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: aiam3165OpenMr. E. M. Ryan, Ward Industries, Inc., P.O. Box 849, Highway 65 South, Conway, AR 72032; Mr. E. M. Ryan Ward Industries Inc. P.O. Box 849 Highway 65 South Conway AR 72032; Dear Mr. Ryan: This responds to your October 8, 1979, letter asking whether your ne bus design will comply with Standard No. 217, *Bus Window Retention and Release*. The window exit that you plan to install in the bus would slide open rather than push out and would be operated by a squeeze-type force application that is parallel to the horizontal centerline of the bus.; Standard No. 217 requires buses to be equipped with emergency exit that comply with a variety of requirements. In the case of window exits, the force application for opening them depends upon the location of the release mechanism. For example, the required force application in the high force access region, according to the standard (S5.3.2), is straight and perpendicular to the exit surface.; In applying the above requirement to your vehicle, it appears that you bus would not comply with the standard. From the pictures that you enclosed with your letter, it appears that your release mechanism falls in the high force access region. If so, the force application for opening the exit is in the incorrect direction as specified by the standard. Further, your bus would use window exits that slide open rather than push out. Although, sliding emergency exits are not prohibited by the standard, they must comply with all of the standard's requirements. Also, they must be capable of complying when the non-exit half of the window is either open or closed. The agency prefers the use of push-out emergency exits, because they are less likely to 'bind up' during a side impact than sliding emergency exits.; The standard was written in its present form to provide uniformity o emergency exits in buses. A uniform exit system can help prevent confusion during accidents and facilitate emergency exit of vehicles. The vehicle that you plan to build would be unlike other buses now in operation with respect to emergency exits. The NHTSA does not think that this would be desirable or in the interest of safety.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3470OpenDick Sorensen, Brekhus Buick-International, Box 1357, Rapid City, SC 57701; Dick Sorensen Brekhus Buick-International Box 1357 Rapid City SC 57701; Dear Mr. Sorensen: This is in response to your letter of September 10, 1981, in which yo requested information on the Federal odometer disclosure requirements and specifically on their applicability to trucks with a gross vehicle weight rating (GVWR) of over 16,000 pounds. I have enclosed a copy of Title IV of the Motor Vehicle Information and Cost Savings Act (15 U.S.C. 1981 et seq.) which sets forth the Federal law pertaining to odometers. Section 404 of the Act prohibits any person from altering the odometer of any motor vehicle including trucks of more than 16,000 pounds GVWR.; I have also enclosed a copy of the odometer disclosure requirements (4 CFR Part 580). I have highlighted in red the exemption that applies to large trucks. The agency found that purchasers of these trucks do not rely on the odometer as an indicator of their mileage and, therefore, exempted them from the disclosure requirements. Before you decide whether or not to issue odometer disclosure statements for these trucks, I would like to alert you to the fact that at least one court has held that the agency exceeded its authority in fashioning this exemption and has declared it void. *Lair v. Lewis Service Center*, 428 F.Supp. 778 (D.Neb. 1977). The holding is not binding on any other court and the agency believes the exemption is valid. Nevertheless, you should be aware that should the issue arise again, another court could take a similar view.; I hope that this information is useful to you. If you have any furthe questions, please do not hesitate to write.; Sincerely, John Womack, Assistant Chief Counsel |
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ID: aiam3020OpenMr. John Cordner, Technical Assistant, Product Compliance, Subaru of America, Inc., 7040 Central Highway, Pennsauken, NJ 08109; Mr. John Cordner Technical Assistant Product Compliance Subaru of America Inc. 7040 Central Highway Pennsauken NJ 08109; Dear Mr. Cordner: This is in response to your letter of April 23, 1979, in which yo requested the agency's opinion whether a four-wheel drive hatchback sedan could be classified as a multi- purpose passenger vehicle (MPV).; As was stated by Eileen Leahy of my staff in telephone conversation regarding your request, the agency cannot give an opinion regarding this vehicle's classification for purposes of compliance with Federal Motor Vehicle Safety Standards without knowing whether the vehicle has