NHTSA Interpretation File Search
Overview
NHTSA's Chief Counsel interprets the statutes that the agency administers and the standards and regulations that it issues. Members of the public may submit requests for interpretation, and the Chief Counsel will respond with a letter of interpretation. These interpretation letters look at the particular facts presented in the question and explain the agency’s opinion on how the law applies given those facts. These letters of interpretation are guidance documents. They do not have the force and effect of law and are not meant to bind the public in any way. They are intended only to provide information to the public regarding existing requirements under the law or agency policies.
Understanding NHTSA’s Online Interpretation Files
NHTSA makes its letters of interpretation available to the public on this webpage.
An interpretation letter represents the opinion of the Chief Counsel based on the facts of individual cases at the time the letter was written. While these letters may be helpful in determining how the agency might answer a question that another person has if that question is similar to a previously considered question, do not assume that a prior interpretation will necessarily apply to your situation.
- Your facts may be sufficiently different from those presented in prior interpretations, such that the agency's answer to you might be different from the answer in the prior interpretation letter;
- Your situation may be completely new to the agency and not addressed in an existing interpretation letter;
- The agency's safety standards or regulations may have changed since the prior interpretation letter was written so that the agency's prior interpretation no longer applies; or
- Some combination of the above, or other, factors.
Searching NHTSA’s Online Interpretation Files
Before beginning a search, it’s important to understand how this online search works. Below we provide some examples of searches you can run. In some cases, the search results may include words similar to what you searched because it utilizes a fuzzy search algorithm.
Single word search
Example: car
Result: Any document containing that word.
Multiple word search
Example: car seat requirements
Result: Any document containing any of these words.
Connector word search
Example: car AND seat AND requirements
Result: Any document containing all of these words.
Note: Search operators such as AND or OR must be in all capital letters.
Phrase in double quotes
Example: "headlamp function"
Result: Any document with that phrase.
Conjunctive search
Example: functionally AND minima
Result: Any document with both of those words.
Wildcard
Example: headl*
Result: Any document with a word beginning with those letters (e.g., headlamp, headlight, headlamps).
Example: no*compl*
Result: Any document beginning with the letters “no” followed by the letters “compl” (e.g., noncompliance, non-complying).
Not
Example: headlamp NOT crash
Result: Any document containing the word “headlamp” and not the word “crash.”
Complex searches
You can combine search operators to write more targeted searches.
Note: The database does not currently support phrase searches with wildcards (e.g., “make* inoperative”).
Example: Headl* AND (supplement* OR auxiliary OR impair*)
Result: Any document containing words that are variants of “headlamp” (headlamp, headlights, etc.) and also containing a variant of “supplement” (supplement, supplemental, etc.) or “impair” (impair, impairment, etc.) or the word “auxiliary.”
Search Tool
NHTSA's Interpretation Files Search
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ID: aiam4412OpenMr. Roger M. Cox, R & R Lighting, Inc., Route 1, Box 190, Gadsden, AL 35901; Mr. Roger M. Cox R & R Lighting Inc. Route 1 Box 190 Gadsden AL 35901; Dear Mr. Cox: This is in reply to your letter of July 8, 1987, with respect t whether a lighting product you intend to market is 'in violation of any federal regulation when mounted on a motor vehicle.'; You describe your product as a 'lighted decal' which can be mounted i the rear window of any car or pick-up truck, and the photographs you enclosed show it mounted in the center of the rear window of a pre-1980 model Seville.; The decal will be wired into the brake system and when activated by th brake 'only the letters in the decal will be lighted.' You state further that although the letters will appear red to an observer 'this product is not designed nor will it be marketed as a brake light or a tail light.'; In our opinion, your product may or may not be in violation of Federa requirements depending upon the following uses. The product does not appear to be intended as a substitute for the center highmounted stop lamp that has been standard equipment on passenger cars manufactured on or after September 1, 1985. Indeed, it could not be so used unless it met all requirements for such a lamp. The principal requirements are that such lamps have a minimum of 4 1/2 square inches of illuminated lens area, that it meet specified