Hear No Diesel, Smell No Doesel

Image of diesel has already undergone a change in Europe. It seems like it's begining to happen in Asia as well. Will it happen in the U.S.? NOx standards are a real problem with Diesels in the U.S. There is a clear trade-off here. Can there a be a freeze in Diesel NOx standards for, let's say, five years to allow car companies to sort their problems out. No doubt, it will cost some more, but if we can get fuel economy AND better air quality performance from diesels, that is worth considering.