Interpretation ID: nht90-1.39

TYPE: Interpretation-NHTSA

DATE: February 7, 1990

FROM: Dipl.-Ing. H. Westermann -- Hella KG Hueck & Co.

TO: Richard van Iderstine -- Rulemaking Department., NHTSA

TITLE: Request for written response - CHMSL unity.

ATTACHMT: Attached to letter dated 2-21-90 To Taylor Vinson and From Dipl.-Ing. H. Westermann (OCC 4484); Also attached to letter dated 4-25-90 To Dipl.-Ing. H. Westermann and From Stephen P. Wood (A35; Std.108)

TEXT:

One of our customers prefers to place a logo within or in between the light emitting surface of a CHMSL. The enclosed sketches show two such designs: one for inside mounting behind the rear window (encl. 1), an other for top mounting on the trunk of a convertible (encl. 2). According to ECE Regulation 48, 5 2.14.2, a signalling lamp consisting of juxtaposed elements forms a single unit if the smallest rectangle circumscribing the several light emitting surfaces is occupied by not less than 60 percent of light emitting area. E/ECE/324 E/ECE/trans/505 Rev.1/Add.47 Regulation No. 48 page 6 2.14.2. "two lamps" or "an even number of lamps": a single light-emitting surface in the shape of a band or strip if such band or strip is placed the median longitudinal plane of the vehicle, extends on both sides to within at least 0.4 m of the extreme outer edge of the vehicle, and is not leas than 0.8 m long; the llumination of such surface shall be provided by not less than two light sources placed as close as possible to its ends; the light-emitting surface may be constituted by number of juxtaposed elements on condition that the projections of the several individual light-emitting surfaces ona transverse plane occupy not less than 60 per cent of the area of the smallest rectangle circumscribing the projections of the said individual light-emitting surfaces;

In above design this requirement is fulfilled and the total area exceeds the required 4.5sq.inch. We ourself see no problem in such a design for a CHMSL since neither the signal configuration (triangle of stop lamps) nor acuity (by luminance and intensity) are affected. Since neither SAE nor FMVSS 108 yield a clear definition of signal unity if constituted of partial areas, we would like to learn whether NHTSA supports the ECE definition and can accept such CHMSL design as not violating the FMVSS requirements. A soon answer on this item is very much appreciated.

Enclosures 2 Graphics Omitted.