any special features for off-road use other than four-wheel drive. An MPV is defined in 49 CFR S 571.3(b) as 'a motor vehicle with motor power, except a trailer, designed to carry 10 persons or less which is constructed either on a truck chassis or with special features for occasional off-road operation.' Since the vehicle you describe is not constructed on a truck chassis, it must have 'special features for occasional off-road operation' in order to qualify as an MPV. The agency interprets this language as requiring that the vehicle contain more than a single feature designed for off-road use. This interpretation is based on the use of the word 'features' in the plural rather than the singular in the definition, and on the fact that a vehicle's total design determines its likely use. Four-wheel drive would be useful in snow on public streets, roads and highways, so this feature cannot be determinative of the vehicle's classification if there are no features for off-road use.; Also, the agency is reluctant to exempt a vehicle from compliance wit any of its safety standards purely on the grounds that it is equipped with four-wheel drive. There is little likelihood that a vehicle that is identical to a passenger car in every other respect will be used differently than other passenger cars. Under these circumstances, the agency sees no reason for treating such vehicles any differently from other passenger cars with respect to the applicability of safety standards.; Therefore, unless you can provide us with additional informatio (including, but not limited to, pictures or drawings of the vehicle) concerning other special features of this vehicle that would make it suitable for off-road operation, the agency cannot concur with the opinion expressed in your letter that this vehicle should be classified as a multipurpose vehicle for purposes of compliance with Federal motor vehicle safety standards. Also, I would refer you to 49 CFR S 523.5(b)(2) for a description of some of the characteristics that would be considered as 'special features for off-road operation' although that section relates primarily to fuel economy.; If you will provide us with additional information, we will be happy t offer a final opinion.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam2261OpenMr. Richard H. Barry, President, Barry Tank and Bumper Co., Maple Plain, MN 55359; Mr. Richard H. Barry President Barry Tank and Bumper Co. Maple Plain MN 55359; Dear Mr. Barry: I am writing in response to your March 22, 1976, telephone conversatio with Mark Schwimmer of this office concerning the treatment of plastic fuel tanks under Federal Motor Vehicle Safety Standard No. 301-75, *Fuel System Integrity*.; As Mr. Schwimmer explained, the National Highway Traffic Safet Administration has issued no safety standards that apply directly to fuel tanks. Standard No. 301-75, which applies to entire vehicles, specifies fuel spillage requirements for barrier crash and rollover tests, but does not include a flame envelopment test. In addition to passenger cars and school buses, the vehicles that are subject to the standard are multipurpose passenger vehicles, trucks, and buses with a Gross Vehicle Weight Rating of 10,000 pounds or less.; Standard No. 301- 75 applies to new vehicles. In addition, the Federa Highway Administration's Bureau of Motor Carrier Safety has established requirements for certain vehicles in use in interstate commerce. I understand that a fuel tank flame envelopment test is among these. For information concerning such a test, you should communicate with that agency.; For your convenience, a copy of Standard No. 301-75 is enclosed. Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam3889OpenMr. Nick Martz, Regional Sales Manager, Isuzu Diesel of North America, 41169 Vincenti Court, Novi, MI 48050; Mr. Nick Martz Regional Sales Manager Isuzu Diesel of North America 41169 Vincenti Court Novi MI 48050; Dear Mr. Martz: This responds to your letter asking about identification requirement applicable to water temperature, oil pressure and alternator instruments on bread delivery trucks. You asked whether the symbols specified by Standard No. 101, *Controls and Displays*, are required for such trucks and, if so, whether it is permissible to use transparent decals with the proper symbols on the lenses. You also asked whether waivers can be issued. The answers to your questions are provided below.; Federal Motor Vehicle Safety Standard No. 101, *Controls and Displays* specifies requirements for the location, identification, and illumination of motor vehicle controls and displays. Water temperature, oil pressure and alternator instruments are displays. While the standard's requirements for controls apply to all trucks, the standard's requirements for displays are only applicable to trucks with a gross