Which is why people with heavier vehicles seem to be favoring it, but the number seems to be completely meaningless and the term pound-miles per gallon makes it even more meaningless. At least mpg per pound made sense though it's hardly an absolute and doesn't tell you much vehicle to vehicle.
mpg/ton would give a larger number overall. At 44 mpg my car would be 48.7 mpg/ton.
I just don't like numbers that don't have any particular meaning and unless somebody can give me a concise, rational explanation for pound-miles per gallon it I'll vote against it.
Vehicle weight is going to be a greater factor with people who do a lot of city driving or a lot of steep hill climbing. I agree that if we are going to come up with some kind of equation to give everyone a level playing field, then cdA is going to have to be factored into the mix.