Managing Pedestrians During Evacuation of Metropolitan Areas > Table of Contents

1  Introduction

1.1    Background

The hurricane seasons of the past few years produced vivid images of major highways filled to capacity with residents evacuating from coastal areas.  Other less-widely publicized evacuations take place on a relatively frequent basis across the United States each year.  A January 2005 study commissioned by the Nuclear Regulatory Commission cites that evacuation of 1,000 or more individuals occurs once every three weeks in this country.1  The study, which evaluated evacuation operations over a 12-year period, indicated that most evacuations result from wildfire threats to populated areas, floods, hurricanes and tropical storms, fixed site and transportation-related industrial accidents where airborne releases of gases often dangerous to humans occur, transportation accidents, and malevolent acts.  During these scenarios, emergency responder assessments of the situation may prompt the incident commanders to ask law enforcement officials, often supported by transportation agencies, to order nearby residents to leave immediately.  These events typically involve the evacuation of small towns or areas around industrial complexes. Dozens to maybe a few thousand people get in the family cars and drive a few miles to a safer location, directed away from the potential hazard area by law enforcement officers and traffic barriers which also prohibit any incoming traffic.

The September 11, 2001, (or 9/11) attacks on the high-profile workplaces of the World Trade Center (WTC) in New York City and the Pentagon, just outside Washington, D.C., made real the impact of an unexpected, or “no-notice,” event in a metropolitan setting.  The news coverage of the events of this infamous day showed thousands of people leaving the area of the WTC on foot.  The evacuation from the borough of Manhattan included not only the typical traffic congestion expected in an evacuation in the United States, but thousands of pedestrians moving along with, or among the streams of outbound and inbound vehicles. Even though numerous emergency response vehicles arrived at the WTC complex almost immediately, hundreds of others continued to converge on the immediate scene from more distant locations. When the Pentagon also was hit, national news coverage included pictures of the highways near the Pentagon filled with barely moving vehicles, much of it having originated in the District even before the Pentagon was evacuated.  That morning the local and federal transportation agencies in the District were first-hand witnesses to the thousands of persons leaving government and other office buildings filling sidewalks to capacity.  In places, they were spilling into the gridlocked traffic in order to make better progress or cross to take a different route.

When a large-scale, damaging event has occurred or the imminent threat of one has become known, transportation agencies working with public safety officials have traditionally had two principal objectives:

• Minimize the time it takes to get an adequate force of emergency responders to the scene where they can help victims, provide assessments, and control access.
• Maximize the proportion of the population moved away from the hazardous area without being subjected to other risks (e.g., traffic crashes; prolonged exposure to the danger).

Evidence that large numbers of pedestrians may be part of an evacuation raised questions within FHWA about what actions are needed to manage pedestrian traffic during metropolitan evacuations and what FHWA can contribute in this area to ensure safe and effective movement of pedestrians while minimizing their impact on vehicular movement.  While the U.S. has not experienced large scale, “no-notice” urban evacuations, emergency managers responsible for urban areas understand the potential for this type of evacuation to occur following natural, industrial, or malicious emergency events.  Planners continue to look to the limited U.S. experiences of evacuations in response to no-notice events in cities to uncover lessons learned, findings and best practices to use in their efforts to plan for the worst and hope for the best.  These instances include the NYC and Washington, D.C., 9/11 evacuations, the Oklahoma City bombing spontaneous evacuations, the Atlanta Summer Olympics bombing, and the movement resulting from the Northeast Blackout of 2003.  FHWA is trying to aid planners by studying this often-overlooked component of evacuation to aid metropolitan evacuation planners in their efforts to balance the safety and mobility needs of both vehicle and pedestrian evacuees. 

1.2    Overview of the Report

The reader should consider this report a cursory view of the topic.  This report addresses what is already known about managing pedestrian traffic in U.S. metropolitan evacuations.  Researchers tapped a large variety of information sources for insights.  Since this is a very new area of research on evacuation, little actual research on the topic exists.  A more complete definition of the issues necessitates further in-depth research on temporary evacuations from large highly urbanized city centers in reaction to a sudden unanticipated event, something that has rarely occurred in the U.S. 

The term “metropolitan evacuation” here refers to an emergency evacuation taken as a protective action that is implemented for a portion of a densely built-up downtown area in larger cities in the United States.  The basic situation assumed for the discussion of the issues is the following: 

• The triggering event will be one without notice (e.g., terrorist attack; explosion or toxic release).
• The scope of the event will be such that the emergency evacuation activity will be critical for only a portion of the metropolitan area.
• Emergency response actions will occur to mitigate the injury and damage from the destructive or threatening event even as the evacuation is taking place.
• The evacuation is expected to be temporary for those parts of the area that were not badly damaged or contaminated. 

The report is organized as follows:

• Chapter 2 covers the approach for identifying literature that addresses or in some way includes the topic of pedestrian evacuation and what was discovered.  The literature review was designed to touch on pedestrian behavior from a variety of disciplinary viewpoints.  Newspaper accounts and findings from various types of research were examined, as well as a series of recent in-depth case reports done under the auspices of the FHWA, to examine transportation operations during several large scale catastrophic events.  In addition, some selected events were examined through publicly available “after action reports” written from the perspective of emergency response.
• Chapter 3 presents information gathered through telephone interviews with fifteen agency officials in urban areas to obtain practitioner insights.  Several cities were selected based on information that the city had experienced a major emergency event or conducted robust emergency planning for downtown areas. The fifteen telephone interviews included conversations with representatives of transportation, emergency response, and emergency planning agencies in the San Francisco Bay area, New York City, Seattle, Washington, Washington, D.C., metropolitan area, and Cleveland, Ohio.   
• Chapter 4 addresses examples of variables in the evacuation context and evacuation management beliefs and summarizes the discussions of the multi-disciplinary panel of eight subject matter experts that was convened to share different perspectives on the nature and management of pedestrian evacuations.
• Chapter 5 outlines conceptual approaches for achieving mobility and safety for pedestrians and minimizing interference of pedestrians and drivers with each others’ mobility. Evidence of the existence of these approaches was found in evacuation implementation or planning of some cities. However, no research was found that described details or issues related to the evacuation implementation. Other approaches had not yet been implemented in an actual event involving pedestrian evacuees.
• Chapter 6 outlines research needs and provides a brief summary of different perspectives from practitioners and researchers on the topic of pedestrians in evacuations and a final conclusion about the relevance of the topic to public safety and emergency management agencies faced with the possibility of the need to handle an emergency evacuation of some portion of a highly urbanized area.