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Public Health Emergency Preparedness

This resource was part of AHRQ's Public Health Emergency Preparedness (PHEP) program, which was discontinued on June 30, 2011, in a realignment of Federal efforts.

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Chapter 1: Summary

With funding from the Agency for Healthcare Research and Quality (AHRQ), Abt Associates developed the Mass Evacuation Transportation Model, which estimates the time required to evacuate patients from healthcare facilities. This document describes the Transportation Model and how the model was pilot tested in two test sites — New York City and Los Angeles. A companion report (the Mass Evacuation Transportation Model: User Manual) provides instructions on how to run the model.

This work is part of an AHRQ Task Order with Abt Associates and its subcontractor, Partners Healthcare, to support development of a national strategy for the design, development, and implementation of an interagency mass patient and evacuee movement, regulating and tracking system. The National Response Plan assumes that up to 100,000 patients and evacuees may require transport, regulating, and tracking during a catastrophic incident. The AHRQ project was undertaken in collaboration with the Federal Emergency Management Agency, the U.S. Department of Defense (DoD), and the U.S. Department of Health and Human Service' Office of Public Health Emergency Preparedness. AHRQ and DoD jointly led the project. A project steering committee was also convened that guided the project and three day-long meetings were held. (Go to Appendix 1 for a list of committee members.)

The larger project had two overall goals:

  • Build a Web-based Mass Evacuation Transportation Planning Model for use before a mass casualty/evacuation incident to estimate the transportation resources needed to evacuate patients and evacuees from healthcare facilities and other locations.
  • Develop recommendations for a National Mass Patient and Evacuee Movement, Regulating, and Tracking System that could be used during a mass casualty or evacuation incident for the purposes of locating, tracking, and regulating patients and evacuees, as well as provide decision support to persons and organizations with responsibility for patient and evacuee movement and care, healthcare and transportation resource allocation, and incident management.

This report addresses the first of these two project goals. A separate AHRQ report details the recommendations for the National Mass Patient and Evacuee Movement, Regulating, and Tracking System.

Model Summary

The model calculates the time required to transport patients from evacuating facilities to receiving facilities. The model considers:

  1. Evacuation Resources: The fleet of vehicles available in an emergency is a key input of the model. The user must identify how many advanced life support (ALS) and basic life support (BLS) ambulances, wheelchair vans, and buses are available for use during the evacuation, and how many patients each vehicle can carry at a time.
  2. Facilities: Users can input any number of facilities into the model. The key attributes of each facility are whether it is an evacuating or receiving facility, the assumed transportation needs of the patients at the facility during the evacuation (i.e., the percent requiring an ALS ambulance, BLS ambulance, wheel chair van, or bus), the facility capacity and occupancy rate, and its location. Each facility may have a different patient mix. Patients are thus grouped by acuity rather than the specific diagnosis and are prioritized during the evacuation to ensure that the most severely ill patients travel the least distance.
  3. Additional inputs: Additional features include: accounting for traffic congestion by lengthening expected travel times, specifying the loading or unloading time for each vehicle type, and designating an "overflow facility" for patients who cannot be accommodated in the designated receiving facilities.

The primary output of the model is the number of hours necessary to transport patients from the evacuating facilities to the receiving facilities. In addition to the total hours for evacuation, the model shows the number of trips made by each vehicle type, thus indicating which vehicles are most in demand. This will help planners anticipate resource needs.


New York City and Los Angeles participated in this project and served as pilot test sites for the model. In New York City, AHRQ and project staff worked with the City's Office of Emergency Management (OEM) to assist them in developing plans to evacuate coastal hospitals and nursing homes in the event of a Category 4 hurricane. Working closely with OEM, project staff obtained input data, ran the model under a variety of assumptions, and delivered an analysis of the output to OEM and AHRQ. A copy of the analysis is in Appendix 2.

In Los Angeles, AHRQ and project staff worked with the Los Angeles Emergency Preparedness Department (EPD) to prepare and conduct an earthquake tabletop exercise that required the evacuation of three hospitals. The model was used to estimate the transportation resources needed to evacuate the three hospitals under a variety of assumptions.

The remainder of this report includes a detailed description of user inputs, assumptions, model processes, and outcomes.

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