• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 249
  • 69
  • 34
  • 4
  • 4
  • 4
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 447
  • 447
  • 122
  • 101
  • 71
  • 68
  • 63
  • 50
  • 43
  • 42
  • 42
  • 39
  • 39
  • 35
  • 32
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Measuring the Success of a Transportation Project - Loop 202 (Red Mountain Freeway) Case Study

January 2012 (has links)
abstract: Measuring the success of a transportation project as it is envisioned in the Regional Transportation Plan (RTP) and is detailed in an Environmental Impact Statement (EIS) is not part of any current planning process, for a post construction analysis may have political consequences for the project participants, would incur additional costs, and may be difficult to define in terms of scope. With local, state and federal budgets shrinking, funding sources are demanding that the performance of a project be evaluated and project stakeholders be held accountable. The Transportation Research Board (TRB) developed a framework that allows transportation agencies to customize their reporting so that a project's performance can be measured. In the case of the Red Mountain Freeway, the selected performance measure allows for comparing the population forecasts, the traffic volumes, and the project costs defined in the final EIS to actual population growth, actual average annual daily traffic (ADT), and actual project costs obtained from census data, the City of Mesa, and contractor bids, respectively. The results show that population projections for both Maricopa County and the City of Mesa are within less than half a percent of the actual annual population growth. The traffic analysis proved more difficult due to inconsistencies within the EIS documents, variations in the local arterials used to produce traffic volume, and in the projection time-spans. The comparison for the total increase in traffic volume generated a difference of 11.34 percent and 89.30 percent. An adjusted traffic volume equal to all local arterials and US 60 resulted in a difference of 40 percent between the projected and actual ADT values. As for the project cost comparison, not only were the costs within the individual documents inconsistent, but they were underestimated by as much as 75 percent. Evaluating the goals as described in an EIS document using the performance measure guidelines provided by the TRB may provide the tool that can help promote conflict resolution for political issues that arise, streamline the planning process, and measure the performance of the transportation system, so that lessons learned can be applied to future projects. / Dissertation/Thesis / M.U.E.P. Geography 2012
112

Problems of Transportation Planning During Winter Storms in Portland, Oregon, and Seattle, Washington: A Comparative Study

January 2015 (has links)
abstract: Winter storms decrease the safety of roadways as it brings ice and snow to the roads and increases accidents, delays, and travel time. Not only are personal vehicles affected, but public transportation, commercial transportation, and emergency vehicles are affected as well. Portland, Oregon, and Seattle, Washington, both suffer from mild, but sometimes extreme, storms that affect the entire city. Taking a closer look at the number of crashes reported by the City of Portland and the City of Seattle, it is seen that there is an increase in percent of crashes with reported road conditions of snow and ice. Both cities appear to have nearly the same reported crash percentages. Recommendations in combating the issue of increased accidents and the disruption of the city itself include looking into communication between the climate research institution and city planners that could help with planning for better mitigation during storms, a street or gas tax, although an impact study is important to keep in mind to make sure no part of the population is at risk; and engineering revolutions such as Solar Roadways that could benefit all cities. / Dissertation/Thesis / Masters Thesis Urban and Environmental Planning 2015
113

Empirical analysis and modeling of freeway merge ratios and lane flow distribution

January 2015 (has links)
abstract: This dissertation research is concerned with the study of two important traffic phenomena; merging and lane-specific traffic behavior. First, this research investigates merging traffic behavior through empirical analysis and evaluation of freeway merge ratios. Merges are important components of freeways and traffic behavior around them have a significant impact in the evolution and stability of congested traffic. At merges, drivers from conflicting traffic branches take turns to merge into a single stream at a rate referred to as the “merge ratio”. In this research, data from several freeway merges was used to evaluate existing macroscopic merge models and theoretical principles of merging behavior. Findings suggest that current merge ratio estimation methods can be insufficient to represent site-specific merge ratios, due to observed within-site variations and unaccounted effects of downstream merge geometry. To overcome these limitations, merge ratios were formulated based on their site-specific lane flow distribution (LFD), the proportion of flow in each freeway lane, for two types of merge geometries. Results demonstrate that the proposed methods are able to improve merge ratio estimates, reproduce within-site variations of merge ratio, and represent more effectively disproportionate redistribution of merging flow for merges where vehicles compete directly to merge due a downstream lane reduction. Second, this research investigates lane-specific traffic behavior through empirical analysis and statistical modeling of lane flow distribution. Lane-specific traffic behavior is also an important component in evaluating freeway performance and has a significant impact in the mechanism of queue evolution, particularly around merges, and bottleneck discharge rate. In this research, site-specific linear LFD trends of three-lane congested freeways were investigated and modeled. A large-scale data collection process was implemented to systematically characterize the effects of several traffic and geometric features of freeways in the occurrence of between-site LFD variations. Also, an innovative three-stage modeling framework was used to model LFD behavior using multiple logistic regression to describe between-site LFD variations and Dirichlet regression to model recurrent combinations of linear LFD trends. This novel approach is able to represent both between and within site variations of LFD trends better, while accounting for the unit-sum constraint and distribution assumptions inherent of proportions data. Results revealed that proximity to freeway merges, a site’s level of congestion, and the presence of HOV lanes are significant factors that influence site-specific recurrent LFD behavior. Findings from this work significantly improve the state-of-the-art knowledge on merging and lane-specific traffic behavior, which can help to improve traffic operations and reduce traffic congestion in freeways. / Dissertation/Thesis / Doctoral Dissertation Civil and Environmental Engineering 2015
114

