Emergency evacuation in a health care environment has focused on methods for evacuating a facility, resources for transferring patients, and sufficient capacity at sheltering facilities. What has been overlooked is the interaction between health care facility evacuation and any communitywide evacuation that would result in significant roadway congestion. This paper focuses on how to route hospital vehicles during a hurricane evacuation. To provide an analytical comparison of evacuation time, delay, and routes across various evacuation scenarios, a simulation model is developed that combines hospital and general population traffic. The tailored model incorporates mesoscopic traffic flow concepts to evaluate a region covering several hundred miles with the ability to control speeds and make decisions at the individual vehicle level. With this novel modeling approach, evacuation planners can easily program the routes, test the travel times, and quickly consider different scenarios. It can be a useful tool for hospital evacuation planners and statewide or regional evacuation planners making decisions about traffic operational strategies. The analysis includes consideration of the evacuation of the Charleston, South Carolina, metropolitan area during a hurricane threat. The study found that to evacuate all patients 6 h before a hurricane landfall, the hospital evacuation must start at least 12 h before the mandatory evacuation order (a typical 24-h notice). Alternatively, the hospital evacuation can take place at the same time as the mandatory evacuation if both begin 48 h before landfall.

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Simulation is a useful and cost effective tool for evacuation planning. However, extensive data collection and preparation is necessary to build a traffic evacuation simulation model that can closely replicate real life conditions. In a community-wide evacuation process during an emergency, which covers hundreds of miles, input data related to simulation of traffic evacuations include (1) Traffic and roadway geometry, (2) Geographic distribution of the affected area, (3) Travel demand modeling, and (4) Behavioral analysis of potential evacuees. This paper presents a framework for preparing simulation inputs and ultimately developing a simulation model. Brief excerpts from a case study on the evacuation of Charleston, South Carolina are also included. An accurate input analysis is very important to the success of a simulation project since without correct input data, the output of a simulation cannot contribute to more effective decision making. This paper presents a simple and efficient methodology for data preparation regarding a large scale city evacuation simulation involving long distance trips.

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In this paper a new simulation modeling approach to support evacuation traffic management is introduced and a case study is presented. Traditional traffic simulation models neglect some real-life factors that need to be considered in an evacuation, such as the effect of road information and active control measures to manage traffic flow while vehicles are competing to find the best or preferred route. A passive equilibrium-seeking modeling approach may not be suitable for evacuation trip analysis due to limited route capacity and likely severe congestion during an evacuation. This paper introduces a new updated cell transmission model using discrete-event simulation, which can review and analyze the preferred path of evacuation traffic from multiple starting locations (or originations) to multiple destinations. Using this approach, case studies are conducted based on the user equilibrium principle, since it represents a natural behavior in an evacuation process. This research also demonstrates that, with the help of the cell transmission simulation model, an active traffic control mechanism can be evaluated. This study found that active traffic control measures are capable of decreasing total travel time during an evacuation by thousands of vehicle hours. Incorporating behavior consideration into the evacuation planning can help form a more accurate and realistic analysis of an evacuation plan.