Interpretation ID: nht81-3.14

DATE: 09/04/81

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Mid Bud Inc.

TITLE: FMVSS INTERPRETATION

TEXT:

NOA-30 SEP 4 1981

Mr. Fred S. Barrington Vice-President Engineering Mid Bus Inc. 710 East Wayne Street P.O. Box 1985 Lima, Ohio 45802

Dear Mr. Barrington:

This responds to your July 28; 1981, letter asking whether a portion of your school bus would be considered part of the sidewall or roof for purposes of complying with Standard No. 222, School Bus Passenger Seating and Crash Protection.

Paragraph S5.3.1.1 defines the head impact zone in which the head protection requirements apply. The bus sidewall, windows and doors are exempted from complying with the requirements for head impact protection even if they fall within the head impact zone. The bus roof, on the other hand, must comply with the requirements if it falls within the zone. In the bus to which you refer in your letter, the bus wall and roof structure are not distinctly separated. You ask, therefore, where the roof stops and the sidewall begins.

The agency has stated by interpretation that the roof begins where the radius of curvature of the interior structure decreases sharply. From the sketch that you enclosed with your letter, it appears that the roof would begin at the point marked "B". Assuming that your diagram is correct, the side of the bus below point "B" would be considered part of the bus sidewall and would not be required to comply with the head impact requirements.

Sincerely,

Frank Berndt Chief Counsel

July 28, 1981

Mr. Roger Tilton National Highway Traffic Safety Administration Office of Chief Counsel, Room 5219 400 7th Street, S.W. Washington, D.C. 20590

Dear Mr. Tilton:

Mid Bus Inc. builds a van type school bus under 10,000 lbs. GVWR. In this type unit there is a considerable amount of slant or tumble home in the sides. The enclosed sketch shows a typical side of our bus.

FMVSS 222 paragraph S 5.3.1.1 states that the head protection zones are spaces in front of each school bus passenger seat which are not occupied by bus side wall, window or door structure.....etc.

Refer to the enclosed sketch and note that Point "A" is where the side wall intersects the head protection zone. The wall extends upward and inward from that point. The shaded area on the sketch is that portion of the bus that falls in the head protection zone.

On September 28, 1977 NHTSA (NOA-30) made an interpreation for Ward Body Company that the side wall ended and the roof began at a point where the radios of curvature of the interior structure decreases sharply. Can we assume that this same point which is shown on the enclosed sketch as Point "B" is above the head impact zone and anything below Point "B" does not have to meet the head impact requirements?

Thank you for considering this matter.

Cordially,

Fred S. Barrington Vice-President Engineering

FSB:pas

Enclosure