This is the point at which some 'greens' will jump in and shout about diesel pollution and soot and carbon black, but I just don't buy the argument that Europeans are blindly killing themselves with diesel cars while states like California and New York are saving lives by preventing their residents from owning diesel cars. Just doesn't add up. Why aren't Calif-orkians pushing to ban all diesels, including semis, which are almost universally diesel? Probably because a. those trucks truck in many goods and foods that the Calif-orkians consume, and b. diesels really are more efficient and, overall, less polluting.
Furthermore, while it is possible to argue that a person who needs a car to get from A to B should choose an electric or hybrid over a diesel, it is NOT possible to argue that a person who needs to haul a couple of tons of stuff from A to B over hilly terrain should buy a hybrid, because there are no hybrids than can do that (yet?).
There is no escaping the fact that diesels extract more power from fuel than gasoline engines. You only have to compare the two on a hilly country road. A diesel can maintian speed with fewer revs and fewer downshifts than a gas engine of comparable displacement. It is simply more powerful. Articles and blog posts in the US that compare a big Mercedes sedan with a teeny gas or gas/hybrid car are missing the point, largely because they are written in the absence of small diesel cars for comparison. The big Mercedes is hauling around a lot more weight. The real comparison is the sort of small diesel family car people buy by the millions in Europe, regularly getting 50+ miles to the gallon (like the Citroen I bought in 1992--great performance, great handling, a smooth and quiet highway cruiser at better than 50 mpg).
That is why, according to PSA, the collective Peugeot and Citroën brand, "the percentage of the European fleet [18 EU countries including France, Germany and the UK] of new car registrations has risen from 22.3% in 1997 to 50.8% in 2006."
Note that the country with the highest percentage of diesel cars is France with 71.4% of new cars registered in 2006 being diesel (over 1.4 million). According to California green thinking, the French must be hell bent on mass suicide.