Interpretation ID: 20754ogm

Patrick M. Raher, Esq.
Hogan and Hartson, L.L.P.
Columbia Square
555 Thirteenth Street, NW
Washington, DC 20004

Dear Mr. Raher:

This is in response to your inquiry regarding the visual and audible seat belt warning requirements incorporated into Federal Motor Vehicle Safety Standard No. 208, Occupant Crash Protection. Your letter describes the operation of the visual and audible warning systems in the 2000 model year Mercedes-Benz M-Class vehicle. In this vehicle, the visual and audible warning system may operate in one of two modes depending on whether the driver fastens his or her seat belt before or after turning the ignition key to the "on" or "start" position. You indicate that if the driver enters the vehicle and turns the key to the "on" or "start" position prior to fastening his or her seat belt, a visual warning will flash and an audible warning will sound for eight seconds or until the driver fastens his or her seat belt. If the driver enters the vehicle, fastens his or her seat belt and then turns the key to the "on" or "start" position, the visual warning will flash for 4 to 8 seconds and the audible warning will sound for approximately two seconds. You ask if the latter mode of operation, which you describe as "a vehicle start up systems check" complies with the requirements of Standard No. 208, particularly the provisions of S7.3 of that standard.

While acknowledging that S7.3 of Standard No. 208 indicates that an audible warning may only sound when the key is turned to the "on" or "start" position and the driver's belt is not fastened, you submit that the two second audible signal present in the Mercedes-Benz vehicle when a belted driver turns the key to the "on" or "start" position is not an audible warning as that term used in Standard No. 208. Instead, you indicate that the two second audible warning is a limited duration signal that provides the driver with notification that the audible belt warning system is functioning properly. In your view, the two second duration of this "check" signal is sufficiently shorter than the 4 to 8 second warning established by S7.3 so that drivers will neither be confused or annoyed by a signal that sounds when the belt is fastened, even though this is the same signal that is activated when the belt is not fastened. In addition, as S7.3 specifies that the audible warning shall be 4 to 8 seconds in length, you submit that a shorter or longer signal is permissible.

The agency does not agree with your suggested interpretation. Paragraph S7.3 of Standard No. 208 requires a seat belt warning system that activates a 4 to 8-second warning light when the vehicle's ignition switch is moved to the "on" or "start" position (condition "a"), and a 4 to 8-second audible signal when condition "a" exists and the driver's lap belt is not fastened (condition "b"). Under the mode of operation you describe as occurring when the seat belt is fastened prior to the key being turned to the "on" or "start" position, the audible signal would be activated when ignition switch is moved to the "on" or "start" position and when the driver's lap belt is fastened - when both conditions "a" and "b" exist. However, it would also be activated when a driver's belt is fastened - when condition "a" alone exists.

The functioning of the audible signal when the driver's belt is fastened is not permissible under the standard. The rulemaking notices which led to adoption of the current requirement stated that the agency's intent was that the audible signal operate only if the driver's lap belt is not in use. The agency expressed that same intent in the standard by specifying the light was to function when ignition switch is moved to the "on" or "start" position and the audible signal was only to sound when the ignition switch is moved to the "on" or "start" position and the driver's belt remains unfastened. To interpret the standard to permit the audible signal to operate when the ignition switch is moved to the "on" or "start" position condition regardless of whether the belt is fastened would be to make purposeless the specification that the audible signal sound only when a belt is not fastened.

Further, as NHTSA has emphasized in past interpretations and rulemaking notices, the audible warning signal is most effective when employed judiciously. In establishing the warning signal requirements, restrictions were placed on the operation of the audible warning signal in consideration of the irritation factor associated with the signal but not with the light. To provide a reminder and incentive for safety belt use and to avoid subjecting the conscientious belt user to having to hear an audible reminder to do something that he or she has already done, the agency specified that the signal would not function if the driver's safety belt was fastened.

Your letter indicates that Mercedes-Benz believes that the operation of the audible warning when the driver's belt is fastened serves a valuable purpose, i.e. it purportedly serves as a "vehicle start-up systems check" that alerts the driver that all warning systems are operational. The sounding of the audible warning is, you contend, no different from that illumination of various warning light telltales that are activated when the ignition key is first switched to the on position. Mercedes-Benz believes, therefore, that the sounding of the audible warning for a 2 to 4 second period at this time will neither confuse or annoy drivers any more than the flashing of a telltale at the same time. You further submit that the agency has never indicated, either by regulation or interpretation, that an audible warning that sounds for less than the regulatory time frame of 4 to 8 seconds is prohibited. Last, you indicate that most drivers fasten their belts after turning the ignition switch to the "on" position. In such a case, these drivers would never be subjected to the audible warning that would occur in the Mercedes-Benz vehicle when the belt is already fastened.

NHTSA disagrees with your view of the utility of the audible warning sounding when a belt is already fastened. An examination of the owner's manual for the 2000 model year M-Class vehicle does not reveal any mention of an audible warning "check" function. Without denying the importance of a functioning belt warning system, NHTSA believes that operation of the audible belt warning when the belt is fastened could both confuse and aggravate drivers. This phenomenon becomes particularly acute where, as here, vehicle users are not informed as to the nature and purpose of the "check" signal. The agency also disagrees with your view that our regulations and past interpretations indicate that any such audible warning that is shorter or longer in duration than 4 to 8 seconds when a belt is already fastened is permissible. Both the regulations and our past interpretations make it clear that the audible warning may only sound for 4 to 8 seconds when the ignition switch is moved to the "on" or "start" position and the driver's belt remains unfastened. In regards to your contention that most drivers will never be subjected to the superfluous audible warning, we note that the requirements for belt warnings are intended to establish performance that will adequately protect all drivers.

I hope that this is responsive to your request. If you have any further questions or would like to discuss this matter further, please contact Otto Matheke of my staff at (202) 366-5253.

Sincerely,
Frank Seales, Jr.
Chief Counsel
ref:208
d.7/12/00