Modeling social network influence on hurricane evacuation decision consistency and sharing capacity

Abstract

Evacuations in major disasters such as hurricanes involve complex decision-making and depend on several interrelated factors. Mass evacuation created traffic gridlocks with hours of added travel time in previous hurricane evacuations. To leverage this, shared mobility as an alternative evacuation strategy can ensure compliance to evacuation orders. Besides, previous evacuation studies examined evacuation decision-making for a given hurricane, however the empirical literature is inconclusive of what governs evacuation decision consistency of previous (evacuated or not) and future (will evacuate or not) hurricanes. As such, the purpose of this study is to explore the influence of personal social networks and day-to-day sharing activity on hurricane evacuation decision consistency and shared evacuation capacity (number of people with whom one will evacuate). By adopting a Personal Network Research Design (PNRD) framework and conducting an online survey of south Florida residents, the evacuation decision consistency of people is modeled using multinomial logistic regression method. An ego-centric social network analysis is also conducted which focuses on the survey respondents (egos) and the people in their close contacts (alters). Shared evacuation capacity is modeled using zero inflated Poisson (ZIP) approach. Tobit regression techniques are used to estimate the influence of day-to-day joint activities on shared evacuation decisions. Results showed that these variables are influenced by similarity in race, religion, marital status, bike ownership, use of social media and day-to-day shared activity. The age and income of people also significantly affect these decisions. The results will help in developing decision support frameworks for evacuation management applications and encourage emergency planners to promote shared evacuations in vulnerable communities.

Keywords

• Social network
• Shared mobility
• Hurricane evacuation
• Evacuation consistency
• Shared evacuation capacity