Mr. Mark Steele
Steele Enterprises
225 Merrill Place
Goshen, IN 46528

Dear Mr. Steele:

Thank you for your letter of October 21, 1999, enclosing a copy of my letter to you of October 7, 1999, regarding the unacceptability of automatic activation of rear lamps to signal that the ABS has been activated. You have asked the following three questions:

" Where does Standard 108 designate the method of actuation of the hazard warning signal?"

Tables I and III of Standard No. 108 require motor vehicles to be equipped with vehicular hazard warning signal operating units, as specified in SAE Recommended Practice J910, February 1966. Paragraph 1 of SAE J910 defines the operating unit, in part, as "a driver controlled device which causes all turn signal lamps to flash simultaneously." This means that the hazard warning signal unit must be activated by the driver and not automatically. Standard No. 101, Controls and Displays, complements this requirement by specifying identification and illumination requirements for hand-operated hazard warning signal controls.

"Since the hazard warning signal is one of the required signals per Standard 108 (ref. S5.1.1.5 and S5.5.5 . . .), how can the hazard warning signal be considered an 'additional lamp, reflective device or other motor vehicle equipment' per S5.1.3?"

When a lamp is modified to perform in a manner that differs from its original design, we consider it to be an "additional lamp" within the meaning of the phrase during the time of its non-standard operation. When it performs in a manner that differs from its original performance, it must not impair the effectiveness of the required lighting equipment.

We don't understand your references to S5.1.1.5 (whose subject is turn signals).

"If you do not know the position, color and candlepower of the additional lights proposed, how can they be said to 'impair the effectiveness of lighting equipment required by this standard?'"

We advised you on October 7 that S5.1.3 would prohibit motor vehicles from being equipped with separate lamps that flashed immediately after activation of the stop lamps because of "the potential to cause confusion and momentary hesitation in a following driver, and, in that sense, impair the effectiveness of the stop lamps." We do not need to consider "position, color and candlepower" to reach a conclusion that a steady burning stop signal immediately followed by a flashing signal from a new and unfamiliar lamp has the potential to cause confusion and momentary hesitation. It's the performance that is relevant.

Frank Seales, Jr.
Chief Counsel