There was never any requirement for the 1-mile in 5 straight areas for landing in the laws that authorized the interstate system, or in subsequent rules. There were initially designed to accommodate military aircraft in the event that the cities/bases were taken out by an attack on the United States.
The interstates were designed in part, so mobile missile launcher could be driven around the country. Originally they wanted to make the whole thing straight, but it causes road hypnosis.
The frequently repeated “fact” that United States highways were designed to work as emergency runways is little more than an urban legend, despite its prevalence (a lot of people seem to know about it) and its longevity (no one seems to know when it actually originated, but it can be traced to legislation that dates back to the 1940s). The people who originally thought up this urban legend accounted for some of those questions.
This ratio is supposedly enough to account for turns, elevation changes and densely populated areas. Since using a highway as a runway would only happen in the kind of unprecedented theoretical emergency in which planes wouldn't even have time to divert to the closest commercial airport, there's absolutely no way local law enforcement could close and clear the highways quickly enough to provide a safe emergency landing.
What's the plan, then, if there's ever an emergency that requires airborne planes that are unable to reach their destinations to land immediately? There are actually little-used and little-known (that is, not for public commercial travel) runways all over the place that are a logical location for an emergency plane landing in a war or terrorist situation.
Shake Shack catches flak for 'lazy' Korean fried chicken The IHS was built for the movement of troops, equipment, and supplies across the country in the event of a major war, in part.
Back in the 20s or 30s a young army officer named Dwight Eisenhower was given the task of moving a military unit across the continental US by vehicle. It took a very long time, because no national road system existed.
At that time rail was the way to move a lot of stuff long distances. The Nazis developed and used a road system called the autobahn to move troops rapidly.
Eisenhower like what he saw, so when he became President he made it one of the major projects of his administration. The U.S. Interstate and National Defense Highway System was, in fact designed so that sections could be used as emergency airstrips.
President Dwight Eisenhower, former General of the Army, had a big influence in its development. Claim: The American interstate highway system was designed to be used for emergency airstrips in case of war.
Origins: Numerous folks swear Interstate highways in the United States must be designed so that one mile in every five is perfectly straight and flat. According to this whispered bit of facetious lore, if the U.S. ever comes under attack, those straight, flat stretches will be used as landing strips.
The only actual historical citation of an attempt I could find for a large plane landing on a U.S. Highway was Southern Airways Flight 242, a DC-9, in 1977. As the aircraft descended from its cruise altitude of 17,000 feet (5,200 m) to 14,000 feet (4,300 m) near Rome VOR, it apparently entered a thunderstorm cell and encountered a massive amount of water and hail.
The crew attempted unsuccessfully to restart the engines, gliding down unpowered while simultaneously trying to find an emergency landing field within range. Cartersville Airport, a general aviation airport about 15 miles (24 km) north with a much shorter runway intended for light aircraft was considered, but it was behind the aircraft and now out of reach.
As the aircraft ran out of altitude and options, gliding with a broken windshield and no engine power, the crew made visual contact with the ground and spotted a straight section of a rural highway below. They executed an unpowered forced landing on that road, but during the rollout, the aircraft collided with a gas station/grocery store and other structures.
One passenger initially survived the crash but died on June 5, 1977. A seriously injured person on the ground died around one month later.
Minimum number of lanes: At least two lanes in each direction, and more if necessary for an acceptable level of service in the design year, according to the current edition of AAS HTO's A Policy on Geometric Design of Highways and Streets. Climbing lanes and emergency escape ramps should be provided where appropriate.
With three or more lanes in each direction, the inside paved shoulder should be at least 10 feet (3.05 m) wide. If truck traffic is over 250 Directional Design Hour Volume, shoulders at least 12 feet (3.66 m) wide should be considered.
This goes up to about 11,500 feet (2.2 miles, 3505 meters) on a wet runway with a fully loaded aircraft. Although more detailed study would be needed, I believe a pilot's best bet for attempting this under controlled conditions would probably take you west of the Mississippi River due to lower overall population density (and presumably fewer things crossing or being placed near freeways).
The Great Plains and the desert Southwest are the likeliest regions where this might work. Numerous folks swear Interstate highways in the United States must be designed so that one mile in every five is perfectly straight and flat.
Another way to counter this myth would be to make a larger argument that yes, Americans considered driving so important that the government was willing to subsidize the construction of interstates. President Eisenhower supported the Interstate System because he wanted a way of evacuating cities if the United States was attacked by an atomic bomb.
The efficiency and faster speeds of the system, made possible by engineering techniques that tend to cut through land rather than following its natural contours, have resulted in safer but less-sometimes less scenic drives. While for a short drive, a state route may be more interesting, 1200 miles of nothing but small towns gets old, fast.
Around the turn of the 20th century, the supply of good roads in America came nowhere near meeting the growing demand. Instead of using names and colored bands on telephone poles, this new system used uniform numbers for “inter-state” highways and a standardized shield that was intended to be universally recognizable.
The Federal-Aid Highway Act of 1938 called on the then Bureau of Public Roads to study the feasibility of creating a toll-financed system of three east-west and three north-south superhighways. The Federal-Aid Highway Act of 1944 called for designation of a National System of Interstate Highways, so located as to connect by “paved routes the principal metropolitan areas, cities, and industrial centers, to serve the National Defense.” Neither the 1944 act nor subsequent legislation in the 1940s authorized funds specifically for an Interstate System.
Under the leadership of President Eisenhower, the question of how to fund an Interstate Highway System was resolved with enactment of the Federal-Aid Highway Act of 1956, which Act called for significant Congressional funding and served as a catalyst for the system’s development and, ultimately, its completion. The 1956 Highway Act was championed mightily by Eisenhower, who was influenced both by his experiences as a young solder trying to cross the country in 1919 following the route of the Lincoln Highway, and by his appreciation of the German autobahn network, which Eisenhower personally witnessed as Supreme Allied Commander during World War II.
Also, on August 2, 1956, Missouri awarded a contract for work to be done on U. S. 40 now I-70, the Mark Twain Expressway in St. Charles County. When this fact is taken into account, perhaps “the very first interstate highway” was that stretch of the Pennsylvania Turnpike between Irwin and Carlisle.
When this stretch opened on October 1, 1940, the Pennsylvania Turnpike gave motorists their first real chance to experience what someday would be known as an “interstate.” Transcontinental Interstate 10 serves the southern tier of the United States by providing the main east-west link from San Monica and Greater Los Angeles in the west to Jacksonville in the east.
It enters the desert just beyond the narrow San Gorgon Pass, west of Palm Springs. One potential civil defense use of the Interstate Highway System is for the emergency evacuation of cities in the event of a nuclear war.
An option for maximizing speedy evacuation is to reverse the flow of traffic on one side so that all lanes become outbound thoroughfares. This procedure, known as “contraflow” was witnessed in 2005 in the Interstate 10 evacuations of Houston (successful) and New Orleans (unsuccessful) prior to the respective arrivals of Hurricanes Rita and Katrina.
Prominent interstates in the West that motorists are fond of driving along include 40, 17, 10, 8, and 19 in Arizona, 80 and 15 in Nevada, and 10, 8, 15, 40, 5, and 80 in California. Many Americans take these magnificent ribbons of concrete and occasional asphalt for granted; yet for those of us who grew up in the middle part of the 20th century and who can actually remember Dwight Eisenhower, the five-star general and President, they are an indelible part of the landscape that has, for better or worse, helped define the American experience.