There is a link in the article to metric interstate highway of Arizona. I-19 from Tucson to Nogales is signed in metric. When you enter the freeway there is a sign that says "This highway signed in metric" Every sign on the freeway is in metric, EXCEPT for the speed limit sign. I realize they did that so people wouldn't be doing 100+ MPH but I always wanted to drive it at 60KPH, and explain to the judge "the sign was in metric"