Bwaaahahaha!

This probably seemed reasonable to a generation exposed to Free to be You and Me. Thankfully, even in the age of disco, cooler heads prevailed. From WSJ.com's "Financial Flashback" item (subscription required):

The Wall Street Journal, April 26, 1977
The government plans to switch highway speed-limit signs to the metric system in late 1978. Under the tentative highway administration plan, the federally mandated 55 miles-an-hour speed limit would be converted to 90 kilometers an hour on road signs.