Office of Transportation                             EPA420-F-06-062
Urited States         and Air Quality                                   October 2006
Environmental Protection  	
                 EPA's  Fuel Economy Programs
                 This fact sheet describes the U.S. Environmental Protection Agency's
                 (EPA) Fuel Economy Program. EPA is responsible for providing the fuel
                 economy data that is used by the U. S. Department of Energy (DOE)
                 to publish the annual Fuel Economy Guide, by the U. S. Department
                 of Transportation (DOT) to administer the Corporate Average Fuel
                 Economy (CAFE) program, and by the Internal Revenue Service (IRS)
                 to collect Gas Guzzler taxes.
                 Fuel economy, or gas mileage, continues to be a major area of public
                 and policy interest for several reasons. Passenger vehicles account for
                 approximately 40 percent of all U.S. oil consumption, so increasing
                 energy efficiency helps reduce our dependence on imported oil and
                 enhances the nation's energy security. Likewise, it helps conserve our
                 fossil resources for future generations. Passenger vehicles also contrib-
                 ute about 20 percent of all U.S. carbon dioxide emissions, so increasing
                 fuel efficiency helps reduce greenhouse gas emissions. Finally, the more
                 miles a car gets per gallon of gasoline, the more money the owner saves
                 on fuel costs. Given the importance of fuel economy, the federal govern-
                 ment administers three programs to provide information to consumers
                 about fuel economy and to encourage the production of fuel efficient

Fuel Economy Labels and Fuel Economy Guide
Once a year, EPA and DOE publish the Fuel Economy Guide listing the
fuel economy estimates (expressed in miles per gallon) of new passenger
vehicles. The Fuel Economy Guide is published and distributed by DOE
based on EPA's data. The fuel economy estimates listed in the guide are
based on laboratory testing performed by the auto manufacturers and
What Vehicles Are Tested?
Not every vehicle is tested for fuel economy. Instead, manufacturers are
required to split each model into smaller groups, based upon the various
options available that can impact fuel economy (such as vehicle weight,
transmission type and engine size). A vehicle from each of these groups
with the highest projected sales must be tested. Also, passenger cars and
light trucks with a gross vehicle weight rating (GVWR) greater than
8,500 pounds are exempt from fuel economy requirements, and are not
tested for fuel economy (however, they are still subject to Federal emis-
sion requirements.)

Manufacturers test all the vehicles at their laboratories. EPA confirms
about 10-15 percent of the vehicles at its National Vehicles and Fuel
Emission Laboratory in Ann Arbor, Michigan.
How are Vehicles Tested?
Vehicles are driven over identical driving patterns by professional driv-
ers in controlled laboratory conditions on a dynamometer, which is like a
treadmill for cars. The conditions that occur during driving, such as wind
drag and inertia are accounted for on the dynamometer. There are two
types of tests that are conducted: city and highway tests.

The city test is approximately 11 miles long and simulates a stop and go
trip with an average speed of about 20 miles per hour (mph). The trip
lasts 31 minutes and has 23 stops. About 18 percent of the time is spent
idling (as in waiting for traffic lights). A short freeway driving segment
is included in the test. The engine is initially started after being parked

The highway test simulates a 10 mile trip with an average speed of 48
mph. The vehicle is started "hot" and there is very little idling and no

How Are the Label Estimates Calculated?
Fuel economy estimates are calculated from the emissions generated dur-
ing the tests using a carbon balance equation. We know how much carbon
is in the fuel, so by precisely measuring the carbon compounds expelled in
the exhaust we can calculate the fuel economy.

After the vehicles have been tested, the results are adjusted downward to
account for conditions that occur on the road that can affect fuel economy
which don't occur during laboratory testing, such as cold temperature,
aggressive driving, excessive use of power-hungry accessories, among
others. The city is adjusted downward by 10 percent, and the highway by
22 percent.
The equation for calculating the city or highway average fuel economy,
given in miles per gallon (mpg), is:

FEave = (total sales / [(salesl/FEl)+ (sales2/FE2) + ...+ (salesn/FEn)]

The calculation for combined fuel economy weights the city at 55 percent
and the highway at 45 percent using the following equation:

FEcomb = 1 / (( .55 / city FE) + (.45 / hwy FE))
What Information Is In The Fuel Economy Guide and
on The Fuel Economy Label?
The fuel economy city and highway estimates are printed in the Fuel
Economy Guide and posted on the window sticker labels of all new cars
and light trucks. Also included on the labels and in the Guide are the
projected annual fuel costs as determined from the combined city and
highway fuel economy, assuming 15,000 miles traveled per year and using
estimated fuel costs (provided by the Department of Energy) from the fol-
lowing table (for 2007 model year vehicles):

