Interstate 19: Miles or Kilometers?

Interstate 19, which is entirely in Arizona, is an oddity among U.S. interstate highways. I-19, which runs from Tucson to Nogales, is the country's only continuous highway that lists distances in kilometers, rather than in miles.

As the Associated Press reported earlier this month, the highway's embrace of the metric system dates to the Carter administration. The idea was to make the interstate more accessible to tourists coming from Mexico, where kilometers are the standard unit of measuring distances.

Our bosses at the Arizona Department of Transportation have tried to change I-19's signs back to miles before. The signs have to be replaced periodically anyway. But businesses along the highway say doing so would make their shops harder to find, since the exit numbers would also change.

So, what do you think? Should I-19 go back to miles or stick with kilometers? Let us know in the comments. Regardless of how you feel, we hope you'll take a drive down I-19 soon; it passes through some stunning terrain, and Nogales is a charming border town. Look for a Scenic Drive that originates from I-19 in our February 2015 issue.


The majority of people living in those distances are Mexican /Chicano. I believe there is so much racial profiling all over Arizona these days..sometimes things need to be left alone. It depends on who has brought this subject up also to determine the answer. :)

We have driven Hwy. 19 many, many times. Maybe we are just used to it but, it has never been a problem. In fact it's hardly noticeable . Don't see any great reason to change. Shouldn't have been done in the first place, they don't change their signs to miles when we go there! But what the heck do I know, I live in Montana!

How about making them bilingual, with both kilometers AND miles? Just add a sign below each old one with an equal sign and the equivalent distance in miles.

Never should have been in Kilometers, this is in the US. Having both kilometers and mileage is the best idea. Just leave the exit number as they are.

yes, I noticed it when driving down there a couple of years ago. We are from England and in the UK we are supposed to be using metric units, but all our road signs are still in miles. I think all US roads should be signposted in miles, no exceptions.

20 years ago, when I lived there, they used to have the mile markers a little ways off the road & facing the Interstate. If you knew what to look for, you'd find them. I preferred miles because that's what I grew up with & my vehicle(s) read in miles not kilometers. I know in the seventies they tried to push the metric system in this country but people aren't interested, it never caught on. Change it back. I loved the desert, & I miss it. Arizona is a beautiful place.

I say to leave the signage in kilometers. I've driven it many times and never have had a problem, in fact it's fun. Could become the country's longest roadside attraction ;0)

Since our country (and me in particular) never embraced the metric system and since the majority of our highways and freeways are signed in miles, not kilometers, I personally would orefer changing the signage back to miles.

MPH! This is the USA not Mexico. I spent 3 years in Germany and they did not change to MPH from Kilometers so foriegners could figure it out. This should have never been an issue to start with.

The rest of North America and the world use the metric system. I live here on 1-19 and love it as a friendly border with Mexico. I say keep the kilometers.

I think 19 should stay kilometers. I think all highways should be covered to metric actually. It's so much simpler

its completely insane that the whole US is not metric. Even third world countries are metric.

No road in Arizona should be marked in kilometers. This is America, not Mexico!

Miles is the standard in the US, right? The speed limit is in miles...

Metric better!

Leave it be the way it is, please.

The article states it was easier for tourist, the original reason was the higheay was built in the 70's when America was pushing to convert to the metric system. The Arizona DOT installed signs in kilometers as a progressive approach to the change in measurement. But as we all know the metric system never took. Leaving I-19 as a bit of an oddity, a relic of a change that never happen. It does seem being so close to the border that it was an accommodation for Mexican travelers but seriously when has America adapted our ways for others?

I personally love the fact that we have the only interstate in the country that has this distinction. There's nothing racial or un-American about it. I hope they never change it

In 2010 Obama gave state $1.5 million in STIMULUS funds to change the signs to miles. What happened to the money? I've driven from Tucson to the Titan Missile Museum 3 times this month and noticed not one sign has been changed to miles. Who pocketed those taxpayer dollars?

Hi, I would enjoy to know more about the February 2015 Issue - Scenic Drive. I chair a local Tourism Council as well as being a Nogales AZ resident & love my community, at large. We are happy to assist in enlarging the vision of the scenic drive.... I lived in Asia for many years, and my most favorite EVER view is driving home after a very long flight along I19 at sunset... no place like home.