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Interstate highways are assigned a special level of federal funding, but they are owned, designed, built and maintained by the state in which they are located. The only exception is the federally-owned Woodrow Wilson Bridge on the Capital Beltway ( I-95 / I-495 ). , and with cross-traffic limited to overpasses and underpasses.]] The highways in the system are typically known as Interstate XX or '''I-XX'''; sometimes '''Interstate Highway XX''' ('''IH XX''') or '''Interstate Route XX''' ('''IR XX''') is used. In some areas, the more generic '''Route XX''' or '''Highway XX''' is used. The system serves all major U.S. cities. Unlike counterparts in most industrialized countries, Interstates go through Downtown areas. This facilitated the emergence of automobile-oriented postwar suburban development patterns, a phenomenon pejoratively named " Urban Sprawl ." The system is prominent in American daily life. The distribution of virtually all goods and services involve Interstate Highways at some point. Residents of American cities commonly use urban Interstates to travel to employment. Most long-distance journeys of less than 300 miles (500 km), whether for vacation or business, use the interstate highway system at some point. Alaska and Puerto Rico have roads designated as Interstates for funding purposes but which are neither planned for or currently built to Interstate Standards . The public controlled-access highways of Puerto Rico are the Autopistas (PR-22, PR-52, and PR-53). HISTORY The interstate system was authorized by the Federal-Aid Highway Act Of 1956 , popularly known as the ''National Interstate and Defense Highways Act of 1956''. It was lobbied for by major U.S. Automobile manufacturers and championed by President Dwight D. Eisenhower , and was influenced by both his experiences as a young soldier crossing the country in 1919 following the route of the Lincoln Highway , and by his appreciation of the German Autobahn network. Planning for a system of new superhighways began in the late 1930s , even before federal commitment to build the Interstate highway system came in the 1950s . Construction on the world's first public limited-access highway, the Bronx River Parkway , had begun in New York as early as 1907 . By the 1920s, longer highways such as the New York City Parkway system had been built as part of local or state highway systems. As automotive traffic increased, planners saw a need for such an interconnected national system to supplement the existing, largely non- Freeway , United States Numbered Highway system. The '' General Location Of National System Of Interstate Highways , including all additional routes at urban areas designated in September, 1955'' maps what became the interstate system, and is informally known as the ''Yellow Book''. Although construction on the Interstate Highway system continues, it was officially regarded as complete in 1991 (though 1.5 miles of the original planned system remain unconstructed As Of 2005 {Link without Title} ). The initial cost estimate for the system was $25 billion over twelve years; it ended up costing $114 billion, taking 35 years to complete. As of 2004, the system contains over 42,700 miles (68,704 km) of roads, all at least four lanes wide. The removal of the last Traffic Signal on Interstate 90 in Wallace, Idaho on September 15 , 1991 is often cited as the completion of the Interstate System. However, due to the cancellation of the Somerset Freeway , Interstate 95 has not been completed in Pennsylvania and New Jersey ; the Pennsylvania Turnpike/Interstate 95 Interchange Project will complete that route, the last section of the original (1947) plans to be completed (though a few routes, like Interstate 80 in central Ohio , have been majorly relocated). Several other routes have non- Freeway sections (see List Of Gaps On Interstate Highways ), but are considered to be complete. STANDARDS Main article: Interstate Highway Standards The American Association Of State Highway And Transportation Officials (AASHTO) has defined a set of standards that all new Interstates must meet unless a waiver from the Federal Highway Administration (FHWA) is obtained. These standards have become stricter over the years. One almost absolute standard is the Controlled Access nature of the roads. With few Exceptions , Traffic Light s (and cross traffic in general) are limited to Toll Booth s and Ramp Meter s (metered flow control for lane merging during Rush Hour s). Speed limits Interstates generally have the highest Speed Limit s of any road type. The highest rural speed limits are generally in western states, with 70 to 75 mph (112 km/h to 120 km/h) speed limits. The lowest rural speed limits are generally in northeastern states, with 60 to 65 mph (96 km/h to 104 km/h) speed limits. Urban interstate speed limits are generally 5 to 20 mph (8 km/h to 32 km/h) lower than rural limits. Dual-purpose design In addition to being designed to support automobile and heavy truck traffic, interstate highways are also designed for use in Military and Civil Defense operations within the United States, particularly troop movements. One potential Civil Defense use of the Interstate Highway System is for the