Interpretation ID: aiam1447
Volkswagen of America
Inc.
Englewood Cliffs
NJ 07632;
Dear Mr. Riechel: This responds to your March 8, 1974, letter reviewing our dispositio 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 fo 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 'n 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 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 b required if the protective system were not present 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 th 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 huma occupant enter the vehicle without taking any 'additional actions' to displace the belt, to note the location of the belt on him before he exits, 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 bel system under the language of the May 4, 1971, interpretation.; Sincerely, Lawrence R. Schneider, Chief Counsel