Toward Enhanced Resilience of Interdependent Critical Infrastructures: Robustness Analysis of a Multi-modal Public Transport Network Subject to Power Grid Failures with Integrated Travel Demand Data

Electric mobility is spreading worldwide to reduce carbon emissions. This massive electrification intensifies interactions between transportation and electricity networks, causing significant management and planning challenges when disruptions occur. This study proposes a comprehensive methodology for assessing the robustness of multimodal public transportation systems under power outage scenarios, emphasizing critical interdependencies between electric power and transport infrastructures. The proposed approach relies on a modeling framework based on graph theory to represent the structure of mobility services and analyze associated travel times. By combining topological and demand-weighted analyses, the research assesses network performance, focusing on metrics such as average travel time ( ATT ) and node betweenness centrality ( NBC ). While ATT provides a global efficiency perspective, NBC offers insights into station importance, with notable divergences between the two metrics that demonstrate their complementary insights. Additionally, the scalability and adaptability of the framework are validated through real-world data application, providing a valuable template for analyzing other urban systems. Application to Lyon identifies metro line D as critical and central, underscoring the need for targeted maintenance and enhanced emergency preparedness. This study addresses research gaps by incorporating electrical dependencies of multimodal transit networks, providing insights for urban infrastructure resilience and risk assessment. The work supports the incorporation of security considerations into transportation system planning and operations, offering strategies for effective risk mitigation and emergency response.