Equitable Resilience in Infrastructure Systems: Empirical Assessment of Disparities in Hardship Experiences of Vulnerable Populations during Service Disruptions

The objective of this study was to examine social inequality in exposure and hardship experienced by various groups due to infrastructure service disruptions in disasters. After more than two decades, the existing literature related to infrastructure resilience mainly focuses on system performance and considers the impacts of service disruptions to be equal for the public. The public, however, is not a monolithic entity, and different subpopulations have distinct needs and expectations of infrastructure systems. Thus, the same duration of service loss will not be experienced equally by the affected residents. Social subpopulations in a community have preexisting differences, or sociodemographic characteristics, which account for differential variations in disaster experience, and often socially vulnerable groups are disproportionally affected. Unfortunately, there is limited empirical information regarding inequity in the societal impacts of infrastructure service disruptions during disasters. This study addresses this knowledge gap by developing an equitable infrastructure resilience approach that integrates both the physical characteristics of the infrastructure systems and the sociodemographic characteristics that contribute to risk disparity experienced by individual households. The risk disparity was assessed by considering both the duration of the service disruptions (exposure) and people's ability to withstand disruptions (zone of tolerance). The study investigated empirical data related to the transportation, power, communication, and water service disruptions caused by Hurricane Harvey in 2017 for Harris County residents. The results concluded that certain socially vulnerable groups reported significant disparity in the hardship people experienced due to infrastructure service disruptions caused by the disaster. The significant experienced hardship was rooted in the group's having a lower zone of tolerance for service disruptions, experiencing a significantly higher duration of service outages, or a coupling effect when there was both greater exposure and lower zone of tolerance. The findings further revealed the following: (1) households with low socioeconomic status reported a coupling effect for communication and water disruptions and reported a lower zone of tolerance for transportation and power disruptions; (2) racial minority groups reported a coupling effect for transportation, communication, and water disruptions and a lower zone of tolerance for power disruption; and (3) households with younger residents reported a coupling effect for communication disruption, greater exposure to transportation and water disruptions, and lower zone of tolerance for power disruption. The findings uncovered existing inequalities in exposure and hardship experienced due to infrastructure service disruptions for various vulnerable subpopulations. Hence, the study establishes the fundamental knowledge and empirical information needed for an equitable resilience approach in infrastructure systems in order to better prioritize investments and therefore effectively reduce the risk disparity of vulnerable populations during service disruptions. (C) 2020 American Society of Civil Engineers.