Greetings From…Green Valley, Arizona

by Michael Boyink /

Green Valley, Arizona

I’m old enough to remember.

5th grade.


The previous December, just in time for America’s bicentennial celebration, President Gerald Ford signed the Metric Conversion Act into law.

The Metric Conversion Act declared the metric system as “the preferred system of weights and measures for United States trade and commerce.”

In West Michigan, where I went to school, the teachers took it seriously. 

That school year they made sure we learned how to measure size, distance, weight, volume, and area using the metric system.

Because that was our future.

Yet, 43 years later, we’re mostly still working in inches, miles, pounds, ounces, and acres.

What happened?

The law hasn’t changed. The metric system is still, officially, the preferred system for the United States.

The problem? Ford’s law didn’t have any teeth.

Conversion was “completely voluntary.”

Change is hard. Change costs money. Change takes time. 

So most places simply chose not to convert.

Most, but not all.

Consider I-19.

It’s called an Interstate, yet its 63 mile run exists entirely inside the borders of Arizona. I-19 connects Tucson south to Nogales, Arizona, near the Mexican border.

And in 1980, the State of Arizona joined my teachers in taking Ford’s law seriously. 

They paid to have all of the I-19 distance signs renewed, using only metric measurements (speed limits remained posted in miles per hour).

Decades later, when we visited, the metric signs remained. 

We wondered if we had somehow slipped over the border without noticing.

I had to squint at the small numbers on the truck speedometer, figure out our speed in kilometers per hour, then do the math to calculate the time until our next exit. 

After years in the intense sun, the signs are showing their age. Arizona has wanted to replace them for years. 

With distances measured in miles.

But every time the state brings up the issue, locals complain and vote it down.

Changing the unit of measure for distances means changing the exit numbers. 

Businesses that have spent years advertising their location as “off exit 55” would have to start over.

The area is also popular with Mexican tourists, who are used to the metric system.

Ultimately? The metric signs have become part of the I-19 culture.

Change is hard. Change costs money. Change takes time.

And maybe, if you’ve been in Ava for a while, you can understand why the residents of Southern Arizona might be reluctant to change their signs.

Green Valley, Arizona is 20 miles south of Tucson and has stayed true to its roots as a retirement community. Read the local headlines at

A highway sign on Interstate 19, the only USA highway measured entirely in Kilometers.