Interpretation ID: nht91-5.18

DATE: August 8, 1991

FROM: Paul Jackson Rice -- Chief Counsel, NHTSA; Signature by Stephen P. Wood

TO: H. George Johannessen, P.E. -- Chairman, Seat Belt Technical Committee, Automotive Occupant Restraints Council

TITLE: None

ATTACHMT: Attached to letter dated 3-22-91 from H. George Johannessen, P.E. to Paul Jackson Rice (OCC 5858)

TEXT:

This responds to your letter seeking an interpretation of Standard No. 209, Seat Belt Assemblies (49 CFR S571.209). More specifically, you asked about the meaning of the requirement in S4.1(b) of Standard No. 209 that "...the pelvic restraint shall be designed to remain on the pelvis under all conditions, including collision or roll-over of a motor vehicle." I am pleased to have this opportunity to explain this provision.

You explained that some have asserted that a safety belt fails to comply with S4.1(b) if it actually moves off an occupant's pelvis during a crash. To reach such a conclusion, one must ignore the words "be designed to" and treat the requirement as though it read "...the pelvic restraint shall remain on the pelvis under all conditions, including collision or roll-over of a motor vehicle." Such a reading is plainly incorrect, because it reads the phrase "be designed to" out of the regulation.

You explained that you believe S4.1(b) of Standard No. 209 is merely a hortatory phrase that is essentially meaningless. According to your letter, this language first appeared in a standard developed by the Society of Automotive Engineers (SAE), and was subsequently adopted verbatim in the safety belt standard issued by the Department of Commerce and in Standard No. 209. You asserted that the SAE committee that developed this language included it as a design goal only, since the committee members "were aware that they had no objective test procedure to confirm compliance with this design goal," and "were aware that the seat belt would not necessarily remain on the pelvis during the entire collision event in all of the varied collisions encountered in the field."

We cannot agree with your suggestion that S4.1(b) of Standard No. 209 is merely a hortatory design goal. The National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq.) requires each safety standard to meet certain requirements, including, among other things, that the standard be practicable, meet the need for motor vehicle safety, and be stated in objective terms. When NHTSA adopted Standard No. 209 as one of the initial Federal motor vehicle safety standards, the agency concluded that Standard No. 209, including S4.1(b), met all applicable statutory criteria.

It is true that there is no compliance test procedure specifically for S4.1(b) of Standard No. 209. However, the meaning of that provision becomes clear when it is viewed in the context of the occupant protection requirements in Standard Nos. 208, Occupant Crash Protection, Standard No.

210 Seat Belt Assembly Anchorages, and the rest of Standard No. 209. Standard No. 208 requires, among other things, that vehicles be equipped with safety belts and that the lap belt portions of those belts adjust to fit persons ranging in size from a 6-year-old child to a 95th percentile adult male (See S7.1.1). Standard No. 209 requires that safety belts meet specified strength, durability, and other performance requirements. Standard No. 210 requires that the anchorage holding the safety belt in the vehicle meet stringent strength requirements, so that the belt will remain attached to the vehicle in a crash, and lap belt location requirements (S4.3.1), including a minimum lap belt mounting angle, to reduce the likelihood of occupant submarining, i.e., having the lap belt move off the pelvis. See the detailed discussion of the minimum lap belt mounting angle at 55 FR 17970, at 17974; April 30, 1990.

Viewed in this context, we believe that the requirement of S4.1(b) of Standard No. 209 means that safety belts must be designed to be capable of being properly adjusted and positioned on the pelvis of occupants ranging from 6-year-old children to 95th percentile adult males. The belts must also be capable of remaining on the pelvis of such occupant during collision or roll-over. A belt system that was not capable of being positioned on the pelvis and remaining there during crashes would not comply with S4.1(b).

Given this meaning and purpose, we offer the following observations. First, the fact that a lap belt moved off the occupant's pelvis during a collision would NOT of itself show that the lap belt failed to comply with S4.1(b) of Standard No. 209. Compliance with S4.1(b) of Standard No. 209 is determined by the design of the safety belt system, not the performance of individual safety belts while in service. Second, the actual performance of a safety belt in a vehicle (e.g., a lap belt moving off the occupant's pelvis during a crash) COULD indicate that the lap belt failed to comply with S4.1(b) of Standard No. 209. If the agency had information indicating that a particular belt design was not capable of being properly positioned on the pelvis or not capable of remaining on the occupant's pelvis when installed in particular vehicles in particular crash modes, the agency might well investigate whether that safety belt design complied with S4.1(b). However, NHTSA has no such information about any safety belt systems at this time.