Starting with 2008 model year vehicles, the EPA will change the way it calculates miles per gallon estimates. The new math is supposed to be more realistic, and from my two months of driving a Prius I believe the new numbers more than the old ones.
- 2007 Prius, currently rated at 60/51 (city/hwy) will drop to 51/46.
- 2006 Honda Odyssey, currently 19/26 (city/hwy) will decrease to 17/24.
- Infiniti G35x goes from 19/25 to 17/23
- Altima goes from 26/35 to 23/32
Although it sounds like the Prius drops much more than other cars, in fact it amounts to the same absolute amount of gas, since the Prius uses less gas to start with.
I've been getting in the low 40's overall so far, disappointingly low but explainable because:
- The MPG is generally low during the first 5000 miles of "break in"
- My commute is only 13 miles, which is not enough time for the engine to warm up. My MPG is closer to 50 if you start calculating 5 minutes after startup.