Interpretation ID: nht93-1.49
DATE: 02/24/93
FROM: JOHN WOMACK -- ACTING CHIEF COUNSEL, NHTSA
TO: WILLIAM R. WILLEN -- MANAGING COUNSEL, PRODUCT LEGAL GROUP, AMERICAN HONDA MOTOR CO., INC.
TITLE: NONE
ATTACHMT: ATTACHED TO LETTER DATED 12-7-92 FROM WILLIAM R. WILLEN TO PAUL JACKSON RICE (OCC 8112)
TEXT: This responds to your letter of December 7, 1992 requesting an interpretation of the definition of "designated seating position" in 49 CFR Section 571.3. You request confirmation of your belief that a proposed Honda seat design would have two designated seating positions. For the proposed design, "(t)he hip room is 44.2 inches over the length of the seat, and the seat width is only 39 inches. The seat is flat and does not have stiff inboard seat belt receptacles."
The term "designated seating position" is defined at 49 CFR @ 571.3 as:
any plan view location capable of accommodating a person at least as large as a 5th percentile adult female, if the overall seat configuration and design is such that the position is likely to be used as a seating position while the vehicle is in motion, except for auxiliary seating accommodations such as temporary or folding jump seats. Any bench or split-bench seat in a passenger car, truck or multipurpose passenger vehicle with a GVWR less than 10,000 pounds, having greater than 50 inches of hip room (measured in accordance with SAE Standard J1100 (a)) shall have not less than three designated seating positions, unless the seat design or vehicle design is such that the center position cannot be used for seating.
If the seat has only 44.2 inches of hip room, the seat would probably qualify as having only two seating positions, since this value is below the 50-inch specification in the definition of "designated seating position." Please note, however, that the 50-inch specification does not mean that some vehicle seats with less than 50 inches of hip room should not also have more than two designated seating positions if the vehicle and seat design is such that three positions would likely be used. The specification is merely the amount of space the agency will consider as conclusive evidence that there should be at least three designated seating positions.
You ask if our answer would be different if fixed or movable armrests were provided. A fixed armrest does affect the measurement of designated seating position, since a fixed armrest would impede a person from sitting in the center position. NHTSA has stated in the preamble to the rule adopting the definition of designated seating position that the space occupied by a fixed, stationary armrest "would not be considered hip room and would not be included in the measurement of the 50-inch limitation." 44 FR 23229; April 19, 1979. A fixed armrest on your seat would show your intent that the position is not intended to be used as a seat.
Your letter also asked if the interpretation would be different if the seat width was greater than 39 inches. The number of designated seating positions is determined by the hip room, therefore, if the hip room remained the same, the seat would have the same number of designated seating positions even if the seat width was increased. Finally, you asked if the interpretation would be different if the seat were installed in a wider vehicle or positioned differently in the vehicle. Again, those modifications would only require an increase in the number of designated seating positions if the hip room were increased by these changes.
Finally, I emphasize that this letter only represents the agency's opinion based on the information supplied in your letter. NHTSA does not pass approval on any vehicle design, prior to the actual events that underlie certification. It is up to the manufacturer to determine whether its vehicles comply with all applicable safety standards and regulations, and to certify its vehicles in accordance with that determination.
I hope you find this information helpful. If you have any other questions, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992.