INNOVATIONS, IDEAS, & INSIGHTS
With every summer comes the threat of hurricanes and, as a result, the necessity to evacuate large coastal populations out of harm’s way. Implementing an evacuation order is a complex operation that requires significant planning, analysis, and coordination to execute the order in an efficient and effective method. Communities cannot underestimate the importance of conducting a hurricane evacuation study and the value of evacuation clearance time modeling to help facilitate good decision-making and operational effectiveness.
Recent new advancements in technology will not only improve decision-making, but also serve as an invaluable tool to operationally visualize evacuation behavior patterns and improve evacuation operations.
A Hurricane Evacuation Study typically consists of major components, each utilized to inform decision making within evacuation scenarios. These five components are as follows:
Hazards Analysis: Utilized to determine the probable worst-case effects from the various intensities and approaching direction of hurricanes that could strike the region.
Vulnerability Analysis: Utilized to identify the areas, populations, and facilities that are potentially vulnerable to storm surge, flooding, and tremendous wind damage under a variety of hurricane threats.
Behavioral Analysis: Forming assumptions that must be made regarding the manner in which the population in and around the vulnerable area will react to the threat, including the percentage that will evacuate, response times to evacuation orders, probable destinations, the number of vehicles that will be used (including the number that may be motor homes or towing boats/campers), the evacuation response of tourists, movement of evacuees from other jurisdictions into the area of study, and the percentage of evacuees who would require public assistance for emergency transportation.
Shelter Analysis: Utilized to estimate the number of evacuees that will seek public shelter and the number of shelter spaces available and to provide information for use in determining the Evacuation Clearance Times in the transportation analysis.
Transportation Analysis: Utilized to calculate the clearance times needed to conduct a safe and timely evacuation for a range of hurricane threats. Other purposes are to define the evacuation roadway network and to evaluate traffic control measures/highway improvements for improved traffic flow.
In conducting a transportation analysis, a primary means of planning and preparing for evacuations involves the use of computer modeling to calculate evacuation clearance times. These traffic models have been used for a variety of emergency/evacuation/reentry scenarios by changing the appropriate network and traffic flow parameters. Evacuation Clearance Time is the estimated time necessary to safely evacuate people, from the time an evacuation order is given until the time when either the last evacuee leaves the evacuation zone (given various factors such as the type of hazard or threat, level of notice of the incident, population characteristics of the area at the time, and public behavior) or the remaining population is forced to shelter-in-place due to conclusion of operations as the hazard begins to impact the area. Clearance times are used by emergency management staff to determine the window of opportunity available to initiate an evacuation order, and ensure that evacuees have enough time to reach safety before the threat or hazard arrives.
Integrated Solutions Consulting is currently deploying new evacuation simulation modeling technologies to assist communities in not only estimating evacuation clearance times, but also simulate complex vehicle interactions on a macro and micro level, help to identify system bottlenecks, understand evacuation behaviors, and aid in evaluating traffic management strategies based on various operational and behavioral conditions and assumptions
There are a number of evacuation simulation modeling software tools available in the marketplace, all with varying capabilities and functionalities. Integrated Solutions Consulting’s evacuation modeling experts have composed a list of recommendations for what factors should be included in an ideal model. While no model may be able to achieve every one of the recommendations listed, jurisdictions should work to ensure that as many of the factors as possible are incorporated into their planning efforts for the most accurate forecast outcomes.
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