Household No-Notice Evacuation Logistics: How Well Do Households Optimize?
In no-notice events, adults must decide whether and how to gather household dependents. This article examines how effectively households plan their evacuation logistics for a daytime event in a multimodal network and how these plans match the outcomes of a nonlinear integer optimization approach that simultaneously determines optimal meeting locations, final destinations, and family member pickup assignment and sequencing. The model outcomes are compared to information from 59 in-depth interviews. Households largely assign emergency-gathering activities to the parent normally responsible for child-related travel and prefer to meet at home; these decisions are optimal only in some cases. The authors also identify the sensitivity of the optimized logistics to the time adults spend at pickup locations gathering their dependents and ?break-even? points where a combination of walking and trains become competitive with personal vehicles. For some households, the additional travel time to make these modes competitive is fewer than 2 h, which is not necessarily an unexpected delay during evacuations. Thus, emergency management agencies should continue to include transit agencies in their planning process and ensure that employees are available to provide services for cases where severe congestion is encountered, and not just for socioeconomically vulnerable populations.