photometrics at 13 test points, and that it produce a signal visible from 45 degrees from the right to the left and from five degrees up to five degrees down. If your device does not meet these requirements, removal of the lamp and replacement with your device would violate a prohibition of the National Traffic and Motor Vehicle Safety Act against rendering inoperative equipment installed in accordance with a Federal motor vehicle safety standard, in this case Safety Standard No. 108, *Lamps, Reflective Devices, and Associated Equipment*. However, a dealer could install it on a new pick-up truck, or to one side of the center lamp in a new passenger car before their initial sale, provided the device did not impair the effectiveness of the rear lighting equipment required by Standard No. 108, and the device could be installed on some vehicles in use (cars built before September 1, 1987, and any pick-up) provided that it did not render inoperative in whole or in part other required rear lighting equipment.; By this we mean that the device appears allowable for these vehicle under Federal law provided that wiring it into the brake system does not reduce the stop lamp output or otherwise affect the operation or the effectiveness of the stop lamp system.; You should also ensure that your product is acceptable under State an local laws as well. Because there are no Federal requirements for your product, each State may regulate it as it deems proper.; I am enclosing the samples that you enclosed, and hope that we hav answered your questions.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam5027OpenMr. Steven Rovtar General Manager Blazer International Corp. 2960 Hart Drive Franklin Park, IL 60131; Mr. Steven Rovtar General Manager Blazer International Corp. 2960 Hart Drive Franklin Park IL 60131; "Dear Mr. Rovtar: This responds to your letter of May 28, 1992, askin for 'a written ruling' that the product you described 'meets current SAE/DOT guidelines.' The product is intended for the vehicle towing trailer market. Currently, lamps on towed vehicles are activated by splicing into the wiring harness of the towing vehicle. Your product eliminates the need for this type of hard wiring. This product 'utilizes photodetectors to read the output of the towing vehicle's stop and turn signal lamps, and in turn activate the lamps of the towed vehicle.' Photodetectors are embedded in suction cups which are attached to the towing vehicle's stop and turn signal lamps. The device is plugged into the cigarette lighter receptacle of the towing vehicle, and the harness of the towed vehicle is plugged into the device. When the stop lamp or turn signals of the towing vehicle are activated, the photodetectors read the light emitted, and the towed vehicle's lamps are activated via the completed circuit. For purposes of this discussion we shall assume that the device is intended for aftermarket distribution. Further, from your description, it appears to be the type of device that is simple enough to be installed by the vehicle owner. The product itself is not directly regulated by Federal Motor Vehicle Safety Standard No. 108 Lamps, Reflective Devices and Associated Equipment, because it is not replacement equipment intended to replace original equipment. Its installation on a vehicle in use by the vehicle's owner is outside the prohibition contained in the National Traffic and Motor Vehicle Safety Act. That prohibition forbids 'manufacturers, distributors, dealers, and motor vehicle repair businesses' from 'rendering inoperative, in whole or in part,' mandated safety equipment such as stop lamps and turn signal lamps. Were the device installed by a person in these categories we would be concerned that the addition of the suction cups would partially obscure the original equipment stop and turn signal lamps and, thus, render them 'partially inoperative' within the meaning of the prohibition. That concern is not lessened by the fact that the device may be installed by a person not covered by the prohibition, such as the owner of the towing vehicle. However, as a practical matter, we realize that the safety impact may be minimal since the presence of the trailer will obscure the lamps on the towing vehicle to which the suction cups are applied. We cannot advise you on whether the product meets SAE requirements. The legality of the use of equipment that is not regulated by NHTSA is determinable under the laws of States where the towing-towed vehicle combinations are operated. We are unable to advise you on these laws, and suggest that you write the American Association of Motor Vehicle Administrators, 4600 Washington Boulevard, Arlington, Va. 22203, for an opinion. