abstract: This study examines the outcomes of roundabouts in the State of Arizona. Two types of roundabouts are introduced in this study, single-lane roundabouts and double-lane roundabouts. A total of 17 roundabouts across Arizona were chosen upon several selection criteria and according to the availability of data for roundabouts in Arizona. Government officials and local cities’ personnel were involved in this work in order to achieve the most accurate results possible. This thesis focused mainly on the impact of roundabouts on the accident rates, accident severities, and any specific trends that could have been found. Scottsdale, Sedona, Phoenix, Prescott, and Cottonwood are the cities that were involved in this study. As an overall result, both types of roundabouts showed improvements in decreasing the severity of accidents. Single-lane roundabouts had the advantage of largely reducing the overall rate of accidents by 18%, while double-lane roundabouts increased the accident rate by 62%. Although the number of fatalities was very small, both types of roundabouts were able to stop all fatalities during the analysis periods used in this study. Damage rates increased by 2% and 60% for single-lane and double-lane roundabouts, respectively. All levels of injury severities dropped by 44% and 16% for single-lane and double-lane roundabouts, respectively. Education and awareness levels of the public still need to be improved in order for people to be able to drive within the roundabouts safely. / Dissertation/Thesis / Masters Thesis Civil and Environmental Engineering 2016

abstract: This study explores an innovative framework for a self-sustained traffic operations system using vehicle-to-vehicle (V2V) communications alone. The proposed framework is envisioned as the foundation to an alternative or supplemental traffic operation and management system, which could be particularly helpful under abnormal traffic conditions caused by unforeseen disasters and special events. Its two major components, a distributed traffic monitoring and platoon information aggregation system and a platoon-based automated intersection control system, are investigated in this study. The distributed traffic monitoring and platoon information aggregation system serves as the foundation. Specifically, each equipped vehicle, through the distributed protocols developed, keeps track of the average traffic density and speed within a certain range, flags itself as micro-discontinuity in traffic if appropriate, and cross-checks its flag status with its immediate up- and down-stream vehicles. The micro-discontinuity flags define vehicle groups with similar traffic states, for initiating and terminating traffic information aggregation. The impact of market penetration rate (MPR) is also investigated with a new methodology for performance evaluation under multiple traffic scenarios. In addition to MPR, the performance of the distributed traffic monitoring and platoon information aggregation system depends on the spatial distribution of equipped vehicles in the road network as well. The latter is affected by traffic dynamics. Traffic signal controls at intersections play a significant role in governing traffic dynamics and will in turn impact the distributed monitoring system. The performance of the monitoring framework is investigated with different g/C ratios under multiple traffic scenarios. With the distributed traffic monitoring and platoon information aggregation system, platoons can be dynamically identified on the network in real time. This enables a platoon-based automated intersection control system for connected and autonomous vehicles. An exploratory study on such a control system with two control stages are proposed. At Stage I, vehicles of each platoon will synchronize into a target speed through cooperative speed harmonization. Then, a platoon of vehicles with the same speed can be treated as a single vehicle for speed profile planning at Stage II. Its speed profile will be immediately determined given speed profiles of other platoons and the control goal. / Dissertation/Thesis / Doctoral Dissertation Civil, Environmental and Sustainable Engineering 2017

Os modelos de redes de filas ainda são pouco utilizados na área de Logística e Transportes, apesar de algoritmos e ferramentas computacionais eficientes estarem disponíveis atualmente. Este trabalho objetiva justamente mostrar alguns desses modelos de redes de filas e aplica-los em exemplos específicos. Inicialmente, é feita uma breve revisão dos principais modelos e algoritmos encontrados na literatura, para, em seguida, resolver-se um problema de determinação de uma função de produção, usando um modelo de rede de filas em regime estacionário. Como segundo exemplo, é montado um modelo para análise de um sistema de transporte que opera com transientes, onde é utilizada a aproximação por filas determinísticas. Em ambos os casos, é realizada uma discussão sobre o conceito de saturação em uma rede de filas, sendo proposta extensão da definição do conceito para o caso de redes mistas de filas. / Queueing networks models have seldom been used in the Logistics and Transportation realm, although being very popular in modelling other complex systems in the Computer Sciences. This work intends to briefly describe the most common models of queueing networks and apply them in some particular cases. First of all, a production function for a logistic system is developed, using a stationary probability model. Then, a transportation system with trasients is analised, using a fluid approximation model. For both cases, the saturation concept for a closed chain is defined, and is extended for mixed queueing networks.

