Interpretation ID: nht72-2.36

DATE: 12/08/72

FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA

TO: P. F. Middleton, Esq.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of November 22, 1972 to the National Highway Traffic Safety Administration asking "whether when a school bus is being used to transport pupils, the red lights must go on when the entrance door is opened without exception."

If the system is one of red lamps only, its activation according to SAE Standard J887 is not automatic but manual. The situation differs with respect to the combination amber and red lamps system. Paragraph S4.1.4(b)(ii) of Standard No. 108 effective January 1, 1972, which you reference, states

"The school bus signal lamp system shall be wired so that the amber signal lamps are activated only by manual or foot operation, and if activated, are automatically deactivated and the red signal lamps automatically activated when the bus entrance door is opened."

This means that the red lamps are only activated if the amber lamps have been activated before the door is opened. Activation of the red lamp system is thus dependent upon the action of the bus operator in prior activation of the amber lamp system. From the standpoint of safety we hope that his activation of the amber lamp system will be "without exception" whenever he is transporting pupils.

Because paragraph S3.1.3.2 of Standard No. 108 as it was in effect from January 1, 1969 to January 1, 1972, which you also reference, could mistakenly be interpreted to require activation of the red lamp system without exception whenever the door was opened, the National Highway Traffic Safety Administration adopted the language of S4.1.4 to clarify the ambiguity.