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam5221OpenMr. Ron Marion Sales Engineer Thomas Built Buses, Inc. P.O. Box 2450 1408 Courtesy Road High Point, N.C. 27261; Mr. Ron Marion Sales Engineer Thomas Built Buses Inc. P.O. Box 2450 1408 Courtesy Road High Point N.C. 27261; "Dear Mr. Marion: This responds to your inquiry about the applicabilit of Standard No. 131, School Bus Pedestrian Safety Devices, to school buses you wish to sell to a customer in the United States Virgin Islands. You stated that these buses will be built as right hand drive vehicles with the entrance door located on the left side, since vehicles are driven on the left side of the road in this jurisdiction. You asked whether you can install, on the right side of the bus, the stop signal arm that is required by FMVSS 131. The answer is yes. The National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381, 'Safety Act') requires new school buses sold in this country and in the U.S. Virgin Islands to comply with all applicable Federal school bus safety standards. (See, 15 U.S.C. 1391(8) for reference to the Virgin Islands.) Standard No. 131 requires school buses to be equipped with a stop signal arm 'on the left side of the bus.' (S5.4) The purpose of this standard is 'to reduce deaths and injuries by minimizing the likelihood of vehicles passing a stopped school bus and striking pedestrians in the vicinity of the school bus.' (S2) When NHTSA specified that the stop arm must be placed on 'the left side of the bus,' the agency meant the driver's side. Comments to the notice of proposed rulemaking (NPRM) and preamble of NHTSA's final rule all assumed that the left side of the bus meant the driver's side. (56 FR 20363, 20367). For example, while endorsing the proposed requirement for the stop arm, several commenters stated that an arm is needed near the driver's window. Moreover, S5.4.1(b) states that, for locating the arm, 'the top edge of the stop signal arm is parallel to and not more than 6 inches from a horizontal plane tangent to the lower edge of the frame of the passenger window immediately behind the driver's window.' (Emphasis added). This provision indicates that the agency assumed that the 'left' side is the driver's side. Further, a stop arm would not be needed on the non-traffic side of the vehicle. Since the left side is not the driver's side for the school buses in question, the agency's general assumption was incorrect. In light of your letter, we will issue a technical amendment of Standard 131 so that S5.4 will require the stop signal arm on the driver's side of the bus. Until the amendment is issued, we will not take enforcement action regarding a manufacturer's locating a right hand drive school bus with a stop signal arm on the bus's driver's side. I hope this information is helpful. If you have any questions about NHTSA's safety standards, please feel free to contact Marvin Shaw at this address or by telephone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam4172OpenMr. Brian Peck, President, Rearscope International (U.S.A.) Ltd., 15255 Hesperian Boulevard, San Leandro, CA 94578; Mr. Brian Peck President Rearscope International (U.S.A.) Ltd. 15255 Hesperian Boulevard San Leandro CA 94578; Dear Mr. Peck: Thank you for your letter of May 19, 1986, asking how our regulation apply to your product, which is called the 'Rearscope Wide Angle Lens.' Your letter and the brochure you enclosed describes your product as a wide angle acrylic lens which mounts on the rear window of a bus and gives the driver a wider field of view to the rear of the vehicle. I hope the following discussion answers your questions.; By way of background, the National Highway Traffic Safet Administration has the authority to issue safety standards applicable to new motor vehicles and certain items of motor vehicle equipment. NHTSA, however, does not approve motor vehicles or motor vehicle equipment, nor do we endorse any commercial products. Instead the National Traffic and Motor Vehicle Safety Act establishes a 'self-certification' process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. The agency periodically tests vehicles and equipment items for compliance with the standards, and also investigates other alleged safety-related defects.; We have issued Federal Motor Vehicle Safety Standard No. 205, *Glazin Materials*, which specifies performance and location requirements for glazing used in vehicles. These requirements include specifications for minimum levels of light transmittance (70% in areas requisite for driving visibility, which includes all windows in passenger cars) as well as other performance requirements for glazing.; Standard No. 205 does not directly apply to add-on window coverings such as tinting films, sunscreening devices, and lens. However, no manufacturer or dealer is permitted to install a device on the glazing, such as the viewing lens described in your letter, in *new* vehicles without certifying that the vehicle continues to be in compliance with the light transmittance and other requirements of the standard.; After a vehicle is first sold to a consumer, modifications to a vehicl are affected by section 108(a)(2)(A) of the Vehicle Safety Act. That section prohibits commercial businesses from tampering with safety equipment installed on a vehicle in compliance with our standards. Thus, no