This research aims to maximize the logistics outsourcing benefits through developing new hybrid models for evaluating and selecting Logistics Service Providers (LSPs). The growing demand for logistics outsourcing and the increase in the number and type of LSPs highlight the increasing importance of the LSP evaluation and selection process. Firms use various approaches to evaluate and select their LSP partners. Most of these approaches seem to have overlooked the strategic side of the logistics outsourcing process. Additionally, the uncertainty issue of data, the complexity of the decision and the large number of criteria involved increase the attractiveness of the Multi-Criteria Decision-Making (MCDM) approaches. A comparative literature review was used in order to identify crucial factors and methods that are used in logistics literature in fragmented ways and therefore, to establish and design a conceptual framework and models for logistics outsourcing. First, a long list of evaluation criteria was developed. Three main dimensions were identified: logistics performance, logistics resources and logistics services. Then a conceptual framework was developed using the three main dimensions with their related factors. Based on the comparative literature review outcomes, a number of integrated models have been developed and used to achieve this aim with emphasis given to FDEMATEL, FTOPSIS and FQFD techniques. Whereas the FDEMATEL technique contributed to construct influence relationships between factors under each dimension, develop impact-relationship maps and identify dependent and independent success factors (ISFs), the FTOPSIS technique used the weighted success factors to evaluate, rank and select the best LSP in three case studies. Twenty-one ISFs have been identified to be used in the final approach. These ISFs consist of eight LKPIs, seven logistics services and six logistics resources and capabilities. All of the factors were used to evaluate and select the best LSP alternative and ISFs were used to conduct the evaluation process. Different sensitivity analysis tests are used to confirm models’ robustness. Based on the outcomes of both cases, decision makers can use independent factors alone to evaluate and select the best LSP, which simplified the logistics outsourcing process in our study. The FQFD technique was used to link the LSUs strategic objectives with logistics requirements and the ISFs to develop a new strategic logistics outsourcing approach. Finally, two case studies representing the supply chain upstream and downstream are used to demonstrate the new hybrid approach effectiveness. The comparison of both cases’ findings highlighted their differences in terms of strategic objectives, logistics requirements and ISFs.

The container liner shipping industry (CLSI) can be defined as one consisting of a fleet of vessels that provides a fixed service at regular intervals between ports of call. It is noteworthy that the CLSI is remarkably acting as an artery in making contributions to the growth of the global economy. However, in an era of unprecedented global changes, the CLSI faces a variety of internal and external risks. Moreover, the reliability and capability of liner shipping operators (LSOs) vary under different environmental conditions. Consequently, it is important for LSOs to ensure that the safety and reliability of their internal operations as well as external environments through proactive assessment of their reliability and capability are intact. The literature indicates that disruptive events have been assessed and investigated by many researchers and practitioners whilst the root causes arising from external risks have not yet been fully identified. The aim of this research was to develop integrated frameworks for assessing risk and reliability in the CLSI under high uncertainties. As a result, three interlocking levels of analysis have been highlighted in this research: 1) business environment-based risk (BEBR), 2) organisational reliability and capability (ORC) of LSOs, and 3) punctuality of containerships. To achieve the aim, firstly, this research employed a combination of different decision-making methods (i.e. Analytic Hierarchy Process (AHP), Fuzzy Set Theory (FST) and Evidential Reasoning (ER)) for the assessment of the BEBR. The research outcomes are providing LSOs with a powerful decision-making tool to assess the risk value of a country prior to investment and strategic decisions. In addition, LSOs are also able to regularly assess the overall level of existing BEBR in a host country prior to development of mitigation strategies that can help to minimise financial losses. Secondly, this research employs the Fuzzy Bayesian Belief Network (FBBN) method for evaluating the ORC of LSOs. By exploiting the proposed FBBN model, LSOs are able to conduct a self-evaluation of their ORC prior to the selection of a strategy for enhancing their competitive advantages in the CLSI. A significant concern in container liner shipping operations is the punctuality of containerships. Therefore, thirdly, this research concentrated on analysing and predicting the arrival punctuality of a liner vessel under dynamic environments by employing a combination of Fuzzy Rule-Base (FRB) and FBBN methods. Finally, a probabilistic model for analysing and predicting the departure punctuality of a liner vessel was generated. Accordingly, from the outcomes of this research LSOs are able to forecast their vessels’ arrival and departure punctuality and, further, tactical strategies can be implemented if a vessel is expected to be delayed. In addition, both arrival and departure punctuality models are capable of helping academic researchers and industrial practitioners to comprehend the influence of uncertain environments on the service punctuality. In order to demonstrate the practicability of the proposed methodologies and models, several real test cases were conducted by choosing the Malaysian maritime industry as a focus of study. The results obtained from these test cases have provided useful information for recommending preventive measures, improvement strategies and tactical solutions. The frameworks and models that have been proposed in this research for assessing risk and reliability of the CLSI will provide managerial insights for modelling and assessing complex systems dealing with both quantitative and qualitative criteria in a rational, reliable and transparent manner. In addition, these models have been developed in a generic sense so that they can be tailored for application in other industrial sectors.

