Interpretation ID: nht74-3.4

DATE: 08/05/74

FROM: RICHARD B. DYSON -- NHTSA ACTING CHIEF COUNSEL

TO: JACK R. GILSTRAP -- GENERAL MANAGER SOUTHERN CALIFORNIA RAPID TRANSIT DISTRICT

TITLE: N40-30 [ZTV]

ATTACHMT: LETTER DATED 07/17/74 FROM JACK R. GILSTRAP TO RICHARD B. DYSON-NHTSA, RE FEDERAL MOTOR VEHICLE SAFETY STANDARD 108; LETTER DATED 12/26/73 FROM WARREN M. HEATH TO JACK R. GILSTRAP

TEXT: Dear Mr. Gilstrap:

This is in reply to your letter of July 17, 1974, asking whether S4.6 of Standard No. 108 prohibits a bus manufacturer from installing wining that could later be connected by the purchaser to normally steady-burning clearance lamps, enabling them to be flashed to signal a crime in progress. The vehicle modifications here concerned are the installation both of certain wiring by General Motors and dual filament bulbs in each clearance lamp by the Southern California Rapid Transit District.

Paragraph S4.6 requires that signalling lamps specified in Standard No. 108 shall flash when activated, and that "all other lamps" shall be steady-burning. Paragraph S4.1.3 in part prohibits the installation of motor vehicle equipment that impairs the effectiveness of the lighting equipment required by Standard No. 108.

We construe the phrase" all other lamps" in S4.6(b) to mean lamps that are required by Standard No. 108. Supplemental lamps on ambulances and police cars, for example, that flash in normal use are not included in the standard. Similarly , it would appear that when the clearance lamp you discuss is operated as a warning lamp it becomes an item of lighting equipment outside the coverage of Standard No. 108. Therefore the fact that it flashes when activated would not violate the intent

2 of S4.6(b). Similarly, the wiring that is installed by GM is not considered additional equipment that impairs the effectiveness of the required equipment.

The modifications you described, therefore, are not prohibited by Standard 108.

Yours truly,