Arizona at crossroads on kilometer-marked Interstate 19

TUCSON, Ariz. — North of the U.S.-Mexico border, a relatively barren stretch of an Arizona highway is lined with road signs that tell drivers how many kilometers they are from their destination — not how many miles.

The markers from Nogales to Tucson are a relic of a failed pilot program from Jimmy Carter’s administration that aimed to persuade Americans to adopt the system of measure in use across much of the rest of the world.

Interstate 19 — a roughly 60-mile stretch (or about 100 kilometers) — is the only continuous highway in the U.S. with metric signs, and it’s the subject of a long-simmering spat over whether they should be changed back to the standard system.

“When I’m driving, I definitely can’t do that math,” said Nick Rodriguez, a 24-year-old who lives in Rio Rico.

Some who agree with Rodriguez took a shot at changing the signs four years ago when the state, which oversees them, received $1.5 million in federal stimulus funding.

The Arizona Department of Transportation at the time said the signs were outdated and needed to be replaced with ones that are brighter and easier to read. “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,” spokesman Dustin Krugel said.

They also said the new signs would be in miles. The plan sparked vocal opposition that helped stall the replacement project. Area business owners said new signs in miles would change the exit numbers they advertise. The highway is measured in kilometers, so road markers and exit numbers would change, they said.

“It had a lot of opposition because people felt it was something that relates to tourism,” said Jim DiGiacomo, president of the Green Valley-Sahuarita Chamber of Commerce. “The hotels and businesses would have to change all of their info.”

Mexico also uses the metric system, and many in the area consider the signs a hospitality measure for Mexican tourists who visit Tucson and Phoenix. The Tucson Hispanic Chamber of Commerce said in August that Mexicans spend about $1 billion each year in shopping and tourism in Pima County.

The need to change approximately 400 signs still stands, but the state doesn’t have the funds to replace them, Krugel said.

Next time around, however, the department plans on seeking public comment before deciding whether the new signs will still be in kilometers or miles.

“Ultimately, we got a lot of feedback from the public that they didn’t want the signs replaced. When we re-examine this issue in the future, we’re going to get community feedback to find out what the people want through that corridor,” Krugel said.