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treadmill. These procedures ensure that each
vehicle is tested under
identical conditions.
There are two different fuel economy estimates for each vehicle, one for
city driving and one for highway driving. To develop these two estimates,
separate tests are used to represent typical everyday city and rural
driving.
The test used to determine the city fuel economy estimate simulates a 7.5
mile (12 km), stop and go trip with an average speed of 20 mph (32
km/h). The trip takes 23 minutes and has 18 stops. About one fifth of the
time is spent idling, as in waiting at traffic lights or in rush hour traffic.
Two kinds of engine starts are used: a cold start, which is similar to
starting a car in the morning after it has been parked all night and a hot
start, which is similar to restarting a vehicle after it has been warmed up,
driven and stopped for a short time.
The test used 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 (17 km) trip with an average speed of 48 mph (77
km/h).
The test is run from a hot start and has little idling time and no
stops.
To assure that the fuel economy numbers are most useful for consumers,
the 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 on the fuel economy window sticker and the Gas Mileage
Guide. The city estimate is lowered by 10 percent and the highway
estimate is lowered by 22 percent from the laboratory test results.
Experience has proven that these adjustment.s make the mileage
estimates correspond more closely to the actual fuel economy realized by
the average driver.
Even though these figures are adjusted, they still represent what the
average driver will get. Your fuel economy may be significantly higher or
lower, depending on how, when, and where your vehicle is driven. Here
are some things you can do to increase fuel economy;
0
Combine errands into one trip.
0
Turn the engine off rather than letting it idle for more than a minute.
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