The carmaker, which now has ‘clean diesel’ TDI versions of its A8L, A7, A6, Q7 and Q5 models in the United States, recently commissioned Harris Interactive to poll 2,041 randomly selected drivers about attitudes to diesel technology.

According to the results, 57% of respondents believed the government had placed an unfair advantage on hybrid and electric models compared to diesels, while two thirds believe green incentives should be available for diesel vehicles too.

Scott Keogh, president, Audi of America, said: ‘Government has set very rigorous standards for future fuel economy, and we believe that clean diesel is perfectly positioned to help us achieve those goals. But, we argue that diesel needs an even playing field set by state and federal governments.

‘Audi believes there are a variety of viable alternative fuel solutions, including electric, but diesel is readily available today. If you take away the disincentives that state and federal taxation policy create, we potentially could see a big uptick in clean diesel vehicles sales.’