They have public transportation vastly superior to ours. They are used to _forced_ mandatory evacs. One of the problems with evacuating NOLA would have been the panic introduced with a forced evacuation. Rumors would have flown. A very minor subset of the population would have refused entirely, making trouble as they did.
I can only tell you this: to evacuate the Tampa Bay area it takes 57 hrs. To evacuate S. Florida and Tampa Bay, it takes 105 hrs.
They don't even _try_ to evacuate 100%, even though a Cat 5 could leave St. Pete an island, only boats able to reach it. From the flooding last year, I will never be caught dead at Tarpon Springs Middle school refuge or any refuge at all. They are wholly inadequate to the task of housing peole for more than 2-3 days.
Our highway infrastructure simply can't handle the load at 5 pm on a normal day. The average hurricane moves at 12 MPH, which is faster than you'll be moving on the evac routes in your Bronco. :)
The evac sitch is obviously better in NOLA than here since our evac problems make us only second to NOLA in terms of likely death and destruction, but I'll bet not by much. Under the conditions they faced, I don't think there would be that many fewer deaths. To me, the point would be to highlight the need for public transportation.
"Finish your beer. There are sober kids in India."
-- rwmartin