Ordenação de alternativas para suporte às decisões relativas ao transporte intermunicipal e para reduzir o tempo de parada para manutenção

Dusi, Francisco Emilio 06 June 2014 (has links)
Existem muitas decisões a serem tomadas no setor de transportes, tais como logística, custos de manutenção, satisfação do cliente e tempo de parada para manutenção, entre outros. Assim, mais pesquisas, estudos e modelos precisam ser desenvolvidos a fim de fornecer opções para o apoio a decisão para a redução desses problemas. Este estudo tem como objetivo apoiar a tomada de decisão em relação aos problemas na área de transporte público. Para os tomadores de decisão no setor de transportes, são necessárias alternativas de manutenção que podem ser potencialmente eficazes para resolver os problemas por ordem de prioridade.Com uma abordagem multicritério, é proposto um modelo que oferece uma classificação para essas alternativas em ordem de prioridade, para apoiar a tomada de decisão e com base no método ELECTRE II. Este modelo também considera os aspectos subjetivos e objetivos ao mesmo tempo, a fim de fornecer aos decisores uma visão mais clara e mais abrangente, onde as alternativas podem resolver os múltiplos objetivos definidos pelas empresas. Isso é realizado considerando-se as preferências dos decisores através de um enfoque sob os aspectos de sustentabilidade, econômicos e ambientais. Através deste modelo é possível reconhecer as ordens de prioridades para apoiar a gestão da manutenção, bem como as principais alternativas possíveis para resolver problemas relacionados com paradas de manutenção que afetam o setor de ônibus intermunicipais. Este estudo também apresenta os resultados de uma aplicação deste modelo dentro de uma empresa de transporte público no Brasil. / There are many problems related to decision-making in the transportation sector, such as logistics, maintenance costs, customer satisfaction and downtime for maintenance, among others. Thus, more research, studies and models need to be developed in order to support decision-making to reduce such problems. This study aims to support decision-making in relation to problems that may arise in the area of public transportation. For decision-makers in the transportation sector, maintenance alternatives are required that can be potentially effective for solving problems in order of priority. In the multi-criteria approach, a model is proposed which offers a ranking for these alternatives in an order of priority through decision-making based on the ELECTRE II outranking method. This model also considers subjective and objective aspects simultaneously, in order to provide decision-makers with a clearer and more comprehensive view, in which the alternatives can address the multiple objectives set by companies. This is done by considering the preferences of decision-makers through focusing on sustainability and economic and environmental aspects. Through this model, it is possible to recognize the orders of priorities to support the management of maintenance, as well as the major potential alternatives to solve problems related to maintenance downtime that affect intercity buses. This study discusses the results of an application of this model within a public transportation company in Brazil.
115

Ordenação de alternativas para suporte às decisões relativas ao transporte intermunicipal e para reduzir o tempo de parada para manutenção

