Interpretation ID: 86-6.9

TYPE: INTERPRETATION-NHTSA

DATE: 12/08/86

FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA

TO: Mr. James R. Mitzenberg

TITLE: FMVSS INTERPRETATION

TEXT:

Mr. James R. Mitzenberg Product Safety Engineer The Flexible Corporation 970 Pittsburgh Drive Delaware, OH 13015

Dear Mr. Mitzenberg:

Forgive our delay in replying to your letter of August 21, 1985, asking for an interpretation of Motor Vehicle Safety Standard No. 108, with respect to a deceleration warning system you have been asked to install as original equipment on city transit buses However, on the basis of the information you provided Taylor Vinson of this Office in a phone call on August 13, 1986, we have a better understanding of the system described.

The system as described consists of three amber lamps mounted on the vertical centerline below the rear window. They provide a steady-burning light when the ignition is "on," and when the accelerator is released. They are extinguished when the accelerator is depressed. We have concluded that these aspects of the system are not prohibited by paragraph S4.1.3, which you cited, and which forbids the installation of equipment that impairs the effectiveness of the required lighting equipment.

However, there are two further aspects to the system. The amber lights are also extinguished when the brakes are applied and the normal stop lamps are illuminated, but if the brake application continues for at least 3 seconds the amber lamps will flash at a rate of approximately 60 cycles a minute. You have cited paragraph S4.6 of Standard No. 108 which requires all vehicle lights to be steady-burning, except for turn signals and hazard warning signals, and side marker lamps and headlamps that are flashed for signaling purposes. We have interpreted S4.6 as applying to all lighting equipment on non-emergency vehicles, and not just the equipment required by the standard. This means that the deceleration system must be steady-burning in every mode. There is a good reason for this requirement, as simultaneous use of flashing (amber) and steady-burning (red) lamps have the potential for creating confusion in vehicles to the rear of the bus, and impairing the effectiveness of the required stop lamps within the meaning of S4.1.3.

I hope that this answers your questions.

Sincerely,

Erika Z. Jones Chief Counsel

August 21, 1985

Mr. Jeffery R. Miller Office or Chief Counsel National Highway Traffic Safety Administration 400 Seventh Street, S. W. Washington, D. C. 20590

Dear Mr. Miller:

The Flexible Corporation, a manufacturer or city transit buses, has been requested by several city transit authorities to install a rear deceleration warning light system. These customers have demanded factory installation and operational hook-up of this deceleration warning light system. Other bus manufacturers are supplying such systems without question. Due to this, and by our not agreeing to install the system and make it fully operational, we have found ourselves to be at s distinct marketing disadvantage. We are concerned about certifying our vehicle to FMVSS 108 with an OEM installation or this deceleration light system.

The deceleration light system specified for installation on our bus is manufactured by Safety Development Systems, Haines, Oregon and requires installation on the rear centerline of our bus. See Attachment 11 which depicts the proposed installation method. The housing contains three horizontally aligned amber lights. These amber lights would be installed and operated independently from our normal rear lights and reflectors, which are required FMVSS 108 equipment. These three amber lights operate as described below:

A. When the ignition is "on", the amber lights are illuminated, burning.

B. When the accelerator is depressed, the amber lights are extinguished.

C. When the accelerator is released, the amber lights are illuminated, steady burning, and remain illuminated as long as the accelerator is released.

D. When the brake is applied, the amber lights are extinguished and the normal red atop lights are illuminated. If the brake is continually applied /or three seconds or more, the amber deceleration lights will flash (approximately 60 cycles per minute).

E. The normal amber (red color is optional) rear turn signal could then be illuminated simultaneously with the stop lights and the deceleration lights.

Paragraph S4.6 of FMVSS 108 provides that required signaling lamps shall flash when activated and all other lamps shall be steady burning, except that means mar be provided to flash headlights and side marker lights for signaling purposes.

Paragraph S4.1.3 or FMVSS 108 provides that no additional lamp, reflective device, or other motor vehicle equipment shall be installed that impairs the effectiveness or lighting equipment required by this standard.

In order that we may be customer responsive, we request an interpretation from NHTSA concerning any non-compliance with FMVSS 108 on an OEM installation of these deceleration warning lights functioning as described above.

Sincerely,

James R. Mitzenberg Product Safety Engineer