We’ve all had this feeling: You’re driving along on your commute to work and what was a smooth highway now gives way to that grinding, sandpaper feeling beneath your wheels, like you’re driving across a waffle iron. It sets your teeth on edge, the rattle and roar vibrating in your ears and interrupting the radio program you’re listening to. Now imagine that same feeling as you’re headed over Lake Lanier, dozens of feet above the water’s surface on an aging, worn, rough-surfaced bridge.