I spent five hours out in that mess last night, and discovered that while every freeway was a bumper-to-bumper parking lot (I made only 9.2 miles in an hour and twelve minutes at one point), the surface streets were wide open and clear. Anyone heading anywhere should pre-plan a route using littler roads, you'll get there a heck of a lot faster, plus the gas stations off the freeway still have gas, while the ones on the freeway have long lines and/or no gas. It's amazing what a difference two blocks makes, if you just get away from the highway.
We see this a lot in Atlanta because most people "ain't from around here." They move here as short term corporate transfers, and if the interstates back up they have no idea what to do. The radio stations try to help, but if you don't know the names of the back roads it isn't much help.
We usually take to the back roads when we're visiting family on big holidays and the interstates back up. It usually works pretty well.