Interpretation ID: 1983-1.9

TYPE: INTERPRETATION-NHTSA

DATE: 01/28/83

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Velvac, Inc.

TITLE: FMVSS INTERPRETATION

TEXT:

Jan 28 1983

NOA-30

Mr. Robert R. Brester Velvac, Inc. 2900 South 160th Street New Berlin, Wisconsin 53151

Dear Mr. Brester:

This responds to your November 18 letter to Roger Fairchild of this office. In that letter, you asked whether certain heavy duty trucks may have installed on each side of the vehicle two mirrors each of 25 square inches surface area. The dual mirrors would be mounted in a common bracket with a gap between the mirrors.

The language of FMVSS 111 clearly envisions that there shall be a single mirror of at least 50 square inches of surface area on each side of the vehicle. Section 7.1 of the standard provides that such trucks must have exterior mirrors "each with not less than 50 in2 of reflective surface...." (Emphasis added.) Further, the agency questions whether the performance of the dual mirror would be equivalent to that of a single mirror. For example, images could temporarily be lost in the gap between the two mirrors, potentially presenting a hazard to the driver. Further, the mirrors could have slightly different orientations in the common mounting, possibly misleading the driver as to the speed and location of an object viewed in the mirrors. Therefore, we conclude that the split system does not comply with FMVSS 111.

If you have further questions on this matter, please feel free to contact us.

Sincerely,

Frank Berndt Chief Counsel

November 18, 1982

Mr. Roger Fairchild National Highway Traffic Safety Administration Federal Motor Vehicle Safety Standard No. 111 Room 5219 United States Department of Transportation 400 Seventh Street SW Washington D.C. 20590

Dear Mr. Fairchild,

I am writing you this letter in response to a phone conversation I had with Mr. Kevin Cavey, Office of Vehicle Safety Standards in regards to compliance with F.M.V.S.S. 111 using a flat mirror split system.

Specifically, I addressed the question to Mr. Cavey, "Will two flat mirrors mounted on a common bracket with a combined square area meeting current F.M.V.S.S. specifications be equivalent to a single flat mirror?" (see example).

FLAT MIRROR

**INSERT** Would this be acceptable under the current FMVSS 111?

Mr. Cavey said he is not in the position to comment on this matter verbally and that I should contact you in writing.

Please give this matter your prompt attention as we have a customer desiring to purchase this split system to eliminate a blind spot that is caused by one large mirror.

If you have any questions regarding this matter please contact me at 1-414-786-0706.

Sincerely,

Robert R. Brester-Chief Engineer

c.c. W. Sandham R. Hosmer