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
| Interpretations | Date |
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ID: aiam2173OpenMr. Warren M. Heath, Commander, Enforcement Services Division, Department of California Highway Patrol, P.O. Box 898, Sacramento, CA, 95804; Mr. Warren M. Heath Commander Enforcement Services Division Department of California Highway Patrol P.O. Box 898 Sacramento CA 95804; Dear Mr. Heath: This is in response to your letter of December 8, 1975, asking fou questions, the answers to which would provide an interpretation of Standard No. 108 with respect to separation distance of a turn signal lamp from the nearest edge of a Type 2 headlamp.; SAE Standard J588d, *Turn Signal Lamps*, June 1966, incorporated b reference in Standard No. 108, requires in pertinent part that 'The optical axis (filament center) of the front turn signal lamp shall be at least 4 inches from the inside diameter of the retaining ring of the headlamp unit providing the lower beam . . . .' We agree with your opinion that the reference to filament center may have been added because of the difficulty of determining the location of the optical axis in certain instances. In the vast majority of cases, however the filament center is on the optical axis, and the addition of the provision assists in determining compliance with the requirement.; You have asked:>>> '1. Is the filament center always to be taken as the center of th optical axis?'<<<; The answer to this question is no. In some instances the filamen center will not be on the optical axis. When this is the case the standard is ambiguous as to whether distance is measured from the optical axis or the filament center. While we prefer the optical axis, under the present wording either must be viewed as legally supportable.>>>; '2. Is the center of the emitted light always to be taken as the cente of the optical axis?'<<<; The answer is yes.>>> '3. If the answers to the above two questions are no, does the vehicl manufacturer have the choice as to which method is most favorable to him?'<<<; Yes, because of the ambiguity the manufacturer may choose either th optical axis or filament center as the point of measurement.>>>; '4. What is the optical axis of a two- or three- compartment lamp?'<<< The optical axis of a multi-compartment lamp is the center of the ligh emitted by the array, treated as a single complex light source. The 'half-value' method you described in your letter is a valid method of finding the optical axis of a complex light source as well as that of a simple one.; Finally you have asked whether, if we agree with the need fo clarification, the letter can be considered a petition for rulemaking or whether a formal petition should be submitted.; We agree that clarification is needed and accordingly plan to issue notice of proposed rulemaking in the near future.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2489OpenMr. Salvatore Messina, The Govmark Organization, Inc., P.O. Box 807, Bellmore, NY, 11710; Mr. Salvatore Messina The Govmark Organization Inc. P.O. Box 807 Bellmore NY 11710; Dear Mr. Messina: This responds to your December 10, 1976, letter asking whether Standar No. 302, *Flammability of Interior Materials*, applies to the living area of motor homes and mobile homes.; The National Highway Traffic Safety Administration (NHTSA) no longe regulates mobile homes. The National Mobile Home Construction and Safety Standards Act of 1974 (42 U.S.C. 5401 et seq.) ('the Mobile Home Act') established within the Department of Housing and Urban Development a comprehensive program for the regulation of mobile homes. We have concluded that one result of that statute's enactment was the implied repeal of the NHTSA's authority with respect to mobile homes. Accordingly, we consider that the enactment had the effect of amending the Vehicle Safety Act's definition of 'motor vehicle' to exclude 'mobile homes' as the latter term is defined in the Mobile Home Act.; A motor home, on the other hand, is classified as a multipurpos passenger vehicle (or a bus if it is designed to carry more than 10 persons) and is subject to the requirements of Standard No. 302. The standard mandates that certain enumerated components located within the vehicle occupant compartment meet specified burn test requirements. The living area of a motor home constitutes part of the vehicle occupant compartment, and therefore, any component listed in S4.1 of the standard and situated within the living area must comply with the standard.