Actually, on the day of the earthquake, they let the federal workers go home early, which clogged up the roads quite a bit. Led me to think that in the event of a major catastrophe, very few could get out of the area. Too much traffic, not enough roads.
As far as the hurricane predictions, as it's going to graze us Saturday night so everyone will be at home. I don't see any major traffic fluctuations heading west from my area. I would imagine that the shore areas would have some traffic heading west, though.