emergency Evacuation of cities in the event of a potential Nuclear War . The Interstate Highway System has been used to facilitate evacuations in the face of Hurricanes and other natural disasters. An option for maximizing throughput is to reverse the flow of traffic on one side so that all lanes become outbound lanes. This procedure is known as Contraflow , and could be seen in 2005 in the evacuations of New Orleans, Louisiana and Houston, Texas prior to hurricanes Katrina and Rita , respectively. Several Interstates in the South , including I-16 in Georgia , I-40 in North Carolina , I-65 in Alabama , I-10 , I-55 & I-59 in Louisiana , and I-55 & I-59 in Mississippi, are equipped and signed specifically for contraflow, with crossovers inland after major interchanges to distribute much of the traffic. This is however not limited to Interstates; State Road 528 in Central Florida has the same setup. "1 in 5" landing strip urban legend A widespread in World War II for just such a purpose. After the war, specific portions were custom-built and maintained throughout the Cold War . {Link without Title} TERMINOLOGY While the name implies that these highways cross State lines, Many Interstates do not. Rather, they are ''funded'' federally with money shared ''between the states''. There are interstate highways in Hawaii , funded in the same way as in the other states, but entirely within the populous island of Oahu . They have the designation of H-X, and connect Military Base s. Similarly, both Alaska and Puerto Rico have public roads that receive funding from the Interstate program, though these routes are not signed as Interstate Highways. Primary routes The numbering scheme for the Interstate Highway System (as well as the , I-5 and I-8 . Within this category, east-west highways are assigned even numbers, and north-south highways are assigned odd-numbers. Odd route numbers increase from west to east, and even numbered routes increase from south to north. Numbers Divisible by 5 are intended to be major among the primary routes, carrying traffic long distances. For example, I-5 runs from Canada to Mexico along the west coast (the only interstate to do so) while I-95 runs from Miami north to Canada . In addition, I-10 runs from Los Angeles, California to Jacksonville, Florida while I-90 runs from Seattle to Boston . However, not all primary routes divisible by 5 traverse long distances. I-45 runs from Galveston, Texas north to Dallas, Texas , a distance of only 284 miles. It is the only primary route divisible by 5 that does not cross state lines. See List Of Intrastate Interstate Highways for other primary routes that do not cross state lines. It should be noted that I-50 and I-60 do not exist (and there are no even-numbered Interstates from 46 to 62), mainly because they would most likely have passed through the same states that already have will Overlap US 74 in North Carolina , and I-41 will do the same with US 41 in Wisconsin . Several two-digit numbers are shared between two roads at opposite ends of the country, namely I-76 , I-84 , I-86 and I-88 . Some of these were the result of a change in the numbering system in the 1970s ; previously letter-suffixed numbers were used for long spurs off primary routes; for example, western I-84 was I-80N, as it went north from I-80 . In the 1970s, AASHTO decided to eliminate these; some became additional two-digit routes, while others became three-digit routes (see below). Only two pairs of these exist; I-35 splits into I-35W and I-35E through both the Dallas-Fort Worth and the Minneapolis-St. Paul areas. Strict adherence to the directional nature of the system results in some amusing oddities. For a nine-mile stretch east of Wytheville, Virginia , the driver can be traveling on both I-81 ''North'' and I-77 ''South'' at the same time (and vice versa) (see also Wrong-way Concurrency ). For the sake of efficiency, some Interstates double up for short or sometimes long distances, as in the example above. Another notable example are Interstates I-90 and I-94, which double and then separate several times as they criss-cross the upper Midwest and Great Plains. Three-digit Interstates See Also: List of auxiliary Interstate Highways Three-digit route numbers are for auxiliary Interstate Highways. They consist of a single digit prefixed to the two-digit number of a primary Interstate highway and are used to designate spur or loop routes branching from either the primary route or one of its other auxiliary routes. A spur route is one that deviates from its parent and does not end at another Interstate; it is given an odd first digit. A loop route is one that returns to its parent; it is given an even first digit. The number given to the first digit of a route that branches from the parent to end at another Interstate depends on the state; some consider these routes spurs and assign odd first digits, while others consider them loop connectors giving them even first digits. When letter-suffixed two-digit Interstate (see above) were in abundance, their auxiliary routes were given a number without a letter suffix. Due to the large number of these routes, auxiliary route numbers may be repeated in different states along the mainline; but no two three-digit Interstates in the same state can share a number. For instance, I-90 in New York alone has a full set of three-digit Interstates - I-190 , I-290 , I-390 , I-490 , I-590 , I-690 , I-790 , I-890 and I-990 . Closed loops usually retain a single designation for the entire route. For example, Cincinnati , like many other cities, features a large loop around the city that intersects with the primary routes I-71 , I-74 , and I-75 . The entire 84-mile loop is labeled I-275 . Of course, there are exceptions to these guidelines:
