Not later than December 31, 1998, the state board shall adopt, by regulation, a statewide program to commence in 1999 that does all of the following:

from appropriate sampling. The numerical value of credits may be constant over a defined lifetime, or may decline with age measured from the time of origination of the credits. In all cases, the numerical value of the credits shall reflect the useful life expectancies and the projected in-use emissions of the retired vehicles in a manner consistent with the assumptions used in determining the emissions inventory. The credits shall be fully recognized by the United States Environmental Protection Agency, the state board, and the districts.

credits to public or private entities to be used to achieve the emission reduction requirements of the 1994 state implementation plan, meet the requirements of the inspection and maintenance program, satisfy compliance with other emission reduction mandates, as determined by the district or the state board, create local growth allowances, or satisfy new or modified source emission offset requirements. Nothing in this article limits a district’s authority to apply emission discount factors pursuant to district rules that regulate emissions banks, trades, or offsets.