To amend the Internal Revenue Code of 1986 to clarify the application of the retail tax on heavy trucks and trailers.

Amends the Internal Revenue Code, with respect to the retail tax on heavy (in excess of 33,000 pounds) trucks and trailers, to: (1) exempt tractors not suitable for such vehicles; (2) treat certain repairs or modifications as non-manufacture; and (3) provide for a specified tire tax credit.