Interpretation ID: nht91-7.21

DATE: November 27, 1991

FROM: Paul Jackson Rice -- Chief Counsel, NHTSA

TO: None (Confidential)

TITLE: None

ATTACHMT: Attached to letter dated 9-9-91 to Paul Jackson Rice

TEXT:

This responds to your September 9, 1991 letter requesting an interpretation of Standards No. 101, Controls and Displays (49 CFR S571.101) and No. 208, Occupant Crash Protection (49 CFR S571.208). More specifically, you stated that your company is planning to incorporate seat belt pretensioners for the manual safety belts installed at front outboard seating positions in some future models. Your company intends to provide an onboard diagnostic system, including a malfunction display, to inform the driver about the functional status of the pretensioner system. You asked how Standards No. 101 and 208 would affect three alternative visual displays your company is contemplating. I am pleased to have this opportunity to explain our standards for you.

Before discussing the substantive issues raised in your letter, I would like to indicate how this letter is responding to your request that NHTSA not publicly release the identity of your company. NHTSA granted your request in a 1991 letter signed by Kathleen DeMeter, our Assistant Chief Counsel for General Law. To reflect this agency determination, we will make available to the public only the version of your letter to me that your company purged of all references to your company's identity and a version of this letter that is purged of all references to your identity.

Your letter set forth three alternative means of providing information about the functional status of the pretensioner system to the driver. Under Alternative #1, your company would use the existing seat belt telltale display field to provide information in the event of a pretensioner malfunction. The seat belt telltale light currently illuminates for a six second period following the ignition being switched on, regardless of whether the seat belt is fastened. In the event of a pretensioner malfunction, you propose to have the seat belt telltale light go off for a five second period, and then begin blinking a "pretensioner malfunction" message.

Alternative #2 would also combine the "fasten seat belt" and "pretensioner malfunction" messages in the same display. For this alternative, if belts are fastened prior to ignition, the seat belt telltale light would illuminate for a seven second period following the ignition being switched on. In the event of a pretensioner malfunction, a pretensioner malfunction message would begin flashing on and off. If the seat belts are not fastened prior to ignition, the seat belt telltale light would remain illuminated until the seat belts are fastened. In the event of a pretensioner system malfunction, a fasten seat belt/pretensioner malfunction message would begin flashing on and off. If the belts were later fastened, this would be replaced by a pretensioner malfunction message.

Alternative #3 would combine the pretensioner malfunction message with the readiness indicator for the air bag system, which is required by S4.5.2 of Standard No. 208. Under this alternative, the readiness indicator would flash steadily in the event of a malfunction in either the air bag system or the pretensioner. Only trained service technicians would be able to determine which of those two systems was experiencing the malfunction.

You then posed several questions about these alternatives. Underlying all of these questions is the issue of whether your company is required to provide an indication of a malfunction in the pretensioner system for manual belts. The only source for such a requirement would be S4.5.2 of Standard No. 208, which reads as follows:

An occupant protection system that deploys in the event of a crash shall have a monitoring system with a readiness indicator. The indicator shall monitor its own readiness and shall be clearly visible from the driver's designated seating position.

It is plain that pretensioners for manual belts are designed to activate in the event of a crash. However, the basic occupant protection system, the manual belts, are already deployed at that time, assuming they have been manually fastened. Further, if the belts have not been manually fastened, the pretensioners will not deploy the belts in the event of a crash. Thus, we do not view the pretensioners as "deploying" the belts but instead providing a final, albeit important, adjustment to belts which have already been deployed. Therefore, a manual belt system is not required to include a readiness indicator by S4.5.2, even if it includes pretensioners that activate in the event of a crash.

Further support for this position comes from reviewing the preambles for both the proposal and the final rule (35 FR 7187, May 7, 1970, and 35 FR 16927, November 3, 1970, respectively) adding the readiness indicator requirement to Standard No. 208. Those preambles make clear that NHTSA was focusing on newly developed occupant protection systems, some of which deployed in the event of a crash (e.g., air bags), and not on improvements and modifications of existing manual seat belt systems.

Since neither S4.5.2 of Standard No. 208 nor any other provision of the safety standards requires your company to provide a readiness indicator for the pretensioner in the manual belt systems, the decision to provide a readiness indicator for those pretensioners is voluntary. The issue then arises of whether and how the safety standards would affect the voluntarily provided readiness indicator for the pretensioners.

NHTSA has long said that systems or components installed IN ADDITION TO required safety systems are not required to comply with the provisions of the safety standards, provided that the additional systems or components do not destroy the ability of the required safety systems to comply with the safety standards. See, e.g., this office's December 1, 1986 letter to Mr. Francois Louis and this office's October 13, 1988 letter to Mr. Paul Utans. The question for each of your three alternatives, then, is whether the combination of the voluntarily provided pretensioner telltale with the

required seat belt telltale or air bag readiness indicator would result in the required equipment failing to comply with Standards No. 101 and/or 208.