dealer, manufacturer, repair business or distributor can install a device for the owner of the vehicle, if the device would cause the window not to meet the requirements of Standard No. 205. Violation of the 'render inoperative' provision can result in Federal civil penalties of up to $1,000 for each violation.; Section 108(a)(2)(A) does not affect vehicle owners, who may themselve alter their vehicles as they please, so long as they adhere to all State requirements. Under Federal law, the owner may install any type of device regardless of whether the installation adversely affects the window. Individual States govern the operational use of vehicles by their owners and therefore it is within the authority of the States to regulate the use of viewing devices in vehicles.; If you need further information, please let me know. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam5036OpenMr. Eugene Welker 774 Harbor Island Clearwater, FL 34630; Mr. Eugene Welker 774 Harbor Island Clearwater FL 34630; "Dear Mr. Welker: This responds to your letter about a mirror syste designed to improve a driver's view of areas behind a motor vehicle. You explained that a 35' vertical post would be bolted near a vehicle's rear bumper. This would result in a mirror being located a few inches above the top rear window stop light and facing forward at a 45 angle. You asked whether such a device would be legal. The following discussion and the enclosed information sheet, 'Information for New Manufacturers of Motor Vehicles and Motor Vehicle Equipment,' explain your responsibility under NHTSA's regulation. By way of background information, the National Highway Traffic Safety Administration (NHTSA) does not approve, endorse, or certify motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act ('Safety Act'), the manufacturer is responsible for certifying that its vehicles or equipment comply with applicable Federal motor vehicle safety standards. The Safety Act requires that these safety standards establish minimum levels of performance for vehicles or equipment. Once the performance level has been established, vehicle or equipment manufacturers are free to choose any means they wish to achieve the required level of performance. NHTSA has exercised its authority to establish performance requirements for new vehicles in Standard No. 111, Rearview Mirrors (49 CFR 571.111, copy enclosed). Standard No. 111 establishes performance and location requirements for rearview mirrors installed in any new vehicle. This means that the vehicle manufacturer must certify that each vehicle it manufactures complies with the specified requirements. Standard No. 111 requires that passenger cars be equipped with an inside rearview mirror and a driver's side outside rearview mirror that provide the field-of-view specified in S5.1.1. A passenger's side outside rearview mirror is required in situations where the inside rearview mirror does not provide the specified field-of-view. Additional requirements for other vehicle types are set forth in S6, S7, and S8. No provision in the Standard specifies requirements for a mirror that attaches to the vehicle's rear bumper. Accordingly, a mirror like yours would not be prohibited from being installed on any vehicle by the current requirements in Standard No. 111. Accordingly such a mirror would be permitted, but only as a supplement to the required mirrors. In installing the mirror, one must take care to avoid obscuring the vehicle's lighting devices, including the center highmounted stop lamps (CHMSL). Please be aware that NHTSA does not regulate vehicles while they are in use. The American Association of Motor Vehicle Administrators, 4600 Washington Blvd, Arlington, VA 22203 may be able to advise you about the laws of the individual States related to the use of equipment such as your own. I hope this information is helpful. If you have any further questions about NHTSA's safety standards, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam4122OpenThe Honorable Ralph Davenport, South Carolina Legislature, P.O. 1301, Spartanburg, SC 20394; The Honorable Ralph Davenport South Carolina Legislature P.O. 1301 Spartanburg SC 20394; Dear Mr. Davenport: This is to follow up on your phone conversation with Stephen Oesch o my staff concerning the effect of Federal regulations on the tinting of motor vehicle windows. I hope the following discussion answers your questions.; Some background information on how Federal motor vehicle safety law and regulations affect the tinting of vehicle windows may be helpful. Our agency is authorized, under the National Traffic and Motor Vehicle Safety Act, to issue safety standards applicable to new motor vehicles and certain items of motor vehicle equipment. We have issued Federal Motor Vehicle Safety Standard No. 205, *Glazing Materials*, which specifies performance and location requirements for glazing used in vehicles. These requirements include specifications for minimum levels of light transmittance (70% in areas requisite for