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam5423OpenMr. Karl-Heinz Ziwica General Manager Environmental Engineering BMW of North America, Inc. BMW Plaza Montvale, NJ 07645-1866; Mr. Karl-Heinz Ziwica General Manager Environmental Engineering BMW of North America Inc. BMW Plaza Montvale NJ 07645-1866; "Dear Mr. Ziwica: This responds to your request that the Nationa Highway Traffic Safety Administration (NHTSA) determine that a proposed modification to a previously approved antitheft device on the BMW 7 car line constitutes a de minimis change to the device. The proposed modification is to be effective beginning with the 1995 Model Year (MY). As explained below, the agency concludes that the proposed change to the antitheft device is not a de minimis change. In a Federal Register notice dated October 9, 1986 (51 FR 3633), NHTSA determined that the antitheft device installed as standard equipment on the MY 1988 BMW 7 car line was likely to be as effective as parts marking. In assessing whether changes are de minimis, the agency has focused its inquiry on whether the changed device would continue to provide the same aspects of performance as did the device on which the exemption was based. An example of a de minimis change is the substitution of new components for old components, without changing the aspects of performance provided by the device. NHTSA has also determined that adding a new aspect of performance, making an exempted antitheft device even more effective, while leaving the original aspects undisturbed, is a de minimis change. The change from the original BMW MY 1988 antitheft device to the one proposed for the MY 1995 BMW 7 car line does not present a simple case of either substituting new components for old, without changing the aspects of performance provided, or enhancing the effectiveness of an existing device, by adding a new aspect. Instead, the change is more complex, involving not only the addition of a new aspect (monitoring glass breakage), but also the deletion of some original aspects (monitoring the radio and glove box). The agency is uncertain about the net effect of these changes and is therefore also uncertain whether the new modified device would be at least as effective as the original device. Monitoring glass breakage might decrease the likelihood that a would-be thief would ever enter a vehicle. On the other hand, adding this aspect of performance would not necessarily enhance effectiveness of the antitheft device. If a thief were to gain access to the passenger compartment with a slim-jim or other tool, without breaking the glass, no alarm would sound, making the inside compartment vulnerable to theft. Further, no alarm would sound if the thief then tampered with the radio or glove box, individually. NHTSA believes that the necessity for making judgments about the relative effectiveness of new and removed aspects of performance, and the complexity of the issues underlying those judgments, indicate that the changes are not de minimis. Indeed, these judgments are similar to the ones that the agency must make in considering a new petition for exemption. Accordingly, if BMW wishes the planned MY 1995 device to be the basis for a theft exemption, it must submit a petition with NHTSA pursuant to 49 CFR 543.9(c)(2). Please note that the petition for modification must provide the same information or the modified device as is required under 543.6 for a new device. This includes the statement in 543.6(a)(1) that the antitheft device will be installed as standard equipment on all cars in the line for which an exemption is sought. If you have any questions, please contact Barbara Gray or Rosalind Proctor on (202) 366-1740. Sincerely, Barry Felrice Associate Administrator for Rulemaking"; |
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ID: aiam1933OpenMr. Donald J. Gobeille, Jr., Product Safety Engineer, Volvo of America Corporation, Rockleigh, New Jersey 07647; Mr. Donald J. Gobeille Jr. Product Safety Engineer Volvo of America Corporation Rockleigh New Jersey 07647; Dear Mr. Gobeille: Please forgive the delay in responding to your letter of March 24 1975, requesting an interpretation of Federal Motor Vehicle Safety Standard No. 110, *Tire Selection and Rims--Passenger Cars*.; You have inquired whether the placard required by S4.3 of the standar may display information in addition to the items specified in S4.3(a) through (d). The NHTSA has no objection to such placarding, provided that the addition information is set apart from, not placed among, the required items.; Sincerely, James C. Schultz, Chief Counsel |
