Identifier

etd-03192010-102911

Degree

Doctor of Philosophy (PhD)

Department

Civil and Environmental Engineering

Document Type

Dissertation

Abstract

Several recent mass evacuations, including those in advance of Hurricane Katrina in New Orleans and Hurricane Rita in Houston, have demonstrated the effects of limited planning for carless populations. The lack of planning left a significant portion of the mobility-limited population of both these cities unable to flee in advance of the storms. Since 2005 however, both of these cities (as well as others across the United States) have developed transit assisted mass evacuation plans at various levels of detail. Since these plans are relatively recent and do not have a history of experience on which to base their performance, it is difficult to know how well, or even if, they will work. This research describes one of the first attempts to systematically model and simulate transit-based evacuation strategies. In it, the development of and the results gained from an application of the TRANSIMS agent-based transportation simulation system to model assisted evacuation plans of New Orleans are described. In the research, a range of varying conditions were evaluated over a two-day evacuation period, including two alternative evacuation transit routing scenarios and four alternative network loading and demand generation scenarios resulting in eight evacuation scenarios. In the research, average travel time and total evacuation time were used to compare the results of a range of conditions over a two-day evacuation period, including two alternative transit evacuation routing plans and four alternative network loading scenarios. Among the general findings of the research was that the most effective scenarios of transit-based evacuation were those that were carried out during time periods during which the auto-based evacuation was in its “lull” (non-peak/overnight) periods. These conditions resulted in up to a 24 percent reduction in overall travel time and up to 56 percent reduction in the total evacuation time when compared to peak evacuation conditions. It was also found that routing buses to alternate arterial routes reduced the overall travel time by up to 56 percent and the total evacuation time by up to 22 percent. The impact of including transit evacuation on the network traffic operation was also tested using average evacuation speed and queue length, it was found that the transit evacuation had no impact on arterial traffic operation but it increased the average queue length on the interstate evacuation route. An evaluation of the transit-based evacuation plan was also completed. It was found that at least 68 percent of the transit dependent evacuees spent half an hour or less not on transit (walking towards the bus stop and/or waiting at the bus stop) and only 0.19 percent of them spent more than an hour not on transit in their evacuation trip. Finally, the number of buses needed for the carless evacuation under each evacuation scenario was estimated. A total of 56, 42, 61, and 43 local buses, for transporting people from the pickup locations to the processing centers, were required for network loading scenarios A, B, C, and D respectively. Also, 601 RTA buses, for transporting people from the processing centers to shelters, were needed.

Date

2010

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Wolshon, B

DOI

10.31390/gradschool_dissertations.3668

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