vehicles weight rating of less than 10,000 pounds. See section S5.; Assuming that your bread trucks do have a gross vehicle weight ratin of less than 10,000 pounds, the instruments must be identified by the symbols specified by Standard No. 101. Section S.2.3 provides in relevant part:; >>>Except for informational readout displays, any display locate within the passenger compartment and listed in column 1 of Table 2 that has a symbol designated in column 4, shall be identified by that symbol. Such display may, in addition be identified by the word or abbreviation shown in column 3.... Additional words or symbols may be used at the manufacturer's discretion for the purpose of clarity. The identification required or permitted by this section shall be placed on or adjacent to the display that it identifies. The identification of any display shall, under the conditions of S6, be visible to the driver and appear to the driver perceptually upright.<<<; The displays described by your letter are conventional gauges rathe than informational readout displays. (Informational readout displays are defined by the standard to be displays using light-emitting diodes, liquid crystals, or other elector illuminating devices where one or more than one type of information may be displayed.) Table 2 specifies symbols for, among other displays, oil pressure gauges, coolant temperature gauges, and electrical charge gauges. Therefore, under S5.2.3, the displays must be identified by the specified symbols.; Standard No. 101 does not specify the nature of the material to be use in identifying displays, i.e., paint, decals, etc. Therefore, it is permissible to use decals.; You also asked whether waivers can be issued. In a telephon conversation with Edward Glancy of this office, you indicated that some trucks have been produced using words rather than symbols to identify the gauges discussed above. 49 CFR Part 556 sets forth procedures for petitioning for exemption from the notification and remedy requirements of the National Traffic and Motor Vehicle Safety Act due to the inconsequentiality of a noncompliance with a safety standard as it relates to motor vehicle safety. I have enclosed a copy of Part 556 for you convenience, as well as a copy of Standard No. 101.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3923OpenMr. Lynn R. Metzger, President, Mid Bus Inc., P.O. Box 1985, Lima, OH 45802; Mr. Lynn R. Metzger President Mid Bus Inc. P.O. Box 1985 Lima OH 45802; Dear Mr. Metzger: This responds to your February 22, 1985 letter to the National Highwa Traffic Safety Administration (NHTSA) requesting clarification of this agency's definition of a bus. A 'bus' is defined in the definitions section of our motor vehicle safety standards (49 CFR 571.3) as 'a motor vehicle with motive power, except a trailer, designed for carrying more than 10 persons.' You asked whether a vehicle's classification under our regulation is based on the seating capacity of the vehicle as designed, which may vary, or the actual seating capacity of the vehicle as manufactured.; The National Traffic and Motor Vehicle Safety Act require manufacturers to certify that their vehicles as manufactured, comply with our safety standards. Thus, the agency uses the actual seating capacity of the vehicle as manufactured to determine the classification of the vehicle. NHTSA determines the seating capacity of a motor vehicle by identifying the number of designated seating positions in the vehicle. 'Designated seating position' is defined in S571.3 as 'any plan view location capable of accommodating a person at least as large as a 5th percentile adult female, if the overall seat configuration and design and vehicle design is such that the position is likely to be used as a seating position while the vehicle is in motion, except for auxiliary seating accommodations such as temporary or folding jump seats....' Consistent with this definition, we have also counted positions designed to accommodate wheelchairs in determining vehicle seating capacity for the determination of vehicle classification. Under our regulations, a vehicle having a total of more than 10 designated seating positions and wheel chair positions is a bus and a vehicle having a total of 10 or less positions is either a passenger car or a multipurpose passenger vehicle (MPV).; You asked why you are not permitted to build a 6 passenger MPV exactl as you manufacture a school bus. As a MPV, your vehicle must be certified as meeting all of the standards applicable to that vehicle type. You may also voluntarily manufacture the vehicle in compliance with the requirements of our school bus safety standards, as long as the vehicle continues to comply with our standards for MPV's.; A final rule was recently published in the Federal Register (50 F 12029, March 27, 1985) amending Standard No. 206, *Door Locks and Door Retention Components* to exclude doors equipped with wheelchair lifts and audible or visual alarms from the requirements of the Standard. Since you expressed an interest in that amendment, I have enclosed a copy of the final rule for your information.