driving visibility, which includes all windows in passenger cars).; You first asked if the Federal motor vehicle safety standards apply t foreign vehicles sold in the United States. As with all our standards, Standard No. 205 applies to any new vehicle, whether made by a foreign or domestic company, manufactured for sale in the United States. Thus, no manufacturer or dealer is permitted to install solar films and other sun screen devices, such as the one described in your letter, in *new* vehicles without certifying that the vehicle continues to be in compliance with the light transmittance and other requirements of the standard. Violation of Standard No. 205 can result in Federal civil penalties of up to $1,000 for each violation. In addition, a manufacturer of a vehicle that does not comply with our standards is required to remedy any noncompliances in its vehicles.; You also asked how Federal law affects businesses that tinted th windows of used vehicles. After a vehicle is first sold to a consumer, modifications to a vehicle are affected by section 108(a)(2)(A) of the Vehicle Safety Act. That section prohibits commercial businesses from tampering with safety equipment installed on a vehicle in compliance with our standards. Thus, no dealer, manufacturer, repair business or distributor can install a sun screen device for the owner of the vehicle, if the device would cause the window not to meet the requirements of Standard No. 205. Violation of the section 108(a)(2)(A) can result in Federal civil penalties of up to $1,000 for each violation.; Section 108(a)(2)(A) does not affect vehicle owners, who may themselve alter their vehicles as they please, so long as they adhere to all State requirements. Under Federal law, the owner may install sun screening devices regardless of whether the installation adversely affects the light transmittance. Individual States govern the operational use of vehicles by their owners and therefore it is within the authority of the States to preclude owners from using sun screens in their vehicles.; If you need further information, please let me know. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam2089OpenMr. Joe Steininger, Tiffin Metal Products, 450 Wall Street, Tiffin, OH 44883; Mr. Joe Steininger Tiffin Metal Products 450 Wall Street Tiffin OH 44883; Dear Mr. Steininger: This is in response to your request for an opinion on the applicabilit of Federal Motor Vehicle Safety Standard 205 to a road grader intended for use in highway construction.; The National Highway Traffic Safety Administration issues safet standards for 'motor vehicles.' Therefore, our regulations apply to a vehicle and its manufacturer only if the vehicle qualifies as a motor vehicle under the provisions of the National Traffic and Motor Vehicle Safety Act of 1966. Section 102(3) of the Act defines motor vehicle as:; >>>any vehicle driven or drawn by mechanical power manufacture primarily for use on the public streets, roads, and highways, except any vehicle operated exclusively on a rail or rails.<<<; Thus, a motor vehicle is a vehicle which the manufacturer expects wil use public highways as part of its intended function.; Tracked and other vehicles incapable of highway travel are not moto vehicles. In addition, vehicles intended and sold solely for off-road use (e.g. aircraft runway vehicles and underground mining vehicles) are not considered vehicles even if operationally capable of highway travel. They would, however, be considered motor vehicles if the manufacturer knew that a substantial proportion of his customers actually would use them on the highway.; Just as clearly, vehicles which use the highway on a necessary an recurring basis to move between work sites are motor vehicles. The primary function of some vehicles is of a mobile, work performing nature and as such their manufacturer contemplates a primary use of the highway. Mobile cranes, drill rigs, and towed equipment such as chippers and pull-type street sweepers are examples in this area. Even if the equipment uses highways infrequently, it is considered a motor vehicle. An exception to this is that occasional use of the highway in the immediate periphery of the work site, as is the case with some farm and construction equipment, would not by itself cause a finding that the vehicle is a motor vehicle. The motor vehicles described above generally qualify as trucks or trailers. As such they are subject to several of the motor vehicle safety standards, and the manufacturer must comply with other regulations in Chapter V of Title 49, code of Federal Regulations.; There are some vehicles which are excepted from the motor vehicl classification despite their use of the highway. Highway maintenance and construction equipment, lane stripers, self-propelled asphalt pavers, and other vehicles whose maximum speed does not exceed 20 miles per hour and whose abnormal configuration distinguishes them from the traffic flow are not considered motor vehicles. This would appear to include road graders whose maximum speed does not exceed 20 miles per hour, if intended for use in highway construction.; From these guidelines you should be able to determine whether a piec of equipment qualifies as a motor vehicle.; Please write again if you are unable to make this determination. