• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 13
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 25
  • 25
  • 11
  • 7
  • 7
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 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.
11

Short continuously reinforced concrete pavement design recommendations based on non-destructive ultrasonic data and stress simulation. / Recomendações de projeto baseadas em dados ultrassônicos não destrutivos e simulação de tensões para pavimento de concreto continuamente armado de curta extensão.

Lucio Salles de Salles 19 May 2017 (has links)
Four sections of continuously reinforced concrete pavement (CRCP) were constructed at the University of São Paulo campus in order to introduce this kind of pavement structure to Brazil\'s technical transportation community. Sections were designed as 50 m long concrete slab, short in comparison to traditional CRCP, in order to simulate bus stops and terminals - locations of critical interest for public infrastructure. The thesis presented herein concludes this research project initiated in 2010. As the initial goal of this study was the development of coherent, reliable and intuitive design recommendations for the use of CRCP technology in Brazil, a profound understating of its structural and performance peculiarities was needed. For that, the cracking process of the experimental CRCP sections was recorded over a span of seven years. Due to the sections\' short length and lack of anchorage, the experimental \"short\" CRCP presented a cracking behavior quite different than traditional CRCP. There were much less visible cracks than expected. To address this issue, a novel technology in ultrasonic non-destructive testing of concrete structures was applied. Through ultrasonic signal interpretation it was possible to discover several incipient non-visible cracks within the slabs - many of these became apparent on the slab surface in later crack surveys - and to characterize visible and non-visible cracks regarding crack depth. The updated crack map with non-visible cracks showed similarities with traditional CRCP. Additionally, the ultrasonic data analysis provided important information on thickness variation, reinforcement location and concrete condition that were applied in theoretical simulations (finite element software) of the short CRCP. Simulations were attempted considering different slab geometries, firstly with transverse cracks as joints with high load transfer efficiency (LTE) and secondly with a continuous slab without cracks or joints. The latter simulation was more accurate reaching a shift factor between field and simulated stresses in the order of 0.7 to 1.0. Deflection data and LTE analysis from cracks and panels in between cracks further attested the slab continuous behavior, which contradicts current CRCP design models and performance predictors. Furthermore, critical traffic and environmental loading conditions concerning Brazil\'s climate and bus traffic characteristics were investigated and related using a selected fatigue model resulting in design recommendations in a chart format for the short CRCP aimed at long-term projects for over 20 years of operation. The design chart was successfully applied to investigate three failures presented by the experimental short CRCP due to thickness deficiencies pointed out by the ultrasonic testing. / Quatro seções de pavimento de concreto continuamente armado (PCCA) foram construídas no campus da Universidade de São Paulo, com o objetivo de introduzir esta estrutura, de reconhecido sucesso internacional, à comunidade técnica de engenharia de transportes brasileira. As seções foram projetadas com uma placa de concreto de 50 m de extensão, curta em comparação ao PCCA tradicional, com a finalidade de simular paradas e terminais de ônibus - locais de grande interesse para a infraestrutura pública. A tese aqui apresentada conclui este projeto de pesquisa iniciado em 2010. Como o objetivo inicial deste estudo foi o desenvolvimento de recomendações de projeto coerentes, confiáveis e intuitivas para a utilização do PCCA no Brasil, foi necessário um profundo entendimento de suas peculiaridades estruturais e de desempenho. Para isso, o processo de fissuração das secções experimentais foi acompanhado durante sete anos. Devido à curta extensão e falta de ancoragem das seções, o PCCA \"curto\" apresentou um padrão de fissuração diferente do PCCA tradicional com muito menos fissuras visíveis na superfície do que o esperado. Para abordar esta questão, uma nova tecnologia ultrassônica para ensaios não destrutivos de estruturas de concreto foi aplicada. Pela interpretação do sinal de ultrassom, foi possível descobrir várias fissuras incipientes (não visíveis) dentro das placas - muitas dessas foram observadas na superfície da placa em levantamentos de fissuras posteriores - e caracterizar fissuras visíveis e não-visíveis quanto à profundidade da fissura. O mapa de fissuração atualizado com fissuras não visíveis mostrou semelhanças com PCCA tradicional. Além disso, a análise dos dados de ultrassom forneceu informações importantes sobre a variação da espessura, localização da armadura longitudinal e condição do concreto, que foram aplicados em simulações teóricas (software de elementos finitos) do PCCA curto. Simulações foram propostas considerando diferentes geometrias, primeiramente com fissuras transversais como juntas com alta eficiência de transferência de carga (LTE) e posteriormente com uma placa contínua, sem fissuras ou juntas. Esta última simulação foi mais precisa alcançando um fator de conversão entre tensões de campo e simuladas na ordem de 0,7 a 1,0. Dados de deflexão e análise de LTE em fissuras e placas entre fissuras atestaram novamente o comportamento contínuo das placas, o que vai em contradição com os modelos atuais de dimensionamento e de previsão de desempenho para o PCCA. Ademais, o tráfego crítico e condições de carga ambiental correspondentes ao clima e tráfego de ônibus típicos brasileiros foram investigados e relacionados usando um modelo de fadiga resultando em recomendações de projeto para o PCCA de curta extensão sendo direcionado para projetos de longo prazo para mais de 20 anos de operação. O gráfico de projeto foi aplicado com sucesso para investigar três falhas apresentadas pelo PCCA curto experimental devido a deficiências de espessura apontadas pelo teste ultrassônico.
12