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ID: aiam0621OpenMr. Ronald B. Stewart, Manager of Product Engineering, Newell Companies, Freeport, IL, 61032; Mr. Ronald B. Stewart Manager of Product Engineering Newell Companies Freeport IL 61032; Dear Mr. Stewart: This is in reply to your letter of February 25, 1972, concerning Moto Vehicle Safety Standard No. 302. In your letter you ask whether the standard applies to drapery hardware and cords, plastic pulleys and carriers, and if so, whether burn rates for these components can be based on the 'Modern Plastics Encyclopedia,' which in turn is based on ASTM Test Method D635.; The standard lists the categories of interior components to which i applies. This list does not include drapery hardware, cords, plastic pulleys, or carriers, and we do not consider the standard to apply to those items.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1899OpenD. R. Bernard, Esq., Messrs. Bernard & Bernard, 4100 One Shell Plaza, Houston, TX 77002; D. R. Bernard Esq. Messrs. Bernard & Bernard 4100 One Shell Plaza Houston TX 77002; Dear Mr. Bernard: This is in reply to your letter of April 21, 1975, asking whethe certain 'safety lights' would violate the National Traffic and Motor Vehicle Safety Act of 1966.; As you describe it, your client's device flashes two lights at the rea of a motorcycle when brakes are applied. These lights are supplemental 'to the normal brake lights and turn signal lights.'; Paragraph S4.1.3 of 49 CFR 571.108, Motor Vehicle Safety Standard No 108, *Lamps, Reflective Devices, and Associated Equipment*, prohibits the installation of additional lighting equipment 'that impairs the effectiveness of lighting equipment' required by Standard No. 108.; Without knowing the size and photometric output of the lights, thei color and location, and whether they 'flash' in operation or are steady burning, we are unable to offer an opinion whether they are prohibited by paragraph S4.1.3. We would be happy to provide you with our views if you care to describe this system more fully.; Yours truly, Richard B. Dyson Assistant Chief Counsel |
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ID: aiam5073OpenMr. Tim Bohn Portec, Inc. Construction Equipment Division West 21st Street P.O. Box 20 Yankton, SD 57078; Mr. Tim Bohn Portec Inc. Construction Equipment Division West 21st Street P.O. Box 20 Yankton SD 57078; "Dear Mr. Bohn: This responds to your inquiry about whether portabl construction equipment that you manufacture would have to comply with the Federal Motor Vehicle Safety Standards, particularly those standards related to brakes. You explained that your construction equipment is transported over public roads, but only between job sites and from the factory. In a telephone conversation with Marvin Shaw of my staff, you further described your equipment as a portable conveyor belt that typically spends extended periods of time at a single construction site but is occasionally towed over the public roads to other construction sites. I am pleased to have this opportunity to explain our regulations to you. This agency interprets and enforces the National Traffic and Motor Vehicle Safety Act under which the Federal Motor Vehicle Safety Standards are promulgated. The Act defines the term 'motor vehicle' as follows: 'any vehicle driven or drawn by mechanical power manufactured primarily for use on the public streets, roads, and highways, except any vehicle operated exclusively on a rail or rails.' Whether the agency will consider a construction vehicle to be a motor vehicle depends on its use. It is the agency's position that this statutory definition does not encompass mobile construction equipment, such as cranes and scrapers, which use the highway only to move between job sites and which typically spend extended periods of time at a single job site. In such cases, the on-highway use of the vehicle is merely incidental and is not the primary purpose for which the vehicle was manufactured. In instances where vehicles, such as dump trucks, frequently use the highway going to and from job sites, and stay at a job site for only a limited time, such vehicles are considered motor vehicles for purposes of the Safety Act, since the on-highway use is more than 'incidental.' Based on the above considerations, it appears that your portable conveyer belt is not a 'motor vehicle' within the meaning of the Safety Act. Therefore, it would not be subject to our Federal Motor Vehicle Safety Standards. This conclusion is based on your statements that your equipment spends extended periods of time at a single construction site and only uses the public roads infrequently to move between job sites. Thus, the agency would consider the use of your portable conveyor belt on the public roads to be incidental and not its primary purpose. 