The evacuation tail and its effect on evacuation decision making

Abstract

Over the past decade, several major incidents have occurred in the United States that have demonstrated the need for a better understanding of the behaviors, characteristics, and requirements of persons traveling during emergency evacuations. In addition to numerous emergency management and preparedness organizations, the agencies charged with the review and approval of plans for emergencies associated with nuclear power plants have also taken particular interest in these issues. Through their support of evacuation-related research, entities like the Nuclear Regulatory Commission and the Federal Emergency Management Agency are leading efforts to recognize and understand the lessons learned from evacuations associated with both natural and technological hazards so that they are not repeated in the future. One area of particular interest (and the one that is the focus of this article) is the segment of an evacuating population known as the “evacuation tail.”The evacuation tail is loosely defined as the last 10 percent of the population that departs during an evacuation. This group is of particular interest because the evacuees that make up the tail have been recognized to take a disproportionally longer amount of time to prepare and travel than the rest of the population. Depending on the specific characteristics of an emergency, such delays can put the tail population at a significantly elevated risk. In this article, the evacuation tail is described within the context of preevacuation activities and evacuee travel characteristics for the purpose of improving the overall evacuation process. It is thought that with this knowledge, the techniques and lessons learned from nuclear power plant evacuation planning can be applied to evacuations of any hazard type or location.