Spatial Analysis of Burglary and Robbery Crime Concentration Near Mass-Transit in Portland

Barthuly, Bryce Edward 28 June 2019 (has links)
The relationship between mass-transit and the concentration of burglary and robbery crimes is inconsistent within the available literature in environmental criminology. A number of studies have provided evidence of crime concentration at and near mass transit locations where paths intersect, referred to as a node. These empirical studies bring in environmental criminology theory with the idea that crime is clustered, and the pattern of the concentrations is substantially influenced by how and why people travel and move in a city. It is suggested that public transit allows for a large proportion of the population to move around the community along a restricted number of destinations and paths; therefore, this concentration of population frames opportunities, and increases overall concentrations of crime. Establishments and environments surrounding transit nodes may act as crime generators or attractors, as a high influx of people are drawn to the area via nearby transit services. More recent literature has identified contrasting results, finding that crime does not concentrate near mass transit areas. In some cases, transit facilities appear to act as protective nodes, with lower counts of crime occurring in and around these locales. Given the conflicting results of existing research about crime at and near transit nodes, this study advances work in environmental criminology by analyzing the concentration of burglary and robbery events in Portland, Oregon. Recognizing that crime concentrations may vary depending on the level of analysis, this study explores crime concentrations at multiple levels of analysis. At the macro-level, this study examines burglaries and robberies across Portland as a whole to determine whether these events concentrate around mass transit nodes, when compared to other areas of the city. The meso-level examines within the broad category of mass transit, to explore whether burglary and robbery events cluster differently around different types of mass transit. Finally, the micro scale investigates the five highest-crime transit nodes to explore how burglary and robbery events concentrate in close proximity to these important locations. This study finds that while crime concentrates at higher levels surrounding mass transit nodes within Portland, the patterns of this concentration changes as the spatial level of analysis changes.
13

The value of real time information at bus stop in Hong Kong

Chan, Su-yee, 曾淑儀 January 2002 (has links)
published_or_final_version / Transport Policy and Planning / Master / Master of Arts in Transport Policy and Planning
14

Tryggheten vid busshållplatsen : En studie om tryggheten vid busshållplatser i Umeås lokalbusstrafik / Safety at the bus stop : A study of the safety at bus stops in Umeå’s local bus traffic

Ögren, Markus January 2021 (has links)
The purpose of this study was to examine how the safety was regarded by the public at three differently located bus stops in Umeå’s local bus traffic. Umeå is in the context a medium sized town located in the northern of Sweden.    The study was conducted through interviews at bus stops in three different locational districts within Umeå’s municipal borders. Vasaplan, Ålidhem and Röbäck. The bus stops differentiate from one another through means of population density, location, repute, and the availability of amenities in the area. A total of 38 recipients was interviewed at these bus stops, the questions asked to the recipients treated how the safety was perceived according to the time of the day at each location, if they had been exposed to or observed any alarming events at the bus stops as well as which attributes, they thought could increase or decrease said safety at the bus stop.    The data has been analyzed through the theoretical approaches of grounded theory. The result concludes that there are differences in the perceived safety between the bus stops. Röbäck was in many regards considered the safest bus stop. Whereas the definition in the safety between Vasaplan and Ålidhem was more difficult to define. The result also contains the attributes which the recipients have opinionated contributed most to the safety at the bis stop in both a positive and a negative way. The safety at the bus stop was largely dependent upon the time of the day, as evenings were when most recipient felt unsafe in the transit environments.
15

