(a) Promulgation of standards
Not later than 24 months after November 15, 1990, the Administrator shall promulgate regulations under this part containing clean-fuel vehicle standards for the clean-fuel vehicles specified in this part.

(b) Other requirements
Clean-fuel vehicles of up to 8,500 gvwr subject to standards set forth in this part shall comply with all motor vehicle requirements of this subchapter (such as requirements relating to on-board diagnostics, evaporative emissions, etc.) which are applicable to conventional gasoline-fueled vehicles of the same category and model year, except as provided in section 7584 of this title with respect to administration and enforcement, and except to the extent that any such requirement is in conflict with the provisions of this part. Clean-fuel vehicles of 8,500 gvwr or greater subject to standards set forth in this part shall comply with all requirements of this subchapter which are applicable in the case of conventional gasoline-fueled or diesel fueled vehicles of the same category and model year, except as provided in section 7584 of this title with respect to administration and enforcement, and except to the extent that any such requirement is in conflict with the provisions of this part.

(c) In-use useful life and testing

(1) In the case of light-duty vehicles and light-duty trucks up to 6,000 lbs gvwr, the useful life for purposes of determining in-use compliance with the standards under section 7583 of this title shall be—

(A) a period of 5 years or 50,000 miles (or the equivalent) whichever first occurs, in the case of standards applicable for purposes of certification at 50,000 miles; and

(B) a period of 10 years or 100,000 miles (or the equivalent) whichever first occurs, in the case of standards applicable for purposes of certification at 100,000 miles, except that in-use testing shall not be done for a period beyond 7 years or 75,000 miles (or the equivalent) whichever first occurs.

(2) In the case of light-duty trucks of more than 6,000 lbs gvwr, the useful life for purposes of determining in-use compliance with the standards under section 7583 of this title shall be—

(A) a period of 5 years or 50,000 miles (or the equivalent) whichever first occurs in the case of standards applicable for purposes of certification at 50,000 miles; and

(B) a period of 11 years or 120,000 miles (or the equivalent) whichever first occurs in the case of standards applicable for purposes of certification at 120,000 miles, except that in-use testing shall not be done for a period beyond 7 years or 90,000 miles (or the equivalent) whichever first occurs.