Interpretation ID: nht76-2.7

DATE: 05/05/76

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Blue Bird Body Company

TITLE: FMVSS INTERPRETATION

TEXT: This responds to Blue Bird Body Company's March 29 and 31, 1976, and April 14, 1976, requests for confirmation of several interpretations you have made regarding the new safety standards for school buses and the definition of "school bus" as they become effective in October 1976.

Your interpretation is correct that "bus passenger compartment" as used in S5.2.3.1 of Standard No. 217, Bus Window Retention and Release, means that portion of the bus that is rearward of the forwardmost point on the windshield.

Your request confirmation that the requirement in S5.7(a) of Standard No. 220, School Bus Rollover Protection, to open emergency exits during the application of force to the bus roof are inappropriate and therefore not applicable in the case of roof exits. Your interpretation is correct, and the NHTSA intends to modify the language of Standard No. 220 appropriately.

You request confirmation that the knee impact requirement of S5.3.2.1 of Standard No. 222, School Bus Passenger Seating and Crash Protection, does not apply to the rear row of seating in a school bus because there is no passenger seating behind this row. Your interpretation is correct. I would like to point out that the seat back of the rear row of seating also is not subject to the requirements of S5.3.1.1 for the same reason. You are also correct that "school bus passenger seat" as defined in S4 does not include a wheelchair that is placed in a school bus to transport non-ambulatory bus passengers. Our response on other issues concerning special arrangements for handicapped passengers will be forthcoming as a response to the outstanding Sheller-Globe petition for reconsideration of Standard No. 222.

In your March 31, 1976, letter you asked whether a bus that is sold for purposes that include carrying kindergarten and nursery school children to and from school or related events would be considered a school bus under the redefinition of "school bus" that becomes effective October 27, 1976 (40 FR 60033, December 31, 1975). The answer to your question is yes, because the statutory definition underlying the NHTSA definition of school bus specifically lists preprimary students as passengers of school buses. See 15 U.S.C. @ 1391(14).

In your April 14, 1976, letter you ask whether the requirement of S5.3.1.3 of Standard No. 222 for a minimum "contact area" on a described spherical head form refers to the area of actual contact on the surface of the spherical head form, or the area of contact on the head form as seen in projected view. The "contact area" refers to the area of actual contact on the surface of the head form.

SINCERELY,

BLUE BIRD BODY COMPANY March 29, 1976

Thomas W. Herlihy Office of Chief Counsel National Highway Traffic Safety Administration

We have several questions requiring interpretations for recently issued safety standards which apply to school buses.

FMVSS 217

S5.2.3.1 states in part "Each school bus shall provide at the manufacturer's option one emergency door on each side in the rear half of the bus passenger compartment . . .". We need a definition of the term "bus passenger compartment." Are we correct in assuming that this means the front of front windshield to the back of the bus body so that the engine hood on a Conventional type school bus is effectively eliminated? This in effect would define the bus passenger compartment as the "box" which the passengers occupy. We feel that this is the most workable definition of the term since any other definition would have to reference some other bus component which would not be easily identified in all bus configurations.

FMVSS 220

S4b states in part "each emergency exit of the vehicle provided in accordance with Standard 217 (571.217) shall be capable of opening as specified in that standard during the full application of the force and after release of the force . . .".

S5.7a states in part "In the case of testing under the full application of force, open the emergency exits as specified in S4b while maintaining the force applied in accordance with S5.4 and S5.5."

These requirements seem unrealistic and indeed practically impossible with respect to roof emergency exits. As written the force application plate would have to have an access hole through which the roof emergency exit would open. Obviously, roof emergency exits will be in different protions of the bus for different bus sizes and, therefore, would necessitate a variety of complicated force application plates. More importantly would be the questionable meaning of such a test since the configuration of the access hole in the force application plate would significantly affect the deflection in the area of the roof emergency exit. This, of course, would affect the operation of the emergency exit as far as latch forces and opening forces are concerned. In addition, this requirement does not seem to be realistically required in accident situations. The only time a roof load would be imposed is when the bus is in the rolled over orientation. Obviously, in this condition passengers would not be able to use roof emergency exits and would choose one of the other emergency exits that are required on all bus configurations.

We, therefore, request that roof emergency exits need not be tested during the application of the roof load but rather before and after the application of the roof load. Because of the timing involved, we must proceed on this assumption in order to meet tooling deadlines for the October 26 effective date.

We request your written approval of this approach and rulemaking action which would clarify this requirement.

FMVSS 222

We are somewhat unsure of the requirements of S5.3.2.1 with respect to knee impact requirements for the last row of seats in a bus. As we understand this requirement the rearmost seat in a bus does not have to meet the knee impact requirements on its seat back since there will be no occupants behind it. These are special seats because of the rear emergency door exit requirements of FMVSS 217 and, therefore, require special tooling. We are committing tooling on this assumption and request your concurrence.

From previous conversations with NHTSA personnel it is our understanding that wheelchair seating positions in buses for transporting handicapped students need not meet the requirements of FMVSS 222. For buses which have occupant positions for both wheelchair confined passengers and ambulatory passengers we are assuming that the seating and barrier requirements of FMVSS 222 only apply to those ambulatory passengers who will occupy a standard type school bus passenger seat. In other words, we are assuming that the definition of "school bus passenger seat" in FMVSS 222 does not apply to a wheelchair in a school bus.

We feel that there will be many questions regarding the applicability of FMVSS 222 to handicapped buses in the future. Some general guidelines form NHTSA concerning this matter should be considered.

May we have your early written reply to each of these matters?

W. G. Milby Staff Engineer

BLUE BIRD BODY COMPANY

April 14, 1976

Tad Herlihy Office of Chief Counsel National Highway Traffic Safety Administration

SUBJECT: FMVSS 222

We need an interpretation on Paragraph S5.3.1.3, head form force distribution, of the subject standard. The last sentence of this paragraph reads: "Where any contactable surface within such zones is impacted by the head form from any direction at 5 feet per second, the contact area on the head form surface shall be not less than three square inches."

Do the words "contact area" refer to the spherical contact area on the head form or the projected contact area?

W. G. Milby Staff Engineer

BLUE BIRD BODY COMPANY

March 31, 1976

Thomas W. Herlihy Office of Chief Counsel National Highway Traffic Safety Administration

Part 571, Docket No. 75-24; Notice 02, Redefinition of "School Bus."

The question has arisen as to whether a bus that carries kindergarten and nursery school children would be defined as a "school bus."

Thanks for a ruling on this matter.

W. G. Milby Staff Engineer