Conclusion

No question, the American car market has got the green message.

In the first instance, it's rushing to catch up with the rest of the world, as the introduction of diesel engines from BMW, Mercedes and Acura testifies.

At the moment, though, it's suffering in the same way as Europe and Asia, because the models that are being rolled out were being developed long before the green bug bit.

As a result, if some of the changes sound a bit half-hearted - a 5% reduction in carbon dioxide emissions here, an E85 option there, even if it is a two-tonne truck - that's because the technology has been added late in the day.

Longer-term, though, you get the feeling the industry is well prepared for change.

GM's Saturn and Volt plug-ins are well advanced, for instance, and its investment in just about every green technology you can name, as well as some we probably haven't even heard of, bodes well for the future.

It doesn't mean the end of the big truck or performance car yet - but it does mean that prices of these vehicles are going to soar.