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  • 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.
731

Resilience of Transportation Networks Subject to Bridge Damage and Road Closures

Unknown Date (has links)
Resilience simply means to rebound when exposed to a disruptive event. Damage to bridges in transportation networks usually result in long detours and increased travel time hence have massive cost implications. Transportation networks composed of major bridge infrastructures frequently depend on the bridges to carry high traffic volumes. Transportation network resilience explains the ability of transportation networks to contain and recover from disruptions. Transportation network resilience entails the transportation network’s capability to continue functioning in spite of hazard-induced breakdown to network segments and how quickly those sections can be restored for the network to return to pre-disaster performance levels. Most resilience-related research in this area have primarily focused on physical bridge resilience without necessarily considering the resilience impact of bridge damage on the overall or regional network. This thesis is focused on filling this research gap by considering the resilience of transportation networks subject to bridge damage and road closures. This research further proposes the use of regional travel demand models and Geographic Information Systems (GIS) visualization techniques for network level impact visualization and accessibility analyses. The socio-technical approach associated with transportation system resilience is broad and multidisciplinary, focusing on the network’s ability to sustain functionality and recover speedily when faced with disruptions or shocks. Academic works in this area are generally viewed in terms of having qualitative or quantitative frameworks. There is also significantly less literature evaluating response and recovery phases of resilience. Developed resilience indexes have sparsely touched on many salient aspects of resilience; hence they are only applicable to very specific scenarios. Further investigative efforts are therefore necessary for post-disaster phases of resilience, evaluating the applicability of resilience indexes on multiple hazard events for transportation networks, and developing resilience indexes based on regional road network models while considering all network links and not just alternative routes. Temporary, long-term, and partial closures to bridges can result in enormous cost implications. However, bridge closures are inevitable not only due to the likelihood of hazard-induced damages, but routine maintenance, repair, and rehabilitation (MR&R) activities may also warrant closures. It is a current practice that vehicles are rerouted to the shortest alternative route (detour approach) during bridge closures. In an initial study, a scenario-based network approach for evaluating the impact of bridge closures on transportation user cost is proposed. Both the detour-based and network-based approaches were applied to the Tampa Bay regional network model while considering five bridge closure scenarios. User costs were computed in terms of delay and vehicle operating costs. Findings indicated that for closures to I-275, Gandy, Highway 580 and W.C.C Causeway bridges, there were increases of about 42%, 18%, 61%, and 45% respectively, in total user costs for the network-based approach when compared with the current detour-only approach, indicating a significant network impact captured by the network-based approach. The proposed methodology captures the effects of bridge closures on all road segments within the regional network jurisdiction, provides a more rigid framework for analysis by ensuring user costs are computed efficiently while avoiding overestimation, takes into account the fact that road users may have advance knowledge of roadway conditions prior to trips hence significantly influencing route choices, and provides sufficient information for agencies to implement preemptive measures to cater for network-level disruptions due to bridge closures. Also, regional network resilience was assessed, first through a schematic framework developed for selecting at-risk bridges during hurricane events by: (i) computing exposure probabilities for hurricane events at bridge locations; (ii) developing bridge damage state functions and damage state rating assignments using historical data from the National Bridge Inventory (NBI) database; (iii) identification of bridges at risk to hurricane-induced damage; and (iv) computing aging accessibility to hospitals from which resilience was measured. Results indicated an increase from about 1200 minutes to 2100 minutes and from about 900 to 1100 minutes, for the congested travel time (CTT) and free flow travel time (FFTT), respectively, representing about 75% and 15% for CTT and FFTT, respectively. Furthermore, an additional total travel distance of 52.85 miles was observed for CTT and FFTT. The mean travel times after bridge closures increased from 8.43 to 15.1 minutes and from 6.6 to 7.76 minutes for CTT and FFTT, respectively. The resulting resilience index scaled from 0 to 1 was computed with 1 representing a network which can recover immediately after a disruption (or a network without any performance loss) and zero for one that may never recover to its pre-disaster form. Restoration to moderately damaged bridge led to functionality improvement from 0.87 to 0.94 considering FFTT, and from 0.57 to 0.83 considering the CTT. Reinstating extensively-damaged bridges resulted in functionality increase from 0.94 to 0.96, and 0.83 to 0.85, respectively, for FFTT and CTT. The resilience index for this study was computed as 0.94 and 0.81 for FFTT and CTT respectively, implying a significant loss in senior mobility hence the need for mitigation measures A framework for assessing the regional network resilience was developed by leveraging scenario-based traffic modeling and Geographic Information System (GIS) techniques. High impact zones location identification metrics were developed and implemented in preliminarily identifying areas affected by bridge closures. Resilience index measures were developed by utilizing practical functionality metrics based on vehicle distance and hours traveled. These are illustrated for the Tampa Bay area. Findings for ten bridge closure scenarios and recovery schemas indicate substantial regional network functionality losses during closures. I-275 bridge closure yielded the highest functional loss to the regional network: the aggregated resilience index below 0.5 reflects severe network performance deficit and mobility limitations. Closure to the WCC Causeway bridge results in a network level resilience index value of 0.87, while the indexes for the other scenarios range between 0.76 and 0.97. These results reflect the high dependency of the network on the I-275 bridge. Damage to this bridge is foreseen to have a massive impact on the network in terms of travel cost. Lower resilience index values imply either significant functionality losses or lengthy closure durations or both. To demonstrate the proposed methodology, a hypothetical network illustration indicated that: (i) Single bridge closure scenarios recorded significant performance losses for bridges which directly connected to the destination zone; (ii) Resilience indexes echoed the need to compare predicted recovery times to scheduled restoration times since index measures are either compensated or penalized the speed of predicted recovery with respect to scheduled recovery durations; (iii) Sensitivity analyses reinforced the previous assertion by accounting for both performance loss and restoration or recovery times; (iv) Multiple closures had a significant impact on network performance hence rapidity is vital in improving network resilience. Like any study, there are some limitations identified in this research. While it was clearly identified that variation in response and recovery times may have a significant impact on explaining and formulating resilience measures, there is insufficient data on the road closure and bridge closure durations after hazard events. Such databases will help researchers in evaluating resilience more accurately. Furthermore, even though case studies in this thesis took into account large networks, the utilized models were based on static traffic assignment which suffices for long-term transportation planning. However, it is recommended that use of dynamic traffic assignment models should be explored since they are known to reflect more accurate travel times. This is especially important for equity-based case study applications with respect to post-disaster accessibility. The use of user equilibrium assignment which accounts for each road user minimizing his or her travel time was used for this study, it is recommended that the system optimal solution which minimizes the overall network travel time should be considered since it may be of specific interest to agencies. Solution-based resilience studies are encouraged, especially efforts which incorporate the influx of connected and autonomous vehicles and other shared mobility solutions. This study also recognized the need for collaborative efforts between management authorities and researchers to facilitate the development and implementation of necessary policies and systems for the enhancement of transportation systems’ resilience. / A Dissertation submitted to the Department of Civil and Environmental Engineering in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Summer Semester 2018. / July 19, 2018. / Bridges, Hazards, Infrastructure, Network Performance, Resilience, Transportation Networks / Includes bibliographical references. / John O. Sobanjo, Professor Directing Dissertation; Eric Chicken, University Representative; Ren Moses, Committee Member; Eren E. Ozguven, Committee Member.
732

