Back in 1999 and 2000, the EPA issued the requirement that all US diesel fuel sulfur content be reduced 97 percent from 500 part per million (ppm) to only 15 ppm by 2007. The purpose was to a) reduce emissions in all existing diesels moderately with no harm to them and b) to allow the installation of NOx reducing components in 2007 that would otherwise be poisoned by the higher sulfur content. The petroleum refiners and the engine makers resisted strongly but the EPA held its ground and the regulation stayed.
Now, 6 months into 2007, the results reported in Diesel Progress are all pretty good. The fuel change has been essentially seamless. If you pull up to a diesel pump most anywhere in the US, you have only one choice - ULSD - Ultra Low Sulfer Diesel. Now, about the engines: Most truckers avoided having to buy 2007 engines by buying as many 2006 engines as possible. However, those that have bought 2007 engines have been finding little/no problems with them. No drop in fuel economy as happened in 2002 under 2002 EPA requirements. No extra service problems or drops on reliability. Nope, everything is just fine. Confidence in the technology is building. Trust is increasing that the federal government, the engine and after treatment makers, the fuel providers, and the truckers can all get along even with those tree-hugging environmentalists. Don't forget truckers and their families have noses and lungs, too. They don't want to pollute. They just want to make a living and breathe clean air like the rest of us.
By the way, one fleet manager reported fuel economy at 6.4 mpg on diesel fuel pulling trucks weighing up to 80,000 lbs., the national limit. Think about that if your light duty vehicle weighing less that one-tenth of that is getting about 12 - 15 mpg. Has to due with driving cycle and with the fuel. Imagine, they haul 10 times the weight but only use twice the amount of fuel.
[Source: Diesel Progress]