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam2631OpenMr. Takeo Shimoguchi, General Manager, Daido Kogyo Co., Ltd., 1-197 Kumasaka-cho, Kaga, Ishikawa-pref., Japan; Mr. Takeo Shimoguchi General Manager Daido Kogyo Co. Ltd. 1-197 Kumasaka-cho Kaga Ishikawa-pref. Japan; Dear Mr. Shimoguchi: This responds to your April 30, 1977, comments concerning Standard No 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*. Your comments question the advisability of requiring the rim size designation to be stated in the order of diameter by width. This designation would be the reverse of existing Japanese and European practices.; The National Highway Traffic Safety Administration (NHTSA) examine this issue in its response to petitions for reconsideration of Standard No. 120 (42 FR 7140). The agency determined that the rim size designation should be expressed on the label in the manner proposed in the standard (diameter by width) to avoid confusion with the tire size designation which is measured in terms of width by diameter. Since publication of our response to petitions for reconsideration (which included your petition), we have received no information presenting new reasons to alter the chosen format. Therefore, the NHTSA will continue to implement the standard as published in the February 7 Notice.; In a second question, you ask whether the NHTSA requires that th information specified in S5.2 of the standard be listed in any particular order. Although the agency has not specified the order in which the information required in S5.2 should be listed, the NHTSA expects that for purposes of clarity the information in paragraphs (a), (b), and (c) would be grouped together as would the information in paragraphs (d) and (e).; Finally, you note that the symbol 'JIS' must be marked on the rim i accordance with requirements od the Japanese Industrial Standard while NHTSA requires only the letter 'J.' For purposes of uniformity the agency will continue to require the letter 'J' even though this may result in the double marking situation to which you refer.; I trust that this responds fully to your comments. Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam0381OpenMr. Louis L. Allen, President, Chase Manhattan Capital Corporation, 1 Chase Manhattan Plaza, New York, NY 10005; Mr. Louis L. Allen President Chase Manhattan Capital Corporation 1 Chase Manhattan Plaza New York NY 10005; Dear Mr. Allen: This is in reply to your letter of June 21, 1971 concerning the Tir Identification and Record Keeping regulation (49 CFR Part 574). We are concerned with the points you raise in your letter regarding the confidentiality of tire dealers customer's lists and the extra burden the regulation causes dealers who handle more than one brand of tires.; However, under the National Traffic and Motor Vehicle Safety Act we d not feel we have authority to require the tire manufacturer to choose someone as his designee. Section 113(f) of the Act makes the tire manufacturer responsible for maintaining the records of first purchasers.; As you probably know, any use of the customer's list by the tir manufacturer is expressly prohibited by the regulation. Any violation of this prohibition will be enforced.; I have enclosed for your information a copy of a notice published i the *Federal Register* May 28, 1971 which is relevant to the points you raise.; Thank you for your comments and interest in auto safety. Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam5479OpenMr. Earl L. Hartley, Jr. Ryan Freight Services, Inc. 2595 Chandler #10 Las Vegas, Nevada 89120; Mr. Earl L. Hartley Jr. Ryan Freight Services Inc. 2595 Chandler #10 Las Vegas Nevada 89120; Dear Mr. Hartley: This responds to your letter concerning 49 CFR Par 583, Automobile Parts Content Labeling. I apologize for the delay in our response. You stated that you need to provide country of origin information to the auto manufacturers you sell to, and would like confirmation that you are properly interpreting the regulations. We understand that you are an 'outside supplier,' i.e., your company is not owned by an auto manufacturer. (Requirements differ for outside suppliers and allied suppliers.) Your questions, and our responses, are set forth below. Question 1. 