Exceptions Interstate 238 near Oakland, California is one of two major exceptions to the numbering scheme, as no Interstate 38 exists. This number exists because Interstate 238 replaced a segment of State Route 238 , and no appropriate number was available. The other exception is Interstate 99 in Pennsylvania , which was written into law as I-99 by Pennsylvania Congressman Bud Shuster ; I-99 (which is also U.S. Route 220 ) is west of several Interstates that are numerically less than 99, and was the nearest available unused two-digit number. Some proposed future Interstate routes have been given similarly non-conforming designations by their legislative proponents. For example, backers of the proposed Third Infantry Division Highway, a route in Georgia and Tennessee , have suggested it be named Interstate 3 , in honor of the Division for which the highway is named. Other notable examples
The following two-digit Interstates change signed direction from their normal (even=east-west, odd=north-south) direction:
Two-digit Interstates in Hawaii , as well as the "paper" Interstates of Alaska and Puerto Rico , are numbered sequentially in order of funding, without regard to the rules on odd and even numbers. Business Loop and Business Spur Interstates are not subject to any of the Interstate Standards . Their designation is simple - a Business Loop heads into a downtown area from its parent and returns to its parent; a Business Spur ends downtown, occasionally continuing from the end of the main Interstate. Business routes can split from either two- or three-digit Interstates, and can be repeated within a state. In a few cases, where an Interstate has been realigned, the old road has been designated a Business Loop because it is not up to standards. FINANCING About 56% ( 2003 FHWA summary ) of the construction and maintenance costs are funded through User Fee s, primarily Gasoline Tax es, collected by states and the federal government, and Toll s collected on Toll Road s and Bridge s. The rest of the costs come out of the federal budget. In the eastern United States, large sections of some Interstate Highways planned or built prior to 1956 are operated as Toll Roads . The taxes dedicated to the construction and maintenance of highways are often criticized as a direct subsidy from the government to promote and maintain auto-oriented development as we know it today. As American suburbs push ever outward, the costs incurred of maintaining freeway infrastructure has started to catch up with the economy, leaving little in the way of funds for new interstate construction Field, David. "On 40th birthday, interstates face expensive midlife crisis." ''Insight on the News'', 29 July 1996 , 40-42.. This has led to the proliferation of the toll road (turnpike) as the new method of building limited-access highways in suburban areas. Also, some interstates are being privately maintained now (VMS in Texas, I-35) in order to cut rising costs of maintenance and allow state departments of transportation to focus on serving the fastest growing regions in their respective states. The future of the interstate system as we know it is in question. It is entirely possible that parts of the system will have to be tolled in the future to meet maintenance and expansion demands, as is done with adding toll HOV/ HOT Lanes in certain cities like San Diego , Minneapolis , Houston , Dallas , and Washington, D.C. The federal role in financing The dominant role of the federal government in road finance has enabled it to achieve legislative goals which fall outside its power to regulate Interstate Commerce as enumerated in the federal Constitution . By threatening to withhold highway funds, the federal government has been able to stimulate state Legislature s to pass a variety of laws. Although some object on the ground that this infringes on States' Rights , the Supreme Court has upheld this practice as a permissible exercise of the Congress 's Spending Power . The first major example was the introduction of a Maximum Speed Limit of 55 Mile s per hour (88km/h) . This was originally done to save fuel in the wake of the 1973 Energy Crisis , but stayed in force for more than two decades. The acceptance of the national speed limit emboldened various Presidents and Congress to enact several additional pieces of legislation, most of which have nothing to do with highways or transportaion. Other examples include:
