Interpretation ID: aiam4336

Dear Mr.: Thank your for your letter requesting an interpretation of how Standar No. 205, *Glazing Materials*, would apply to your proposed 'head-up display.' You described your head-up display as a system consisting of components located in the instrument panel and windshield that are capable of optically projecting instrument readings so that they appear forward of the lower part of the windshield. You stated that having the readings projected in this manner places them closer to the driver's line of sight and thus allows the driver to view the information more readily and clearly than if the driver had to look for the information on the instrument panel. As discussed below, the agency has conclude that the standard does not prohibit the use of your proposed display.; Before discussing the substantive question you asked, I want to addres your request that the agency not publicly release two types of information contained in your letter. First, you requested the agency to provide confidential treatment to the detailed description of the technology used in your head-up display. Second, you requested that the agency not disclose the name of your company. You explained in your letter requesting confidential treatment that while the device has been installed on a car displayed at a public automobile show, the technical details of the device are not a matter of public knowledge. You subsequently provided the agency with a copy of your letter in which the proprietary technical details have been deleted. Because the technical details of your proprietary device have not been publicly disclosed, we will treat the technical details as confidential. In addition, we will not disclose the name of your company. However, since all for the agency's interpretations are a matter of pubic record, we will place a copy of your letter, which has been purged of the confidential information and your company name, and our response in the agency's public interpretation file.; In the copy of your letter that has been purged of confidentia information, you explain that your head-up display uses a small membrane that is attached to the windshield to reflect certain information from the instrument panel. You explained that the area of the windshield on which the membrane is attached can meet all of the applicable requirements of Standard No. 205 set for glazing materials used in a windshield, except the requirement that the light transmittance through the glazing material be at least 70 percent. You further explained that the membrane is not opaque, but does have a light transmittance that is less than 70 percent.; Based on your analysis of the requirements of Standard No. 205 and th requirements of the American National Standard 'Safety Code for Safety Glazing Materials for Glazing Motor Vehicles Operating on Land Highways,' (ANS Z26) incorporated by reference in Standard No. 205, you stated that the 70 percent transmittance requirement does not apply to all window areas. You noted that ANS Z26, a manufacturer can place a shade band on the upper edge of a windshield that has a light transmittance of less than 70 percent. You further noted that Standard No. 205 and ANS Z26 do not define the boundaries of the shadeband or set a minimum light transmittance level for the glazing materials used in the shadeband. Futhermore, you pointed out that Standard No. 205 and ANS Z26 do not specifically define what areas of the glazing are requisite for driving visibility.; In support of your position that the area of the windshield affected b your head-up display is not requisite for driving visibility, you noted that the membrane used in the display system covers a small area of the glazing that is located toward the lower left edge of the windshield. To demonstrate that the membrane is not within an area requisite for driving visibility, you examined the effect of the membrane's location on the ability of the car to comply with the requirements of Standard No. 103, *Windshield Defrosting and Defogging*, and 104, *Windshield Wiping and Washing*. Standards No. 103 and 104 define three different areas on the windshield and require the wiping system and the defrosting/defogging system of a car to wipe or defrost/defog a prescribed minimum percentage of each of the three areas. Based on your evaluation of a windshield that has a head-up display membrane, you demonstrated that the area of the windshield covered by the membrane represent only a minimal portion of the three areas of the windshield that are required by those standards to be wiped or defrosted/defogged. You further demonstrated that a car could comply with the requirements of Standard Nos. 1-3 and 104 even though the membrane slightly projects into the areas regulated by those standards.; In further support of your position that the head-up display is no located in an area requisite for driving visibility, you provided a comparison of the effects of the head- up display versus the effects of a vehicle's hood design or unretracted head lamp on a driver's forward and downward visibility. In this comparison, you presented information that measure, from the driver's eyepoint, the locations and amount of the driver's forward visibility that would be obstructed by portions of the hood design and by an unretracted head lamp. You then compared the obstruction caused by those design features with the effects of the head-up display on the driver's visibility. The information you provided shows that a vehicle's hood design or an unretracted head lamp can extend as far up in the driver's field of view as the head-up display and provide more obstruction to a driver's forward visibility than the head- up display.; You are correct that while Standard No. 205 and ANS Z26 apply a 7 percent light transmittance requirement to areas of the glazing that are 'requisite for driving visibility,' neither Standard No. 205 nor ANS Z26 specifically defines what areas of the glazing are requisite for driving visibility. In fact, as you pointed out in your letter ANS Z26 specifically defines what areas of the glazing are requisite for driving visibility. In fact, as you pointed out in your letter, ANS Z26 specifically provides, in a footnote to S4.2 of ANS Z26, an exception to