I have a car imported from US here in the EU and while driving it I just look at the smaller print in km/h, I honestly don't even notice the larger letters in miles now, it just became natural to look at the smaller print.
It still doesn't make much sense here though. I assume that where you are the speed limit is in km/h. Here it's mph. No matter what I have to know how fast I am going in mph so it makes no sense to bother knowing what I'm doing in km/h. If they changed all the signs to km based speeds (overnight) then I would probably do it but more likely I would remember where on the mph gauge the common km speeds and use those anyways.
Yeah, it sounds likely - but my point is that you would get used to it after a few days,and could continue using your car exactly as you did before. And all new cars would be produced with dials using km/h as the main unit,so the problem would eventually go away on its own. The only problem that I can think of occurs if your car somehow doesn't have a dual kph/mph dial,and shows miles per hour only. Then yes, it becomes an issue.
