VW has been very busy with Fuel Economy Marathons as of late

The TDI is the world?s most successful diesel engine technology. Now the latest Audi TDI is making its way to the US: Audi is introducing the world?s cleanest diesel to the streets of America inside the Audi Q7 3.0 TDI with its own branded ?ultra low emission system?. Once there, and prior to its market launch, it will be put through an endurance test of notoriety, that being the Audi Mileage Marathon. The Audi Mileage Marathon covers more than 4,800 miles from New York to Los Angeles through major cities and passing countless US points of interest.