abstract: Traffic congestion is a major externality in modern transportation systems with negative economic, environmental and social impacts. Freeway bottlenecks are one of the key elements besides the demand for travel by automobiles that determine the extent of congestion. The primary objective of this research is to provide a better understanding of factors for variations in bottleneck discharge rates. Specifically this research seeks to (i) develop a methodology comparable to the rigorous methods to identify bottlenecks and measure capacity drop and its temporal (day to day) variations in a region, (ii) understand the variations in discharge rate of a freeway weaving bottleneck with a HOV lane and (iii) understand the relationship between lane flow distribution and discharge rate on a weaving bottleneck resulted from a lane drop and a busy off-ramp. In this research, a methodology has been developed to de-noise raw data using Discrete Wavelet Transforms (DWT). The de-noised data is then used to precisely identify bottleneck activation and deactivation times, and measure pre-congestion and congestion flows using Continuous Wavelet Transforms (CWT). To this end a methodology which could be used efficiently to identify and analyze freeway bottlenecks in a region in a consistent, reproducible manner was developed. Using this methodology, 23 bottlenecks have been identified in the Phoenix metropolitan region, some of which result in long queues and large delays during rush-hour periods. A study of variations in discharge rate of a freeway weaving bottleneck with a HOV lane showed that the bottleneck discharge rate diminished by 3-25% upon queue formations, however, the discharge rate recovered shortly thereafter upon high-occupancy-vehicle (HOV) lane activation and HOV lane flow distribution (LFD) has a significant effect on the bottleneck discharge rate: the higher the HOV LFD, the lower the bottleneck discharge rate. The effect of lane flow distribution and its relationship with bottleneck discharge rate on a weaving bottleneck formed by a lane drop and a busy off-ramp was studied. The results showed that the bottleneck discharge rate and lane flow distribution are linearly related and higher utilization of the median lane results in higher bottleneck discharge rate. / Dissertation/Thesis / Doctoral Dissertation Civil and Environmental Engineering 2014

<p> The future success of traffic management is contingent upon the advancement of information logistic systems. The ability to provide accurate, valid, and timely information is critical to the effectiveness of an intelligent transportation system&rsquo;s ability to improve public safety and economic growth. Traffic Operation Centers (TOC) receive and disseminate information with various actors in real-time and near real-time environments. Using the traffic incident management business process for a Traffic Operation Center, this research explores the effects of designing a traffic management system in context to the business process. Two system designs for a TOC are compared using the system architecture maps and incident duration time stamps captured during the use of each system. The results show the impact of using process-oriented information logistics (POIL) during the design phase when developing traffic management systems. </p><p>

<p> In the year 2000, Loukaitou-Sideris and Banerjee conducted a study on the Blue Line light rail system in Los Angeles. The study examined eight station areas between Long Beach and Los Angeles that were in some of the more neglected, inner-city areas. The study concluded the presence of light rail alone would not be sufficient enough to stimulate the economic development necessary to attract successful transit oriented development in those areas because of 11 antecedents identified by the authors. However, it can be argued that since only 10 years of rail service had passed when the original study was done, it was not enough time for the Blue Line to attract transit oriented development to the area. </p><p> The existing literature on TOD and inner cities argues that it can take up to 25 years for the benefits of light rail to fully establish. Using this argument to revisit the area studied by Loukaitou-Sideris and Banerjee, this study seeks to find out if and how conditions of the Blue Line have changed and if the 11 antecedents remain. By mirroring the methods used in the original study, this study investigates the same eight stations analyzed in the original study to determine if light rail can spark development and if areas are still hindered by the same antecedents.</p><p>

