Longer than that, I'd say. I remember watching videos about the metric system when I was in grade school back in the 70's. ("You can measure how far from your car to a star -- with the metric system!")
I mean, not if there was an actual metrication effort. There isn’t. Nobody’s putting up any speed limit signs in kilometres per hour or using celsius for the weather forecast.
not just speed limit signs. Mile markers, exit numbers, distance signs. There's millions of them all over the US. It would cost unfathomably (lol) large amounts of money to do that, and for arbitrary reasons.
Longer than that, I'd say. I remember watching videos about the metric system when I was in grade school back in the 70's. ("You can measure how far from your car to a star -- with the metric system!")