http://www.cnn.com/2008/TECH/08/08/air.car/index.html According to the story, the car runs on compressed air at speeds less than 35 MPH. At speeds above 35 MPH, fuel is burned to heat the compressed air and expand it, thereby increasing its range.
Yeah they've been using this in India, I believe. Well ok I guess they dont have these cars on the street yet in India.