Dusi, Francisco Emilio 06 June 2014 (has links)
Existem muitas decisões a serem tomadas no setor de transportes, tais como logística, custos de manutenção, satisfação do cliente e tempo de parada para manutenção, entre outros. Assim, mais pesquisas, estudos e modelos precisam ser desenvolvidos a fim de fornecer opções para o apoio a decisão para a redução desses problemas. Este estudo tem como objetivo apoiar a tomada de decisão em relação aos problemas na área de transporte público. Para os tomadores de decisão no setor de transportes, são necessárias alternativas de manutenção que podem ser potencialmente eficazes para resolver os problemas por ordem de prioridade.Com uma abordagem multicritério, é proposto um modelo que oferece uma classificação para essas alternativas em ordem de prioridade, para apoiar a tomada de decisão e com base no método ELECTRE II. Este modelo também considera os aspectos subjetivos e objetivos ao mesmo tempo, a fim de fornecer aos decisores uma visão mais clara e mais abrangente, onde as alternativas podem resolver os múltiplos objetivos definidos pelas empresas. Isso é realizado considerando-se as preferências dos decisores através de um enfoque sob os aspectos de sustentabilidade, econômicos e ambientais. Através deste modelo é possível reconhecer as ordens de prioridades para apoiar a gestão da manutenção, bem como as principais alternativas possíveis para resolver problemas relacionados com paradas de manutenção que afetam o setor de ônibus intermunicipais. Este estudo também apresenta os resultados de uma aplicação deste modelo dentro de uma empresa de transporte público no Brasil. / There are many problems related to decision-making in the transportation sector, such as logistics, maintenance costs, customer satisfaction and downtime for maintenance, among others. Thus, more research, studies and models need to be developed in order to support decision-making to reduce such problems. This study aims to support decision-making in relation to problems that may arise in the area of public transportation. For decision-makers in the transportation sector, maintenance alternatives are required that can be potentially effective for solving problems in order of priority. In the multi-criteria approach, a model is proposed which offers a ranking for these alternatives in an order of priority through decision-making based on the ELECTRE II outranking method. This model also considers subjective and objective aspects simultaneously, in order to provide decision-makers with a clearer and more comprehensive view, in which the alternatives can address the multiple objectives set by companies. This is done by considering the preferences of decision-makers through focusing on sustainability and economic and environmental aspects. Through this model, it is possible to recognize the orders of priorities to support the management of maintenance, as well as the major potential alternatives to solve problems related to maintenance downtime that affect intercity buses. This study discusses the results of an application of this model within a public transportation company in Brazil.
116

Peak Travel in a Megacity: Exploring the Role of Infrastructure Saturation on the Suppression of Automobile Use

January 2014 (has links)
abstract: Contrary to many previous travel demand forecasts there is increasing evidence that vehicle travel in developed countries may be peaking. The underlying causes of this peaking are still under much debate and there has been a mobilization of research, largely focused at the national scale, to study the explanatory drivers but research focused at the metropolitan scale, where transportation policy and planning are frequently decided, is relatively thin. Additionally, a majority of this research has focused on changes within the activity system without considering the impact transportation infrastructure has on overall travel demand. Using Los Angeles County California, we investigate Peak Car and whether the saturation of automobile infrastructure, in addition to societal and economic factors, may be a suppressing factor. After peaking in 2002, vehicle travel in Los Angeles County in 2010 was estimated at 78 billion and was 20.3 billion shy of projections made in 2002. The extent to which infrastructure saturation may contribute to Peak Car is evaluated by analyzing social and economic factors that may have impacted personal automobile usage over the last decade. This includes changing fuel prices, fuel economy, population growth, increased utilization of alternate transportation modes, changes in driver demographics , travel time and income levels. Summation of all assessed factors reveals there is at least some portion of the 20 billion VMT that is unexplained in all but the worst case scenario. We hypothesize that the unexplained remaining VMT may be explained by infrastructure supply constraints that result in suppression of travel. This finding has impacts on how we see the role of hard infrastructure systems in urban growth and we explore these impacts in the research. / Dissertation/Thesis / M.S. Civil Engineering 2014
117

Impacts of light rail in job accessibility in Phoenix

January 2014 (has links)
abstract: It has been identified in the literature that there exists a "spatial mismatch" between geographical concentrations of lower-income or minority people who have relatively lower rates of car ownership, lower skills or educational attainment and who mainly rely on public transit for their travel, and low-skilled jobs for which they more easily qualify. Given this situation, various types of transportation projects have been constructed to improve public transit services and, alongside other goals, improve the connection between low-skilled workers and jobs. As indicators of performance, measures of job accessibility are commonly used in to gauge how such improvements have facilitated job access. Following this approach, this study investigates the impact of the Phoenix Metro Light Rail on job accessibility for the transit users, by calculating job accessibility before and after the opening of the system. Moreover, it also investigates the demographic profile of those who have benefited from improvements in job accessibility----both by income and by ethnicity. Job accessibility is measured using the cumulative opportunity approach which quantifies the job accessibility within different travel time limits, such as 30 and 45 minutes. ArcGIS is used for data processing and results visualization. Results show that the Phoenix light rail has improved job accessibility of the traffic analysis zones that are along the light rail line and Hispanic and lower-income groups have benefited more than their counterparts. / Dissertation/Thesis / M.U.E.P. Urban and Environmental Planning 2014
118

Um processo sintetizado para planejamento de transportes urbanos. / A synthesized model for urban transportation planning.

