HANNIBAL â Drivers crossing the Mark Twain Memorial Bridge over the Mississippi River in Hannibal will have to move over to allow bridge inspection crews to do their annual inspection of the the bridge. The inspection includes evaluating all parts of the bridge including the piers, superstructure (below the deck) and the deck, as well as any components on the bridge. The inspection began Monday on the eastbound lanes. This will be a work zone, so drivers need to pay attention and move over to allow inspectors and their equipment plenty of room to work.