Interpretation ID: nht68-3.12
DATE: 01/26/68
FROM: AUTHOR UNAVAILABLE; Roger H. Compton: NHTSA
TO: Fire Department, Lynn, Massachusetts
TITLE: FMVSS INTERPRETATION
TEXT: In your letter of December 12, 1967, you questioned several requirements of Initial Motor Vehicle Safety Standard No. 108 as applied to fire trucks.
Paragraph S3.1.1.3, which permits the installation of additional equipment if it does not impair the effectiveness of the required equipment, will not prohibit the installation of rotary flashing lights on fire trucks. Therefore, a waiver of this clause is not necessary for fire trucks.
Paragraph S3.5 a revised by the latest amendment to Standard No. 108, and issued December 11, 1967, (copy enclosed), permits the flashing of steady-burning lamps for signalling purposes. Therefore, the flashing of side marker and clearance lamps on fire trucks to signify an emergency vehicle will not be prohibited by the requirements of this paragraph.
Standard No. 108 does not require that front identification lamps be located on the roof of the vehicle cab, but only that they be "as near as practicable to(Illegible Word) vertical centerlines." If, however, they are mounted on the upper body structure, "no part of the lamps or mountings may extend below the top of the vehicle's windshield." This mounting flexibility will permit a selective location of identification lamps and rotary warning lamps which will not cause the rotary lamps to blot out the identification lamps. Also to be considered is the effectiveness of the identification lamps when the vehicle is operated on the highway and without illumination of the rotary lamps. Therefore, fire trucks need not be excepted from the requirement for front identification lamps.
Rear identification lamps mounted on the edge of or under the rear step of a fire truck will meet the location requirements as specified in Standard No. 108. Adequate guards or protective shields are available and commonly used on lamps located in these positions. Therefore, fire trucks need not be excepted from the requirement for rear identification lamps.
If you have any further comments or questions on the requirements of Standard No. 108, I hope you will let us know.