I'm seeing more talk recently about CAFE standards, and with that comes much objection to them. You're probably familiar with these. (It's top-down; it's less efficient and less moral than just taxing gasoline; you can't will technical improvements into existence; if increased efficiency really "pays for itself" people will invest in it anyway; miles per gallon is the incorrect metric to use anyway; ...)
One I haven't seen is questioning why the "fleet" is a meaningful unit of analysis. Why assume that the average fuel consumption of all Hyundais should be the same as all Mercedes and all Nissans and all Fords? I understand politically why you do this. I wonder why does anyone think this is a reasonable approach by itself. The goal is to reduce total fuel consumption in relation to miles traveled. The badge on the cars doesn't matter to that any more than the color of their paint.
Sitting here with my engineer hat on CAFE seems so kludgy that I'm actually having trouble coming up with an analogy.
Let's say we want to reduce our society's collective consumption of cotton. Who would say that J. Press, Gap, and H&M must all aim for getting the same number of shirts per yard of cloth? They have different approaches to making shirts, and offer different products to different consumers. Why homogenize their outputs?
I have one other iron-clad argument against CAFE standards, or whatever the eurocrats call their version of them: the Aston Martin Cygnet
(1) The Cygnet is an absolute boil on the capital-B Beauty of the Aston Martin line. It is so ugly there are parts of me which refuse to believe it exists. Any legislation which causes such a deformity should be struck down on aesthetic grounds alone.
(2) On a more serious note, if it becomes rational for Aston Martin to buy up Toyota iQs, spend money giving them cosmetic facelifts and reselling them at inflated prices that should be an indication that the legislation is an ugly hack, an attempt to control a complex system through simplistic means.