Interpretation ID: 24778rbm

Mr. Klaus Hillenbrand
Siemens Restraint Systems GmbH
Carl-Zeiss-Strasse 9
63755 Alzenau

Dear Mr. Hillenbrand:

This responds to your letter asking about the seat positioning procedure in S8.1.2 of Federal Motor Vehicle Safety Standard (FMVSS) No. 208, Occupant crash protection, and S6.3 of FMVSS No. 214, Side impact protection.The text of the two different provisions is the same. You have requested clarification of the seating procedure because your interpretation of the language in these two sections differs from an explanation of the language that was provided in a 1995 legal interpretation provided to Patrick Raher of Hogan & Hartson, L.L.P. I am pleased to provide a response.

The seat position specifications of FMVSS No. 208 (S8.1.2) and FMVSS No. 214 (S6.3) read as follows:

Adjustable seats are in the adjustment position midway between the forwardmost and rearmost positions, and if separately adjustable in a vertical direction, are at the lowest position. If an adjustment position does not exist midway between the forwardmost and rearmost positions, the closest adjustment position to the rear of the midpoint is used.

In your letter, you stated that you read this language to mean that the longitudinal midposition would be determined by moving the seat in the most forward and most rearward position without moving the height adjustment and then marking the midposition at the seat rails. Height adjustment would then be made to the lowest level without any readjustment of the seat rails. Your primary question is whether the reference for the longitudinal midposition must be measured at the seat rails (where determination of the most forward/rearward position would be independent of any height adjustment) or if it can be measured somewhere at the seat pan (where height adjustment could influence the most forward/rearward position).

As discussed in the 1995 interpretation, there are two conditions concerning how an adjustable seat is positioned in a crash test. The first condition, for the longitudinal position of the seat, is for the seat to be in the adjustment position midway between the forwardmost and rearmost positions, irrespective of seat height in those positions. The second condition is that the vertical position be in the lowest position obtainable with the seat in the longitudinal midposition. Depending on whether the vertical position is separately adjustable, this may or may not be the lowest achievable position for the seat in any of its longitudinal positions.

The critical issue is whether the longitudinal midposition is referenced along a longitudinal plane at the point midway between the forwardmost and rearmost positions of the seat at any height.The midposition is not qualified by height, so absolute forwardmost and rearmost positions are used to determine the midposition irrespective if height at those positions. The vertical position of the seat is only determined after the longitudinal midposition has been established.

The seat position specification does not require that the longitudinal midposition be referenced at the seat rail, or at any other specific location.Any place in the vehicle that allows for the accurate marking of the longitudinal midposition is acceptable.While many test laboratories may choose to mark the midposition at the seat rail, there is no requirement that they do so.

I hope you find this information helpful. If you have any other questions, please contact Rebecca MacPherson of my staff at this address or by phone at (202)366-2992.

Sincerely,

Jacqueline Glassman
Chief Counsel

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