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Interpretation ID: 24545.drn

    Ms. Doris Schaller-Schnedl
    Homologation Department
    Magna Steyr Engineering
    Liebenauer Hauptstrae 317.A
    8041 Graz

    Dear Ms. Schaller-Schnedl:

    This responds to your June 7, 2002, letter asking whether the Federal motor vehicle safety standards have definitions that are similar to those of the EEC for H-point and R-Point.

      You provided the following EEC definitions of H-point and R-point:

      H-point means the pivot center of the torso and thigh of the 3 DH machine installed in the vehicle seat []. The 'H' point is located in the center of the centerline of the device which is between the 'H' point sight buttons on either side of the 3 DH machine. The 'H' point corresponds theoretically to the 'R' point.

      R-point means a design point defined by the vehicle manufacturer for each seating position and established with respect to the three-dimensional reference system.

    For purposes of our safety standards, 49 CFR 571.3, Definitions, includes a definition for "H point," but not for "R-point." However, 571.3 defines "seating reference point," which is similar in some respects to the "R-point." "H point" is defined in 571.3 as:

      the mechanically hinged hip point of a manikin which simulates the actual pivot center of the human torso and thigh, described in SAE Recommended Practice J826, "Manikins for Use in Defining Vehicle Seating Accommodations," November 1962.

      "Seating reference point" (SgRP) is defined in 571.3 as:

      the unique design H-point, as defined in SAE J1100 (June 1984), which:

      (a) Establishes the rearmost normal design driving or riding position of each designated seating position, which includes consideration of all modes of adjustment, horizontal, vertical, and tilt, in a vehicle;

      (b) Has X, Y, and Z coordinates, as defined in SAE J1100 (June 1984), established relative to the designed vehicle structure;

      (c) Simulates the position of the pivot center of the human torso and thigh; and

      (d) Is the reference point employed to position the two-dimensional drafting template with the 95th percentile leg described in SAE J826 (May 1987), or, if the drafting template with the 95th percentile leg cannot be positioned in the seating position, is located with the seat in its most rearward adjustment position.

    The H point and mostly SgRP are used in the test procedures of a number of NHTSA standards. They include: Standard No. 104, Windshield wiping and washing systems; Standard No. 201, Occupant protection in interior impact; Standard No. 202, Head restraints; Standard No. 207, Seating systems; Standard No. 208, Occupant crash protection; Standard No. 210, Seat belt assembly anchorages; Standard No. 213, Child restraint systems; and Standard No. 214, Side impact protection.

    For your information, we have enclosed a copy of a January 9, 2002, letter to Mr. Mike J. Gower of Trico Products (Europe) Ltd., which discusses a 1993 rulemaking that replaced a reference to "manikin H point with seat in rearmost position" in Standard No. 104 with a reference to "seating reference point."

    You also ask whether there is a requirement in the safety standards similar to that in the European Standards that, "the H-point has to lie within a certain distance from the R-point. (Square of 50 mm, 74/60/EEC)." While it is difficult to find a directly comparable requirement in the Federal motor vehicle safety standards (FMVSSs) cited above, we believe Standard No. 208 comes close to it in the requirement of the "H" point location when positioning the 50th percentile dummy. You can find further details on the use of the "H" point and the "SgRP" in the FMVSSs by referring to the Code of Federal Regulations (CFR), 49 CFR Part 571. Those without a hard copy of the CFR may access them in electronic form at

    I hope this information is helpful. If you need further assistance, please contact Dorothy Nakama of my staff at this address or at (202) 366-2992.


    Jacqueline Glassman
    Chief Counsel