quote:
Ever looked at a new car sticker? "Estimated" fuel mileage info has always had a big spread. Then you get it home and it's not even close. Whassssup wit' dat???
http://www.fueleconomy.gov/feg/info.shtml
Highway test
The test to determine the highway fuel economy estimate represents
a mixture of "non-city" driving. Segments corresponding to different
kinds of rural roads and interstate highways are included. The
test simulates a 10-mile trip and averages 48 mph. The maximum
speed is 60 mph. The test is run with the engine warmed up and
has little idling time and no stops (except at the end of the
test).
Note:
To make the numbers in the Fuel Economy Guide more useful for
consumers, EPA adjusts these laboratory test results to account
for the difference between controlled laboratory conditions and
actual driving on the road. The laboratory fuel economy results
are adjusted downward to arrive at the estimates in the Fuel Economy
Guide and on the labels seen on new cars, light trucks, and vans.
The city estimate is lowered by 10% and the highway estimate by
22% from the laboratory test results. Experience has proven that
these adjustments make the mileage estimates in the Fuel Economy
Guide correspond more closely to the actual fuel economy realized
by the average driver