Drivers' Perceptions Towards Cyclists and Bikeshare Users in the ECOBICI Service Area

Unknown Date (has links)
Despite the rapid global motorization, especially in developing countries, the use of the bicycle as urban transportation has increased in the last 35 years (Shaheen, Guzman, & Zhang, 2012). However, the United States, Canada, and Mexico have low cycling levels with bicycle mode share of little more than one percent (Buehler & Pucher, 2012). Some of the possible alternatives to promote the use of the bicycle is that the presence of bikeshare systems can encourage cycling by providing a safer environment for all types of cyclists (Fischman & Schepers, 2014). This dissertation examines the drivers’ perception towards cyclists and the possible difference in perception towards Ecobici bikeshare users and private cyclists. This research was carried out in Mexico City, at the EcoBici bikeshare service area. Data collection was done by a self-reported survey distributed online and by intercept surveys conducted to drivers who drive within the study area and control area. The analysis of the 710 participants' responses shows that drivers from the control area have a more positive perception towards cyclists, especially on issues related to bicycle investment and bicycle infrastructure. Overall, younger generations reported a more positive perception towards cyclists, and most drivers perceive that cyclists are not predictable on the roads as most of the drivers reported feel nervous when overtaking cyclists. When comparing Ecobici users to private cyclists, the results suggest that drivers do not have a clear preference for Ecobici users over private cyclists. Nevertheless, drivers are also more in favor of encouraging family and friends to use Ecobici bicycles over private bicycles, which could indicate that, unconsciously, participants consider that traveling on an Ecobici bicycle is safer than going on a private bicycle. The results from this study could have an impact on policymakers and transportation practitioners in Mexico City who would like to improve drivers-cyclists’ interactions in the road and to promote the use of the bicycle for transportation. / A Dissertation submitted to the Department of Urban and Regional Planning in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / 2019 / October 31, 2019. / Bikeshare systems, Drivers perception / Includes bibliographical references. / Michael Duncan, Professor Directing Dissertation; Mark Horner, University Representative; Jeffrey Brown, Committee Member; John Felkner, Committee Member.
733

