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Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Civil Engineering

Year Degree Awarded

2017

Month Degree Awarded

May

First Advisor

Eric J. Gonzales

Subject Categories

Business Administration, Management, and Operations | Economic Policy | Energy Policy | Environmental Policy | Environmental Studies | Infrastructure | Operations Research, Systems Engineering and Industrial Engineering | Policy Design, Analysis, and Evaluation | Public Policy | Transportation | Transportation Engineering | Urban Studies | Urban Studies and Planning

Abstract

In urban and suburban locations, public transit can be seen as an effective mode

of daily transportation. The majority of the time, travelers would seek the cheapest, shortest, and possibly most eco-friendly means of transit. When designing public transit network systems, transportation planners and decision-makers, with input from stakeholders, should strive to optimize transportation services to meet the needs of the population most efficiently and at the lowest cost, that is, providing a transportation system that s the three E's of the sustainability concept: environment, social equity, and economic.

Previous studies have focused on sustainability as the primary concern in public

transportation system design and performance; however, studies attempting to model environmental impacts in addition to costs did not account for specific characteristics of the transit vehicle's driving cycle (i.e., time spent cruising, idling, accelerating, and decelerating) or evaluated all the E's of sustainability. This dissertation explores the Pareto frontier of the three aspects of sustainability in the design of multi-modal public transportation routes with unequal space between the stops and stations with no transfers in a linear corridor by simultaneously accounting for greenhouse gas (GHG) costs, capital, operating and maintenance costs, and users' costs. The proposed models do not account for the spatial structure of the city, but allow for a comparison of emissions and costs between various public transit trunk technologies and the use of private vehicles (i.e., conventional and hybrid) operating along the same corridor assuming static traffic conditions.

The goal of this research is to support the transportation planning process by providing a systematic analysis method to evaluate the trade-offs of public transportation modes vis-a-vis the three aspects of sustainability among private vehicles. Additionally, the results of this research aim to assist transit policy-makers and practitioners when solving the multi-criteria problem of minimizing operation and passenger costs as well as the costs of GHGs in terms of CO2-equivalent. To achieve these objectives, analytical models are developed for user cost (a measure of social sustainability), agency cost (a measure of economic sustainability), and GHG emissions (a measure of environmental sustainability). Each of these components is monetized and combined into a single generalized cost function, which is minimized by optimizing stop spacing and service headway along the route. The findings indicate that a dedicated bus lane (DBL) is the most sustainable technology that can meet all three E's of sustainability up to an approximate level of demands of 200 trips per hour per mile compared to the other technologies. When the level of demand is higher than 200 trips per mile per hour, the full bus rapid transit appears to be the most sustainable mode. However, when the level of demand is within the range of 0-3.99 trips per mile per hour, hybrid vehicles are competitive with a dedicated bus lane and the full bus rapid transit (Full BRT) with trade-offs among the other trunk technologies that are investigating in this dissertation. Light rail transit is found to be the most environmentally friendly among all transportation modes or technologies in this dissertation. Furthermore, a mixed traffic (MT) bus is found to be the most eco-friendly trunk transit technology compared to the tram.

Both light rail and tram are competitive in terms of headways with the DBL for a

certain range of demands along the route. The findings also reveal that the cost of

GHG emissions is always the smallest portion of the overall cost of service with this proposed methodology for all studied trunk technologies and the variation of the GHG emissions market value does not affect the decision making when selecting the most sustainable transportation mode(s) for a city. The main takeaway of the research in terms of sustainability is that a full BRT is not always the most sustainable technology for a city, because a DBL has the potential to simultaneously meet all three E's of sustainability at certain level of demands. When the rails' electricity comes from a nuclear/ offshore power-plant, metro heavy rail (MHR), tram, and light rail transit (LRT) were found to be the eco-friendliest, with MHR resulting to the highest and LRT to the lowest emissions.

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