The impact of bus stop micro-locations on pedestrian safety in areas of main attraction

Kovacevic, Vlado S January 2005 (has links)
From the safety point of view, the bus stop is perhaps the most important part of the Bus Public Transport System, as it represents the point where bus passengers may interact directly with other road users and create conflicting situations leading to traffic accidents. For example, travellers could be struck walking to/from or boarding/alighting a bus. At these locations, passengers become pedestrians and at some stage crossing busy arterial roads at the bus stop in areas or at objects of main attraction usually outside of pedestrian designated facilities such as signal controlled intersections, zebra and pelican crossings. Pedestrian exposure to risk or risk-taking occurs when people want to cross the road in front of the stopped bus, at the rear of the bus or between the buses, particularly where bus stops are located on two-way roads (i.e. within the mid-block of the road with side streets, at non-signalised cross-section). However, it is necessary to have a better understanding of the pedestrian road-crossing risk exposure (pedestrian crossing distraction, obscurity and behaviour) within bus stop zones so that it can be incorporated into new design, bus stop placement, and evaluation of traffic management schemes where bus stop locations will play an increasingly important role. A full range of possible incidental interactions are presented in a tabular model that looks at the most common interacting traffic movements within bus stop zones. The thesis focused on pedestrian safety, discusses theoretical foundations of bus stops, and determines the types of accident risks between bus travellers as pedestrians and motor vehicles within the zones of the bus stop. Thus, the objectives of this thesis can be summarized as follows: (I) - Classification of bus stops, particularly according to objects of main attraction (pedestrian-generating activities); (II) - Analysis of traffic movement and interactions as an accident/risk exposure in the zone of bus stops with respect to that structure; (III) - Categorizing traffic accident in the vicinity of bus stops, and to analyse the interactions (interacting movements) that occur within bus stop zones in order to discover the nature of problems; (IV) - Formulation of tabular (pedestrian traffic accident prediction) models/forms (based on traffic interactions that creating and causing possibilities of accident conflict) for practical statistical methods of those accidents related to bus stop, and; (V) - Safety aspects related to the micro-location of bus stops to assist in the micro-location design, operations of bus stop safety facilities and safer pedestrian crossing for access between the bus stop and nearby objects of attraction. The scope of this thesis focuses on the theoretical foundation of bus stop microâ??location in areas of main attractions or at objects of main attraction, and traffic accident risk types as they occur between travellers as pedestrians and vehicle flow in the zone of the bus stop. The knowledge of possible interactions leads to the identification of potential conflict situations between motor vehicles and pedestrians. The problems discussed for each given conflict situation, has a great potential in increasing the knowledge needed to prevent accidents and minimise any pedestrian-vehicle conflict in this area and to aid in the development and planning of safer bus stops.
16

