Later this month, the Maryland State Highway Administration will replace two bridges that span the Baltimore-Washington Parkway. This operation will not involve the costly, time-consuming and traffic-clogging process of tearing them down and then building the new ones. Instead, the old bridges will be rolled away and the new ones rolled in. This will be Maryland's first "bridge on wheels" swap, but it has been done in other states.
Read the story at the Baltimore Sun.