(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.