Summary: Volkswagen has been introducing green vehicles at numerous auto shows in the past few years, and most recently, VW introduced us to its L1 Concept at the Frankfurt Motor Show, touting it as the "most fuel-efficient vehicle in the world." Now they bring to the table the latest in their Up! uber-eco-friendly concepts, the Volkswagen Up! Lite Concept. It hopes to be the "world's most fuel efficient and environmentally friendly four-seat car."