Mr. Tracy Risner
The C. E. White Co.
7272 Boundary Road
P.O. Box 308
New Washington, OH 44854-0308
Dear Mr. Risner:
This responds to your request for an interpretation of whether C.E. Whites proposed seat back and seat back barrier configurations would meet minimum area requirements in Federal Motor Vehicle Safety Standard (FMVSS) No. 222, School bus passenger seating and crash protection. The answer is yes.
As you know, NHTSA does not approve motor vehicles or motor vehicle equipment, nor do we endorse any commercial products. This opinion is based on our understanding of the facts presented in your letter.
Description of C.E. Whites Seat Back and Barrier
You ask about a school bus barrier (shown as B1 in the sketch you enclosed) that has an inward taper as it extends vertically. You state that the barrier meets the area requirement of S5.1.2 of FMVSS No. 222. The school bus seat immediately rearward of the barrier (S1 in your sketch) has no inward taper as it extends vertically. You state that the height of both the seat back and the barrier are 610 millimeters (24 inches) above the seating reference point, as required by FMVSS No. 222. However, with the tapered edges, the barrier does not coincide 100 percent with the seat back in the front projected view.
The requirements for restraining barrier surface area are found in S5.2.2 of FMVSS No. 222. That section states:
S5.2.2 Barrier height, position, and rear surface area. The position and rear surface area of the restraining barrier shall be such that, in a front projected view of the bus, each point of the barriers perimeter coincides with or lies outside of the perimeter of the minimum seat back area required by S5.1.2 for the seat immediately rearward of the restraining barrier. (Emphasis added.)
NHTSA answered your question in an August 11, 1987 letter to Mr. Larry Wort (copy enclosed). In that letter, we explained that a restraining barrier must only coincide with or lie outside of the seat back surface required by S5.1.2 of FMVSS No. 222. If a seat back surface exceeds the size required in Standard 222, the size of the restraining barrier need not coincide.
Similarly, in the situation you present, the seat back for the seat immediately rearward of the restraining barrier exceeds the minimum dimensions specified in S5.1.2 of FMVSS No. 222. It is acceptable to us that barrier B1 does not coincide with the perimeter of seat back S1 in this situation, as long as B1 provides rear surface area equal to the minimum area specified for seat back S1 in S5.1.2.
I hope this information is helpful. If you have any further questions, please contact Dorothy Nakama of my staff at this address or at (202) 366-2992.
O. Kevin Vincent