Thinking carefully is the operative phrase. what Jim spewed out is just another knee-jerk liberal mantra. The euros do it, we must do it too, just like them!
If oil reserves are drying up, then we need to set goals that get us off of oil period - before we are forced to. that might involve higher CAFE standards, but those could be more or less than what the Euros do. And as you pointed out, the metrics may be apples-and-oranges as it is due to their higher use of diesel, which uses more crude to produce in the first place.
I never ceased to be amazed by the typical liberal response of a feel-good gesture which may more may not actually achieve a goal. These are the people who supposedly are "pro-science", and yet never do the real science and number crunching to determine if something actually needs to be done, and to what extent. The important thing is "feeling good" and doing "something".