http://www.time.com/time/magazine/article/0,9171,1053663-1,00.html

An interesting article describing the human factors in surviving disasters.

And in a "PHRASECENSOREDPOSTERSHOULDKNOWBETTER.-friendly" publication too, to boot.

Counting rows, knowing where the exits and stairwells are - all of these are at least as important as any safety measure that can be imposed from above.