Fact Check-The U.S. Interstate Highway System does not require one mile in every five to be straight for plane landings

A myth regarding America’s highways has reemerged on social media. The Dwight D Eisenhower National System of Interstate and Defense Highway System – now known as the U.S. Interstate Highway System – does not require that one mile in every five miles be straight. It is not true that these straight sections of highway were designed to be used as airstrips in times of war or emergency.

A social media post making the claim can be seen here . One comment reads: “Yup. And certain roads were marked so that planes could read from the air.”

The posts show a map of the United States with lines across it to represent highways and it is accompanied by the text, “Fun fact of the day. (I had no idea.) ‘The Eisenhower interstate system requires that one mile in every five must be straight. These straight sections are usable as airstrips in times of war or other emergencies.” says that the U.S. Interstate Highway System, formerly the Eisenhower Interstate System, was developed by the Eisenhower Administration in response to 1950’s public demand for “better road systems” (here). The funding for the project was made possible by the Federal-Aid Highway Act of 1956, seen in the National Archives here .

The number of myths circulating about the interstate systems prompted the U.S. government to create a website addressing them, visible here .

The U.S. Department of Transportation’s Federal Highway Administration says on its website (here) that the myth that one in five miles of the Interstate is straight so airplanes can land in emergencies is false.

The agency explains: “This myth is widespread on the Internet and in reference sources, but has no basis in law, regulation, design manual—or fact. Airplanes occasionally land on Interstates when no alternative is available in an emergency, not because the Interstates are designed for that purpose.”

The claim has been circulating for more than two decades: Snopes debunked it in 2000, (here), as did a 2000 blog post from the Federal Highway Administration Research and Technology (here).


False. The U.S. Department of Transportation’s Federal Highway Administration says claims that one in every five miles of the Eisenhower Interstate Highway system is designed to be straight to allow for emergency plane landings are false.

This article was produced by the Reuters Fact Check team. Read more about our fact-checking work here .