40 CFR 91.1304 - Averaging.
(a) A manufacturer may use averaging across engine families to demonstrate a zero or positive credit balance for a model year. Positive credits to be used in averaging may be obtained from credits generated by another engine family of the same model year, credits banked in previous model years, or credits obtained through trading.
Title 40 published on 2013-07-01
no entries appear in the Federal Register after this date.