Interpretation ID: aiam1736
House of Representatives
Washington
DC 20515;
Dear Mr. Moss: I am pleased to respond to your November 29, 1974, request for ou analysis of Mr. Harris Roseboom's November 8, 1974, suggestion that the 'no lockup' requirements of Standard No. 121, *Air brake systems*, are unnecessary as they apply to trailers used in harvesting crops on dry, level terrain in California.; We understand Mr. Roseboom's concern about the standard as it applie to trailers used for bulk transport of agricultural products. However, Standard No. 121, you will recall, established comprehensive equipment, brake actuation, retardation force, and parking brake requirements for trailers, as well as the 'no lockup' stopping distance requirements to which Mr. Roseboom refers. As a result, any exemption from the standard would mean a loss of *all* of these safety features on those trailers which might qualify for exemption.; Our major concern, of course, is that these trailers could be use during the non-harvest months in regular highway use, or they could be sold for highway use at a future date.; In either case they would operate under the same conditions as an other trailer on the highway. Our authority over them ends at the point of retail sale, and we know of no other way to ensure they are highway- equipped than by mandating it at the time of manufacture.; I would like to note that the delayed effective date for 'heavy hauler trailers is based on the greater complexity of brake system design on vehicles whose function dictates extendable brake lines or a low configuration which limits space for mounting new brake components. The standard becomes effective for these vehicles on September 1, 1976.; As for trucks, the effective date of March 1, 1975, is the earlies date by which adequate supplies of components will be available to build the new systems.; We would appreciate your ideas on how to make provision for specialize use of vehicles like these, while ensuring that they are not operated on the highway under the same conditions as standard highway vehicles.; I am aware of your continued interest in ensuring safety on th highways and hope that you can appreciate our dilemma in cases like the classification of agricultural bulk transport trailers.; Sincerely, James B, Gregory, Administrator