Vulnerability of road-based public transit travel to flooding in Metro Manila, Philippines

• Main Author: Abad, Raymund Paolo B.
• Format: text
• Language: English
• Published: Animo Repository 2020
• Subjects: Floods—Philippines—Metro Manila; Transportation—Climatic factors—Philippines—Metro Manila; Route choice—Philippines—Metro Manila; Commuters—Philippines—Metro Manila; Civil Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_doctoral/1440; https://animorepository.dlsu.edu.ph/cgi/viewcontent.cgi?article=2472&context=etd_doctoral
• Institution: De La Salle University

Flooding impacts society and transport service provision. By disrupting travel patterns, flooding hinders the ability of both passengers and transport vehicle drivers, to perform their daily activities. Yet, there is limited research that quantifies the effects of flooding on the Metro Manila transit network and users. To fill this gap, this dissertation completed a two-part analysis on the ramifications of flooding: (1) on passenger travel behavior, and (2) on transit network performance. Specifically, the first part identified factors affecting travel behavior adaptation by generating discrete choice models. The second part assessed transit network vulnerability through map overlay analyses and transit network simulations. Necessary data were collected through questionnaire surveys administered to daily transport passengers at key locations in Metro Manila (e.g., transport terminals). The survey instrument asked respondents their travel decisions during their last flooding experience as well as during hypothetical flooding situations. The logit models were consistent with previous findings that adaptation primarily depends on the depth of flooding, respondent's travel situation (e.g., travel time), and respondent's risk perception. Sociodemographic profile, previous flood experiences in travel, and traveler's beliefs about changes over time in the frequency of flood also played a role. However, these were less influential in travel behavior adaptation. Ultimately, the stated preference (SP) results indicate that flooding and travel information increase the propensity for behavioral adaptation. A vulnerability assessment of the transit network uncovered that jeepney services in Manila are most affected since most of its routes are at risk of flooding. Flooding in Manila also disrupts several transit nodes for boarding or alighting transport services. From then on, the study conducted a total and single link flood disruptions of the transit network. In total, the research considered four flood simulations that affect the entire study area. The four scenarios include link capacity reduction, passenger movement restriction, a combination of capacity reduction and passenger movement restriction, and route service cancelation. All these scenarios showed that a flood in Metro Manila has consequences in travel times, travel distances, and the number of transit lines taken by each passenger. Next, the study selected different links in the network based on betweenness centrality measures and hazard (flood depth) and exposure (transit flow) interactions. The study simulated a disruption on these links by restricting passenger movement or the turning back of transit services. The simulations revealed that a disruption in one of the links along the southbound direction of EDSA is detrimental to the transit network's overall performance. Also, restrictions in boarding and alighting lead to substantial increases in travel times in all travel modes. From the results of the travel behavior and transit network analyses, the study was able to identify the sources of travel vulnerability to flooding in Metro Manila. The sources of travel vulnerability were determined based on indicators that influence exposure, sensitivity, and adaptive capacity of travels during a flood. These findings contributed to the formulation of policy recommendations that aims to improve the adaptive capacity and mitigate the impacts of flooding to travel.