Interpretation ID: aiam2149
Staff Engineer
Blue Bird Body Company
P.O. Box 937
Fort Valley
GA 31030;
Dear Mr. Milby: This responds to Blue Bird Body Company's November 11, 1975, reques for confirmation that a manufacturer's location of the seating reference point, as the term is defined in 49 CFR S 571.3, may take into account nominal deflection of the seat and seat back cushions.; Blue Bird Body is correct that subparagraph (c) of the NHTSA' definition of seating reference point contemplates some deflection of seat cushions to simulate compression of padding material under the weight of a human torso and thigh. As noted in the preamble of the second proposal for a school bus seating standard (39 FR 27585, July 30, 1974), 'It can be seen that the manufacturer's freedom to locate the point is sharply restricted by the definition which specifies that it actually simulate the position of the pivot center of the human torso and thigh, following SAE placement procedures.'; Blue Bird Body's nominal seat and seat back cushion deflections appea to be reasonable, based on our understanding of the drawing your enclosed.; Yours truly, Richard B. Dyson, Assistant Chief Counsel