Interpretation ID: nht78-3.28

DATE: 03/22/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: Midland Machinery Company, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Midland Machinery Company's February 20, 1978, request for confirmation that Standard No. 121, Air Brake Systems, does not apply to an air-braked trailer that carries no cargo and consists entirely of a portable mixing plant.

Section S3 of Standard No. 121 contains an exclusion for any trailer whose unloaded vehicle weight is not less than 95 percent of its gross vehicle weight rating (GVWR). "Unloaded vehicle weight" means the weight of a vehicle with maximun capacity of all fluids necessary for operation of the vehicle, but without cargo or occupants. You state that the portable mixing plant trailer carries no cargo, and it would thus be excluded from the requirements of Standard No. 121.

Enclosed are copies of Standard No. 108 and 120, along with an information sheet that explains how copies of these and other NHTSA regulations may be obtained.