the 70 percent light transmittance requirement. The footnote explains that a manufacturer can provide an area on the glazing, such as a shade band, that has a light transmittance of less than 70 percent as long as the areas requisite for driving visibility have a light transmittance of 70 percent. In interpreting the requisite for driving visibility requirement, the agency has not specified a minimum area of the windshield that is requisite for driving visibility. Instead, the agency has said, such as in a letter of February 15, 1974, to Mr. George Nield, that in determining what areas are requisite for driving visibility, the agency will use an approach of determining those areas by reference to vertical heights in relation to the driver's eyes.; (I believe it is important to note that the agency's decision, in th context of shade bands, not to adopt proposed specific size limits on areas of the windshield which could have less than 70 percent transmittance, was based on the conclusion that such a requirement was not necessary because of the voluntary practices of the industry. Thus, although the agency has not adopted a specific requirement, it has been relying on the good faith adherence of the industry to that voluntary practice on shade bands. The agency first proposed a limit on the size and light transmittance of shade bands in a notice published in November 1978(43 FR 51677). In commenting on the notice, several vehicle manufacturers said that such a requirement was not needed since the industry was voluntarily following a Society of Automotive Engineers Recommended Practice (SAE J100, 'Passenger Car Glazing Shade Bands') that established boundaries for shade bands used on glazed surfaces in passenger cars. As NHTSA explained in a notice published in January 1981 (46 FR 40), the agency decided to defer further action on the proposed shade band limit until it gathered additional data on the adequacy of the voluntary industry practice.); After reviewing the information you have submitted, the agency ha concluded that the membrane used in your system is located in an area of the glazing that is not requisite for driving visibility. The agency reached this conclusion based on the specific fact of your particular design and the following considerations. The membrane used in your system is small in size, is located near the bottom edge of the glazing area and toward the corner of the glazing area, and although the membrane has a light transmittance that is less than 70 percent, it is not opaque.; In determining that your head-up display is not located in an are requisite for driving visibility, the agency also considered the effect of the display on a car's ability to meet the requirements of Standard Nos. 103 and 104. Although Standard Nos. 103 and 104 do not define the limits of what areas are requisite for driving visibility, the areas of the windshield covered by the performance requirement of those standards do indicate the agency's concern that, at a minimum, specified portions of those areas of the windshield be clear during inclement weather inclement weather to provide the driver with a view of the road. The information provided with your letter shows that a small portion of the head-up display in your vehicle partially falls within the defined areas, but the vehicle still meets the performance requirements of the standards.; Another factor in the agency's decision was the information in you letter showing a comparison of the effects of the membrane versus the effects of a vehicle's hood design or unretracted head lamp on a driver's forward visibility. The information you provided shows that a vehicle's hood design or an unretracted head lamp can intrude as far up into the driver's field of view as the head-up display and provide more obstruction to a driver's forward visibility than head-up display. This information is an additional indication that the head-up display is not located within an area that is requisite for driving visibility.; Although the agency has concluded that in your particular case you head-up display is not in an area requisite for driving visibility, the agency believes that with the advent of new glazing and other technologies using the windshield, such as the head-up display, it is appropriate to again re-examine the issue for whether to specify the size of the area of the windshield that are requisite for driving visibility. It is apparent that there will be a number of new technologies using the windshield. For example, the March 30, 1987 issue of *Automotive News* carried a news article announcing the development, by PPG Industries and Flight Dynamics, of a 6 inch square holographic display on the windshield.; NHTSA believes that the issues associated with these devices should b addressed in a comprehensive manner. In particular, the agency believes that it needs further information on such issues as whether the areas on the windshield used by these display devices need to have a lower light transmittance value and, if so, what that value should be, where on the windshield the devices can be located, and what limitations should be placed on their size. Addressing these issues in a comprehensive manner by setting general performance requirements applicable to all such devices, regardless of the technology used, will avoid the inconsistencies and possible design specific limitations that might arise if the agency attempts to provide case-by-case interpretations for each specific design. For all these reasons, NHTSA has concluded that it will address these issues through a comprehensive rulemaking action.; You raised one final issue in your letter. You asked that if the agenc concluded that your head-up display does not comply with Standard No. 205, it should regard the noncompliance as a technical one which does not warrant enforcement. Since the agency has concluded that your head-up display does not violate the requirements of Standard No. 205, it should regard the noncompliance as a technical one which does not warrant enforcement. Since the agency has concluded that your head-up display does not violate the requirements of Standard No. 205, the issue is moot.; If you have any further questions, please let me know. Sincerely, Erika Z. Jones, Chief Counsel