what routes? name them smarty.
Then there's 10 EAST. As far as I know, Slidell didn't close THAT bridge down, either.
And lastly, There's 10 WEST. There IS no bridge before you get to 51 North, so I ain't sure what your problem is.
GRETNA evacuated ALL of her citizens, and the cops just made sure no one headed SOUTH to loot the empty city..