Interpretation ID: aiam1752
Chairman of the Board
Utility Trailer Manufacturing Co.
City of Industry
CA 91749;
Dear Mr. Bennett: This responds to your January 8, 1975, request for reconsideration o our determination, in a January 3, 1975, letter to Mr. J. B. Markovich, that a bulk transport trailer designed for transporting farm commodities from the field to processing plants over private and public roads does not qualify for exemption from Standard No. 121, *Air brake systems*, as an agricultural vehicle.; There is no specific exemption for agricultural machinery in th language of the 'National Traffic and Motor Vehicle Safety Act of 1966' (15 U.S.C. 1391 et seq.), and there is little legislative history on the subject. We have concluded that Congress only intended to exclude agricultural machinery that is designed for working on the fields--implements of husbandry--and whose on-road use is strictly limited, at low speeds, and only incidental to its main function.; The NHTSA has interpreted the definition of 'motor vehicle' to agre with this Congressional intent. Our criteria for a 'non-motor vehicle' have been (1) a maximum speed not exceeding 20 mph, and (2) an abnormal configuration which distinguishes it from the traffic flow. These criteria separate 'agricultural machinery' from those vehicles which are related to agriculture but use the highways as a primary purpose.; The NHTSA does not interpret 'motor vehicle' to exempt a vehicle whic has a highway speed capability, even if it uses the highway infrequently. For example, house trailers are subject to safety standards although they sometimes use the highways only once to be moved to a permanent homesite. Mobile cranes and drill rigs which use the highways between job sites are another vehicle type which has also been determined to be a motor vehicle. The important consideration is that their configuration permits unlimited use of the highways.; From your description, your bulk transport trailers are capable o highway speed and use the highway in the same way as other air-braked full trailers. Accordingly, your request for reclassification is denied.; You mentioned difficulty in meeting Standard No. 121's parking brak requirements. I enclose a copy of correspondence on this same matter with a railroad company that finds it necessary to manually release parking brakes under some circumstances.; Sincerely,