Mr. Junichi Yoshimoto
Deputy General Manager
Technical Administration Dept.
Koito Mfg. Co., Ltd.
Shizuoka Works
500, Kitawaki
Shimuzu-Shi, Shizuoka-Ken

Dear Mr. Yoshimoto:

This replies to your letter of June 24, 1997, asking questions about four areas of the headlighting requirements of Federal Motor Vehicle Safety Standard No. 108. I shall discuss them in the order you presented them.

Optical Axis Mark

You have attached a sheet depicting three headlamps. You ask whether the optical axis mark specified by S7.8.5.3(f)(1) is required because, in your opinion, the construction of the headlamps enables one to identify the optical axis of the headlamp.

Paragraph S7.8.5.3(f)(1) reads as follows:

"There shall be a mark or markings identifying the optical axis of the headlamp visible from the front of the headlamp when installed on the vehicle, to assure proper horizontal and vertical alignment of the aiming screen or optical aiming equipment with the headlamp being aimed. The manufacturer is free to choose the design of the mark or markings. The mark or markings may be on the interior or exterior of the lens or indicated by a mark or central structure on the interior or exterior of the headlamp."

Although the choice of the mark is left to the manufacturer, the mark should be of such a nature that it clearly indicates to the operator of headlamp aiming equipment the exact location of the optical axis and where the equipment is to be properly placed, to act as a geometric reference for measuring distances to the floor and between the headlamps and the vehicle's longitudinal axis.

Your question asks, in effect, whether the features shown are sufficient to be the mark required. A trademark is acceptable to indicate an optical axis, and we believe that the trademark in Figure 1 Sealed Beam Headlamp, an oval encircling the name "Koito," clearly indicates its center with the letter "i" thereby indicating the optical axis. The condenser lens in Figure 2 Projector Headlamp has an obvious center, as do all circles, that can be perceived by observers, and is also acceptable as indicating the optical axis. The inner shade in Figure 3 Headlamp with no-fluting lens should provide a clear indication to the operator of headlamp aiming equipment because the axes of the hexagon converge at a clearly designated center point. The last sentence of S7.8.5.3(f)(1) quoted above indicates that the mark may be indicated by a central structure on the interior of the headlamp.

Horizontal Aim

(1) Paragraphs S7.8.5.3(b) and (d) do not specify a horizontal aim adjustment mechanism for visually/optically aimable headlamps. Koito is considering changing some of its existing headlamps to visually aimable ones with "adding the mechanisms (see Figures 4 and 5 in the attached sheet) in which a special cap is put onto the horizontal aiming screw permanently in such a way that it cannot be removed without breakage, to prevent tools from accessing the screw." You ask whether these mechanisms "comply with the requirement of horizontal aim fixation."

The horizontal aiming screw caps are intended to be a permanent part of the lamp, and not intended to be removable with special tools or otherwise. We believe that this is a sufficient safeguard that the headlamps may be considered to comply with the requirement that there shall be no adjustment of horizontal aim of a visually aimable headlamp.

(2) Referring to our letter of June 11, 1997, to Ichikoh, a copy of which you enclosed, you ask whether the horizontal aim should be fixed by the headlamp manufacturer or the vehicle manufacturer. You note that it may be necessary for a vehicle manufacturer to align properly the horizontal aim when the headlamp is installed on a motor vehicle before the horizontal aim is fixed. However, when the horizontal aim is fixed by the vehicle manufacturer, you believe that the vehicle manufacturer should be responsible for certifying compliance with photometric performance requirements.

Paragraph S7.8.5.3 requires a visually/optically aimable headlamp to be designed to conform to the specifications of that paragraph, including the specification of S7.8.5.3(b) that horizontal aim be fixed and nonadjustable. Thus, the design and production of the headlamp is the responsibility of its manufacturer. However, as the preamble to the final rule adopting this requirement stated, "Generally, the vehicle's manufacturer accepts the responsibility for assuring correct aim of new motor vehicles" (62 FR 10710 at 10712). When a headlamp is installed on a motor vehicle, the vehicle manufacturer's required certification of compliance with all applicable Federal motor vehicle safety standards must include photometric compliance.

Aiming Deviation

You believe that S7.8.2.1(a) applies to a visually/optically aimable headlamp "whose construction has no adjustment of horizontal aim." This paragraph reads: "When installed on the vehicle, adjustment of one aim axis through its full on-vehicle range shall not cause the aim of the other axis to deviate more than +/- 0.76 degree." You wish to interpret it as reading: "Adjustment of vertical aim through its full on-vehicle range shall not cause the aim of the horizontal axis to deviate more than +/- 0.76 degree."

This is a correct rephrasing of S7.8.2.1(a) for a visually/optically aimable headlamp whose horizontal aim is fixed.

Visual/Optical Mark

You ask whether your interpretation is correct that the lens of a headlamp that is aimable horizontally by a VHAD, and vertically by visual/optical means, must have its lens marked in accordance with S7.8.5.3(f)(2).

This is correct. Even though the correct horizontal aim is achieved by mechanical means, the fact that the correct vertical aim is determined visually/optically means that the headlamp must have the markings required by S7.8.5.3(f)(2).

John Womack
Acting Chief Counsel