This subpart implements the statutory requirements of section 508 of the Act, which provides for the allocation of credits to fleets or covered persons that:

(a) Acquire alternative fueled vehicles in excess of the number they are required to acquire under this part or obtain alternative fueled vehicles before the model year when they are required to do so under this part;

(b) Acquire certain other vehicles as identified in this subpart; or

(c) Invest in qualified alternative fuel infrastructure or non-road equipment or an emerging technology.