Fuel mileage on first tank w 2006 Prius

With my previous 4-cylinder Audi A4, my year-round average mileage was 24, mostly commuting to work between Raleigh and Research Triangle Park, NC. I thought my new Prius, used in the same way, might average 48. Now after one accurately measured tank, it looks like that will come true!

I didn't count the car's first tank because I wasn't sure how the dealer had filled it. On the second tank, I drove 415 miles, stopping the fillup at the first click-off of the gas pump each time. The car's electronic system estimated 49.4 mpg while taking actual gallons filled yielded 48.6 mpg.

Being January, the daily low temperatures have been about 30 while the daily highs have been 50 to 60 degrees. The miles driven were about 20% city streets with stoplights, 20% 4-lane streets, and 60% Interstate highway. I usually drive 0-5 miles above the speed limit so that meant 65-70 on the Interstate. I have the tire pressures at 42 front, 40 rear.

I know that automotive engineers would consider getting one more mpg out of a conventional car design a difficult and noteworthy achievement. So for me, the achievement of Toyota in designing the Prius to deliver a 100% increase in mileage over an Audi which also has a four-cylinder engine and almost identical passenger and luggage space, is a monumental accomplishment!
That's not to mention the navigation system and the other cool features of the car!