Only three countries on Earth - Liberia, Myanmar, and the United States - use the customary unit system of measurement. In the 1980s, there was a nationwide push toward the metric system here in America, and Arizona is still feeling its effects. I-19 is a metric highway in the US that runs between Nogales and Tucson, Arizona, and it's the only one of its kind in the country. What a quirky claim to fame!
If you frequently spend time in Tucson, chances are you've driven on Interstate 19 , a metric highway in Arizona, at least a handful of times.
The 63-mile highway is located entirely within Arizona, traveling from Nogales to Tucson. Fun fact: it's one of the shortest highways in the country!
Another fun fact about the highway - and what truly makes it stand out from all others - is that its distance signs are measured in meters rather than miles.
The speed limit signs, however, are in miles per hour.
This is a result of the push towards the metric system during the 1980s, when the highway was originally constructed.
Unsurprisingly, the signs caused immense confusion among motorist upon their installation, especially if you're like me and have trouble trying to convert metric to imperial.
As a remedy, the Tucson district of ADOT decided that all new signs would instead use Customary units, and renovations began in 2002.
So if you've never seen the metric distance signs on the I-19, keep an eye out the next time you find yourself on the Arizona metric highway.
They're some of the quirkiest Arizona claims to fame!
Did you know that the only metric highway in the US is in Arizona? If so, have you ever driven on it? Tell us your thoughts in the comments! Don't forget to check out our previous article for another quirky find in Arizona.
Taking a road trip in Arizona? Make sure you check out our Ultimate Road Trip Packing List for everything you'll need for a comfortable car ride.
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