Volkswagen is bringing back the diesel Jetta to the U.S. next year, and is now touring the U.S. to tout the advantages of diesel vehicles. While the company is taking a turn for the better in bringing back the Jetta TDI, VW is currently selling the least green vehicle in the U.S., the V-10 TDI Touareg SUV.

The Jetta 4-door sedan, which will be out early next year as a 2009 model, will get in the "mid-50s" on the highway, according to VW spokesman Tom Wegehaupt. Diesel engines are more fuel efficient than gasoline engines and will be seen as alternatives to hybrids in the coming years, and the Jetta TDI sets a good precedent. Hopefully the Congress will pass legislation that equalizes the tax benefits for ALL vehicles that provide superior fuel efficiency.

The Jetta TDI, which will also be available as a wagon (finally a wagon with decent gas mileage!), will be the only diesel passenger vehicle for sale in all 50 U.S. states, he says. VW's technology does not require using a potentially harmful urea compound to reduce NOx emissions, instead using a particulate trap

Wegehaupt says the 10-cylinder Touareg is being phased out in favor of a 6-cylinder version.

The VW caravan will be carbon neutral as the company is offsetting the emissions from the cross country tour by planting trees in Louisiana. In partnership with CarbonFund.org, VW will also offset the carbon emissions for the first year for each VW vehicle sold until January 2008.

This tree planting won't start sucking up much carbon for a few years (until the trees mature), but it's the thought that counts right?