Pedro Akishino 08 October 2002 (has links)
O principal objetivo desta Dissertação foi o de se definir uma metodologia de planejamento de transportes que fosse sintetizada e menos onerosa que a do processo tradicional e, principalmente, que permitisse dispensar a pesquisa domiciliar, atividade demorada, trabalhosa e cara. O trabalho consistiu de uma análise superficial de diversos trabalhos existentes, elegendo quatro deles para uma análise mais detalhada, o que permitiu definir a metodologia proposta. O método baseia-se na determinação de produções e atrações de viagens a partir do conhecimento do número de unidades de uso de solos (residências, lojas, escritórios, indústrias, etc.) existentes na área de estudo, com suas respectivas características, aplicando-se-lhes taxas transferidas de outros estudos. As produções e atrações de viagens são distribuídas utilizando-se o modelo gravitacional, com parâmetros da função impedância transferidos de outros estudos. A divisão modal e a alocação de tráfego seguem o padrão tradicional, tendo sido indicada a utilização de programas de computador para a realização de alocação de equilíbrio. Segue o modelo de quatro etapas, onde a diferença fundamental está no fato de que, por não se dispor de dados completos, por causa da não realização das entrevistas de O/D domiciliares, são realizados diversos procedimentos de ajustes com o objetivo de se verificar o grau de compatibilidade das taxas transferidas utilizadas. O trabalho restringiu-se à alocação de tráfego na rede viária para o ano base, e à comparação com o fluxo observado, verificando-se que o processo conduz a um resultado aceitável. / The main aim of this work was the definition of a transportation planning methodology that was synthesized and less expensive than the one presented by the traditional process, and, more than this, which could be done without household research. A superficial analysis of several works was conducted, and four of them were chosen for a more detailed analysis, which allowed to define the proposed methodology. The method is based on the determination of trip production and trip attraction once the number of houses, shops, offices, industries, etc. present in the area of study is known, as well as their respective characteristics, and taxes from other studies were used. The trip distribution was performed using the gravitational model, applying parameters of the impedance function transferred from other studies. The modal split and the traffic assignment follow the traditional standard and the use of computational programs to perform the equilibrium assignment has been indicated. It follows the four steps model, where the fundamental difference is that, because complete data were not available, once household O/D interviews were not performed, several adjusting procedures were performed, to verify the degree of compatibility of the used transferred taxes. The work is limited to traffic assignment in the road network for the base year, and to the comparison with the observed flow, and it was verified that the process leads to an acceptable result.
119

Distance based vehicle insurance : actuarial and planning issues

Babiuk, Michelle 05 1900 (has links)
Distance based vehicle insurance (sometimes know as “Pay as you drive,” “Pay by the mile” or “Pay per-km” insurance) has long been advocated by transportation planners as a transportation demand management (TDM) strategy. In addition to reducing congestion and greenhouse gas emissions, it also has the potential to meet a number of planning goals, such as health and equity improvements. Despite the wide interest in and predicted benefits of distance based insurance, there is little consensus on the detailed design of a system that could be implemented. Five main distance based pricing schemes have been proposed: a flat per-km rate, temporal or “time of day” pricing, road-type pricing, demographic pricing and “differential” pricing, which prices low mileages at a higher per-km rate. Each of these systems treats risk differently and thus results in different cross-subsidies between drivers. The proposal’s design thus has implications for an insurance system’s fairness and equity. This report examines the distribution of crash risk across time, across space, and across the different demographic groups. It then compares the current annual insurance system’s treatment of risk with that of various proposals for distance based insurance. It evaluates each proposal, considering its treatment of risk and its potential for increasing fairness and equity of costs and of mobility. It also examines each proposal’s other impacts, such as effectiveness in maintaining privacy and in reducing health impacts, greenhouse gas emissions and congestion. The recommended model is a flat per-km rate. Each driver would pay the same rate for every kilometer driven, regardless of time or place. However, individual drivers’ per-km rates would vary, depending on current insurance rating factors, such as residential location, type of car and driving record. / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate
120

Forecasting patronage on demand response transportation systems: Economic feasibility and environmental impacts

Johnson, John 01 January 1981 (has links)
No description available.

Page generated in 0.1118 seconds