104 STAT. 2434 PUBLIC LAW 101-549—NOV. 15, 1990 Reports. assuring that noncomplying vehicles are not operated on public roads). "(v) Annual emission testing and necessary adjustment, repair, and maintenance, unless the State demonstrates to the satisfaction of the Administrator that a biennial inspection, in combination with other features of the program which exceed the requirements of this Act, will result in emission reductions which equal or exceed the reductions which can be obtained through such annual inspections. "(vi) Operation of the program on a centralized basis, unless the State demonstrates to the satisfaction of the Administrator that a decentralized program will be equally effective. An electronically connected testing system, a licensing system, or other measures (or any combination thereof) may be considered, in accordance with criteria established by the Administrator, as equally effective for such purposes. "(vii) Inspection of emission control diagnostic systems and the maintenance or repair of malfunctions or system deterioration identified by or affecting such diagnostics systems. Each State shall biennially prepare a report to the Administrator which assesses the emission reductions achieved by the program required under this paragraph based on data collected during inspection and repair of vehicles. The methods used to assess the emission reductions shall be those established by the Administrator. "(4) CLEAN-FUEL VEHICLE PROGRAMS. —(A) Except to the extent that substitute provisions have been approved by the Administrator under subparagraph (B), the State shall submit to the Administrator, within 42 months of the date of the enactment of the Clean Air Act Amendments of 1990, a revision to the applicable implementation plan for each area described under part C of title II to include such measures as may be necessary to ensure the effectiveness of the applicable provisions of the clean-fuel vehicle program prescribed under part C of title II, including all measures necessary to make the use of clean alternative fuels in clean-fuel vehicles (as defined in part C of title II) economic from the standpoint of vehicle owners. Such a revision shall also be submitted for each area that opts into the clean fuel-vehicle program as provided in part C of title II. "(B) The Administrator shall approve, as a substitute for all or a portion of the clean-fuel vehicle program prescribed under part C of title II, any revision to the relevant applicable implementation plan that in the Administrator's judgment will achieve long-term reductions in ozone-producing and toxic air emissions equal to those achieved under part C of title II, or the percentage thereof attributable to the portion of the clean-fuel vehicle program for which the revision is to substitute. The Administrator may approve such revision only if it consists exclusively of provisions other than those required under this Act for the area. Any State seeking approval of such revision must submit the revision to the Administrator within 24 months of the date of the enactment of the Clean Air Act Amendments of 1990. The Administrator shall approve or disapprove any such revision within 30 months of the date of the
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