Even if residents decide to evacuate, the evacuation can fail if a portion of the evacuees do not leave early enough. Not all households evacuate at the same time and the circumstances that account for departure timing vary across incidents. In general, evacuees collectively tend to leave promptly or more gradually, depending on the perceived urgency of departure, reflecting the time remaining before the anticipated arrival of the hazard event. Chapter 5 discusses three components that affect a household’s departure time: the authorities’ decision time, the household’s warning receipt time, and the household’s evacuation preparation time.