[Big Dave]

Well, we all make our own value judgments (mine is MPG uber alles), but ULSD/Tier II better show a noticeable improvement in air quality and public health or there will be a backlash. You cannot expect to impose such a huge economic penalty without seeing a proportional benefit or people will start asking: “Is it worth it?” This will be like the failure of the Montreal Protocol, but writ very large and affecting a very large number of people.

In the face of the best ambient air quality in living memory, it will be very difficult for anybody to show any improvement at all from these regs.