Interpretation ID: aiam2000
Chief
Office of Equipment
Department of Transportation
P.O. Box 9067
Sacramento
CA 95816;
Dear Mr. Lightcap: This responds to your letter of June 12, 1975, requesting confirmatio that you as a final-stage manufacturer would only have to check the application and release times of a truck whose chassis you shortened or lengthened in order to certify that vehicle to the requirements of Federal motor vehicle safety standard (FMVSS) No. 121, *Air Brake Systems*.; Certification of vehicles to the standard is an area which ou statutory scheme leaves to the manufacturers, and in which, aside from discussion of general principles, the agency has declined to issue statements of approval.; The National Highway Traffic Safety Administration has stated tha actual road tests by final stage manufacturers are not necessary to establish compliance with Standard No. 121 or other standards, where other reasonable means, such as engineering calculations coupled with laboratory tests, can be used to the same effect. The agency has recognized that small organizations cannot be expected to test to the same scale or by the same methods as the large integrated automotive manufacturers. Supplier warranties and instructions are one of the primary means by which smaller assemblers are expected to use statutory 'due care' to see that their products conform.; From this discussion it should be apparent that verifying only th brake actuation and release functions will probably be an insufficient basis for certifying that the vehicle will comply, for example, with the stopping distance requirements of the standard. Engineering calculations may, however, satisfy you, in the exercise of due care, that the vehicle as modified meets all the requirements of the standard.; The incomplete vehicle documentation provided with the vehicle woul generally serve as the basis of certification to equipment requirements, to the degree that the equipment is undisturbed. The addition of an axle may cause the air reservoirs to no longer satisfy the air volume requirements of the standard.; Sincerely, Frank Berndt, Acting Chief Counsel