The 47,000 miles of highways that make up America\u2019s 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 60 years ago, these super-highways presented both great opportunity and vast challenges. The United States wasn\u2019t the first with super-highways. Those bragging rights go to the Germans, whose Reichsautobahn saw cars zooming along at 100-plus mph in the 1930s. Most credit President Dwight Eisenhower, whose troops rode the Autobahn in World War II, for seeing the military value of an American equivalent, though engineering such a complex across the United States was far more difficult. Of course, by 1940, the United States already had the Pennsylvania Turnpike and by 1954 the New York State Thruway, but private toll roads were just the beginning. Test highway section was built 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, Ill. Half was concrete, and the other half asphalt. The 836 separate sections of test 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 needed to be only a foot thick, while in Maine, the tough winter and freeze-thaw cycles required that Interstate 95 be five feet thick. Use nuclear bombs to help construct? Construction of the highways required moving 42 billion cubic feet of soil. To expedite construction of Interstate 40 in California, there was even a plan to use nuclear bombs to vaporize part of the Bristol Mountain range. In his excellent book \u201cThe Roads that Built America,\u201d author Dan McNichol writes, \u201cVIP 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.\u201d Needless to say, the mountains were moved using more conventional explosives. Outside of Greenbelt Md., another site tested the design of road signs \u2014 white lettering on a black background, white on blue (already adopted by the New York Thruway) or, what proved to be the winning model, white on green. System \u2018completed\u2019 in early 1990s Just 5,200 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 \u201ccompleted.\u201d Bragging rights for the longest of the interstates goes to I-90, running 3,020 miles from Boston to Seattle. Our own beloved I-95 runs 1,920 miles from the Canadian border to Miami, Fla. 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 dollars in repairs. Little did we know 60 years ago what our automotive future might bring. Jim Cameron of Darien is the founder of the Commuter Action Group and also serves on the Darien RTM (town legislative body). The opinions expressed in this column are only his own. You can reach him at CommuterActionGroup@gmail.com.