2010 Toyota Prius
Testing gas mileage is a funny thing. The results on your window sticker may not bear any relationship to what you get, depending on where, when, and how you drive. Sometimes, even large carmakers get caught out by the numbers.
That seems to be what happened to Toyota, which revised its gas mileage figures for the upcoming 2010 Toyota Prius today. The overall rating of 50 miles per gallon stays as is, but the city mileage rises from 50 to 51 mpg, while the highway mileage falls from 49 to 48 mpg.
But let's keep this in perspective. If the highway mileage of your 2010 Prius falls that amount, you're using 0.04 extra gallons every 100 miles you drive. So if you drive 10,000 miles a year, we're talking an extra 4 gallons, or less than $10. Yawn.
How'd it happen? A Toyota spokesperson attributed it to a "misinterpretation of the preliminary data."
Just so you know, the US Environmental Protection Agency's mileage ratings are an offshoot of the emissions testing it does to certify every new car for sale. On a dynamometer, or "rolling road", every car is put through the same routine of accelerating, braking, coasting, stopping, and switching the engine on and off. All of the exhaust is gathered in a huge bag hooked to the tailpipe, and then it's analyzed for levels of pollutants.
The mileage obtained during that standard cycle is then tweaked by a numerical factor to get it closer to "real world" experience. Starting with the 2008 model year, the EPA revised those tweaks to bring hybrid mileage ratings closer to actual usage. (It revised its online mileage data, using the newer formulas for 2007 and earlier cars, so as to compare apples to apples.)
The 2010 Prius returns higher overall mileage than the 48 city / 45 highway rating that the 2009 model carries, despite the new car being more powerful, and offering more luxury features. Toyota has been showing it to select groups in its Prius Connection events since the car's January debut at the Detroit auto show.
You should be able to find a 2010 Prius at your local Toyota showroom right around Memorial Day.
2010 Toyota Prius