Jaderick P. Pabico
Institute of Computer Science
University of the Philippines Los Baños
NOTE: This on-going work was presented as a contributed oral paper to the
11th International Conference on Integrative Disaster Risk Reduction and Management
Eastern Samar State University, Borongan City, Eastern Samar, Philippines
27-29 November 2024
Paper DOI: 10.31219/osf.io/s72zg_v1
Abstract
In this study, we examine the implications of critical road segment failures on the timely evacuation of Borongan City residents, specifically focusing on the elderly demographics who face unique mobility challenges during emergencies. Building upon our prior work (Pabico, 2024), which utilized isochrone mapping to analyze accessibility, we broaden our approach to examine the impact of critical road segment failures on access to evacuation centers during disaster scenarios.
By utilizing network analysis, we simulate potential road segment disruptions to determine the increased evacuation times for affected populations. Our criticality assessment identifies those road segments whose failures would lead to significant delays, emphasizing their influence on evacuation efficiency for elderly residents, who represent the slowest-moving demographic and are therefore highly vulnerable in emergencies. Through this analysis, we not only highlight potential bottlenecks but also propose actionable insights for targeted disaster risk reduction strategies, including alternate route planning and prioritization of road maintenance in critical areas.
Our findings underscore the need for integrative disaster risk reduction and management planning in Borongan City. We aim to provide local governments and emergency planners with evidence-based recommendations for improving evacuation infrastructure, optimizing emergency response protocols, and enhancing overall community resilience. Ultimately, we advocate for prioritizing vulnerable populations in evacuation planning to ensure that all residents, particularly the elderly, have timely access to safe evacuation centers during disasters.
Keywords: critical infrastructure resilience, disaster preparedness, evacuation accessibility
Rationale
The impact of road network failures to evacuation accessibility would be particularly relevant and interesting to Borongan City residents and the city's disaster planners and managers for the following reasons:
Enhancing Disaster Preparedness: We aim to identify critical road segments essential for timely evacuations, allowing residents to understand which routes are most reliable or vulnerable during emergencies.
Increasing Safety for Vulnerable Populations: By focusing on elderly demographics, we highlight specific challenges that slower-moving, at-risk groups face, ensuring that their needs are prioritized in evacuation planning.
Informed Infrastructure Investment: Our research will help disaster planners prioritize maintenance or fortification of key road segments, enabling them to allocate limited resources to areas that can most improve disaster resilience.
Optimizing Evacuation Routes: We intend to assist planners in designing efficient evacuation routes and creating contingency plans for road closures or failures, ultimately leading to faster and safer evacuations for all residents.
Community Awareness and Engagement: Through our findings, we seek to raise awareness among Borongan residents about potential bottlenecks in evacuation routes, encouraging personal preparedness and community-level resilience measures.
Evidence-Based Policy Making: By providing data-driven insights into road infrastructure's role in emergency accessibility, we support evidence-based policies and frameworks for disaster risk reduction and management.
Alignment with Broader Resilience Goals: Our study contributes to long-term resilience planning, ensuring that Borongan City can better withstand and recover from future emergencies by strengthening evacuation logistics.
These points emphasize the practical benefits our study brings to enhancing disaster preparedness and resilience in Borongan City, ultimately aiming to improve community safety and well-being during emergencies.
Background
Disaster Preparedness in the Philippines
Several studies emphasize the importance of disaster preparedness and resilience, especially in areas highly exposed to natural hazards, such as the Philippines. The National Disaster Preparedness Baseline Assessment by the Pacific Disaster Center (2021), in collaboration with the Philippine government, provides a detailed overview of disaster risks across the country and offers data-driven recommendations for preparedness aligned with the Sendai Framework for Disaster Risk Reduction. This study highlights critical infrastructure, socio-economic factors, and governance structures influencing disaster management, making it a valuable resource for planners aiming to enhance resilience.
The DisasterNet Philippines Scoping Study conducted by Bollettino, et al. (2016) through the Harvard Humanitarian Initiative (HHI) also explored the collaboration between governmental and community organizations in bolstering disaster preparedness. It examined factors that increase community-based resilience and identified key stakeholders engaged in disaster response across various regions, offering insights into local and international partnerships critical to effective preparedness and response.
These studies, along with evaluations from institutions like the Philippine Institute for Development Studies (Domingo & Manejar, 2018), underscore the need for local government units to implement targeted policies and strengthen coordination among agencies. The following findings from these studies are especially relevant for Borongan City, where improving access to evacuation routes and ensuring road resilience during disasters could greatly enhance emergency response and community safety:
Disaster Preparedness Assessment
Key Findings: The National Disaster Preparedness Baseline Assessment highlights the need for systematic assessments of local capacities and vulnerabilities to effectively address disaster risks. It emphasizes a multi-hazard approach to preparedness, focusing on risk communication and community engagement.
Insight: Integrating local knowledge and participation in planning processes is crucial for enhancing the effectiveness of disaster preparedness initiatives.
Source: Pacific Disaster Center, 2021
Community-Based Resilience
Key Findings: The DisasterNet Philippines Scoping Study emphasizes the importance of community engagement and local organization involvement in disaster response efforts. It identifies key actors, such as government agencies and NGOs, that play vital roles in fostering community resilience.
Insight: Successful disaster management relies on strong collaboration among various stakeholders, with local communities at the forefront of response strategies.
Source: Bollettino, et al., 2016
Infrastructure and Risk Reduction
Key Findings: The studies indicate that critical infrastructure, including transportation networks, must be prioritized in disaster risk reduction efforts. Improved road conditions and emergency access routes significantly impact evacuation efficiency during disasters.