Contumetro

Guerrero Choque, Kevin Enrique, Lluen Landeo, Pierina Jesabeth, Luna Lozano, Kelly Stephanie, Mateo Soto, Flor Jackeline, Terrones Carrasco, Evelyn Mishel 02 July 2019 (has links)
Actualmente existe la problemática de que las personas invierten mucho tiempo en las colas al momento de realizar recargas en las tarjetas del Metropolitano y la Línea 1 del Metro de Lima. Es por ello, que nuestra propuesta de valor es que se puedan realizar las recargas a través de nuestro aplicativo móvil llamado Contumetro, solo ingresando el número de la tarjeta de crédito o débito y enlazándola con la tarjeta del servicio de transporte y así pueda disfrutar de un servicio rápido y eficiente, asimismo, se cobrará una comisión de 0.20 céntimos por cada viaje. De esta manera, en el presente trabajo se busca validar si nuestro proyecto es sostenible en el tiempo y demostrar la rentabilidad de nuestro proyecto, por tal motivo se han realizado diversos estudios para validar la venta y por otro lado se ha realizado un análisis financiero. Se demuestra la viabilidad de su ejecución, en base a las entrevistas y ventas realizadas a nuestro público objetivo. Para la puesta en marcha se requerirá una inversión inicial de S/. 70,000, siendo financiado por nosotros, en la cual se estima recuperar en el primer año de operaciones. Asimismo, muestra una rentabilidad positiva, ya que cada año genera mayores ingresos. / Currently there is the problem that people invest a lot of time in queues at the time of recharges in the Metropolitan cards and Line 1 of the Lima Metro. That is why our value proposition is that you can make recharges through our mobile application called Contumetro, just entering the credit or debit card number and linking it with the transport service card and so you can enjoy a fast and efficient service, likewise, a commission of 0.20 cents will be charged for each trip. In this way, the present work seeks to validate if our project is sustainable over time and demonstrate the profitability of our project, for this reason several studies have been carried out to validate the sale and on the other hand a financial analysis has been carried out. The viability of its execution is demonstrated, based on the interviews and sales made to our target audience. For the start-up, an initial investment of S /.70,000 will be required, being financed by us, in which it is estimated to recover in the first year of operations. It also shows a positive return, since each year generates more income. / Trabajo de investigación
734

Investigating Bus Rapid Transit Signal Priority, Schedule-based Control and their Interaction on Service Performance and Fuel Consumption

Gulam Mohd Khan, Mohammad Hafiz Bin January 2018 (has links)
No description available.
735

Factors Affecting Parents' Choice of Active Transport Modes for Children's Commute to School: Evidence from 2017 NHTS Data

Sultana, Sharmin 06 September 2019 (has links)
No description available.
736

Towards Sustainable Mobility: the Impacts of Infrastructure Change, Technological Innovation, and Demographic Shift

Wang, Kailai 30 September 2019 (has links)
No description available.
737

Representation of built environment and relationship to travel outcomes

Kreider, Tyler January 2011 (has links)
No description available.
738

The highway transportation problem in Quebec.

Wykes, Neville George. January 1941 (has links)
No description available.
739

Transportation and regional integration in the Caribbean

Blenman, Eustace Hubert Morris January 1976 (has links)
No description available.
740

The arab civil aviation council ACAC /

Said, Elashiq Saad January 1988 (has links)
No description available.

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