Robert Strassburger, Vice President
    Safety and Harmonization
    Alliance of Automobile Manufacturers
    1401 H Street, NW, Suite 900
    Washington, DC 20005


    Dear Mr. Strassburger:

    This responds to your request that we reconsider a May 6, 2003, interpretation letter to Jaguar Cars on the meaning of "daylight opening" in Federal Motor Vehicle Safety Standard (FMVSS) No. 104, Windshield wiping and washing systems. After carefully considering your request, we affirm the opinion stated in our letter. Our reasons are set forth below.

    In its request for interpretation, Jaguar asked whether the daylight opening should be measured to the edge of complete blackout area, the start of dot fade area, or to some point in between. We explained that the daylight opening is measured to the edge of complete blackout area on the indshield.

    Daylight opening is defined at S3 of FMVSS No. 104 as: "the maximum unobstructed opening through the glazing surface, as defined in paragraph 2.3.12 of section E, Ground Vehicle Practice, SAE Aerospace-Automotive Drawing Standards, September 1963." 

    Paragraph 2.3.12 of that SAE standard states:

    The term "Daylight Opening" (abbreviated DLO) refers to the maximum unobstructed opening through any glass aperture, including reveal or garnish moldings adjoining the glass, according to a given direction or projection. If not specified the dimension will be the vertical projection.

    We noted that the definition of "daylight opening" referred to by Jaguar was in a later SAE document (SAE Recommended Practice J1100) and not the one referenced in FMVSS No. 104. One difference between the definition of "daylight opening" in the older document and the one in J1100 is that the newer one treats "opaque coatings" in the same manner as reveal or garnish moldings.

    In our letter, we noted that opaque coatings around the edge of the windshield are now used to serve the function once served by moldings, i.e., covering the glue around the edges of the windshield. Given this changed technology, we believed it was appropriate to treat opaque coatings around the edge of the windshield in the same manner as moldings, in interpreting the term "daylight opening" in FMVSS No. 104. We stated, however, that this is only true for what Jaguar referred to as "complete blackout" or "truly opaque" areas. We stated that the dot fade area is not truly opaque, and is not analogous to moldings. Thus, daylight opening is measured to the edge of complete blackout area.

    In your recent letter, you disagree with our view about the dot fade area. You believe that the dot fade area that is ordinarily inboard of the opaque coatings at the edge of the windshield should not be included in the measurement of "daylight opening."

    According to your letter:

    "Daylight Opening" is defined both in FMVSS No. 104 and in the referenced SAE standard as the maximum unobstructed opening through the glazing surface. The dot-fade area is not "unobstructed." Rather, the dot-fade area is more appropriately viewed as the transition to the opaque area of the windshield, analogous to the edge of a molding in an older design. As moldings would not have been included in the definition of "daylight opening" under the standard, the dot-fade edge of the opaque area should likewise not be included in that definition. For the same reason, Alliance members have not included dot-fade areas as part of the daylight opening when providing windshield measurements to the National Highway Traffic Safety Administration for purposes of FMVSS 104 compliance testing.

    While we have considered your arguments, we do not agree that the dot fade area toward the edges of a windshield represents an obstruction within the meaning of FMVSS No. 104.

    As a technical matter, we believe that the term "unobstructed opening," as used in the 1963 SAE document incorporated into FMVSS No. 104, originally referred to physical obstructions. In our letter to Jaguar, however, we noted that opaque coatings around the edge of the windshield are now used for the function once served by moldings, i.e., covering the glue around the edges of the windshield. Given this changed technology, we believed it was appropriate to treat opaque coatings around the edge of the windshield in the same manner as moldings, in interpreting the term "daylight opening" in FMVSS No. 104.

    After considering your letter, we continue to believe that this is true only for what Jaguar referred to as "complete blackout" or "truly opaque" areas. The dot fade area is not truly opaque and does not cover the adhesive. We therefore do not consider it analogous to moldings or to the "edge of a molding."  (The edge of a molding is a part of the molding and is opaque.)  If anything, the dot fade area is more analogous to shade bands, which are not obstructions. Since a dot fade area neither constitutes a physical obstruction nor is opaque, it comes within the definition of "daylight opening."

    We note that in a letter dated February 24, 2004, you cited a letter from the Vehicle Certification Agency of Great Britain concerning its interpretation of the term "daylight opening" under the applicable ECE regulation and direction. However, that agency was providing an interpretation of different language with different origins from that included in FMVSS No. 104.

    Because there has been some confusion within the industry regarding the proper interpretation of the term "daylight opening," we will begin enforcing FMVSS No. 104 consistent with our May 6, 2003, interpretation beginning with vehicles manufactured on September 1, 2005.

    If you have any further questions, please contact Ms. Dorothy Nakama at this address or at (202) 366-2992.

    Sincerely,

    Jacqueline Glassman
    Chief Counsel

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