States must also meet minimum Enforcement standards for all federally-mandated legislation (for example, minimum penalties for violation of these laws and a minimum number of Per Capita Underage Drinking convictions or a very compelling explanation regarding why this number is not met). This has proved to be controversial. Those who support this feel that it is a way to provide an impetus to states to pass uniform legislation. Others feel that using highway Dollar s in this fashion has upset the balance between federal and States Rights in favor of the federal government, and effectively holds funds as ransom in order to coerce state governments into passing laws that would not have otherwised been introduced. Some have even argued that the current arrangement is Unconstitutional . Law Enforcement agencies in some states have bitterly complained that efforts to meet Quota s for underage drinking convictions have distracted them from more pressing matters and needlessly strained relations with those under 21. Any state which were to lose federal highway funding would quickly face deteriorating infrastructure, fiscal impoverishment or both. Of course, a state which lost federal highway funding ''could'' theoretically threaten to stop maintaining its highways, if that were politically palatable to its citizens. Non-chargeable Interstate routes In addition to Interstate highways financed with federal funds (Chargeable Interstate routes), federal laws allow other highways to be signed as Interstates, if they meet the Interstate Highway standards and are logical additions or connections to the System. Called Non-Chargeable Interstate routes, these additions fall under two categories: # Routes that already meet Interstate standards. These may immediately be signed as Interstates once their proposed number is approved, or may be retained with a non-Interstate designation. # Routes not yet upgraded to Interstate standards. These cannot be signed as Interstates until they have been fully upgraded. SIGNAGE Interstate Highways are signed by a number on a red, white and blue sign as shown to the right. In the original design, the state was listed above the highway number, but in many states, this area is now left blank. The sign itself measures 36 inches high (91 cm) , and is 36 inches (91 cm) wide for two-digit interstates, or 45 inches (114 cm) for three-digit interstates. Business Loop and Business Spur Interstates use a special shield where the red and blue are replaced with green; the word BUSINESS appears instead of INTERSTATE, and the word SPUR or LOOP usually appears above the number. The majority of Interstates have Exit Number s. All Traffic Sign s and Lane markings on the Interstates are supposed to be designed in compliance with the Manual On Uniform Traffic Control Devices (MUTCD). However, there are many local and regional variations in signage. The state of California is now adapting to an exit numbering system after many years as being the only state in the country that did not use such a system after being granted an exemption in the 1950's due to having an already largely completed and signed highway system. At the time placing exit signage on the signs across the state was deemed to be too expensive. In most states, the Exit Number s correspond to the Mile age markers on the Interstates (with an exception being I-19 in Arizona , whose length is measured in Kilometer s instead of miles). Many northeastern states label exit numbers sequentially, regardless of how many miles have passed between exits. Maine, Georgia, Pennsylvania and Florida followed this system for a number of years, but recently converted to having the exit numbers correspond to mileage markers. On even-numbered Interstates, mileage increases to the east and decreases to the west (except on the I-90 portion of the New York State Thruway and the I-190 spur into O'Hare International Airport in Chicago , both of which count up going west); and on odd-numbered Interstates, mileage increases to the north and decreases to the south. In both cases, the exit numbers increase and decrease accordingly. States still numbering sequentially are: Connecticut, Delaware, Massachusetts, New Hampshire, New York, Rhode Island and Vermont. The New Jersey Turnpike also has sequential numbering, but other interstates within New Jersey generally use mile markers. TRIVIA Air rights: Structures built on top of Interstates Several interstate highways have buildings over the highway, using Air Rights .
Long-distance mileage signs on Interstates
Other trivia Most Interstates are maintained by the states or toll authorities. The Woodrow Wilson Bridge , part of Interstate 95 and Interstate 495 , is maintained by the federal government. A few Interstates are maintained by local authorities:
The only Concurrency of two Auxiliary Route s is Interstate 271 and Interstate 480 near Cleveland, Ohio . ;See also All but five State Capitals are directly served by the Interstate System. Carson City, Nevada ; Dover, Delaware ; Jefferson City, Missouri ; Juneau, Alaska ; and Pierre, South Dakota are not. CRITICISM Charles Kuralt has argued, "It is now possible to travel from coast to coast without seeing anything!"Wilson, Amy. U.S. Route 66: Historic Road Is Time Line of America . ''National Geographic News''. January 18, 2002. URL accessed 21:31, 18 February 2006 (UTC). This is an apparent reference to the tendency of Interstate highways to emphasize more rapid, uninterrupted transportation than other road networks. REFERENCES SEE ALSO
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