Interpretation ID: nht90-2.13

TYPE: INTERPRETATION-NHTSA

DATE: 04/10/90

FROM: HIROSHI OZEKI -- EXECUTIVE VICE PRESIDENT MAZDA

TO: STEPHEN P. WOOD -- NHTSA ACTING CHIEF COUNSEL

TITLE: REQUEST FOR INTERPRETATION OF 49 CFR 571.108, "LAMPS, REFLECTIVE DEVICES, AND ASSOCIATED EQUIPMENT"

ATTACHMT: ATTACHED TO LETTER 06/05/90 ON STD 108 FROM STEPHEN P. WOOD -- NHTSA TO HIROSHI OZEKI -- MAZDA; LETTER FROM ERIKA JONES -- CHIEF COUNSEL NHTSA TO JAMES R. MITZENBERG -- FLXIBLE CORP DATED 12/08/86 ON STD 108 INTERPRETATION; LETTER FROM FRANK BE RNDT -- CHIEF COUNSEL TO CHUCK HOWARD -- SAFETY ALERT CO, DATED 06/17/83

TEXT: Mazda is exploring the possibility of installing a deceleration warning system on its future models. Such a system would operate using the vehicle's hazard warning system. Under certain circumstances, as of yet undetermined, the hazard lamps (amber in color and flashing) would be activated concurrently with the stop lamps to provide additional warning to vehicles to the rear.

In reviewing FMVSS No. 108 and previous interpretations concerning this standard and considering how each would apply to deceleration warning systems, Mazda has discovered, what its believes, are conflicting interpretations. For your convenience, the interpretations in question have been reproduced as Attachments 01-02. The purpose of this letter is to request your definitive interpretation of this standard with respect to S4.1.3 and the enclosed attachments.

An interpretation issued on June 17, 1983 (Attachment 01), and written by former NHTSA Chief Counsel Berndt, determined that the simultaneous activation of both the rear stop lamps (red in color and steady-burning) and the rear hazard warning system o r rear turn signal lamps (red or amber in color and flashing) is permissible provided, " . . . the color of light or photometrics required by the standard was not changed." In Mr. Berndt's opinion the operation of the rear stop lamps, and the rear hazard warning lamps or turn signal lamps in this manner would not be in violation of S4.1.3. of FMVSS No. 108.

Conversely, an interpretation issued on December 6, 1986 (Attachment 02), and written by former NHTSA Chief Counsel Jones, expressly states that the described deceleration warning system, ". . . must be steady-burning in every mode. There is a good r eason for this requirement, as simultaneous use of flashing (amber) and

steady-burning (red) lamps have the potential for creating confusion. . .", thus, ". . .impairing the effectiveness of the required stop lamps within the meaning of S4.1.3."

Could you please provide a definitive interpretation of the requirements of S4.1.3 of FMVSS No. 108 as they pertain to the deceleration warning system under consideration by Mazda; as described above.

Should you have any questions regarding this matter, please feel free to contact Mr. Rob Strassburger (313-930-2513) of my staff or Mr. S. (Ted) Kadoya (202-626-3263) at our Washington, D.C. office.

ENCLOSURES