Interpretation ID: aiam2250
School District No. 12
Adams County
10280 North Huron Street
Denver
CO 80221;
Dear Mr. Stacy: This responds to your March 5, 1976, request for written permission t deactivate the '121 brake system' of a school bus manufactured from a Ford chassis with a Kelsey-Hayes antilock system.; From the description of the problems you have encounted (sic) with thi vehicle, I assume that you do not intend to disconnect the entire '121 brake system', but only one or more antilock systems installed in satisfaction of the 'no lockup' requirements of S5.3.1 of Standard No. 121, *Air Brake Systems*. The National Highway Traffic Safety Administration (NHTSA) has made a finding that early models of the antilock system supplied on transit and intercity buses is characterized by malfunction that warrants its deactivation until a correction is fully developed. This finding was not made with regard to the Kelsey-Hayes system that equips your vehicle.; Section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safet Act (15 U.S.C. S 1397(a)(2)(a)) prohibits, with one exception, knowing disconnection of the antilock system by manufacturers, distributors, dealers, or repair businesses. A person that does not fall into these categories is not prohibited from disconnection of the system. Other State or Federal requirements, such as those of the Bureau of Motor Carrier Safety, may prohibit disconnection. In any case, the NHTSA urges that you not disconnect safety devices without consulting the vehicle manufacturer with regard to the safest configuration of the vehicle.; Sincerely, Frank A. Berndt, Acting Chief Counsel