      Regular Unleaded Gasoline        $2.65 per gallon
      Premium Unleaded Gasoline       $2.85 per gallon
      Diesel Fuel                      $2.65 per gallon
      CNG (Gasoline equivalent)        $1.45 per gallon equivalent
      E85 Ethanol Fuel                 $2.20 per gallon
      LPG (Propane)                   $1.70 per gallon
      Hydrogen                       $5.85 per kilogram
      Electricity                       $0.10, 0.15 per kilowatt-hour

The fuel prices were determined in advance to allow time for printing
labels and the Fuel Economy Guide. For more recent fuel cost estimates
using current fuel prices, visit Fuel Economy
Guide is published and distributed to dealerships across the United
States. New car dealers are required to have copies of the Guide avail-
able to consumers. The Guide is also available online at www. fuel econo-
my, gov.
Corporate Average Fuel Economy (CAFE)
Corporate Average Fuel Economy (CAFE) is the required average fuel
economy for a vehicle manufacturer's entire fleet of passenger cars and
light trucks manufactured for sale in the United States for each model
year. There are separate average fuel economy standards for passenger
cars and light trucks. Light trucks include those with a gross vehicle
weight rating (GVWR) of 8,500 pounds or less. CAFE values are ob-
tained using the same test data generated by the fuel economy tests used
to determine the fuel economy estimates for the Guide and labels, but the
test results are not adjusted to account for real-world conditions. Instead,
the results from the city and highway tests are combined. EPA admin-
isters the testing program which generates the fuel economy data and
determines the procedures for calculating the fuel economy values for
CAFE. The National Highway Traffic and Safety Administration (NHT-
SA), which is part of DOT, is responsible for establishing and amending
the CAFE standards for light trucks. Congress sets the CAFE standards
for cars. EPA reports the CAFE results for each manufacturer to NHTSA
annually, and NHTSA determines if the  manufacturers comply with the
CAFE  standards and assesses penalties as required. More information
about CAFE can be found on NHTSA's  web site at
Green Vehicle Guide
Every year since 2000, EPA publishes emissions information for the new
model year cars and light trucks on its Green Vehicle Guide Web site at This user-friendly site is designed to help
consumers identify the cleanest, most efficient vehicle that meets their
needs. It provides consumers with the opportunity to compare the rela-
tive emissions performance of vehicles by means of the 0-10 emissions
rating assigned to each vehicle. Vehicles rated higher than others are
designed to emit fewer pollutants such as carbon monoxide, nitrogen

oxides, hydrocarbons and particulate matter. Vehicles can be viewed indi-
vidually or by class, such as SUVs, sedans, or pickups.

The emissions ratings are based on the EPA emission standards the vehi-
cle was certified to meet. Because manufacturers can choose from a com-
plex set of emission standards, it is not always easy to understand them.
The Green Vehicle Guide "demystifies" these standards, and allows con-
sumers to  see that they may have a choice to buy a cleaner, more efficient
vehicle, regardless of the size, type or style they are interested in.

The Green Vehicle Guide also identifies the cleanest, most fuel efficient
vehicles with a "SmartWaysm" logo. More information about SmartWay
vehicles is found at
Gas Guzzler Tax
The Gas Guzzler Tax is imposed on manufacturers of new model year
cars (not minivans, sport utility vehicles or pick-up trucks) that fail to
meet the minimum fuel economy level of 22.5 mpg. The tax is intended
to discourage the production and purchase of fuel inefficient vehicles.
The fuel economy figures used to determine the tax are based on com-
bined city and highway fuel economy that is unadjusted for real-world
conditions, and thus is different from the fuel economy estimates pro-
vided in the Fuel Economy Guide. The tax is collected by the Internal
Revenue Service and normally paid by the manufacturer or importer after
production has ended for the model year and is based on the total num-
ber of gas guzzler vehicles which were introduced into commerce in the
United States. The amount of the tax paid is displayed on the vehicle's
fuel economy label (the window sticker on new cars). Information on
Gas Guzzler Tax:
For More Information
You can access additional information about these programs at the fol-
lowing web sites:

             Information on EPA's Fuel Economy Program, including
             regulations, test data, and consumer tips:
             www. epa. gov/fueleconomy

Information on vehicle fuel economy, advanced
technoogy, and possible tax incentives, including a down
loadable version of the Fuel Economy Guide:
www. fuel economy, gov

Information on CAFE, including CAFE standards, NHT
SA's annual report summarizing the fuel economy per-
formance of the current fleet, rulemaking activities, and
fines collected:

The IRS's Gas Guzzler Tax form (IRS Form 6197):