How to comply with the Tier 3 and Tier 4 fleet average standards.
EQUATION 1 TO PARAGRAPH (B)
Where:
i = A counter associated with each separate test group or evaporative family.
b = The number of separate test groups or evaporative families from a given averaging set to which you certify your vehicles.
Ni = The actual nationwide sales for the model year for test group or evaporative family i. Include allowances for evaporative emissions as described in § 86.1813.
FELi = The FEL selected for test group or evaporative family i. Disregard any separate standards that apply for in-use testing or for testing under high-altitude conditions.
Ntotal = The actual nationwide sales for the model year for all vehicles from the averaging set, except as described in paragraph (c) of this section. The pool of vehicle models included in Ntotal may vary by model year, and it may be different for evaporative standards, FTP exhaust standards, and SFTP exhaust standards in a given model year.
40 C.F.R. §§86.1860-17