All of the clean diesel legislation in the US has reduced fuel economy. Also, US consumers are more concerned with horsepower. Increased horsepower reduces fuel economy. My biggest complaint about VW's diesel lineup is the fact they charge $4,000 - $6,000 more for their diesel cars, wish I could afford one.
the price differential of a diesle engine vs gasoline engine pluse the gasoline/price differential and only 30C-40Hmpg makes the japenese hybirds superior in design, price, & upkeep cost. And it doesn't help VW's credibility to post on their website that these current TDI's can get up to 90mpg. THAT is deceptive advertising. & BTW, custormers are not necessarily looking for high horsepower as much as they need high torque in the low -to-middle range which the turbo charged TDI can do. A small turbocharged TDI with high mpg is what VW needs. Instead they keep building the gasoline thug-a-klugs