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.