Improving transit facilities through land use planning and urban design

Guppy, Tamsin Wendy Frances Sue 05 1900 (has links)
Transit trips include four parts: the trip from the front door to the transit stop; the wait at the transit stop for the transit vehicle; the transit ride; and the trip from the transit drop off point to the final destination. This thesis explores methods of improving the pedestrian trips to and from the transit stop and the waiting period at the transit stop. People are not satisfied with their transit trips. People want better quality waiting areas, increased safety, comfortable surroundings, transit information, and convenience during the transit trip. This thesis explores the positive relationship between the quality of public streets and transit facilities, and ridership satisfaction. The thesis proposes that the transit trip can be improved by improving transit waiting areas, and the paths people take arriving at and departing from transit stops. BC Transit's Vancouver Regional Transit System's transit facilities are the focus of the study. Transit facilities include: bus stops, bus loops, bus exchanges, SkyTrain stations, and SeaBus terminals. The study reviews people's attitudes towards transit facilities and discusses the items that people consider important to a transit trip. This review includes a survey conducted by the author and a review of surveys conducted for BC Transit. A review of the literature provides further evidence on the basic requirements for transit facilities and a comparison is made with the local situation. The thesis explores the potential for land use planning, urban design and on-site design to improve the safety, comfort, and convenience of transit facilities. The role of BC Transit, in providing adequate transit facilities, is discussed along with the roles and responsibilities of other associated organizations including: the Province, the Greater Vancouver Regional District, municipal governments located within the Vancouver Region, private enterprise, and business improvement districts. The study concludes BC Transit should give more thought to the transit customer in the design and location of transit facilities. And that municipal governments must take action to improve the quality of streets and transit facilities in their own communities.
17

The impact of bus stop micro-locations on pedestrian safety in areas of main attraction

Kovacevic, Vlado S January 2005 (has links)
From the safety point of view, the bus stop is perhaps the most important part of the Bus Public Transport System, as it represents the point where bus passengers may interact directly with other road users and create conflicting situations leading to traffic accidents. For example, travellers could be struck walking to/from or boarding/alighting a bus. At these locations, passengers become pedestrians and at some stage crossing busy arterial roads at the bus stop in areas or at objects of main attraction usually outside of pedestrian designated facilities such as signal controlled intersections, zebra and pelican crossings. Pedestrian exposure to risk or risk-taking occurs when people want to cross the road in front of the stopped bus, at the rear of the bus or between the buses, particularly where bus stops are located on two-way roads (i.e. within the mid-block of the road with side streets, at non-signalised cross-section). However, it is necessary to have a better understanding of the pedestrian road-crossing risk exposure (pedestrian crossing distraction, obscurity and behaviour) within bus stop zones so that it can be incorporated into new design, bus stop placement, and evaluation of traffic management schemes where bus stop locations will play an increasingly important role. A full range of possible incidental interactions are presented in a tabular model that looks at the most common interacting traffic movements within bus stop zones. The thesis focused on pedestrian safety, discusses theoretical foundations of bus stops, and determines the types of accident risks between bus travellers as pedestrians and motor vehicles within the zones of the bus stop. Thus, the objectives of this thesis can be summarized as follows: (I) - Classification of bus stops, particularly according to objects of main attraction (pedestrian-generating activities); (II) - Analysis of traffic movement and interactions as an accident/risk exposure in the zone of bus stops with respect to that structure; (III) - Categorizing traffic accident in the vicinity of bus stops, and to analyse the interactions (interacting movements) that occur within bus stop zones in order to discover the nature of problems; (IV) - Formulation of tabular (pedestrian traffic accident prediction) models/forms (based on traffic interactions that creating and causing possibilities of accident conflict) for practical statistical methods of those accidents related to bus stop, and; (V) - Safety aspects related to the micro-location of bus stops to assist in the micro-location design, operations of bus stop safety facilities and safer pedestrian crossing for access between the bus stop and nearby objects of attraction. The scope of this thesis focuses on the theoretical foundation of bus stop microâ??location in areas of main attractions or at objects of main attraction, and traffic accident risk types as they occur between travellers as pedestrians and vehicle flow in the zone of the bus stop. The knowledge of possible interactions leads to the identification of potential conflict situations between motor vehicles and pedestrians. The problems discussed for each given conflict situation, has a great potential in increasing the knowledge needed to prevent accidents and minimise any pedestrian-vehicle conflict in this area and to aid in the development and planning of safer bus stops.
18