583.6(c) We interpret this to mean that if the U.S./Canada value added is 70% or more we are to report the U.S./Canada percentage to be 100%. If the U.S./Canada value added is less than 70% we are to report the U.S./Canada percentage to be -0-% Is this correct? Response. You are partially correct. It is true that, under 583.6(c), equipment supplied by an outside supplier is considered 100 percent U.S./Canadian if 70 percent or more of its value is added in the U.S./Canada, and 0 percent if less than 70 percent is added in the U.S./Canada. However, the specific information which outside suppliers must provide to auto manufacturers is set forth in 583.10. (Outside suppliers of engines and transmissions must also provide the information specified in 583.12. I will assume for the balance of this letter that you are not a supplier of engines or transmissions.) Rather than requiring outside suppliers to report the 100 percent or 0 percent figure, section 583.10 instead specifies that outside suppliers are to provide a statement that the equipment has, or does not have, at least 70 percent of its value added in the United States and Canada. Question 2. 583.7(a), (e), (f) If the U.S./Canadian percentage of the value is -0-% then we should report the two largest 'Major Foreign Sources' which are over 15% each. Is this correct? Response. No. This question suggests a misunderstanding of the differing requirements for auto manufacturers and suppliers. Auto manufacturers are required to calculate, on a carline basis, 'U.S./Canadian parts content' and 'Major sources of foreign parts content.' Suppliers are required to provide specified information about the equipment they supply to enable the auto manufacturers to make these calculations. As indicated above, the information that outside suppliers must provide is set forth in 583.10. Suppliers are not required to provide the two largest 'Major Foreign Sources' of their equipment. Question 3. 583.7(c)(1) This requirement is completely independent from the determination of the percentage of the value determination. Therefore it is possible for a part to be of U.S.A. origin and have -0-% U.S./Canadian percentage of value. Are we correct in this assumption? Response. The answer is yes. It is true that a part could be of U.S./Canada origin under 583.7(c)(1), for purposes of determining major foreign sources of passenger motor vehicle equipment, even though it has less than 70 percent U.S./Canadian content and is hence considered to have 0 percent U.S./Canadian content under 583.6. This reflects the different purposes of 583.6 and 583.7. Section 583.6 sets forth the procedure for determining the U.S/Canadian content of carlines. Under the American Automobile Labeling Act, equipment supplied by an outside supplier is considered 100 percent U.S./Canadian if 70 percent or more of its value is added in the U.S./Canada, and 0 percent if less than 70 percent is added in the U.S./Canada. Section 583.7 specifies the procedure for determining major foreign sources of passenger motor vehicle equipment. The only effect of a determination under 583.7(c)(1) that a part is of U.S./Canadian origin is that it will not be considered to have been contributed by a foreign source. Question 4a. 583.10(a)-(c) From these parts we assume the following requirements: Our certificate must show: 1. The name and address of the supplier, 2. The part number and description of the part or assembly, 3. The selling price to our customer, 4. Whether the part has or does not have 70% of its value from the United States/Canada as determined under 583.6(c), 5. If the United States/Canada percentage is less than 70% the country of origin determined under 583.7(c), 6. For equipment that may be used in an engine or transmission, the country of origin of the equipment, determined under 583.8(c), 7. A certification for the information, pursuant to 583.13 and the date of the certification, and, 8. One certificate can cover multiple parts and assemblies. Response. Your eight stated understandings are correct. With respect to the second, I note that while 583.10(a) does not specifically mention 'part number,' we assume that would be the customary way of identifying unique equipment. Question 4b. If the United States/Canada percentage of the value added is -0- percent, should we show the two largest 'Major Foreign Sources' which are over 15% on our certificate? This information does not seem to be required by 583.10(a). Response. As discussed in our answer to Question 2, suppliers are not required to provide the two largest 'Major Foreign Sources' of their equipment. Question 5. 583.13 This section requires us to certify the information provided on our certificate to be in accordance with DOT regulations. Please provide us with a copy of these DOT regulations or advise where we can secure a copy of these regulations so we can know the regulations to which we are subscribing. Response. The Department of Transportation (DOT) regulations concerning automobile parts content labeling are simply those set forth in 49 CFR Part 583. Question 6. 