[CaliGirlGodHelpMe]

"There was a huge fleet of city buses in addition to the school buses. The city buses would have held a lot of people."

From what I have read, there were apparently enough buses to evacuate all of the people remaining in the city.

[MizSterious]

That would be my guess, but I'm not an expert. I just know a lot could have been done, but wasn't, from the evacuation to the maintenance of the levees and pumps.