'Metric-nomics' leads to confusion on interstate

Is that sign really in metric? Yes, it is.

And no, you have not accidently driven into Mexico.

A motorist driving down Interstate 19 might do a double take. The 63-mile stretch of freeway that connects Tucson to my hometown of Nogales is signed in metric — not miles — making it unique among U.S. interstates.

However, the speed limit signs are in mph, which I'm sure has confused caused some motorists.

The freeway was built in the late 1970s when the nation was considering converting to the metric system, which is used by most of the world.

The U.S. never made the transition because of resistance, but the signs on I-19 were never changed back, partly because of the cost of replacing all the signs.

I'm glad. I find the metric signs amusing and I can pretend I'm in other parts of the world as I drive down to visit my mom.