Interpretation ID: nht93-6.50

DATE: September 29, 1993

FROM: Dennis G. Moore -- President, Sierra Products Inc.

TO: John Womack -- Acting Chief Council, NHTSA

TITLE: FMVSS #108 INTERPRETATION REQUEST

ATTACHMT: Attached to letter dated 11/16/93 from John Womack to Dennis G. Moore (A41; Std. 108)

TEXT:

I am requesting an Interpretation of the term "at the same height" used in FMVSS #108 when referring to the mounting position of the three I.D. Lights required on Vehicles over 80" in width.

At least on two occasions in the past 20+ years, NHTSA has allowed the slight misalignment of I.D. lights because of "Practical" circumstances. I didn't copy these cases from the Federal Register or from NHTSA's Docket Files so unfortunately I haven't them to refer to.

I'm requesting copies of these Interpretative allowances or better yet, an entirely new Interpretation hopefully allowing the "Practical Misalignment" of I.D. lights used specifically on Boat Trailers.

We are trying to improve the widespread visibility (conspicuousness) and breakage problems associated with mounting "Sizeable" yet Submersible I.D. Lights on a Boat Trailer's rear cross member. To do this, we are offering an I.D. Light Bar that is slightly bendable which corrects the problems outlined in the sketches below.

When slightly staggered, the Vulnerability and Covering problems shown in the sketches are eliminated yet still guaranteeing a protected, longer lasting yet Conspicuous I.D. Light Cluster.

"Conspicuous" is the requirement term used in Section S2. "PURPOSE" of FMVSS #108 and I believe represents the original objective for mandating 3 I.D. Lights. The "Conspicuous" objective is better accomplished even if the three lights are allowed to be somewhat staggered. Also, safety is better served when these lights are protected from damage and/or from being knocked off.

It seems to us that "at the same height" could be defined as where the Top of the middle light is no higher than the Bottoms of the Outboard Lights... or where at least one portion of the three lights are "at the same height".

We hope you concur with our interpretation of this term so that this safety improvement is allowed to be made on Boat Trailers.

TYPICAL BOAT TRAILER I.D. MOUNT AREA Problem 1: Typical Roller or "AT THE SAME HEIGHT" Protective Pad Requirement makes OUTBOARD LIGHTS hang below the Frame Typical V making them "VULNERABLE" to Shaped Cross Frame being DAMAGED or KNOCKED OFF

Typical Roller or Problem 2: Protective Pad "AT THE SAME HEIGHT" Requirement Typical V also encourages the "COVERING" of Shaped Cross Frame the MIDDLE LIGHT

Solution: Typical Roller or ALLOWING SLIGHT STAGGERING Protective Pad yields a PROTECTED yet Typical V "CONSPICUOUS" 3 I.D. Shaped Cross Frame Light Cluster

I would appreciate a response as soon as possible.