NOTE: Bridges that are both
structurally deficient and functionally obsolete are classified as
structurally deficient. Numbers
include the 50 U.S. states, the District of Columbia, and Puerto Rico.
SOURCES: U.S. Department of
Transportation, Federal Highway Administration, National Bridge Inventory,
Deficient Bridges by State and Highway System, various years, available at http://www.fhwa.dot.gov/bridge/britab.htm as of Aug. 14, 2007.