Interpretation ID: nht79-2.9

DATE: 05/21/79

FROM: AUTHOR UNAVAILABLE; S. P. Wood for F. Berndt; NHTSA

TO: Blue Bird Body Company

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your March 13, 1979, letter in which you ask whether a seat that does not have another seat immediately behind it must comply with the rearward performance requirements of Standard No. 222, School Bus Passenger Seating and Crash Protection. The seat to which you refer is abutted by a portion of a lift device for handicapped students. Behind the lift structure, itself, is a restraining barrier and more seats.

Standard No. 222 states that any seat that has another seat behind it must comply with the rearward performance requirements. The effect of this statement is to exclude rear seats from complying with the rearward performance requirements. In the Federal Register notice of April 23, 1975, the agency stated that it was adopting this approach to save costs in school buses without impairing the safety of those vehicles. The agency indicated that the passengers in the rear seat were protected as well as passengers in other seats, because they can "ride down" the vehicle structure rather than the seat back in an accident (40 FR 17855).

The above analysis is equally appropriate for other seats that are directly in front of some substantial vehicle structure. The lift mechanism depicted in your picture and diagram appears to offer similar "ride down" benefits to passengers as does the rear wall structure of a vehicle. Accordingly, the agency considers the rearward performance requirements to apply in situations such as yours only when a seat is immediately in front of another passenger seat. The agency cautions, however, that this interpretation applies only in those instances where the affected seat is in front of some substantial vehicle structure. If the seat does not have the benefit of vehicle structure behind it, it must comply with the rearward performance requirements.

SINCERELY,

BLUE BIRD BODY COMPANY

March 13, 1979

Roger Tilton Office of Chief Counsel National Highway Traffic Safety Administration

SUBJECT: FMVSS 222 PARAGRAPH S5.1.4 SEAT PERFORMANCE REARWARD

REFERENCE: Telephone conversation between W. G. Milby and Roger Tilton March 6, 1979.

Dear Mr. Tilton:

The subject paragraph says "when a school bus passenger seat that has another seat behind it is subjected to the applications of force . . .". The effect of this language is to not require the rear most seats in a school bus to be subject to the rearward performance requirements of FMVSS 222.

The rationale behind this is that the rear structure of the bus body will restrict the seat back from excessive rearward deflection. The purpose of this letter is to seek a similar interpretation for seats which have other structures behind them (such as handicapped passenger lifts as described in the attached photo) which would insure that the rearward deflection does not exceed 8 inches as described in S5.1.4(b). An interpretation is necessary since in some floor plans, such as the ones described on the enclosed form number OE-79122 page 12, it is necessary to have some seating positions rearward of the lift. When this is the case, a barrier is placed between the rear portion of the lift and the next seating position, as shown on the enclosed floor plans. Although these seats are "behind" another school bus passenger seat, they are not immediately behind another seat which is the sense in which the language of S5.1.4 is used.

We thank you for your consideration in this matter and look forward to your early response.

W. G. Milby Manager, Engineering Services

(Graphics omitted)

SCHOOL BUS

ALL AMERICAN BLUE BIRD'S HANDY BUS 35" LIFT

SUGGESTED SEAT PLANS BODY MODEL AAFC3101 Body Sections Front to Rear: 179" W.B. Floor Plan Number: 0917484 5-28, 2-35, 4-28 Seat Plan Number: 0896696

BODY MODEL AAFC3101 Body Sections Front to Rear: 179" W.B. Floor Plan Number: 0914069(1) 3-28, 2-35, 6-28 Seat Plan Number: 0914325

(Graphics omitted)

(1) NOTE: Option 4594 Relocate 60 gal. fuel tank w/barrier must be ordered. Body Sections Front to Rear: 149" W.B. Floor Plan Number: 0850875 5-28, 3-35, 1-28 Seat Plan Number: 0914309

BODY MODEL AAFC2700 Body Sections Front to Rear: Floor Plan Number: 0850875 5-28, 3-35, 1-28 149" W.B. Seat Plan Number: 0850867

(Graphics omitted)