Why did the MPG on the Toyota Prius drop from the 07 model to the 08 model?

check it out...



http://www.gotmpg.com/best-overall-mpg-c



In 2007 the Toyota Prius got 60/51 MPG. Now in 2008 it only gets 48/45. Its still has the best MPG of all comercial cars in the US but it doesn