Insight: Investing in infrastructure resilience directly correlates with enhanced community safety and reduced vulnerability during emergencies.
Sources: Bollettino, et al., 2016; Pacific Disaster Center, 2021
Policy Recommendations
Key Findings: Recommendations include strengthening local governance structures to facilitate better disaster response, improving data collection for risk assessment, and implementing training programs for local disaster response teams.
Insight: Policies that promote decentralized decision-making can empower local governments to tailor disaster preparedness measures to specific community needs.
Source: Domingo & Manejar, 2018
Importance of Multi-Stakeholder Collaboration
Key Findings: Effective disaster preparedness requires a holistic approach involving government, civil society, private sector, and international organizations.
Insight: Collaborative frameworks and partnerships are essential for developing comprehensive disaster risk management strategies that are both effective and sustainable.
Sources: Bollettino, et al., 2016; Pacific Disaster Center, 2021
Network Analysis for Critical Road Identification
Several studies have employed network analysis of critical roads to assess accessibility to evacuation centers, particularly relevant to disaster preparedness in the Philippines and beyond. the following are insights that can be extracted from those studies:
Critical Road Segment Identification
Insight: Identifying critical road segments within transportation networks is essential for understanding which routes are vital during emergencies. This knowledge allows for targeted improvements in infrastructure and ensures that emergency response efforts can be optimized.
Sources: Hyun, et al., 2021; Jana, et al., 2023
Impact of Road Disruptions on Vulnerable Populations
Insight: Research indicates that road disruptions significantly impact vulnerable populations, such as the elderly and disabled. By analyzing the road network's criticality, planners can better ensure that evacuation routes remain accessible for these groups during emergencies.
Sources: Hyun, et al., 2021, Rezvani, et al., 2024
Resilience and Recovery Planning
Insight: Assessing the resilience of road networks contributes to more effective recovery planning. Understanding which roads are essential for evacuations helps in establishing priorities for repairs and maintenance after a disaster.
Sources: Jana, et al., 2023; Rezvani, et al., 2024
Data-Driven Disaster Risk Reduction Strategies
Insight: The integration of data-driven methodologies, such as edge betweenness centrality analysis, provides a quantitative basis for disaster risk reduction strategies. This approach helps planners prioritize interventions based on road network vulnerabilities.
Sources: Jana, et al., 2023; Rezvani, et al., 2024
Scenario-Based Analysis for Flood Risks
Insight: Scenario-based analyses, such as simulating flood events, are critical for understanding the impacts of environmental hazards on transportation networks. This insight aids in preparing road infrastructure for potential disasters, enhancing overall community resilience.
Sources: Rezvani, et al., 2024
Community Engagement in Planning Processes
Insight: Effective disaster preparedness involves engaging local communities in planning processes. Understanding the community’s needs and vulnerabilities allows for the development of more tailored and effective evacuation plans.
Sources: Hyun, et al., 2021; Jana, et al., 2023
Objectives
General Objective: To assess the impact of critical road segment failures on the timely access of Borongan City residents to evacuation centers, focusing on vulnerable demographics, particularly the elderly, in the context of disaster preparedness and response.
Specific Objectives:
To Identify Critical Road Segments: We aim to identify and evaluate critical road segments within Borongan City's transportation network that are essential for timely evacuations during disasters; and
To Analyze the Impact of Road Disruptions on Evacuation Time: We seek to evaluate how disruptions to critical road segments affect evacuation times for residents, using simulations of various disaster scenarios to quantify delays and identify potential bottlenecks in the road network. This analysis provide valuable information to strategic planners to enhance the overall efficiency of evacuation routes.
Methodology
Identification of Critical Road Segments
Data Collection
Road Network Data: We obtained the detailed geospatial data of Borongan City’s road network from a reliable and updated online platform, the open-source OpenStreetMap (OpenstreetMap Contributors, n.d.);
Evacuation Center Locations: We used the list of geo-tagged evacuation centers in Borongan City from Alejandria, et al., (nd). We also considered baranggay halls and public schools as additional evacuation centers and locate their respective geo-location using Google Maps and Street View (Google, n.d.).
Network Analysis Setup
Graph Construction: We represented the road network as a weighted undirected graph G(V, E, w), where nodes represent intersections and dead-ends, edges represent road segments, and edge weights represent the lengths of the road segments.
Walking Time Assignment: Using the weights of the edges and the average gait speed (Fidel, et al., 2021) of the slowest population, the elderly, we assigned the walking time as the time it will take for an elderly person to traverse the road segment from one end-point, an intersection, to another end-point, the next adjacent intersection.
Criticality Metrics: We computed the betweenness centrality (Freeman, 1977; Crucitti, et al., 2006; Jana, et al., 2023) of each edge to determine the importance of the road segment it represent within the network.
Critical Segment Identification
Computation: We used graph theory ideas to identify the critical road segments of the road network.
Bridges: We identified road segments (Tarjan, 1974) whose disruptions result in the isolation of the population on both ends of the segment and thereby remove accessibility to evacuation centers.
Local Bridges: We identified road segments whose disruptions result in the most significant increase in evacuation time.
Impact of Road Disruptions on Evacuation Time
Simulation of Road Disruptions
Disruption Scenarios: Simulate different road failure scenarios by removing key segments from the network and recalculating the shortest paths to evacuation centers.
Travel Time Analysis: Measure and compare evacuation times under normal conditions versus disrupted conditions.
Assessment of Impact
Comparative Analysis: Quantify increases in evacuation times due to road disruptions and identify which routes cause the most significant delays.
Mapping Delays: Visualize the impact using isochrone maps to show areas most affected by road failures.
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