And this will help explain why the cools diesels in Europe don't make it here:
http://www.thetruthaboutcars.com/editorials/1105972578/From link above, this is one of the clearest explanations I've seen of the issues:
European countries are willing to accept the additional air pollution caused by the diesel engine. The trend in European environmental policy has to been to focus on carbon dioxide, which is relatively harmless to people but may cause global warning. Diesels, because they run with an excess of oxygen, produce very little carbon dioxide, and almost no carbon monoxide. American policy has focussed on pollutants that cause real harm to people, such as the particulates emitted by diesel engines. It is a very different approach to basic public health policy issues.
