From Planning for Next Time (Washington Post, free registration req’d):

Ask any hurricane expert, any disaster planner. Or ask anyone who knows about evacuations and he’ll tell you: There are always some people who stay behind.

…

If we have learned one thing from the Katrina experience, it is that all this advice must now be rewritten, and that information must be redirected at the immobile, the unwilling and the distrustful.

…

[How many] district households [that] don’t own a car [would indicate] the bare minimum number of people who will always be left behind, and who will always be the public’s responsibility.

One glaring deficiency was the number of buses and trains made available to those who were able-bodied and who wanted to heed the evacuation order but had no transportation. Actually, were there any available? As far as buses were concerned the answer is yes, but they weren’t used.

Were there not enough drivers? We can only speculate though I’m sure this would be one of the many things that will be corrected – we sincerely hope so.