The interstate highway system was finally launched in 1956 and has
been hailed as one of the greatest public works projects of the
century .To bulid its 44,000-mile web of highways,bridge.and tunnels
hundreds of unique engineering designs and solutions had to be
worked out.Consider the many geographic ,features of the
country:mountains,steep grades,wetlands,rivers,desorts and
plains.Variables included the slope of the land,the ability of the
pavement to support the load.Innovative, designs of
roadways,tunnels,bridges,overpasses,and interchanges that could run
through or bypass urban areas soon began to weave their way across
the country ,forever altering the face of American .
Long-span,segmented-concrete,cable-stayed bridges such as Hale Boggs
in Louisiana and the Sunshine Skyway in Florida,and remarkable
tunnels like Fort Mchenry in Maryland and Mr.bakerin Washington
developed under the nations physical challenges,Traffic control
systems and methods of construction developed uder the interstate
program soon influenced highway construction around the world,ang
were invaluable in improving the condition of urban streets and
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