As far as why diesels for consumers are so rare, you can thank the antiquated hippy laws in states like California that perhaps at one point were noble due to diesel fuel being more polluting back in the 1970s.
As someone who received an Environmental Study Degree, in the state of California, in 1974, I think I can speak with some authority on this. Diesel has never been considered more polluting then gas fuel. Quite the opposite. It has always been praised as a low emission engine, with one exception. Diesel spews out a lot of particulate matter. Particulate matter in, and of itself, is not always harmful. However, particulate matter is the vehicle by which toxins can enter the lungs.
But I think the reason you don't see Diesel here in the numbers you do in Europe, having grown up in England, is because people rarely keep their vehicles as long as people do in Euope , and, consequently, do not reap the benefits of the diesel outside of a commercial use. And cheaper gas prices in the US make the Diesel change undesirable to most consumers in the US.
Back in the seventies when gas prices shot up during the first U.S. oil crises, there was a big interest in Diesel Mercedes, and Volvo. A doctor friend of mine bought a 240S diesel for exactly this reason. The 240 had the performance of a golf cart. And that is reason number three of why Americans have not been inclined to switch their big fast V8s for reliable, high mileage diesel engines.
However, I am looking forward to a Diesel Toyota truck. Unfortunately, I won't be able to get one that is made in Japan.
Newsflash moonbeams, it's now 2007 and standard diesel has come a LONG way as far as emissions, easily negating the need for these consumer bans. Biodiesel in fact is more clean burning than gas for every type of emission save for smog, it is nearly a carbon neutral fuel.
