Effect of Aggressive Evacuation Behavior Associated with Information-Sharing Using a DTN on Evacuation Time

In a large-scale disaster, providing evacuees with appropriate evacuation routes based on the location of closed road segments and shelters is expected to be useful for rapid evacuation. To enable information-sharing even when communication infrastructure is unavailable, Yahara et al. have proposed a disaster information-sharing system using a heterogeneous wireless DTN, combining short-range broadband wireless communications with long-range narrowband wireless communications. In their system, the locations of closed road segments are shared so that evacuees can avoid the closed road segments. However, the system does not distribute information about congestion. Thus, many evacuees may choose the same route and experience a long evacuation time. The system should provide evacuees not only the location of closed road segments but also evacuation routes selected based on the closed road segments and the congestion of road segments to enable more efficient evacuation. On the other hand, there is concern that evacuees who have received a recommended evacuation route may act against the movement of other evacuees who have not received the recommended route, causing congestion and increasing the evacuation time. We investigated the impact of providing recommended evacuation routes selected based on the road congestion estimated from wireless communication between evacuees and fixed nodes and the aggressive behavior of evacuees who have received a recommended evacuation route through simulations. The simulation results reveal that providing evacuation routes selected based on the closed road segments and the road congestion is effective in shortening the evacuation time; also, the aggressive behavior of evacuees who have received a recommended evacuation route contributes to arranging the evacuation flows so that they can move smoothly when the road congestion is high.