583.10(c)(1)-(2) We can issue our certificate for the calendar year from January 1 through December 31 of each year. Response. Section 583.10(c)(1) provides that, except as provided in (c)(2), the information provided in the certificate is to be for equipment expected to be supplied during the 12-month period beginning on the first July 1 after receipt of the request from the auto manufacturer or allied supplier. Paragraph (c)(2) provides that the 12-month period specified in (c)(1) 'may be varied in time and length by the manufacturer or allied supplier if it determines that the alteration is not likely to result in less accurate information being provided to consumers. Therefore, your certificate can only be issued for the calendar year if the auto manufacturer or allied supplier to which you supply equipment makes such a determination. I hope this information is helpful. If you have further questions, please feel free to contact Edward Glancy of my staff at this address or by telephone at (202) 366-2992. Sincerely, Philip R. Recht Chief Counsel; |
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ID: aiam3954OpenMr. H. Nakaya, Branch Manager, Mazda (North America), Inc., 24402 Sinacola Court, Farmington Hills, MI 48018; Mr. H. Nakaya Branch Manager Mazda (North America) Inc. 24402 Sinacola Court Farmington Hills MI 48018; Dear Mr. Nakaya: Please forgive our delay in responding to your letter of May 30, 1984 asking for interpretations of Standard No. 108 as it applies to center high-mounted stoplamps.; In your letter you stated that the preamble to the final rule discusse the definition of 'window opening' and concluded that the rear window opening shall be the perimeter of the rear glazing that is unobstructed and free of opaqueness. You have presented two rear window designs in which (1) ceramic opaque dots descend in increasing size to the bottom of the glazing and in which (2) shaded material becomes progressively darker as it descends, though the material is translucent, not opaque. You also show a design with an interior-mounted windshield wiper, including motor and cover, placed on the rear vertical centerline above the bottom of the glazing. In each instance you have asked at what point would the National Highway Traffic Safety Administration (NHTSA) consider an 'obstruction' exists for purposes of defining the bottom of the window.; The phrase 'window opening' does not appear in Standard No. 108. Th preamble discussion appears to be irrelevant with respect to the final rule, and was intended as a clarification of proposed location requirements which, in fact, were not adopted. The notice of proposed rulemaking of January 8, 1981, proposed a definition of 'daylight opening' as 'the maximum unobstructed opening through the glazing surface...,' relating to three alternative locations proposed for the lamp in which the term 'daylight opening' was used as a locational reference. For instance, in Alternative 1, proposed paragraph S4.3.1.9(a) would have placed 'the center of the lamp within 3 inches of the outside bottom edge of the rear window daylight opening.' When the final rule was adopted in October 1983, none of the three alternatives was judged acceptable and a requirement allowing more design freedom was adopted omitting all reference to 'daylight opening.' Paragraph S4.3.1.8 simply specified that 'no portion of the lens shall be higher than the top of the back window or lower than three inches below the bottom of the back window. The requirement was even further relaxed in the May 1984 response to petitions for reconsideration in which paragraph S4.3.1.8 was amended to allow mounting 'at any position on the centerline' (note, no limitation on upper mounting height relative to the rear window) and if 'mounted below the rear window, no portion of the lens shall be lower than 6 inches on convertibles, or 3 inches on other passenger cars.' The preamble also clarified that, if the lamp were mounted on the interior, photometric compliance would be judged with the glazing in place.; Thus, whether glazing is opaque or obstructed is not the question manufacturer must ask in determining the location of the lamp with respect to the lower edge of the window. If the lamp is mounted on the interior, it must meet photometric and visibility requirements with the glazing in place, taking into account any graduated dots on or opaqueness of that glazing, and any wiper motor. If the lamp is mounted on the outside, its upper permissible height is determined by the height of the car and not by the window. The question of opaqueness or obstruction is irrelevant to the lower permissible height of 3 inches below the window. The window is the perimeter of its glazing, and 3 inches is measured from the lower edge.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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.