"Until we begin to plan and coordinate across municipal and county government to coordinate with transit agencies and nonprofit service providers for vulnerable population groups, we will fail to have effective mass evacuations," Renne says.
Renne says the solution is not complicated, but is rarely put in play because it requires a combination of strong leadership, adequate funding and resolute commitment.
"Currently, there are no standards even specifying which government agencies should have the mandate for planning and funding regional evacuations, especially with respect to accommodating the needs of the carless and other vulnerable population groups," Renne says.
Renne says his research has found that cities that have had experience with major evacuations, such as Miami, New Orleans and Houston are much better prepared than cities that have not had the same experiences. For example, the evacuation of New Orleans during Hurricane Gustav in 2008 was much improved over Hurricane Katrina in 2005, and the evacuation of Houston-Galveston during Hurricane Ike in 2008 was much more efficient as compared to Hurricane Rita in 2005, he says.
"Cities like New Orleans and Houston were embarrassed during Katrina and Rita, so a lot of effort across local, state and federal levels was invested to ensure mistakes would not be repeated," Renne says.
However, cities in other parts of the country that have not had mass evacuation incidents are not as well prepared because evacuation planning has not been as much of a focus for those leaders.
Brian Wolshon, a civil and environmental engineering professor at LSU, recently completed a study for the Transportation Research Board titled "Transportation's Role in Emergency Evacuation and Reentry."
He says in some cases, formal detailed evacuation plans do not exist, even when there are fairly regular evacuation requirements. In Southern California, for example, conditions associated with wildfires are too variable to establish firm evacuation routes. The number of people threatened, the size of the region, amount of warning time, available routes and shelter destinations are at whim of changing winds and weather conditions.
"As a result, emergency preparedness and response agencies find it more effective to work from a general framework that permits flexibility to respond to rapidly changing conditions," Wolshon says. Traffic modeling systems can be useful here.
Renne and Wolshon have used a traffic modeling program known as TRANSIMS to help model evacuation strategies for New Orleans. But ultimately, Renne believes traffic management itself is not the biggest issue.
"The major problem is that there is no policy on which agency takes responsibility for planning and implementing regional-scale evacuations," he says. "Unless there is a mandate for local governments to collaborate, we will continue to fail to prepare our regions for mass evacuations."
Douglas Page writes about science, technology and medicine from Pine Mountain, Calif. He can be reached at firstname.lastname@example.org.