Newswise — As the Jan. 20 presidential inauguration nears, Washington, D.C., officials are likely finalizing the city's evacuation plan to be used in emergencies. 

Yue Liu, an associate professor of civil and environmental engineering at the University of Wisconsin-Milwaukee’s College of Engineering & Applied Science, was key in developing the D.C. area's official evacuation plan implemented for the 2009 presidential inauguration of Barack Obama. “Our plan included using 50,000 metro and school buses to evacuate the area,” he says.

Since Hurricane Katrina, Liu says, many U.S. cities have implemented evacuation plans to manage natural and manmade disasters, from earthquakes to acts of terrorism, and recurrent, civic events such as sporting events. City evacuations have been Liu’s area of expertise for 10 years. He was key in creating official evacuation plans for several U.S. cities and regions, including Baltimore; Ocean City, Maryland; the state of Maryland; and the East Coast – from Delaware to North Carolina – to use in the event of a hurricane.

Below, he briefly answers questions about city evacuation plans. He could expand on any of these in an interview.  Why was an evacuation plan created for the D.C. area? A terrorist attack was the main reason.

Why was an evacuation plan created for the coasts?Along the East Coast and in the South, hurricanes prompted the implementation of evacuation plans. In fact, most people in hurricane-prone areas are well aware of their cities’ evacuation plans.

What is the biggest mistake made in creating evacuation plans?Converting highways to one-way routes. Most cities believe this will increase the systems’ capacity to move people. But that’s not always what happens.

One-way routes create a major bottleneck, because at some point in the system you will lose lanes. Four lanes will merge to two, for example. There is no way to speed up merging and drivers will cue up for extended periods of time. This is what happened when Hurricane Rita hit Houston in 2005. It took 24 hours to evacuate the city and people died in the gridlock.

Also, it takes more manpower than you might think to reverse highways, guide traffic, and erect signs and barriers. For example, some drivers will drive in the wrong direction and need to be guided.

What’s the most important element of a good evacuation route? Consistent capacity, meaning that there are no lanes dropped on the exit roads. Do cities like Milwaukee use evacuation plans?In cities that are not prone to natural disasters, residents may not be aware of evacuation plans. However, many such cities use elements of evacuation plans for recurring civic events. During Summerfest and State Fair, Milwaukee needs to shift heavy traffic over the entire network and uses elements of an evacuation plan.

Who typically oversees an area’s evacuation plan?State departments of transportation.