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The Debunker: Was the U.S. Interstate System Designed to Provide Emergency Landing Strips for Aircraft?

by Ken Jennings

November is here, and you know what that means—National Aviation History Month! Yes, like all good citizens, you undoubtedly wait all year for this fun-filled celebration of great achievements in the history of flight. But as you get together with loved ones during this festive flight-themed season, we want to make sure you don't perpetuate any myths and misconceptions. Ken Jennings, high-flying Jeopardy! whiz, is here all month to correct a lot of common aviation knowledge that's just plane wrong.

The Debunker: Was the U.S. Interstate System Designed to Provide Emergency Landing Strips for Aircraft?

We're so blessed to live in a time when humankind has invented the Internet, an amazing digital utility used mostly to store pornography and pages of "Completely Random and Useless Facts You Should Know." These numbered trivia lists nearly always include this standby: "The U.S. interstate highway system requires that one mile in every five be straight. These straight sections function as airstrips in times of war and other emergencies." What a fun thing to consider, as we travel the highways and byways of this great land: the interstate system's Eisenhower-era engineers had Cold War paranoia on their minds as they surveyed it!

The Debunker

Sadly, this little-known historical fact is about as true as much e-mail forward trivia, which is to say, not true at all. Richard Weingroff, information liaison specialist for the Federal Highway Administration, wrote that this is one of the most common—and frustrating—questions he now fields. The Defense Highway Act of 1941 did provide for a series of emergency flight strips to be placed near highways nationwide, but that program was phased out by the time Congress began planning the interstate system in earnest in 1944. There has never been any legislation anywhere that contains the phantom "one mile in every five" clause.

Writing for the FHA's Public Roads magazine in 2000, Weingroff seems more than a little aggrieved by the persistent falseness of this factoid. "I try to reply patiently without rolling my eyes or groaning," he confides, "and I try not to give the impression I've heard this 'fact' once or twice or maybe a hundred times before." At the end of the article, he switches to all-caps, and I like to imagine one eyelid starts to twitch a little bit. "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!" he begs. Reader, I believe him.

Quick Quiz: Which U.S. state has no interstate highways that are signed as such?

Ken Jennings is the author of eleven books, most recently his Junior Genius Guides, Because I Said So!, and Maphead. He's also the proud owner of an underwhelming Bag o' Crap. Follow him at or on Twitter as @KenJennings.