By Aubrey Samost
The logistics of evacuating a major city are
mind-boggling. The evacuation of New Orleans
during
Katrina ran surprisingly smoothly, with very few traffic accidents or
fatalities, causing fewer traffic backups. The
evacuation plan enacted was the result of two botched
evacuations
for hurricanes Georges and Floyd, both of which fortunately passed east
of the
city. Committees of people went to work
trying to improve the evacuation plans to allow everyone to get out of
the city
in the fastest and most efficient way possible. The
result was the creation of contraflow patterns for
traffic in the
city. There were also some issues with
getting everybody out of the city because a lot of people did not own a
car or
were elderly and could not evacuate. Another
major issue was a failure of communication. There
was no way for officials to know which
routes out of the city were backed-up and which routes were flowing
freely (Wolshon,
2004).
There are many different factors to take
into account when
trying to create an evacuation plan. In
New Orleans, the exit capacity is roughly 67% (American Highway Users
Alliance,
2006), which means that if all of the evacuation goes smoothly, the
roads outside
of New Orleans will only be able to take two-thirds of the people in
twelve-hours. The city with the best
exit capacity is Kansas City, with 98% (American Highway Users
Alliance, 2006)
of the people getting out of the city in the peak twelve hours. To improve New Orleans, there would have to be
wider
roads with more entrance and exit points to prevent bottlenecking on
the major
highways. The contraflow plan also helps
with this figure.
Another useful figure that ties in with exit
capacity is the
internal traffic flow. This is a measure
of traffic within the city during an evacuation. It
is based on the average travel delay time
during an evacuation. New Orleans did fairly well in this
category
with an average travel delay time of about 19%, corresponding to an
internal
traffic flow rating of 81% (American Highway Users Alliance, 2006). This is measured with the Travel Time Index,
which uses the ratio of the commute in an evacuation to the time that
it takes
to travel that distance on any normal day (Bureau of Business Research,
2006). In the case of New Orleans, it takes about 19% more
time to
travel from one part of town to the other when there is an evacuation
going on
then when there is no significant traffic.
The final major factor in determining the
overall evacuating
capacity of a city is the percentage of people who have access to a car. This does not mean that they own a car. It only means that they can find a ride out
of the city, either with a neighbor, family member, or a friend. In New
Orleans, about 91% of the population has access
to a
car to get out of the city (American Highway Users Alliance, 2006). Finally, all of these factors were averaged
together with different weights to calculate the evacuation capacity of
New Orleans. This figure is used to rank New Orleans
amongst other major towns. In a study of
thirty-seven major cities with
a population of over one million people, New Orleans ranked twelfth with an
evacuation capacity of
67.3% (American Highway Users Alliance, 2006). This
number represents the likely percentage of people who
will be able
to evacuate New Orleans
in the peak twelve hours of the evacuation process.
Another figure that can be calculated is the
roadway capacity, or the percentage of people who can theoretically
evacuate
the city if the roads were the only limiting factor.
This is found by averaging the internal
traffic flow and the exit capacity to get 74%, which is higher than the
evacuation capacity because the evacuation capacity takes into account
the
people who do not have cars (American Highway Users Alliance, 2006).
These figures are not set in stone. There are many ways to improve this figure
when rebuilding New Orleans,
including widening the highways from four to six lanes.
Evacuating the city is a difficult situation because New Orleans
is
bounded on the north by the lake, which limits the routes out. We could also look at making public
transportation an integral part of evacuating. There
are nine percent of people without cars who still
need to somehow
get out of the city, so it makes sense to enlist the help of buses. Another possibility is to look into creating
safe shelters within the city limits. This
gets rid of the need to bus people long distances out
of the city,
which puts less of a strain on the public transportation (American
Highway
Users Alliance, 2006). There is all
ready the Superdome, which could easily be reinforced and more prepared
to
serve as an emergency shelter.
Overall, New Orleans has an all right method
of evacuating at
present. During Katrina, the people who
evacuated did so with very few problems. The
major issue right now is to deal with the people who
could not or
did not evacuate the city. To keep New Orleans
safe, it is
necessary to implement an evacuation plan that moves everyone to safety. There is no need for people to be stuck on
top of their rooftops waiting for boats and helicopters to come by and
help
them out.