I don't know if 10 percent of the Russian government's income comes from the sale of vodka. I don't know if a cow can go upstairs, but not downstairs. And I certainly don't know if a duck's quack doesn't echo.
But I do know the following statement is false: The Eisenhower Interstate Highway System requires that one mile in every five must be straight so that these straight sections can be used as airstrips in times of war or other emergencies.
False though it is, this "fact" has become a fixture of Internet web sites with names such as "You Probably Didn't Know That..." and "Weird Fact Heaven."
For a historian, even an unofficial one, who believes that a fact should be, by definition, factual, what is particularly frustrating is that everyone seems to know this "fact." People get a twinkle in their eye when I mention the Interstate Highway System. "Did you know," they say to me cheerily as I grit my teeth, "that one in every five miles..."
When that happens, I feel like the staffer at the information desk of the Smithsonian Natural History Museum who told me the most frequently asked question she receives is, "Where's the rest room?" Like her, I try to reply patiently without rolling my eyes or groaning, and I try not to give the impression I've heard this "fact" once or twice or maybe a hundred times before.
As with Dracula, it is very difficult to put a stake through the heart of this "fact." It's like the "urban myths" we have all heard -- untrue things that people nevertheless believe. For example, that alligators thrive in our sewer systems. Now there are "Internet myths" -- untrue claims that bounce around the Internet like juicy gossip with reality never having a hope of catching up with them.
That's what happened with the one-out-of-five claim about airplane use of the Interstate Highway System. (Next, it will probably show up on the ABC game show "Who Wants to Be A Millionaire?" where 20 million people will see it -- maybe as the $200 question.)

I have no idea where the one-out-of-five claim originated. Perhaps it is giving too much credit to whoever originated this "fact" to suggest that it began with a misreading of history. Under a provision of the Defense Highway Act of 1941, the Army Air Force and the Public Roads Administration (now the Federal Highway Administration) operated a flight strip program.
The flight strips consisted of a runway, laid down in the direction of the prevailing wind, and a shelter with a telephone for the custodians of the site and for itinerant flyers in an emergency. Fuel storage facilities were not provided; instead, oil companies were required to keep stocks of aviation gasoline at gas stations along the highway and truck it to the flight strips as needed.
Some references to the one-out-of-five "law" attribute it to the Federal-Aid Highway Act of 1956. The act launched the Interstate Highway Program by creating the Highway Trust Fund and committing the federal government to build what became the 42,800-mile Eisenhower Interstate Highway System. President Dwight D. Eisenhower fully supported the Interstate Highway system as vital to our economy, safety, relief of congestion, and defense. However, he didn't propose a one-out-of-five rule, and Congress didn't include such a requirement in the 1956 act. The one-out-of-five rule was not part of any later legislation, either.
In the hope that this article will be seen by Internet surfers, I will conclude by saying that, for all I know, there are 293 ways to make change for a dollar, snails can sleep for three years without eating, and an ostrich's eye is bigger than its brain. But no law, regulation, policy, or sliver of red tape requires that one out of five miles of the Interstate Highway System must be straight.
Trust me on that. Please!

This is an edited version of an article appearing in the May/June issue of the FHWA's "Public Roads" magazine. Richard F. Weingroff is an information liaison specialist in the FHWA's Office of Infrastructure.