the presented studies show the major benefits of TSP implementations for transit operations and small disruptions for vehicular traffic. Depending on the selected strategies and level of TSP, the travel time savings for transit can be between 10% and 30%, the reduction in intersection delay can exceed 60%, while running time reliability and headway adherence are greatly improved. These improvements in transit operations can make transit more efficient and competitive to private cars, justifying the TSP implementation. This research offers significant contributions to the state of TSP practice and research. It provides detailed insights into TSP operations, develops methods for its evaluation, and describes algorithms for achieving different levels of TSP. A significant part of the research is dedicated to the use of Software-in-the-Loop (SIL) traffic controllers in microsimulation. Through this research, SIL is proven to be a powerful tool for simulating complex traffic signal operations and TSP

Development of Performance Matrices for Evaluating Innovative Intersections and Interchanges [MPC-19-391]

MPC-465Innovative intersections and interchanges have proliferated in the State of Utah over the past several years. Continuous flow intersections and diverging diamond interchanges seem to offer improved traffic performance and safety due to their innovative designs. However, there are no clearly defined guidelines or methodologies for monitoring and measuring their performance. Yet, they have a broad impact on operations, safety, access, transit, land use, economic development, and pedestrian and non-motorized traffic. Due to these numerous and overlapping variables, there is a need to develop a standard methodology to further evaluate innovative designs with regards to different performance measures. The goal of this research is to develop a matrix of performance measures, which can be applied in practice to effectively evaluate innovative designs in terms of operations, safety, access, and multimodal accommodations. The study develops and tests an Excel-based tool for evaluation and comparison of different conventional and innovative designs. The tool is based on the existing methodologies and those currently being developed, and they provide analyses of these designs for different performance measures, such as operational, safety, transit and non-motorized user performance, access, and user costs. It can be used for planning, designing, and monitoring performance of innovative designs

Assessment of Motorcycle Safety in Wyoming: Fatal and Severe Crashes, Contributing Factors and Potential Countermeasures [Addendum]

RS04222Motorcycle riders and passengers are much more likely to be killed or severely injured in a crash, and on average about 15 percent of all traffic fatalities include motorcyclists. Motorcyclists and their passengers are particularly vulnerable on the roads, which accounts for their higher percentage of fatal and severe crash accidents. To take appropriate safety measures, it is important to investigate the factors that affect crash injury severity. This part of the study explores the use of two machine learning methods: Random Forest and Support Vector Machine classifiers. The Random Forest model showed better performance, therefore it was used to assess the significance of each type of contributory variable on the crash, person, and vehicle level datasets. The most important factors identified from the crash-level analysis were driver action, vehicle maneuver, type of collision, junction relation and helmet use. The driver injury area, driver action, and presence of alcohol in particular were observed to influence crash injury predictions at the person-level, whereas the vehicle maneuver, most damaged area of the vehicle and the vertical grade of the roadway were found to be relevant to motorcycle injury severity predictions at the vehicle-level. Collectively, this study revealed how motorcycle crash injury severity can be predicted from the identified factors in each data dataset. This finding will assist WYDOT and other transportation agencies in providing proactive solutions for motorcycle crashes

Operational and Safety Analysis with Mitigation Strategies for Freeway Truck Traffic in Wyoming [MPC 19\u2013396]

MPC-519The State of Wyoming road network is characterized by heavy truck traffic. In 2015, truck traffic was approximately 22% of vehicle miles traveled (VMTs) along all routes in Wyoming, according to the WYDOT Annual Traffic Report. The heaviest truck traffic exists along I-80 with about 47% truck VMTs. Trucks have significantly different physical and driving characteristics than passenger cars, especially on grades, which has impacts on operational efficiency, safety, and pavement deterioration. The presence of heavy vehicles reduces the capacity of freeway segments, with the reduction being more significant along specific grades. This study focuses on the benefits of climbing lanes on operations and safety of freeway truck traffic. Various methodologies were used in this assessment. The results show that the addition of climbing lanes reduces delays and increases overall traffic speeds on upgrades, and can reduce the total and truck-related crashes from 6% to 34%, and from 1% to 16%, respectively, depending on the analyzed location and applied methodology

MS

thesisIn recent years, traffic simulation software packages have become powerful tools in developing and studying the impacts of different traffic scenarios. This study presents a use of the VISSIM traffic simulation software in evaluating Transit Signal Priority (TSP) strategies using two types of emulated signal controllers: the Ring Barrier Controller (RBC) emulator, and the ASC/3 Software-in-the-Loop (SIL) traffic controller. The two signal control types were evaluated and compared for their abilities to provide TSP and the impacts it causes on the overall traffic. The results have shown benefits of the evaluated traffic controllers within VISSIM in simulating different TSP strategies, despite some differences and problems with controller settings. On the test-case network, the results have shown reductions in transit travel times from 4 to 7%, which are assigned to TSP. With combined Bus Rapid Transit (BRT) and TSP strategies, these travel time savings were in a range from 15 to 20%. Impacts on general purpose traffic along the main corridor were not observed, while TSP causes an increase in delays on side streets of approximately 1% and an increase in the number of stops of approximately 0.5%. The results also showed some differences in the way the two controller types implement TSP strategies

Securitização de recebíveis de exportação : mecanismo de captação externo para empresas brasileiras

