May 12, 2014
America's Interstate Highways
The 47,000 miles of highways that comprise America’s interstate highway system are nothing short of an engineering marvel, surpassed only by what China has built in the last few years.
We take them for granted, but when they were designed almost sixty years ago these super-highways presented both great opportunity and vast challenges. The US wasn’t the first with super-highways. Those bragging rights go to the Germans, whose Reichsautobahn saw cars zooming along at 100+ mph in the 1930’s.
Most credit President Eisenhower, whose troops rode the Autobahn in WWII, for seeing the military value of an American equivalent, though engineering such a complex across the US was far more difficult.
Of course by 1940 the US already had the Pennsylvania Turnpike and by 1954 the NY State Thruway, but private toll roads were just the beginning.
To build a road expected to last, in 1955 the federal government, AAA and automakers first built a $27 million seven mile test road near Ottawa, Illinois. Half was concrete, the other half asphalt. The 836 separate sections of highway had various sub-surfaces and 16 bridges. For two years army trucks drove night and day, seeing which road designs would hold up.
Weather and traffic dictated different designs: in desert areas the highways need be only a foot thick, while in Maine the tough winter and freeze-thaw cycles required that I-95 would be five feet thick.
Construction of the highways required moving 42 billion cubic feet of soil. To expedite construction of I-40 in California, there was even a plan to use nuclear bombs to vaporize part of the Bristol Mountain range.
As author Dan McNichol writes in his excellent book “The Roads that Built America”, “VIP seating was even planned for the event. The (nuclear) bombing was to produce a cloud 12,000 feet high and a radioactive blast 133 times that of Hiroshima.” Needless to say, the mountains were moved using more conventional explosives.
Outside of Greenbelt MD another site tested the design of road signs… white lettering on a black background, white on blue (already adopted by the NY Thruway) or, what proved to be the winning model, white on green.
Just 5200 of the original 41,000 miles of Interstates were to be built in urban areas, but those few miles accounted for almost half of the $425 billion total cost. By 1992 the system was deemed “completed”. Bragging rights for the longest of the interstates goes to I-90 running 3020 miles from Boston to Seattle and own beloved I-95, which runs 1920 miles from the Canadian border to Miami FL.
As anyone who drives on I-95 in Connecticut knows, the interstates have far surpassed their expected traffic load and are in need of billions of repairs. Little did we know 60 years ago what our automotive future might bring.