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4751OpenThe Honorable Lawrence J. Smith U. S. House of Representatives Washington, D.C. 20515; The Honorable Lawrence J. Smith U. S. House of Representatives Washington D.C. 20515; "Dear Mr. Smith: I am writing in response to your letter forwardin correspondence from your constituent, Mr. Joel Leitson, with respect to litigation recently brought by the United States against several firms that install plastic film, or 'tint,' on automobile windows. You have asked about the statutory authority under which these suits were brought. Pursuant to section 103 of the National Traffic and Motor Vehicle Safety Act of 1966 ('Safety Act'), 15 U.S.C. 1392, the National Highway Traffic Safety Administration ('NHTSA') has issued safety standards applicable to new motor vehicles and items of motor vehicle equipment. One of the standards that we have issued under this authority is Federal Motor Vehicle Safety Standard No. 205, Glazing Materials (49 CFR 571.205), which applies to all new vehicles and all new glazing materials for use in motor vehicles. Among the requirements set forth in Standard No. 205 are specifications for minimum levels of light transmittance (70 percent light transmittance in areas requisite for driving visibility, which includes all windows in passenger cars). Section 108(a)(i)(A) of the Safety Act, 15 U.S.C. 1397(a)(1)(A), provides that no person may manufacture or sell any vehicle unless it is in conformity with all applicable safety standards. Pursuant to section 108(b)(1) of the Safety Act, 15 U.S.C. 1397(b)(1), this paragraph does not apply after a vehicle is first sold to a consumer. However, both before and after the first sale, section 108(a)(2) of the Safety Act, 15 U.S.C. 1397(a)(2), provides that 'No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative, in whole or part, any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard . . . .' Thus, by installing tint film on automobiles that reduces the light transmittance of their glass below 70 percent, the firms in question have been rendering those vehicles 'inoperative,' in violation of the Safety Act. The same principle would apply to a service station that removed an airbag or a safety belt from a vehicle, since such an action would create a noncompliance with the occupant protection requirements of NHTSA's standards. You also asked for our comments on whether Florida's statutes are preempted by these suits. We assume that you are referring to the provision of Florida law that prohibits the operation of any vehicle in the State of Florida that has glazing with less than 35 percent light transmittance. This statute, and similar statutes adopted by other states, do not purport to legitimize conduct -- the rendering inoperative of glazing by tint installation firms -- that is illegal under the Safety Act. Thus, there is no conflict with Federal law, and Florida may continue to enforce its operating rules. I hope that this responds to your questions. If we can be of further assistance, please let me know. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam4547OpenMr. George Ziolo DOT Paperwork Processor 234l7 Everett Place Ramona, CA 92065; Mr. George Ziolo DOT Paperwork Processor 234l7 Everett Place Ramona CA 92065; Dear Mr. Ziolo: This is in reply to your letter of April 20, 1988 asking about the acceptability under Safety Standard No. 108 of modifying imported vehicles so that they are equipped with two Type 2D1 and two Type 1C1 headlamps. You have been informed by the agency's Office of Vehicle Safety Compliance that this is impermissible 'because they are 'nonconforming' 'headlight systems'.' You disagree because you believe that the minimum requirements of the Standard are satisfied by the Type 2D1 lamps, and that 'S4.4 appears to permit such a combination.' Paragraph S4.4 is not applicable to the situation you present as it refers to combinations of lamps serving different functions, in your discussion, the lamps serve the identical function of headlighting. Given the fact that the Type 2D1 sealed beam 7' diameter headlamps fulfill the headlighting requirements of the Standard, your question must be viewed as whether a supplement to the headlighting system is permissible under Standard No. 108. Paragraph S4.l.3 of Standard No. 108 permits the addition of nonrequired lighting equipment provided it does not impair the effectiveness of the equipment that the standard requires. The two Type 1C1 5 3/4' diameter sealed beam lamps in a four lamp headlighting system form the major portion of an upper beam headlighting system. The two Type 2D1 lamps in a two lamp headlighting system form the whole of an upper beam headlighting system. Thus, a vehicle furnished with the