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Manufacturers are quick to point to those fuel mileage numbers on that window sticker when the digits suggest a vehicle will wring 30 or more miles per gallon from a gallon of gasoline, especially when that gallon costs $3 or more.
But the truth is that those numbers are
largely fantasies and have been for years.
The government agency that comes up with
those city-highway mileage estimates, the Environmental
Protection Agency, or EPA, admitted as much last year
when it announced it would for the first time since
1985 change how it tests vehicles, starting sometime
in the 2007 model year.
How critical will the change be?
Consumer Reports found last year that more than 90 percent
of vehicles it tested between 2000 and 2006 delivered
significantly lower fuel mileage than the government
estimates. In some cases the EPA numbers were off by
as much as 50 percent, even on vehicles touted as high-mileage
cars.
That finding came as no surprise to anyone
who has bought a new car and was dismayed to find that
he or she couldn't achieve the numbers on the window
sticker. The EPA says it will almost certainly downgrade
the mileage numbers for nearly all vehicles, perhaps
by as much as 20 percent. Even then, it's unlikely every
driver will be able to match the predictions.
Here's what's happening: The EPA mileage tests use laboratory conditions to achieve the economy numbers. Historically, those tests haven't taken into account such everyday factors as changes in temperatures, hills, wind and even different tire pressures, all of which affect fuel mileage. EPA testers also didn't even turn on a car's air conditioner, which usually increases the load on a car's engine.
60 mph on the interstate? Suuuure
The EPA also assumed that no one drove more than 60
mph on the open highway -- a delusion apparent to anyone
who drives 70 mph on the interstate and is passed by
almost everyone. The ratings don't take into account
the dramatically increased time drivers now spend idling
in gridlock in city traffic.
But no matter what final calculations the EPA implements to get more realistic mileage estimates, the numbers on that sticker will not be equaled consistently by real-world driving.
The reason is that we all drive differently -- some just can't resist a sharp stab at the gas pedal when coming off a stoplight, others are not content to engage the cruise control on long trips.
So for 2007, savvy buyers should do what they have always done -- use the government fuel mileage figures as yardsticks to compare vehicles to find out which ones will go farther on a tank of gasoline. For now, at least, your mileage will vary.
Terry Jackson is an automotive editor and columnist based in Florida.
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