Improving transit facilities through land use planning and urban design

Guppy, Tamsin Wendy Frances Sue 05 1900 (has links)
Transit trips include four parts: the trip from the front door to the transit stop; the wait at the transit stop for the transit vehicle; the transit ride; and the trip from the transit drop off point to the final destination. This thesis explores methods of improving the pedestrian trips to and from the transit stop and the waiting period at the transit stop. People are not satisfied with their transit trips. People want better quality waiting areas, increased safety, comfortable surroundings, transit information, and convenience during the transit trip. This thesis explores the positive relationship between the quality of public streets and transit facilities, and ridership satisfaction. The thesis proposes that the transit trip can be improved by improving transit waiting areas, and the paths people take arriving at and departing from transit stops. BC Transit's Vancouver Regional Transit System's transit facilities are the focus of the study. Transit facilities include: bus stops, bus loops, bus exchanges, SkyTrain stations, and SeaBus terminals. The study reviews people's attitudes towards transit facilities and discusses the items that people consider important to a transit trip. This review includes a survey conducted by the author and a review of surveys conducted for BC Transit. A review of the literature provides further evidence on the basic requirements for transit facilities and a comparison is made with the local situation. The thesis explores the potential for land use planning, urban design and on-site design to improve the safety, comfort, and convenience of transit facilities. The role of BC Transit, in providing adequate transit facilities, is discussed along with the roles and responsibilities of other associated organizations including: the Province, the Greater Vancouver Regional District, municipal governments located within the Vancouver Region, private enterprise, and business improvement districts. The study concludes BC Transit should give more thought to the transit customer in the design and location of transit facilities. And that municipal governments must take action to improve the quality of streets and transit facilities in their own communities. / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate
19

An Empirical Study of Particulate Matter Exposure for Transit Users at Bus Stop Shelters

Moore, Adam 01 January 2012 (has links)
Congested traffic corridors in dense urban areas are key contributors to the degradation of urban air quality. While waiting at bus stops, transit patrons may be exposed to greater amounts of vehicle-based pollution, including particulate matter, due to their proximity to the roadway. Current guidelines for the location and design of bus stops do not take into account air quality or exposure considerations. This thesis provides a unique contribution to roadside air quality studies and presents an innovative method for the consideration of bus shelter placement. Exposure to roadside pollutants is estimated for transit riders waiting at three-sided bus stop shelters that either: 1) face roadway traffic, or 2) face away from roadway traffic. Shelters were instrumented with particulate matter monitoring equipment, sonic anemometers for wind speed and direction, and vehicle counters capable of categorizing vehicles by length. Temperature and relative humidity were gathered from a nearby monitoring station. Data were collected for two different days at three shelters during both the morning and afternoon peak periods for a total of eleven data periods. Bus shelter orientation is found to significantly affect concentration of four sizes of particulate matter: ultrafine particles, PM1, PM2.5, and PM10. Shelters with an opening oriented towards the roadway were observed to have significantly higher concentrations inside the shelter than outside the shelter. In contrast, shelters oriented away from the roadway were observed to have significantly lower concentrations inside the shelter than outside the shelter. The differences in average particulate matter concentrations are statistically significant across all four sizes of particulate matter studied. Additional correlation and linear regression investigation reveals interactions between particulate concentrations and built environment characteristics, vehicle flow, and weather conditions. Temperature and relative humidity played a large role in the diurnal variation of average concentration levels. In all instances, particulate concentrations were greater during the morning period, often substantially so. Particulate concentrations are shown to vary based on both wind speed and direction. Vehicle flow is correlated with particulate levels, though significance is not consistent. Lagged vehicle flow is demonstrated to be more consistently significant. Regression analysis suggests weather factors such as wind, temperature, and relative humidity explain roughly 70% of particulate variation, while vehicle flow explains less than 6%.
20

Microsimulation of Public Transport Stops for the Optimization of Waiting Times for Users Using the Social Force Model

Mendoza, Francis, Tong, Mayling, Silvera, Manuel, Campos, Fernando 01 January 2021 (has links)
El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Cities in the world aim to ensure the mobility of people, through the implementation of efficient Integrated Transportation Systems (ITS). This aims to improve the transport of people, which guarantees that they can be mobilized safely and without delays in the terminals and bus stops of the public transport system. The present article proposes a design of public transport stops aimed at optimizing the waiting time of users when transferring from one bus to another. For the validity of the proposal, the social force model of the Vissim program was used, where the behavior of the users within the bus stops was reflected. The results showed that the waiting times in the calibrated and validated microsimulation model were optimized by approximately 20%, which generates an improvement in the efficiency of the public transport system. / Revisión por pares

Page generated in 0.063 seconds