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: aiam5589OpenMs. Jane L. Dawson Specifications Engineer Thomas Built Buses, Inc. Post Office Box 2450 1408 Courtesy Road High Point, NC 27261; Ms. Jane L. Dawson Specifications Engineer Thomas Built Buses Inc. Post Office Box 2450 1408 Courtesy Road High Point NC 27261; Dear Ms. Dawson: This responds to your letter to Walter Myers of thi office regarding the May 9, 1995, amendment of Federal Motor Vehicle Safety Standard (FMVSS) No. 217, Bus Window Retention and Release. I apologize for the delay in responding. For your future reference, Mr. Myers is no longer assigned to our school bus standards. You may address requests for interpretation directly to me. The May 9 amendment (60 FR 24562) to FMVSS No. 217 permitted, among other things, bus manufacturers to meet the additional emergency exit area (AEEA) requirements of S5.2 by permitting manufacturers to install two emergency exit windows as an alternative to an emergency exit door. You asked what the location requirements (fore and aft) are for the emergency windows that are used as the first additional emergency exit. FMVSS No. 217 contains no explicit fore and aft location requirements for the two additional emergency exit windows. However, the intent of the final rule was to substitute the location requirements of the side exit door when the windows are used to satisfy the requirement for the first additional emergency exit. This intention is reflected in the use of the conjunctive word 'or' in Tables 1 and 2 of the May 9, 1995, amendment. If a left side exit door would have been installed pursuant to S5.2.3.1(a)(2)(i), then S5.2.3.2(a)(2) requires that it be located as near as practicable to the midpoint of the passenger compartment. The same fore-aft location should be used for the windows. In cases where the fore-aft location is not specified, such as a right side exit door installed pursuant to S5.2.3.1(b)(2)(i), then the windows should be placed so as to provide bus passengers with maximum accessibility to an emergency exit, in accordance with what is reasonable and practicable. Also note the explicit location requirement in S5.2.3.2(c) that exit windows be evenly divided between the left and right sides of the bus. For example, if two exit windows are used instead of a left side exit door, they should be placed on opposite sides at the midpoint of the bus. I hope this information will be of assistance to you. Should you have any further questions or seek additional information, please feel free to contact Paul Atelsek at this address or by calling (202) 366-2992. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam0271OpenMr. Michael Grossman, Peugeot, Incorporated, 300 Fuller Road, Clifton, NJ 07015; Mr. Michael Grossman Peugeot Incorporated 300 Fuller Road Clifton NJ 07015; Dear Mr. Grossman: This is in response to your letter of December 15, 1970, in which yo asked whether it would be permissible to add the words 'and Canadian' to your certification label.; With reference to a telephone conversation between you and Mr. Dyson o this office, I understand that the Canadian authorities will accept the certification statement that we presently require as long as the expression 'U.S.' does not appear on the label. Since use of the 'U.S.' is optional with the manufacturer under 49 CFR S367.4(g)(3), this appears to solve your problem in this regard.; We are pleased to be of assistance. Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam4232OpenMr. Alvin A. Leach, Manager, Corporate Transportation Services, Carolina Power & Light Co., PO Box 1551, Raleigh, NC 27602; Mr. Alvin A. Leach Manager Corporate Transportation Services Carolina Power & Light Co. PO Box 1551 Raleigh NC 27602; Dear Mr. Leach: Thank you for your letter of September 5, 1986, to Administrator Stee concerning the safety belt installation requirements for heavy trucks. The Administrator has asked my office to respond since you asked for an interpretation of the requirements of Standard No. 208, *Occupant Crash Protection*. I hope the following discussion answers your questions.; You first asked whether lap/shoulder safety belts are required in truck with a gross vehicle weight rating greater than 10,000 pounds. S4.3 of the standard, a copy of which is enclosed, sets out the requirements for such trucks. S4.3 permits a manufacturer to install either a lap safety belt, referred to as a Type 1 belt in the standard, or a lap/shoulder belt, referred to as a Type 2 belt, in a heavy truck. At the present time, we do not have any plans to require lap/shoulder belts in heavy trucks. We are taking steps to improve the comfort and convenience of safety belt systems in heavy vehicles. As explained in the attached notice, the agency is currently considering several changes to the standard which would make it easier to use safety belts in heavy vehicles. We expect to issue a final rule on this subject later this year.; If you have any further questions, please let me know. Sincerely, Erika Z. Jones, 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.