U.S. Department of Transportation
Federal Highway Administration
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Washington, DC 20590
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Conditions and Performance
Status
of the Nation's Highways, Bridges, and Transit:
2002 Conditions and Performance Report
|
Exhibit 11-13:
Interstate Bridges
Exhibit 11-13 is a bar graph that shows the construction of interstate bridges. The vertical axis measures number of bridges from 0 to 14,000 in increments of 2,000 bridges. The horizontal axis has 21 bars, one for each 5-year period between 1900 and 2000. The figures don't start rising until 1946-50, as that is when the interstate system was started formally. By 1955, 2,000 interstate bridges had been built. The number rose to 8,000 in 1956-60, 12,300 in 1961-65 and 1966-70. It then dropped to 7,000 by 1975, 4,000 by 1980, and less than 2,500 for each of the 5-year periods to 2000. There are also two lines and a second vertical axis (measuring percentages from 0 to 100 in increments of 10 percent) in this chart. The first, representing cumulative percent of structure population, rises from 0 before 1950 to 40 percent by 1965, climbing further to 80 by 1975 and 100 by 2000. The other line, representing cumulative percentage of ADT, rises from 0 before 1950 to 50 percent by 1965, climbing further to 82 by 1975 and 100 by 2000.
Source: National Bridge Inventory.
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Page last modified on November 7, 2014.