I don't deny that the diesel car probably wouldn't meet the emission standards in the USA
Both the diesel and gasoline (petrol) cars, if made for the European market, do not meet U.S. smog-emission standards and therefore are not directly comparable in terms of fuel-economy.
Somehow this has turned into a Europe vs USA "discussion". That was not my intention. I have no particular axe to grind, being neither European, not American.
Further, it seems clear that the point I was trying to make is not going to be heard, and other points - no doubt valid, but nonetheless tangential - are going to dominate. Perhaps it's wrong, perhaps no one wants to hear it.
Perhaps I just can't express myself clearly enough.
So I'm simply going to walk away from this thread. You have made many valid points which I will remember. Thank you.
Both the diesel and gasoline (petrol) cars, if made for the European market, do not meet U.S. smog-emission standards and therefore are not directly comparable in terms of fuel-economy.