Interpretation ID: nht87-2.22

TYPE: INTERPRETATION-NHTSA

DATE: 06/24/87

FROM: DIETMAR K. HAENCHEN -- VOLKSWAGEN OF AMERICA, INC.

TO: ERIKA Z. JONES -- NHTSA

TITLE: REQUEST FOR INTERPRETATION - FMVSS 205

ATTACHMT: ATTACHED TO LETTER DATED 11/03/88 FROM ERIKA Z JONES TO DIETMAR K HAENCHEN; REDBOOK A32 (2), STANDARD 205

TEXT: Dear Ms. Jones:

The design of passenger cars has changed in recent years to reduce aerodynamic drag and increase fuel efficiency. Volkswagen is planning to improve interior comfort and reduce energy consumption in future car models by introducing selected areas with re duced energy transmission via ceramic dots on the car's glazing. The reduced energy radiation into the interior increases driver's and passenger's comfort and results in increased active safety. We believe that the application of shaded areas on the wi ndows complies with the applicable safety standards. Different methods exist for shading those areas; the glass may be tinted like shade bands applied to windshields, or small ceramic dots can be applied on the glass surface having the same effect on th e reduction of energy transmission. The sections of glass selected for the application of the ceramic paint could, if not for styling aesthetics, be covered with sheet metal in order to avoid questions of interpretation of FMVSS 205. However, the styli ng incentive is compelling and driver visibility with the proposed configuration is better than total blockage with sheet metal, which would clearly be allowable. We are, therefore, seeking the agency's opinion of this concept which we are considering fo r the next new model line. While the agency does not give advance approval of specific product designs, the agency's opinion of whether the configuration proposed herein appears to comply with the applicable Federal Motor Vehicle Safety Standards will a id manufacturers in determining whether the numerous variations of the concept applied to various vehicles will comply with the standards.

Volkswagen has reviewed Standard 205 which in turn refers to ANS z26.1 (1980) which establishes requirements for safety glazing material for use in passenger cars. In Section 4.2 of ANS z26.1, specifications for items 1 and 2 glazing which VW intends to apply to the windshield and side/rear glass respectively refer to footnotes 1 and 3 when specifying Test 2 - Light Transmittance. Those footnotes allow areas of the glazing to have less than 70% light transmittance if the areas are not within the "leve ls required for driving visibility".

The term "levels requisite for driving visibility" has been used by the agency in interpretations and on several occasions has been addressed more precisely such as the interpretation to Mr. G. Nield on 15 February, 1974 as follows: "We (the agency) cons ider the word 'levels' in Standard 205 to mean vertical heights in relation to driver's eyes." To our knowledge the agency has not gone beyond the above interpretation in further defining "levels requisite for driving visibility".

In order to comply with FMVSS 205 Volkswagen deems it appropriate to use engineering judgement, applicable standards and technical recommendations to define these "levels" so that driving visibility is properly maintained with the installation of glazing material having areas within a single sheet of less than 70% light transmittance.

Footnote 1 of ANS z26.1 - 1980, although not expressively stated, refers mainly to shade bands and has been so construed and treated by the industry. The automobile industry so far has determined which areas are "requisite for driving visibility" and ha s marked the shaded areas as required. In these cases the industry determined how far shade bands can extend donward from the upper edge of the window and still be in compliance with FMVSS 205.

SAE J100 (passenger car glazing shade bands) also refers to ANS z26.1 when defining "glazing shade band" as "an area of the vehicle glazing through which light transmission is less than required for use at levels requisite for driving visibility by USAS z26.1". The SAE recommends shade bands above the 95th eyellipse only, but acknowledged at that time that substantial research to establish the driver's field of view did not exist. Volkswagen also believes that these data do not exist currently.

Guidelines for a determination of "levels" which extend upward from the bottom edge of the vehicle glazing are addressed in Directive 77/649 as amended in 81/643 of the European Economic Community (EEC). The directive specifies levels requisite for driv ing visibility in the driver's 180 degrees forward direct field of vision. Section 5.1.3 specifies the boundaries for the driver's forward direct field of vision by a horizontal plane through V[1] (upper boundary) and by three planes at downward angles of 4 degrees through V[2] (lower boundary). The latter describes the minimum field of view for small persons through the lower portion of the glazing.

