Search Interpretations

Interpretation ID: 23658



    Mr. Kenji Tanabe
    Director & General Manager
    Mitsubishi Motors R&D of America, Inc.
    1560 Wilson Boulevard, Suite 1200
    Arlington, VA 22209

    Dear Mr. Tanabe:

    This responds to your letter of October 1, 2001, in which you ask about the lower anchorage marking requirements in S9.5(a) of Federal Motor Vehicle Safety Standard (FMVSS) No. 225, "Child Restraint Anchorage Systems" (49 CFR 571.225).

    By way of background, Standard No. 225 requires vehicles to have child restraint anchorage systems and specifies requirements for those systems to ensure their proper location and strength for the effective securing of child restraints. The required child restraint anchorage system consists of two lower bars and a tether anchorage (S3 of Standard No. 225). The standard contains "marking and conspicuity" requirements for the lower bars of a child restraint anchorage system to increase the likelihood that consumers will know that a child restraint anchorage system is present in their vehicle and that they will remember to use it. The standard requires manufacturers to mark the vehicle seat back with a small circle where the bars are located (S9.5(a)), or to design a child restraint anchorage system such that the bars are visible (S9.5(b)).

        Your question relates to S9.5(a) of the standard, which reads:

        (a) Above each bar installed pursuant to S4, the vehicle shall be permanently marked with a circle:

        (1) That is not less than 13 millimeters (mm) in diameter;

        (2) Whose color contrasts with its background; and

        (3) That is located on each seat back such that its center is not less than 50 mm and not more than 75 mm above the bar, and in the vertical longitudinal plane that passes through the center of the bar. (Emphasis added.)

    The issue you raise in your letter is where the "seat back" begins for the purpose of marking the lower anchorages pursuant to S9.5(a). The term "seat back" is not defined in Standard No. 225. You state that Mitsubishi installs a type of deeply contoured, rounded seat in some of its vehicle lines. On these seats, the bottom cushion curves toward the vertical and supports a portion of an occupant's lower back before a separate "seat back" begins. You state that if the agency considers a portion of a vehicle seat to be the seat back solely by reference to a physical separation between the bottom seat cushion and the seat back, the circle markings would be more than 75 mm above the anchorage bars, which is not permitted by S9.5(a)(3). (1)

    You suggest that the term "seat back" could be defined by reference to the point at which the bottom seat cushion curves toward the vertical direction, where it begins to support the occupant's lumbar area and lower back. You state that this would enable Mitsubishi to locate the circle markings within 75 mm of the lower anchorage bars. You believe that defining "seat back" in this manner would be logical, since the curved portion of the bottom seat cushion forms part of the occupant back support.

    We agree with your position. With most seat designs, the bottom seat cushion is essentially horizontal and is a separate piece from the essentially vertical seat back. However, with the seat design you described, the separation is at a point above where the seat cushion begins to curve upward. The point at which the separation occurs, assuming there is one, should not be determinative as to what portion of the seat is the seat back. (Some vehicle seat assemblies might not have any separation between the seating surface and the seat back.) For the purpose of the marking requirements of S9.5(a) of Standard No. 225, we interpret the term "seat back" as comprising the portion of the seat that supports the occupant's lumbar area and back, including the portion of the seat that begins to angle vertically above the horizontal seating surface.

    We note that Mitsubishi had raised this issue of the meaning of "seat back" in its April 19, 1999, petition for reconsideration of the final rule establishing Standard No. 225, a response to which is pending. We may amend S9.5(a)(3) of the standard to clarify the term "seat back" as used therein in accordance with the interpretation made today.

    Please contact us if you have further questions.

    Sincerely,

    John Womack
    Acting Chief Counsel

    ref:225
    d.1/14/02


    1. 1You also state that the lower anchorages themselves would have to be located in a place that will result in the child restraint being installed at a very awkward and unstable angle. Standard No. 225 has requirements that prohibit the placement of the lower bars in locations that would result in awkward child restraint installation. S15.1.2.2 of the standard (incorporating certain requirements that manufacturers may meet until 2004, as an alternative to those set forth in S9) specifies that the bottom surface of the child restraint fixture used to locate the lower anchorage bar must have attitude angles within certain limits. The angles are measured relative to the vehicle's horizontal, longitudinal and transverse reference planes). (Pitch must be 15 10, roll 0 5, and yaw 0 10.) We will be incorporating the pitch, roll and yaw requirements into S9 of the standard.