I agree but one reason why a same diesel engine would be more polluting in the USA is due to the quality of the diesel which in the USA is less refined than in Europe. However, I believe new environmental rules have been recently put in place which require a dramatic reduction in the sulfur content. This should very soon be reflected in the diesel sold in the USA.

A law just passed though mandating that they start selling the new low-sulfur diesel. By now 80% of stations are supposed to be selling it, eventually 100%. Even the Sunoco down the road from me sells it.

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Traditionally, Europe and North America legislation has differed with respect to vehicle pollution regs. Regulating NOx vs particulates, for example. We got the cleaner low-sulphur fuel from October 2006 onwards, so that is no longer a show-stopper, but the new 2007 pollution regs will be a challenge for all manufacturers. It isn't that they can't meet the regs, it is that they can't safely guarantee that the vehicle will still be clean at 100,000 km or miles, depending on the jurisdiction. The liability issue is huge for the manufacturer, which is why, when diesels are released, they will likely be in very few models, and low volumes, until more experience is gained. Case in point: Mercedes is using urea injection in Europe, and BMW has announced plans to do the same. That approach will likely be used in North America. Will US owners replenish the urea tanks regularly? The vehicle will run fine without the ammonia injection, but it will pollute. Will owners ignore the warning lights when the tank is low? Will they accept a "can not drive further because it isn't legal" message? Will there be 'bypass kits' sold on Ebay? Only time will tell.

None of the European manufacturers want to introduce diesels in North America. I believe it is a losing proposition from a commercial perspective, until they have sufficient volume. Besides, they will have to retool plants to make more diesels, there is more cost. They would rather avoid the issue. They just don't want to be left out if their direct competitor (BMW, Mercedes, Audi, Volvo, take your pick) introduces a diesel. That is why, IMO, the availability dates keep changing. Promising to bring diesels here isn't the same as actually bringing them.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue

This might give some insight into what is going on in Europe with regard to emissions:

http://www.globalinsight.com/SDA/SDADetail7802.htm

At present we're on Euro 4 emission limits and certain options are not available on diesels. My wife has a 2005 E46 330 D MSport Convertible with the same engine as my 'X', but because it was made after April 2005 it had to meet the EU4 regs and no auto option is available as the auto version prevents it meeting EU4 emissions.

It has particulate filtering but the NOx limit is still breached on an auto so BMW did not make it available. The new version will be OK though.

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Me:
Current: 2011 E71 40D Vermilion Red/Beige Nappa

Wifey:
Current: 2012 R80 Countryman SDX Green/Cream

Quite a shame. I'd love a diesel.. Much better economy, good power, and it would be nice to go 700+/- miles on a tank, especially considering the amount of miles I drive.

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