Its been pretty well known that the EPA city mileage figures were pretty much hoo-hah and the highway mileage was practically unattainable except under optimal conditions that actual driving doesnt well imitate.
The prius in particular was heavily assailed over the last few years for failing to live up to its mileage claims unless drivers 'changed the way they drive'. I always wondered if changing the way the owners drove their former cars wouldnt also produce a similar benefit.