Responsible for design and project management for major bridges and structures.  A "major bridge" is an extremely large bridge, a moveable bridge, a tunnel, or other structure which would be extraordinarily expensive, difficult, or disruptive to replace.  Because of the very long project lead times, the need for special funding (possibly outside of normal resources), and the potentially catastrophic consequences of failure of one of these structures, the Department created a unit to focus solely on major bridges.