systems you posit would be equipped with more than one upper beam headlighting system. The Type 2D1 system must be designed to conform to the photometric requirements of SAE Standard J579c DEC79 'Sealed Beam Headlamp Units for Motor Vehicles.' The SAE Standard establishes at two test points, H-V and 4 D-V, maximum allowable candela of 75,000 and 5,000 respectively for each Type 2D1 headlamp. This means that the maximum allowable candela for headlighting systems at these test points is 150,000 and l0,000 candela. The Type 1C1 headlamps will also be designed to conform to SAE J579c. Corresponding maxima at test points H-V and 4 D-V for Type 1C1 systems are 60,000 and 5,000. Thus, a vehicle equipped with the lamps you have described could emit a total of 270,000 candela at test point H-V (when only 150,000 is permitted), and 20,000 at 4D-V (when only l0,000 is allowable). Agency research has shown that candela readings in excess of 150,000 greatly increase the potential for glare with little increase in seeing ability. This glare would be visible both to the driver of an oncoming car, and the driver of the modified vehicle itself through creation of a 'veiling' glare. The addition of the Type 1C1 headlamps would therefore impair the effectiveness of the Type 2D1 headlighting system, and is forbidden by S4.1.3. We appreciate your interest in safety. Sincerely, Erika Z. Jones Chief Counsel; |
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ID: aiam3955OpenMr. L. D. Pitts, Jr., P. O. Box 52592, Houston, TX 77002; Mr. L. D. Pitts Jr. P. O. Box 52592 Houston TX 77002; Dear Mr. Pitts: Thank you for your letter of March 12, 1985, asking about the effect o our regulations on a product you would like to manufacture. I hope the following discussion explains that effect.; You described your product, which you call a glare- shield, as 1/8-inch thick sheet of 'Lexan' plastic with a special scratch resistant coating. Your product is designed to be mounted inside a motor vehicle, as close to the windshield as possible, to reduce glare-related vision problems caused by the sun. You stated that your product would cover the entire windshield and is designed to be held in place by three or six latches. The latches can be released by the driver and the shield can be removed from the car.; Pursuant to the National Traffic and Motor Vehicle Safety Act, we hav issued Federal Motor Vehicle Safety Standard No. 205, *Glazing Materials,* (49 CFR 571.205) which specifies performance and location requirements for glazing used in vehicles. These requirements include specifications for minimum levels of light transmittance (70% in areas requisite for driving visibility, which includes all windows in passenger cars).; Any manufacturer, dealer or other person who installs tinting films o other sun screen devices, such as the one described in your letter, in *new* vehicles must certify that the vehicle as altered continues to comply with the requirements of the standard. Thus, for example, the light transmittance through the combination of the sun-screening material and the glazing must be at least 70 percent in the case of glazing used in windows requisite for driving visibility. Similarly, the combination must also meet the other applicable requirements of the standard, such as the abrasion resistance requirements.; After a vehicle is sold to the consumer, owners may themselves alte their vehicles as they please, so long as they adhere to all State requirements. Under Federal law, an owner may install any device regardless of whether the installation adversely affects light transmittance. The agency does, however, urge owners not to install equipment which would render inoperative the compliance of a vehicle with our standards. Individual States govern the operational use of vehicles by their owners and therefore it is within the authority of the States to preclude owners from using sun screens on their vehicles.; If a manufacturer, dealer, distributor or motor vehicle repair busines installs the sun screen device for the owner of a used vehicle, then S108(a)(2)(A) of the Vehicle Safety Act may apply. That section provides that none of those persons may knowingly render inoperative any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with a Federal motor vehicle safety standard. Violation of the 'render inoperative' provision can result in Federal civil penalties of up to $1,000 for each violation.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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Request an Interpretation
You may email your request to Interpretations.NHTSA@dot.gov or send your request in hard copy to:
The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590
If you want to talk to someone at NHTSA about what a request for interpretation should include, call the Office of the Chief Counsel at 202-366-2992.
Please note that NHTSA’s response will be made available in this online database, and that the incoming interpretation request may also be made publicly available.