Under Alternatives #1 and 2, your company would display the pretensioner telltale on common space with the seat belt telltale required by Standard No. 208. Alternative #1 would provide a seat belt telltale that appears to comply with S7.3(a)(2) of Standard No. 208, and Alternative #2 would provide a seat belt telltale that appears to comply with S7.3(a)(1) of Standard No. 208. Thus, your company's use of a common space to display a voluntary pretensioner malfunction message and the required seat belt telltale does not result in the seat belt telltales failing to comply with Standard No. 208.

The other safety standard that might affect your company's ability to use common space for the pretensioner malfunction message and the seat belt telltale is Standard No. 101. S5(a) of Standard No. 101 provides that "each passenger car, multipurpose passenger vehicle and truck or bus less than 10,000 pounds GVWR with any display listed in S5.1 or in column 1 of Table 2, shall meet the requirements of this standard for the location, identification and illumination of such ... display." Column 1 of Table 2 includes, among other things, the seat belt telltale. This means that your company's voluntary addition of a pretensioner readiness indicator cannot be done in a way that would make the seat belt telltale fail to comply with the requirements of Standard No. 101.

Since Alternatives #1 and 2 would combine the seat belt telltale with the pretensioner malfunction indicator, the most relevant provisions in Standard No. 101 are those in S5.4. S5.4 reads, in part, as follows: S5.4 A common space may be used to display messages from any sources, subject to the following requirements: (a) The telltales for the brake, high beam, and turn signal, and the safety belt telltale required by S4.5.3.3 of Standard No. 208 may not be shown on the common space.

* * * * *

(e) The safety belt telltale must be displayed and visible during the time specified in S7.3 of Standard No. 208

These provisions expressly permit the use of a common space to display messages, except that four telltales cannot be displayed on common space. The relevant one of the four telltales that cannot be displayed on common space is the safety belt telltale REQUIRED BY S4.5.3.3 OF STANDARD NO. 208. S4.5.3.3 sets forth special telltale requirements that must be met by automatic belts. The safety belt telltale for the manual belts in Alternative #1 is required by S7.3(a)(2) and the safety belt telltale for the manual belts in Alternative #2 is required by S7.3(a)(1) of Standard No. 208. Since neither telltale is required by S4.5.3.3 of Standard No. 208, S5.4(a) of Standard No. 101 expressly permits the use of common space to show a pretensioner malfunction message and the seat belt telltales under Alternatives #1 and 2 in your letter.

Further, Alternatives #1 and 2 appear to comply with S5.4(e) of Standard No. 101. That subparagraph requires that the seat belt telltale must be displayed and visible during the time specified in S7.3 of Standard No.

208. For Alternative #1, S7.3(a)(2) requires the seat belt telltale to be visible for four to eight seconds after the ignition is turned "on". The information in your letter indicates that under Alternative #1, even in the event of a pretensioner malfunction, the only information that would be displayed in the common space during the four to eight second period would be the seat belt telltale. For Alternative #2, S7.3(a)(1) of Standard No. 208 requires that the seat belt telltale be visible for not less than 60 seconds after the ignition is turned "on," if the driver's lap belt is not in use. The information in your letter indicates that under Alternative #2, even in the event of a pretensioner malfunction, the seat belt telltale would continue to be displayed alternately with the pretensioner malfunction message until such time as the belt was fastened.

Based on this review, it appears that using common space to display a voluntary pretensioner malfunction message and the required seat belt telltale, in the manner set forth in Alternatives #1 and 2 in your letter, would not violate any provisions of the safety standards.

This leaves Alternative #3, in which the voluntary pretensioner telltale would share common space with the air bag readiness indicator. S4.5.2 of Standard No. 208 requires that the air bag have a readiness indicator, which monitors its readiness, and which is clearly visible from the driver's seating position. The requirements in S5(a) of Standard No. 101 do not include air bag readiness indicators. Therefore, the provisions of Standard No. 101 would not apply to Alternative #3. The only question under Alternative #3, then, is whether the combination of the voluntarily provided pretensioner telltale with the required air bag readiness indicator would result in the air bag readiness indicator failing to comply with Standard No. 208.

Based on the description in your letter, we believe that your proposed Alternative #3 would effectively prevent the air bag readiness indicator from complying with Standard No. 208. Therefore, vehicles equipped with the warning system described in Alternative #3 would not comply with Standard No. 208. This conclusion is based on the following.

It would be permissible under Standard No. 208 to use a common space to display messages for both air bag readiness and a pretensioner malfunction. Nothing in the Standard No. 208 requirement for an air bag readiness indicator either expressly or impliedly precludes the use of common space for displaying the air bag readiness indicator and some other message. However, the messages on the common space would have to be distinguishable from each other. If the messages were not distinguishable, the driver of the vehicle would not know if the illuminated telltale showed a problem with the air bag system or a problem with the other system being monitored. NHTSA concludes that the requirement in S4.5.2 of Standard No. 208 that an air bag system be equipped with a readiness indicator necessarily requires that the air bag readiness indicator be clearly and readily distinguishable by the driver from any other information. Your Alternative #3 would not provide a readily distinguishable air bag readiness indicator, and so would not appear to comply with Standard No. 208.

I hope this information is helpful. If you have any further questions or need some additional information on this subject, please feel free to contact Steve Kratzke of my staff at this address or by telephone at (202) 366-2992.