thompsonx -> RE: Why Do Liberals Love Taxes??? (2/16/2010 2:51:42 PM)
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quote:
we certainly didn't build all of these to facilitate military travel. I did not suggest that military use was the only or primary purpose for the interstate system. I pointed out that Eisenhower was intimately aware of the shortcommings of the U.S. highway system. His time in Germany observing the uses that the Germans made of Todt's "autobhan" was not wasted. The following concerning "vertical clearance" on interstate highways. The point being that the military had a significant impact in the design. quote:
What is vertical clearance and why did the Department of Defense (DOD) object to the minimum vertical clearance for the Interstate System in the 1950s? “Vertical clearance” is the distance from the top of the pavement to the bottom of structures crossing over the highway. It is typically at least 1 foot higher than the legal vehicle height, plus an allowance for future resurfacing that could raise the top of the pavement. Although the Federal-Aid Highway Act of 1956 added the words “and defense” to the name of the Interstate System (now the Dwight D. Eisenhower National System of Interstate and Defense Highways), the primary justification for the network was its civilian benefits, such as economic opportunity, safety, relief of congestion, and evacuation of cities. At the height of the Cold War and with an atomic or hydrogen bomb attack a conceivable possibility, Congress added “and Defense” to the name in recognition of the fact that the Interstate System would benefit the military, too. However, the emphasis on civilian needs was consistent with the position of the Department of War (now Defense, of course) dating to the early 1920s—if we build a road network adequate for civilian needs, it will serve defense needs as well, with some additions to connect with bases or military plants. It would not be possible to justify such an expenditure solely on the basis of military needs. In developing minimum design standards for the Interstate System, the State highway agencies and the Bureau of Public Roads (BPR) agreed in July 1956 to include a minimum vertical clearance of 14 feet in Policy on Design Standards – Interstate System prepared by the American Association of State Highway Officials (AASHO) and adopted by the BPR for use on Interstate projects. This figure wasn't pulled out of thin air. The DOD had previously indicated, in 1949 and 1955, that a 14-foot vertical clearance was adequate for most military vehicles. However, after the Soviet Union launched its Sputnik satellite in October 1957, the DOD determined that a 17-foot vertical clearance was needed for some larger equipment, such as the Atlas intercontinental ballistic missile, that could not be transported by rail. This change led to a debate between the DOD and the BPR that that was resolved by a compromise in 1960. On January 27, 1960, the BPR issued instructions to its field offices changing the minimum standard to 16 feet for Interstate highways in rural areas. In urban areas, “application of the 16-foot clearance shall be limited to a single routing where the revised vertical clearance can be developed most economically, even though that single route is indirect.” All projects under design or construction were to be revised according to the new standard. The first construction project affected by the change was in Michigan, where highway officials using hydraulic jacks lifted the Clear Lake Road overpass on I-94 near Lansing from a clearance of 14-feet, 6-inches to 16-feet, 3-inches. As for the routes built to the old standard, DOD, Federal Highway Administration (FHWA), and AASHO agreed in 1969 on a 26,000-mile priority network that had 350 deficient structures and served about 95 percent of the major military installations. On the priority network, the States were encouraged to implement, as rapidly as practical, those modifications necessary to obtain a 16-foot clearance. Off the priority network, the 16-foot clearance would be implemented only in conjunction with other construction work. The FHWA explained that, “If the work necessary to obtain the clearance is a logical addition and the cost is not excessive, it should be incorporated into the overall project.” The DOD remains concerned about vertical clearance. Today, the minimum vertical clearance standards apply to all rural Interstates (not just a priority network) and a single Interstate through each urban area. All exceptions to this requirement, whether for new construction or a reconstruction project that does not provide for the 16-foot minimum vertical clearance, would be coordinated with the DOD. The FHWA stressed that this agreement applied to the full roadway width, including shoulders for the through lanes, as well as ramps and collector-distributor roadways in Interstate-to-Interstate interchanges. The vertical clearance policy has been incorporated into Policy on Design Standards – Interstate System.
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