[Code of Federal Regulations]
[Title 40, Volume 27]
[Revised as ofJuly 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR600.206-86]

[Page 885-886]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 600--FUEL ECONOMY OF MOTOR VEHICLES--Table of Contents
 
   Subpart C--Fuel Economy Regulations for 1977 and Later Model Year 
       Automobiles--Procedures for Calculating Fuel Economy Values
 
Sec. 600.206-86  Calculation and use of fuel economy values for gasoline-fueled, diesel, and electric vehicle configurations.

    (a) Fuel economy values determined for each vehicle, and as approved 
in Sec. 600.008 (b) or (f), are used to determine city, highway, and 
combined fuel economy values for each vehicle configuration (as 
determined by the Administrator) for which data are available.
    (1) If only one set of city and highway fuel economy values is 
accepted for a vehicle configuration, these values, rounded to the 
nearest tenth of a mile per gallon, comprise the city and highway fuel 
economy values for that configuration.
    (2) If more than one city or highway fuel economy value is accepted 
for a vehicle configuration:
    (i) All data shall be grouped according to the subconfiguration for 
which the data were generated using sales projections supplied in 
accordance with Sec. 600.207(a)(3).
    (ii) Within each group of data, all values are harmonically averaged 
and rounded to the nearest 0.0001 of a mile per gallon in order to 
determine city and highway fuel economy values for each subconfiguration 
at which the vehicle configuration was tested.
    (iii) All city fuel economy values and all highway fuel economy 
values calculated in paragraph (a)(2)(ii) of this section are 
(separately for city and highway) averaged in proportion to the sales 
fraction (rounded to the nearest 0.0001) within the vehicle 
configuration (as provided to the Administrator by the manufacturer) of 
vehicles of each tested subconfiguration. The resultant values, rounded 
to the nearest 0.0001

[[Page 886]]

mile per gallon, are the city and highway fuel economy values for the 
vehicle configuration.
    (3) The combined fuel economy value for a vehicle configuration is 
calculated by harmonically averaging the city and highway fuel economy 
values, as determined in Sec. 600.206(a) (1) or (2), weighted 0.55 and 
0.45 respectively, and rounded to the nearest 0.0001 mile per gallon. A 
sample of this calculation appears in appendix II to this part.
    (b) If only one equivalent petroleum-based fuel economy value exists 
for an electric configuration, that value, rounded to the nearest tenth 
of a mile per gallon, will comprise the petroleum-based fuel economy for 
that configuration.
    (c) If more than one equivalent petroleum-based fuel economy value 
exists for an electric vehicle configuration, all values for that 
vehicle configuration are harmonically averaged and rounded to the 
nearest 0.0001 mile per gallon for that configuration.

[49 FR 13849, Apr. 6, 1984]