Bill Loshbough, President
P.O. Box 25944
Albuquerque, NM 87125
Dear Mr. Loshbough:
This responds to your letter asking for an interpretation of S5.1.3(e) of Federal Motor Vehicle Standard (FMVSS) No. 222, School bus passenger seating and crash protection. S5.1.3(e) specifies that, when a school bus passenger seat is subjected to the forward application of force, Seat components shall not separate at any attachment point. You wish to know if a school bus seat with a sheer [sic] pin on both sides of the seat that break and separate into two pieces and fall loose from the seat is acceptable and meets the intent of FMVSS 222. Based upon the information you provided to the agency and the analysis below, Ive concluded the seat structure you describe would not fail under FMVSS No. 222.
The answer depends on the location of the shear pin. The term attachment point in S5.1.3(e) refers to attachment points to the vehicle body structure, i.e., the pedestal and school bus side wall. The shear pins that we understand are the subject of your question, are part of the internal seat mechanism and are not attached to the vehicle body structure. These shear pins are designed within the seating system to break in certain accident or belt loading scenarios as part of the functionality and protection of the seating system. The breaking of the shear pins in such a school bus seat design would not be a failure to meet S5.1.3(e) of FMVSS No. 222; however all other provisions of S5.1 of the regulation would still need to be met. (I would also observe that this reasoning is similarly applicable to the identical language of S5.1.4(e) of FMVSS No. 222 concerning the rearward application of force.)
I am, for your information, enclosing a copy of a June 16, 1978 interpretation letter to Blue Bird Body Company addressing the meaning of the phrase seat components shall not separate at any attachment point.
I hope this information is helpful. If you have any further questions about the National Highway Traffic Safety Administrations laws, please contact Dorothy Nakama of my staff at this address or at (202) 366-2992.
Anthony M. Cooke