Now that I have had my Prius for almost two months and became familiar with it I have stopped OCDing about gas mileage and how I am driving the vehicle. I turned the HSI off about a week ago and dont even have the miles left till empty displayed. I have also started driving the car like it was meant to be driven, just like any other car. No special techniques when stopping/starting or cruising... I love this car. The Prius was bought to replace a pickup that I sold beause I figured out I could get a Prius and use it to haul most stuff I need. Since I got the Prius I was only driving my C6 Corvette on weekends....I sold it last week also.... So the Prius has allowed us to become a two car household.
Even if you drove it like you stole it, you should still average about 42 to 45 mpg. You don't have your location listed so I'm guessing it's not So. CA where gas is nearly $4.50 a gallon (regular). But then again, almost every other car there is a Prius.