The EPA is doing a good job of putting this country out of business. I agree that we need some regulation, but how clean are these new heavy duty trucks when they are choked down with all of this crap these days. They use more fuel and urea, or whatever that urine stuff is, that they inject in the system. It seems to me that a higher mpg means less exhaust emissions in the long run.
Another example is the diesel Jetta. The European model gets about 65mpg while the same choked down model over here gets about 45mpg. Seems to me in my simple little mind that if it gets 20mpg more, 2 65mpg, it can't be polluting very much at all.
This is the same reason that so much manufacturing has gone to China because of the choking over regulation of the EPA and they must be stopped before we become the United States of China!!!
Direct injection is good, but still has some long term bugs to be worked out.