No way out: Emergency evacuation with no internet access

In urban emergencies and disasters, Internet connectivity is commonly unavailable to a large number of civilians in the affected area since the cellular network infrastructure and WiFi systems are either congested, or they have partially or completely failed. In this paper, we discuss how short-range wireless communications among mobile devices, e.g., smartphones, can be leveraged to construct an ad hoc and disruption tolerant evacuation support system in these typical emergency scenarios. Opportunistic communications among mobile devices are employed to gather and disseminate information on the emergency, such as hazard locations, and personalized evacuation directions are provided to each civilian using this partial information. We evaluate the performance of an opportunistic communications based evacuation support system in both indoor and outdoor evacuations of urban areas using simulation experiments, and show the improvement that can be offered. We also discuss how such a system can be protected against either malicious or inadvertent dissemination of false information, quantifying the effect of false information and the protection offered by our proposed method.