Dear Dr. Baldwin:
This is in reply to your letter of September 1, 1988, asking for an interpretation of paragraph S4.5.11(e) of Motor Vehicle Safety Standard No. l08.
You have developed a center highmounted stop lamp "containing 5 bulbs, where each bulb is illuminated in sequential order." You state that the "time between each lamp illumination is less than 250 ms, providing a steady photometric value, meeting S18.104.22.168(c)", and that "the red lens of the lamp is steadily illuminated, with the illuminated area moveing (sic) in a back and forth motion." In your opinion, the invention meets the requirement of S4.5.11(e) that lamps, other than those enumerated, be steady-burning.
We cannot provide the interpretation you seek. Under paragraph S4.5.4, "the stop lamps on each vehicle shall be activated upon activation of the service brakes." This means that all bulbs providing the center stop lamp signal must be simultaneously activated, not sequentially. In addition, we do not consider a lamp with a moving illuminated area to be one that is steady-burning within the meaning to S4.5.11(e).
Erika Z. Jones Chief Counsel