Trata da abordagem de um mecanismo de captação de recursos para empresas brasileiras. Aborda aspectos gerais relacionado à Balança de Pagamentos, Balança Comercial e o Risco Brasil, bem como mecanismos de captação, por empresas brasileiras, no mercado internacional de capitais, como Depositary Receipts e Bom/s. Aponta aspectos gerais e técnicos sobre Securitização, desenvolvendo urna análise e perspectivas da tendência deste tipo de operação no mercado brasileiro

Effects of capacity and transit improvements on traffic and transit operations

Transportation agencies are facing problems of inadequate capacities to meet growing traffic demand. Street widening, signal operations optimization, innovative designs and multimodal transportation modes are traffic management strategies that can improve traffic operations along congested corridors. The goal of this paper is to assess future 2040 traffic and transit conditions along sections of Redwood Road in Salt Lake County, Utah, and develop and test potential operational improvements through VISSIM traffic simulation. Potential improvements, such as street widening, signal optimization, transit exclusive lanes with Transit Signal Priority (TSP) and adding a Continuous Flow Intersection (CFI) are analyzed. The improvements tested showed potential for reducing vehicular travel times between 6% to 20%, and delays 25% to 35%. Transit travel times reduced up to 40%, with delay reductions up to 60%. A combination of different strategies has the potential to improve traffic and transit operations along the busiest sections of Redwood Road

Use of Spatiotemporal Constraints to Quantify Transit Accessibility Case Study of Potential Transit-Oriented Development in West Valley City, Utah

Accessibility emerges as the transportation performance measure that emphasizes the benefits to transportation system users and captures more than the speed of travel. Transit accessibility shows how easy it is for an individual to travel to a desired destination by using public transit. However, for transit to be considered as an option in mode choice at all, there has to be a feasible transit route leading from a given origin to a desirable destination within the available time frame. This study used spatial and temporal constraints and a set of transit features that affected access to transit to develop a conceptual framework for transit accessibility measurements in a potential transit-oriented development (TOD) location in West Valley City, Utah. As this network develops more transit-friendly features, temporal and spatial accessibility indicators will provide useful information on the opportunities that users can reach by using transit. The proposed methodology was based on traffic and transit data from the case study network and used an open source tool to perform transit accessibility measurements by calculating the number of accessible transit stops from each origin. The methodology considered network features, acceptable walking time, available time budget, transit schedule variability, and spatial constraints as impact factors in accessibility measurements. The goal of the study was to establish a feasible set of transit accessibility indicators that would be used for both the case study street network and transit service modifications to transform the network into a transit-friendly and eventually a TOD environment

Evaluation of GPS-Based Transit Signal Priority for Mixed-Traffic Bus Rapid Transit

GPS-based transit signal priority (TSP) is a new type of transit preferential tool being considered in many North American cities. With GPS detection and advanced communications, GPS-based TSP provides flexible and conditional signal priority to transit vehicles. This is a relatively new system with limited field implementations and evaluations. The research in this study used microscopic simulation, to create a set of TSP scenarios for a 3-mi bus corridor and evaluated the influences of GPS-based TSP on transit and traffic operations. The simulation network was the 3300 South corridor, including side streets, in Salt Lake County, Utah. A proposal was evaluated to upgrade the Utah Transit Authority Bus Route 33 operating along the corridor into a bus rapid transit (BRT) line running in mixed traffic. Eight simulation scenarios were created to cover (a) current field conditions, (b) regular bus with traditional TSP implementation, (c) regular bus with GPS-based TSP, (d) BRT implementation with no TSP, (e) BRT with traditional TSP implementation, (f) BRT with GPS-based TSP, (g) BRT with conditional TSP, and (h) BRT with multiconditional TSP implementation. The evaluation included transit and nontransit operations, and the impacts on side-street traffic. The results show that GPS-based TSP performed as effectively as did traditional TSP. Conditional and multi-conditional TSP strategies showed benefits in providing the transit system considerable delay reduction (13% and 3%, respectively) and travel time savings (7% and 3%, respectively) while having the smallest impacts on side-street traffic (3% and 1% increase in delay, respectively) compared with other TSP strategies

Upgrade Evaluation of Traffic Signal Assets: High-resolution Performance Measurement Framework

Agencies that have large-scale traffic signal systems under their purview often have to face asset upgrade decisions. As one of the most advanced traffic control technologies, Adaptive Traffic Control Systems (ATCS) are among the options that must be taken into consideration. Having in mind the complexity of benefits and costs stemming from ATCS investments, there is a need for information-rich performance measures (PM) used in the evaluation and decision-making. However, individual PMs are often not suitable for evaluating the multidimensionality of ATCS operations, due the inherent variability of ATCS control parameters. To expand the range of PMs used in ATCS evaluation, this research develops a new PM, i.e., average arrivals on green ratio, and proposes a refinement of average delay PM to account for queue formation. The paper also presents an application framework for a multi-criteria analysis, assuming a combination of the proposed and existing PMs. In addition to presenting the analytical PM formulation, the evaluation methodology uses microsimulation for a case study comparison between actuated-coordinated and ATCS operations. The results include a comparison between previous and proposed PMs, based on the processed simulation data as well as field data. In conclusion, the proposed PMs have a high transferability potential, low data collection cost, and high data quality, thus being suitable for use in decision processes for signal asset investment. Finally, this research opens up further opportunities for advancing decision-support methods for traffic operations asset management.Peer reviewe