Here's the central question: Why after five years development does the new 2010 Prius get only three and half miles per gallon better fuel economy than the model it replaces? That's what a lot of people will be asking Toyota as its newest hybrid goes on sale. Officially, the re-engineered and restyled Prius gets a combined fuel efficiency of 50 mpg: 51 city/49 highway. The 2009 model was rated by the US EPA at 48 city/45 highway or a 46.5 combined. Surely with thousands of engineers at its disposal and tens of millions of dollars to invest, the world's most popular gasoline-electric car ought to be even better. Right? Full Article