Sebring & Associates
2735 Mosside Boulevard
Monroeville, PA 15146
Dear Mr. Otto:
This responds to your inquiry dated April 15, 2009 following up on a previous letter to you from this office, concerning the outside rearview mirror requirements of Federal Motor Vehicle Safety Standard (FMVSS) No. 111, Rearview Mirrors.
In your first letter to this office, you asked about an outside drivers side rearview mirror for passenger cars. The mirror contained two parts. On the right portion of the mirror, a section of the mirror contained an FMVSS No. 111-compliant flat mirror, while the left portion of the mirror contained a curved or aspheric component. You asked whether S5.2.1 of FMVSS No. 111 permits a single drivers side mirror containing both a flat portion and a curved or aspheric portion located to the left of the flat portion.
In our January 16, 2009 letter to you, we said the answer is yes. S5.2.1 of FMVSS
No. 111 applies to the drivers side mirrors on passenger cars. It states: [e]ach passenger car shall have an outside mirror of unit magnification. That section does not prohibit an additional curved or aspheric portion to expand the field of view beyond the required viewable area. We also referred to two previous legal interpretations reiterating this point.
In your current letter, you ask if a single drivers side mirror containing both a flat and curved portion would be permitted for other vehicle types under paragraphs S6, S7, S8, and S10 of FMVSS No. 111, if the flat portion alone otherwise is compliant with the applicable requirements. Our answer is that such mirrors would be permitted under the standard.
Paragraph S6 applies to multipurpose passenger vehicles (MPVs), trucks, and buses, other than school buses, with a gross vehicle weight rating (GVWR) of 4,536 kilograms (kg) (10,000 pounds) or less. The section does not contain any language that would prohibit a supplementary curved mirror portion. S6.1(b) states that the vehicle shall have either mirrors that comply with S5, or outside mirrors of unit magnification, each with not less than 126 cm2 of reflective surface, located to provide the driver a view to the rear along both sides of the vehicle. If this requirement is met, there is no specific prohibition on additional mirrored surfaces, which can be convex or aspheric or flat.
S7 applies to MPVs and trucks with a GVWR of more than 4,536 kg and less than 11,340 kg and buses, other than school buses, with a GVWR of more than 4,536 kg. S8 applies to MPVs and trucks with a GVWR of 11,340 kg or more. A similar analysis indicates that paragraphs S7 and S8 do not prohibit the types of mirrors at issue. These sections of FMVSS No. 111 require that the vehicles have outside mirrors of unit magnification, each with not less than 323 cm2 of reflective surface, located to provide the driver a view to the rear along both sides of the vehicle. If this requirement is met, there is no specific prohibition on additional mirrored surfaces, which can be convex or aspheric or flat.
Paragraph S10 applies to motorcycles. S10.1 specifies motorcycles to have either a mirror of unit magnification with not less than 8065 mm2 of reflective surface, or a convex mirror with not less than 6450 mm2 of reflective surface and an average radius of curvature not less than 508 mm and not greater than 1524 mm . The portion of the mirror required by FMVSS No. 111 must be contiguous. A convex or aspheric or flat mirror may supplement the mirror required by S10.
The Federal Motor Carrier Safety Administration (FMCSA) is the agency in the U.S. Department of Transportation responsible for safety regulations concerning motor carrier operations. Among other things, FMCSAs regulations include certain requirements for commercial motor vehicle (CMV) equipment necessary for safe operations, including rear-vision mirrors. For information on FMCSAs requirements for CMV equipment, please contact FMCSA at 1-800-832-5660.
I hope this answers your questions. If you have any further questions, please contact my office at (202) 366-2992.
O. Kevin Vincent
 In a January 15, 1995 letter to Mr. Amin Ahmadi, we stated that [v]ehicle manufacturers may install mirror systems that combine a portion of the mirror with a straight angle with a portion of the mirror that is at a slight variance, provided that the straight mirror portion by itself complies with the requirements in FMVSS No. 111 that are applicable to the vehicle on which the mirror system is installed. Similarly, in a June 22, 1998 letter to Mr. Bobby Kim, we stated that [v]ehicle manufacturers may install mirror systems that combine flat and convex mirrors on their new vehicles, provided that the flat mirror portion by itself meets FMVSS No. 111 requirements applicable to the vehicle on which the mirror system is installed. Both letters are available at http://isearch.nhtsa.gov.
 We note that although mixing of convex or aspheric and flat mirrors is not prohibited, mixing the mirrors could present visual confusion to the vehicle operator.