Arizona’s I-19 is the only US road that exclusively uses the metric system

There was brief period back in the 1970s and the early 1980s where the United States actually attempted to switch over to the metric system. Numerous objections from American nationalists and insane conspiracy theories calling it a Communist or Arab plot prevented the attempt from getting very far, but one highway didn’t get the message: Arizona’s Interstate 19.

Numerous stretches of road in the United States give directions in kilometers, but I-19, which stretches 63 miles from Tucson to the Mexican border, is the only highway in the country that does this exclusively across its entire length. The signs were put up as part of a plan by the Carter administration to convince Americans to make the switch.

“You get wear and tear on them. Obviously, they’re out in the heat in Arizona. Eventually we’re going to have to replace those signs,” Dustin Krugel, a spokesman for the Arizona Department of Transportation said. Unfortunately, when the signs get replaced, they’ll be in miles.

Business owners in the area objected to replacing the signs for many reasons, the biggest of which was tourism from Mexico, which generates more than $1 billion in annual revenue for local businesses. Mexico, like most countries, uses the metric system. However, their concerns fell on deaf ears, and the signs will be replaced once the Arizona Department of Transportation acquires the necessary funds.

Read more about the story at The New York Times.