Oh my god.
SO much misinformation in this thread it's scary. No wonder marketers can bullshit US customers.
First, the US has been using ultra low sulfer diesel for a while now. It's no longer a problem.
Secondly, the problem with diesels is that they have high particulate and NOX emissions. Essentially soot and smog.
US regulates those FAR more tightly that the Europeans, meaning that you can't take diesels from over there and run them over here. (This is a generalization, I believe VW now may have an engine that runs in both places without additional smog controls).
As a result, diesel engines in the US have to have down stream particulate and hydrocarbon traps, and injected Urea (yeah, piss, that's right).
http://phys.org/news145556132.html
Most consumers don't want diesel to begin with. That may be because they think they are noisy and smelly - because the diesels they see on Semis are essentially unregulated. Go Figure.
http://en.wikipedia.org/wiki/Diesel_exhaust
When customers find out that regulatory requirements end up adding equipment that makes a diesel more expensive, they really don't want it. So why isn't diesel over here? Because your government has made decisions that make it less desirable to the US consumer.
In b4 someone starts FUD about "VW does it" (at a loss).
Of course, I'm posting this in a Brian Manahan thread. Had he taken 2 seconds, he could have learned this himself rather than whining. So I guess in the end, I lose, because I took the time to explain it.