The EEC in its effort to set angular limits for the driver's forward direct field of vision used anthropometric data of horizontal head and eye movement to arrive at the 180 degrees limit. The SAE in its information report J985 arrives at the same figur e when the angles of "maximum head movement (is) 60 degrees left and 60 degrees right" and "the eyes can turn 30 degrees to the right in one rapid, smooth movement", are combined.

For the rear visibility in the U.S., the "levels requisite for driving visibility" are not specified if a passenger side rearview mirror is used according to FMVSS 111. Technically, the complete rear glazing can be blocked by a vehicle manufacturer if a passenger side rearview mirror is installed as standard equipment. Volkswagen intends to install a passenger side outside mirror as standard equipment in conjunction with the subject shading configuration and also to provide an area in the rear glazing with transmissability of greater than 70%.

With this background, Volkswagen is planning to include either tinted bands or ceramic dots on glazing as described in Attachments I and II. Volkswagen believes that this concept clearly allows light transmittance in excess of 70% in the areas requisite for driving visibility and consequently should adequately satisfy the safety needs for overall driving visibility.

Volkswagen has tested these boundaries according to the specifications of 77/649/EEC and concluded that ceramic dots in the area defined in 5.1.3 very well cover the vertical heights in relation to even small driver's eyes, which are "requisite for drivi ng visibility". In addition we have designated the area adjacent to the right and left hand outside mirrors as requisite for driving visibility.

This proposal has been approved by the German government (KBA) as recommended by the Technical Service Hannover. This approval was based on the fact that it complies with the driver's direct field of view (forward 180 degrees) and that unobstructed outs ide rearview mirrors are used on both sides to supplement the inside rearview mirror for the driver's indirect field of view. This approval is based on compliance with the applicable EEC Directive and therefore will likely be acceptable to all Common Ma rket countries.

Volkswagen requests the agency's opinion of this proposal and an interpretation of whether the markings described in Section 6 of ANS z26.1 would be required to show the limits of the area that is intended to comply with the 70% transmittance requirement . If required, Section 6 states that the glazing "shall be permanently marked at the edge of the sheet to show the limits of the area that is intended to comply with Test No. 2" (70% transmissability). Interpretation is requested of where these markings should be placed for the configurations shown in Attachments I and II if they are required. Since this is under consideration for the next model year, a timely response is requested.

ATTACHMENTS

ATTACHMENT I

Lichtdurchlassigkeit zwischen 75% and 82% LIGHT TRANSMITTANCE BETWEEN 75% AND 82%

Lichtdurchlassigkeit von 30% , 70% LIGHT TRANSMITTANCE FROM 30% TO 70%

Lichtdurchlassigkeit 30% LIGHT TRANSMITTANCE 30%

Lichtdurchlassigkeit zwischen 75% und 77% LIGHT TRANSMITTANCE BETWEEN 75% AND 77%

Lichtdurchlassigkeit von 30% > 70% LIGHT TRANSMITTANCE FROM 30% TO 70%

Lichtdurchlassigkeit zwischen 72% und 75% LIGHT TRANSMITTANCE BETWEEN 72% AND 75%

Warmeschutzverglasung HEAT ABSORBING GLASS

E/KK - AA 87.01.

ATTACHMENT II

Lichtdurchlassigkeit zwischen 75% und 82% LIGHT TRANSMITTANCE BETWEEN 75% AND 82%

Lichtdurchlassigkeit von 30% > 70% LIGHT TRANSMITTANCE FROM 30% TO 70%

Lichtdurchlassigkeit 30% LIGHT TRANSMITTANCE 30%

Lichtdurchlassigkeit zwischen 75% und 77% LIGHT TRANSMITTANCE BETWEEN 75% AND 77%

Lichtdurchlassigkeit von 30% > 70% LIGHT TRANSMITTANCE FROM 30% TO 70%

Lichtdurchlassigkeit zwischen 72% und 75% LIGHT TRANSMITTANCE BETWEEN 72% AND 75%

Warmeschutzverglasung HEAT ABSORBING GLASS

E/KK - AA 87.01.