Office of Transportation EPA420-F-06-009
United States and Air Quality January 2006
Environmental Protection
Agency
Regulatory
Announcement
EPA Proposes New Test Methods for
Fuel Economy Window Stickers
The U.S. Environmental Protection Agency (EPA) is proposing new test
methods for calculating the fuel economy estimates that are posted on
the window stickers of new cars and trucks. The city and highway miles
per gallon (MPG) estimates help consumers compare the fuel economy
of different vehicles.
Although no single test can ever account for the wide variety of driving
conditions and styles, EPA's proposal will bring the MPG estimates clos-
er to the fuel economy consumers actually achieve on the road. The new
MPG estimates will take effect with model year 2008 vehicles, which will
be available in dealer showrooms in the fall of 2007.
Background / Current Tests and Methods
The city and highway MPG estimates have been provided to consum-
ers since the 1970s as a tool to help shoppers compare the fuel economy
of different vehicles. Currently, EPA relies on data from two laboratory
tests to determine the city and highway fuel economy estimates. The test
methods for calculating these estimates were last revised in 1985, when
the fuel economy derived from the two tests were adjusted downward—
10 percent for city and 22 percent for highway—to more accurately
reflect driving styles and conditions.
The city and highway tests are currently performed under mild climate
conditions (75 degrees F) and use acceleration rates and driving speeds
that EPA believes are generally lower than those experienced by drivers
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in the real world. Neither test is run with the use of accessories, such as
air conditioning. The highway test has a top speed of 60 miles per hour,
and an average speed of only 48 miles per hour.
Since the mid-1990s, EPA's emission certification compliance regu-
lations have required the use of three additional tests which capture
a much broader range of real-world driving conditions; specifically:
high-speed, fast-acceleration driving and the use of air conditioning and
colder temperature operation (20 degrees F). Not only do these condi-
tions impact the amount of air pollutants a vehicle emits, they also have
a significant impact on a vehicle's fuel economy. However, they are not
currently required to be used to measure fuel economy.
The Proposed New Methods to Determine Fuel
Economy
EPA is proposing to incorporate these tests into the methods used to
determine the fuel economy estimates posted on the window stickers of
new cars and light trucks. For the first time, the EPA fuel economy esti-
mates will reflect vehicle-specific data from tests designed to replicate
three real-world conditions that can significantly affect fuel economy:
high speed/rapid acceleration driving, use of air conditioning, and cold
temperature operation. Previously, these conditions were accounted for
by across-the-board adjustments, rather than by vehicle-specific testing.
EPA is also proposing that the fuel economy estimates reflect other con-
ditions that affect fuel economy, such as road grade, wind, tire pressure,
load, and the effects of different fuel properties. The fuel economy for
each vehicle model would continue to be presented to consumers as city
and highway MPG estimates.
Auto manufacturers would be required to perform the fuel economy
testing specified in EPA's proposal. In the 2008 model year, the new
methods would be used to determine the estimates. In 2011, a provision
would take effect that would require manufacturers to perform additional
cold temperature, air conditioning and/or high speed/rapid accelera-
tion driving tests for some vehicles that may be more sensitive to these
conditions. The additional testing would ensure that the fuel economy of
those vehicles is more precisely captured. EPA is proposing to delay this
additional testing until 2011 in order to provide enough time for manu-
facturers to plan for the added testing responsibilities. Nevertheless,
beginning in 2008, the fuel economy for those sensitive vehicles would
still reflect enough of the above effects such that consumers can make
good comparisons.
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How Fuel Economy Estimates Will Change from
Today's Labels
Under EPA's proposal, the new fuel economy estimates would be lower
for most vehicles. This is not because auto makers have designed the
same vehicles to be less fuel efficient—it is because our new test meth-
ods take into account factors that have been missing or not fully ac-
counted for in the current tests. Because some vehicles are more sensi-
tive to these factors than others, the impact of the proposed changes will
vary from vehicle to vehicle. The city MPG estimates for conventional
(non-hybrid) vehicles would drop on average by about 10-20 percent
from today's labels, while the highway estimates would drop by about
5-15 percent, depending on the vehicle.
For hybrid vehicles, the city MPG estimates would drop 20-30 percent
from today's labels. For highway MPG estimates, the change is about the
same as for conventional vehicles. The nature of current hybrid tech-
nology-the addition of a battery as a second source of on-board power,
sophisticated control systems, and sometimes a smaller engine—makes
a hybrid's fuel economy more sensitive to certain factors, such as colder
weather and air conditioning use. However, many hybrid models will
remain among the most fuel-efficient vehicles on the market.
Laboratory Tests Reflect Real-World Conditions
It is essential that EPA's fuel economy estimates continue to be derived
from controlled, repeatable laboratory tests to enable a standardized or
"level playing field," comparison between all vehicle models. However,
the underlying calculations proposed to determine the estimates are
based on data from real-world driving behavior and conditions. Labora-
tory testing also preserves EPA's ability to confirm the results of manu-
facturers' testing.
Auto makers will continue to be responsible for performing the fuel
economy testing and calculating the label MPG estimates. EPA will
continue to confirm the manufacturers' test results by performing audit
testing at its National Vehicle and Fuel Emissions Laboratory in Ann
Arbor, Michigan.
Since everyone drives differently and under varied conditions, there is
no test that could perfectly predict the fuel economy that every driver
will get. With any estimate, there will always be times when a driver's
actual fuel economy will be higher or lower. However, EPA's proposal
will do a better job of bringing the estimates on the window sticker
closer to people's real-world fuel economy experience.
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Fuel Economy Label Design
EPA is also proposing to revise the format and text of the fuel economy
window sticker that appears on new automobiles. This is being done to
more clearly convey the fuel economy information to consumers. The
proposal includes four label options under consideration. The label op-
tions are also available atwww.epa.gov/fueleconomy.
No Impact on CAFE
EPA's proposal has no impact on the Corporate Average Fuel Economy
(CAFE) program. There are separate regulations concerning the test
methods and procedures to determine the fuel economy values under the
CAFE program, which is administered by the Department of Transporta-
tion.
Public Comment
EPA is providing a 60-day comment period on the entire proposal, in-
cluding the new fuel economy testing methodology and label redesign.
Also, EPA will hold a public hearing after the proposal is published in
the Federal Register. For more details about how to comment or to at-
tend the public hearing, please see the Federal Register notice or go to
www.epa.gov/fueleconomy.
For More Information
You can access documents on this rulemaking on EPA's Office of Trans-
portation and Air Quality Web site at:
www.epa.gov/fueleconomy
For further information, please contact the Assessment and Standards
Division at:
U.S. Environmental Protection Agency
Office of Transportation and Air Quality
2000 Traverwood Drive
Ann Arbor, MI 48105
Voice-mail: (734) 214-4636
E-mail: asdinfo@epa.gov
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