Interpretation ID: nht74-5.25

DATE: 04/10/74

FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA

TO: Volkswagen of America, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your March 8, 1974, letter reviewing our disposition of Volkswagen's petition to add a new crash protection option to S4.1.2 of Standard 208 (49 CFR 571.208). You requested a determination of whether the seat belt assembly described in that petition constitutes a passive restraint system for purposes of Standard 208, that is, one that requires "no action" by vehicle occupants.

The Volkswagen assembly consists of a single diagonal belt for restraint of the upper torso and an energy-absorbing knee bolster. Mounting of the upper torso restraint to the door causes the belt to move forward during occupant entry and then fall back across the occupant's torso when he is seated and the door is closed.

The NHTSA issued an interpretation of what constitutes a "passive" restraint system on May 4, 1971 (36 FR 4600):

The concept of an occupant protection system that requires "no action by vehicle occupants" as used in Standard No. 208 is intended to designate a system that requires no action other than would be required if the protective system were not present in the vehicle.

The question of what constitutes "no action by vehicle occupants" in a vehicle equipped with (presumptively) passive belts is best considered in two stages: (1) entry and exit from the vehicle, and (2) positioning of the belt for safety and comfort.

Entry and exit action "that requires no action other than would be required if the protective system were not present

2 in the vehicle" means that a person is not hampered in his normal movements by the presence of the belt system. A test of this is whether a human occupant of approximately the dimensions of the 50th percentile adult male finds it necessary to take additional actions to displace the belt or associated components in order to enter or leave the seating position in question. An example of impermissible action would be the necessity of manually pushing a belt out of the way to gain access to the seat. Displacement of the components incidental to normal entry and exit, or merely for the convenience of the occupant, would not be prohibited. Examples of permissible displacement would be brushing against the upper torso restraint during seating, or grasping the torso restraint to close the door.

The second question relates to the usefulness of the system once the occupant has been seated. The essence of a passive restraint is that it provides at least the minimum level of protection without relying on occupant action to deploy the restraint. At this stage, then, the question is whether an occupant who has seated himself without taking any "additional action" is in fact protected in a 30 mi/h impact. This can be measured by conducting the impact tests with the belt positioned on the test dummy in the orientation that results when a human occupant enters the vehicle according to the first test described above. It would not be required that the belt position itself for maximum comfort of the human occupant, if it met the safety requirements. For example, if the belt were to fall across the upper arm instead of the clavicle, but still passed the test, the system would be considered conforming.

The procedure for conducting this evaluation would be to have a human occupant enter the vehicle without taking any "additional actions" to displace the belt, to note the location of the belt on him before he exists, to position the test dummy in accordance with S8.1 of Standard 208, to position the belt as it positioned itself on the sample occupant, and then to conduct the impact tests. The exit evaluation would require the human occupant to be seated with the restraint normally deployed and then exit the vehicle without needing to take any separate actions to displace the belt.

This discussion is intended to permit you to evaluate your passive belt system under the language of the May 4, 1971, interpretation.

VOLKSWAGEN OF AMERICA, INC.

March 8, 1974

Lawrence Schneider National Highway Traffic Safety Administration

RE: The Volkswagen Passive Belt

This will refer to our telephone conversation of March 6, 1974, concerning Volkwagen's passive restraint system.

On October 1, 1973, Volkswagenwerk AG and Volkswagen of America, Inc. petitioned the National Highway Traffic Safety Administration to add a new crash protection option to Paragraph S4.1.2 of Standard 208 in order to permit use of Volkswagen's passive belt in 1975 as well as subsequent model year passenger cars and to make available other changes in Standard 208. A copy of Volkswagen's petition is enclosed.

The National Highway Traffic Safety Administration by Notice 1, Docket 74-4 published in 39 Federal Register 3834 dated January 30, 1974, denied that part of the petition that requested the additional option. The petition was rejected as unnecessary on the grounds that Paragraph S4.5.3 of Standard 208 already permitted the use of a passive belt system "to meet the crash protection requirements of any option under S4 and in place of any seat belt assembly otherwise required by that option." The Notice further concludes that "thus, this language permits the use of the Volkswagen passive belt system to meet the perpendicular impact protection requirements of Option 2 and to replace the required seat belt assemblies. Option 2 exists, in fact, to accommodate date the introduction of passive restraint systems like Volkswagens, which cannot yet meet all requirements of Option 1."

2

While we have recognized that Notice 1 is essentially a proposal for rule making without binding effect as a rule or regulation, it also disposes unconditionally of that part of Volkswagen's petition which sought the inclusion of an additional option. Nowhere does the Notice call upon interested persons to submit their comments with respect to the National Highway Traffic Safety Administration's denial of Volkswagen's petition for rule making. Comments are invited only in regard to the National Highway Traffic Safety Administration's proposal for amending Paragraphs S4.1.2.2 and S4.5.3.3

Because questions have been raised regarding the qualification of Volkswagen's new restraint concept as a system that requires no action on the part of the occupant, I would appreciate your confirmation that the system described in our petition of October 1, 1973, constitutes a passive belt within the meaning of Paragraph S4.5.3 to meet the crash protection requirements of the second option set forth in Paragraph S4.1.2.2.

Sincerely,

Gerhard P. Riechel Attorney

Enclosure

cc: Philip Hutchinson