NOTE: Percentages include the 50
U.S. states, the District of Columbia, and Puerto Rico.
SOURCE: U.S. Department of
Transportation, Federal Highway Administration, 2006 Status of the Nation's Highways, Bridges, and
Transit: Conditions and Performance,
Exhibit 2-16, p. 2-20, available at http://www.fhwa.dot.gov/policy/2006cpr/pdfs/chap2.pdf
