GREEN VALLEY, Ariz. (KGUN) — A unique stretch of highway in southern Arizona could soon lose what many residents say makes it special. The U.S. Department of Transportation (DOT) is proposing to convert the kilometer-based signage along Interstate 19 — the only such highway in the country — to the standard U.S. system of miles, a change that’s drawing concern and criticism from the Green Valley community.
The 63-mile corridor, which runs from Tucson to the U.S.-Mexico border, has long used metric measurements, a decision made in the 1980s to facilitate cross-border travel and trade. But now, DOT spokesperson Nate Sizemore told The Wall Street Journal the agency wants to “restore American standards” by remeasuring the route and replacing the signs.
While no timeline or formal proposal has been released, the local response has been swift. Residents and business leaders say the existing metric signs are not just functional, but a part of Green Valley’s identity.
“What's wrong with being unique?” asked Bill Berkley, a Green Valley resident. “We've got the shortest interstate in the country, and it’s in kilometers, not miles. That’s a winner. There’s not many places in the U.S. where you get a little math problem while you’re driving.”
Randy Graf, President of the Green Valley Chamber of Commerce and Visitors Center, echoed those sentiments, raising concerns about the potential costs to local businesses. “There are a number of businesses that probably have marketing materials listing the exit numbers,” he said. “So changing them would probably come with some expenses.”
Graf also questioned the rationale behind the proposal, noting that of the roughly 4,000 to 5,000 visitors the Chamber sees each year, none have complained about the metric signage. “The thought process in D.C., I guess, was to change I-19 from kilometers to mileage,” he said. “Other than that, I haven’t heard anything.”
Adding to the confusion, Sue Tinnin, communications manager for the Green Valley Council, confirmed the council has not been contacted by federal officials regarding the change.
This isn’t the first time the metric signs have come under scrutiny. In 2009, a similar proposal by the DOT was halted after then-Governor Jan Brewer intervened. Whether this latest push gains traction remains to be seen.
For now, I-19 continues to offer a rare sight for American drivers — signs marked in kilometers — and Green Valley residents seem determined to keep it that way.
KGUN 9 has reached out to both the Department of Transportation and the Arizona Department of Transportation (ADOT) but has not yet received a response.
Watch the 'Absolutely Arizona' history of the nation's only metric highway:
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Joel Foster is a multimedia journalist at KGUN 9 who previously worked as an English teacher in both Boston and the Tucson area. Joel has experience working with web, print and video in the tech, finance, nonprofit and the public sectors. In his off-time, you might catch Joel taking part in Tucson's local comedy scene. Share your story ideas with Joel at joel.foster@kgun9.com, or by connecting on Facebook, Instagram or X.
