The United States is one of only three countries in the world that has not adopted the metric system of measurements. Instead of kilometers and centimeters, America functions on miles and inches. However, during a brief time in the 70s and 80s, the metric system was considered for use in America, and a historical relic of that time is highway I-19 in Arizona. This road is the only road in the country that still has signs in kilometers, and it has become a bucket list travel spot for metric nerds.
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The road I-19 starts in Tucson and runs south to the Mexican border. Confused motorists may have puzzled looks while traveling down I-19, but it’s the locals that have strongly supported to keep the signs due to its unique metric features.
In 1975, Congress passed the Metric Conversion Act in an effort to transition the country into metric units. Although soft drinks are in liters, medicine is in milligrams and 5K runs can be found all across the country, the act was dismantled only after seven years. However during that time, I-19’s signs were changed to kilometers, and at decades later they still remain.
With the majority of the world functioning in metric units, the pressure for the United States to convert will grow. As of now, the U.S. is not budging an inch. So head down to Arizona’s I-19 to check out these bizarre road signs before they will need to eventually be replaced due to age and weather. Go the whole nine yards, or rather kilometers, when you travel down this highway anomaly in Arizona.
Where: Tucson, AZ to Nogales, AZ