Algorithm to prioritize the restoration of a multiple facility, multiple-hazard road network

Transportation networks are one of several critical infrastructures on which first responders rely in order to deliver emergency services. However, there is no guarantee that a transportation network will be fully operational following a regional event, such as a hurricane or earthquake. Emergency planning and response tools should explicitly integrate this possibility to ensure the completeness of the risk assessment process. This paper considers the elevated vulnerability to which a community is exposed when disruptions in a transportation network slow emergency response. An average weighted vulnerability metric is defined to favor a network restoration strategy that quickly reduces emergency response times to their nominal levels. This metric is incorporated into an algorithm to prioritize network restoration, so that individuals who might require assistance are not exposed to prolonged periods of lengthy response times. The formulation considers a number of types of emergency response facilities and different types of hazard; the hazards can require a response from more than one type of facility. The utility of the approach is illustrated through a series of examples. Our results demonstrate that the approach can offer systematic guidance to reduce emergency response times after a partial or complete outage of a transportation network.