Interpretation ID: aiam1856
House of Representatives
Washington
DC 20515;
Dear Mr. Gonzalez: This responds to your March 7, 1975, request for a copy of Standard No 121, *Air brake systems*, a discussion of the Federal excise tax on trucks and trailers, and an explanation of the manufacturer's certification responsibilities in the case of this standard. I have enclosed a copy of the standard, along with several amendments of it which have been recently issued.; The National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1391 e seq.) provides that the Secretary of Transportation establish performance standards for motor vehicle safety (S 103) and that the manufacturer be responsible for designing solutions that meet those performance requirements and certifying compliance with them (S 114). This law is intended to permit manufacturers latitude in choosing the designs best suited to their needs.; In the case of Standard No. 121, the manufacturer who completes vehicle will receive documentation from the chassis manufacturer that sets out the limits under which he can certify the vehicle without conducting tests or further engineering calculations. If he makes more modifications than authorized by the documentation, he must develop some basis of certification that the vehicle, as modified by him, would still be capable of meeting the requirements if tested by the Department's National Highway Traffic Safety Administration. Warranties from component suppliers, or the manufacturer's own engineering calculations could form the basis of certification.; The Federal excise tax to which you refer is a 10 percent tax on ne trucks, buses, and trailers which have a gross vehicle weight rating of more than 10,000 pounds. I have enclosed a discussion of the tax as it relates to the other taxes that accrue to the Highway Trust Fund.; Sincerely, James B. Gregory, Administrator