The thesis seeks to analyse the electric bicycle (e-bike) transition phenomenon in China by applying the Multi-Level Perspective (MLP) Transition Theory and Multi-scalar Perspective MLP. The research is performed with abductive case studies drawn from mixed methods. Firstly, we synthesised secondary data to investigate the e-bike transition at the national level (China) and the city level (“mini” case studies of Beijing and Fuzhou) to explore the research questions of 1) Can socio-technical transition occur without deliberate policy support (RQ1)? 2) How can we explain the rapid emergence and enduring popularity of e-bikes in China (RQ2)? Then we performed exploratory research in Cardiff, UK and Nanjing, China using semi-structured interviews. The interview results are used to help design survey questionnaire in Nanjing case study. It is the key research step and addresses the following research questions: 1) How are e-bikes embedded in the current transport regime (RQ3)? 2) How much longer can e-bikes continue to be embedded in the transport regime (RQ4)? 3) What are the mechanisms underlying the rapid emergence of e-bikes (RQ5)? To analyse the data collected from the survey, Generalised Linear Models and Binomial Generalised Linear Models are adopted to investigate current mode choice behaviour and predict future choice. In the theoretical aspect, the thesis applied the Multi-scalar Perspective MLP, filling the gap that traditional MLP does not take into account geographical, socio-political heterogeneity. In addition, we paid attention to the individual role in travel mode behaviour. From a practical perspective, the thesis uses substantial empirical data to provide a comprehensive understanding of the e-bike transition. We invited various groups in the survey, including e-bike users, bicycle users, car drivers, pedestrians and traffic police. The thesis explores a wide range of influencing factors, such as user anxiety, feelings related to e-bike adoption, e-bike user charging behaviour, other travel mode users and traffic police attitude towards e-bike development which have not been studied in previous e-bike literatures. The main findings are: 1) The fast emergence of e-bikes in China is spontaneous, without direct policy support from governments; 2) E-bike transition in China begins with transformation pathway (P1), followed by de-alignment and re-alignment pathway (P2); 3) E-bike users in China are mainly young career-aged commuters and have a much higher education level than average, which are different from other countries; 4) E-bikes are well embedded in the current transport regime and they are adopted widely in many aspects of people’s daily lives, including commuting, going shopping, and collecting children; 5) The underlying reasons for the selection of e-bikes are they provide affordable personal mobility due to the advantages of effort saving, flexible trip times, time saving in traffic jams, and high accessibility, whereas environmental and health factors are negligible; 6) E-bikes are possibly an intermediate mode on Nanjing’s motorisation pathway.

<p> Louisiana currently has 30 roundabouts in operation and hundreds of roundabouts in the planning and design stage. The Louisiana Department of Transportation and Development (DOTD) is very interested in knowing the safety performance of existing roundabouts in the state. </p><p> As revealed in this paper, the safety effectiveness of a roundabout depends on its prior traffic control type, conformity to the geometric design guidelines, changes in layout of intersection, and nighttime lighting conditions. All 19 roundabouts investigated by this study demonstrated significant reduction in injury crashes because of lower operating speed, reduced right-angle collisions, and elimination of head-on and left turn crashes. Based on changes in the number of conflicting points and traffic control method, it is understandable why the most significant and consistent safety improvement was associated with the roundabouts previously controlled by stop signs on minor streets. The Crash Modification Factor (CMF), as estimated by the Empirical Bayes (EB) method, for this group of roundabouts is 0.28 with a standard deviation of 0.054. The roundabout is economically justified for its safety benefit alone based on the benefit-cost ratio analysis for this group of roundabouts. </p><p> The study did identify a few compounding factors at the individual intersections, such as questionable geometric design elements, increased number of conflicting points, unpredictable human behavior, and lack of lighting at night.</p><p>