Mass Evacuation

Mass Evacuation

June 01, 2012 – PSPA Editorial Staff

When disaster strikes (whether natural or man-made) emergency responders including police, fire, and ambulance are significant components of service in addition to any number of additional support personnel, including but not limited to, transportation officials who also must be readily available to facilitate the evacuation and effective routing of people out-and-away from an impact zone.

Mass evacuations are difficult to plan and execute. Evacuations can be small to large-scale undertakings that may involve countless numbers (hundreds to thousands) of people exiting one or more areas in a short period of time. In general, American transportation systems, interstate highways, and roadways are not designed for evacuations; rather they are designed for normal day-to-day traffic flow.

Successful evacuation incorporates a number of planning contingencies, including but not limited to: alerting the public at large, deploying city officials, managing exit routes, and providing transportation and/or alternate shelter for people without automobiles who live in/around the impact zone.

Key evacuation dynamics include, but are not limited to:

Evacuation Orders

Government authorities and behavioral researchers have conducted countless studies to determine how the general public responds to evacuation orders in an attempt to determine how to become more effective.

Researchers note that while some municipalities have the authority to make evacuations mandatory, many don’t have the resources to enforce such orders if people ignore them. However, an even bigger factor is that significant numbers of people don’t know they are required to evacuate in the first place and it is not uncommon that a number of people are often unaware an emergency exists or even that an evacuation order has been issued. Additionally, people often don’t know when the evacuation orders refer to their location, because they don’t know which evacuation zone they are located within.

People also respond differently depending on who issues the order. People are more likely to respond to an evacuation order if it is issued by a community leader, such as the police chief, mayor, or governor. Of the people who do receive the evacuation orders and still don’t leave, there are many factors that come into play, from not having anywhere to go and/or not having access to transportation. Social pressure also comes into play; people are more likely to leave or stay depending on what their neighbors and friends are doing. Additional factors include, age, health conditons, pets and the inability to secure personal possessions.  

Advance Notice

A significant component of mass evacuation is providing advance notice, if possible.  

In past years, mass evacuation due to inclement weather related incidents has become an issue in many parts of the country as thousands of people cannot effectively (in a timely manner) exit heavily populate areas. Traffic jams coupled with start-and-stop traffic, especially on interstate freeways where vehicles can’t readily exit for restroom needs, medical problems, food and water issues in addition to automobiles running low or out of fuel, simply leaves people feeling helpless. Additionally, if the traffic standstill or backup lasts long enough, people may not be able to evacuate the impact zone and fall prey to similar or worse risk than they would have experienced if they had not evacuated from the start.

Contraflow / Traffic Re-Direct

Contraflow is a method of reversing the direction of certain lanes of traffic during an evacuation to make the flow out of an area more efficient. For example, if you have several lanes on a highway coming into an area that’s being evacuated, contraflow plans would appropriate some of those lanes to give people more lanes for driving out of the area. Contraflow is being used more often in evacuation planning and has been implemented in several evacuations, including many historically footnoted hurricanes.

Contraflow is reported to be a difficult plan to implement and can’t be used in all situations as effective planning and controls must be established to redirect traffic. Authorities must determine where entrances to the newly reversed lanes will be, and driver-awareness plans must be communicated to ensure people know the lanes are changing.

Staggered Departures

Conducting evacuation orders in stages or phases is an alternate way to mitigate bottlenecks and traffic standstills. Phased evacuation based upon a number of variables including, but not limited to: population concentration, location in relation to impact zone and varying levels of risk can dictate departure timetables.

Special Needs

Countless people have special needs that necessitate special assistance. Hurricane Katrina revealed that Louisiana had several areas that did not have adequate plans for evacuating those who were disabled, unable to drive, did not have vehicles, or were located in high risk areas.

In the years following Katrina, a number of cities and states have made modifications to their emergency preparedness programs. For example, the city of Houston allows residents to register for special needs transportation services for hurricane evacuations. In the city of New Orleans, authorities have implemented a city-assist evacuation plan where residents can visit the city website for information about where their evacuation spots are located as well as register for special-needs assistance.

Lessons Learned

History has provided many lessons learned. The ever-changing weather patterns throughout the U.S. coupled with other risks including natural and man-made disasters further necessitates the need for city officials to study all aspects of human behavior and transportation planning as evacuation is an integral component of an effective emergency action plan. The need for local, state, and federal agencies to work better together has been at the forefront of many on-going discussions and continues to be a large component of effective planning and the safeguarding of lives during times of disaster.   

What You Can Do

Knowledge is power. Stay informed. Know your options. Know your surroundings. Be familiar with entrance and exit routs. Be prepared in advance for known as well as unknown risk factors in/around your place of residence, work, and travel. Understand the fundamentals of safety and security. Always maintain an up-to-date contingency plan to protect you, your family, pets and if applicable, personal possessions.