If half of our passenger car fleet were diesel powered today, we could slash oil imports by about 30%. We begged George Bush to executive-order boutique diesel fuels out of existence, and it wouldn't hurt to stop the insane gasoline blending mandates that differ wildly from metro area to metro area, either.
Thermodynamically, turbo-diesels are pretty sexy. I wish more of the Euro mfrs brought theirs over to this side of the pond.
Tax policy intrudes, creating an ugly practical reality. Many states tax diesel at much higher $/gal rates, to sock the truckers / businesses vs. the masses of voters. So if you’re wanting a diesel as an individual, you get hit with an inequitable taxation burden.