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: nht92-3.37OpenDATE: September 29, 1992 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA TO: Mark V. Schwartz -- Account Executive, Entran Devices, Inc. TITLE: None ATTACHMT: Attached to letter dated 7/9/92 from Mark V. Schwartz to Paul Jackson Rice (OCC-7514) TEXT: This responds to your request for an interpretation of 49 CFR Part 572, Anthropomorphic Test Dummies. Specifically, you were interested in the provisions for the Hybrid III test dummy set forth in Subpart E of Part 572. You noted that S572.36(g) provides that the thorax and knee impactor accelerometers "shall have the dimensions and characteristics of Endevco Model 7231c or equivalent." You provided a sheet setting forth dimensional and electrical response information for an accelerometer model produced by your company, the Entran EGE-72C-750. You then asked if the Entran EGE-72C-750 was "equivalent" to the Endevco Model 7231c, within the meaning of S572.36(g). I am pleased to have this opportunity to explain our regulation for you. Part 572 sets forth specifications with which all test dummies must comply if those dummies are to be used in this agency's compliance testing. In NHTSA's compliance testing to date, we have used only the Endevco Model 7231c for the thorax and knee impactor accelerometers. This should not be misinterpreted as suggesting that this agency believes that only this particular make and model of accelerometer will perform acceptably in compliance testing. Instead, it means that the agency has found that the Endevco Model 7231c performs acceptably in the intended shock environment, in terms of frequency response characteristics, damping, linearity, transverse sensitivity, reliability, repeatability, durability, etc. The dictionary defines "equivalent" as "equal in value, measure, force, effect, significance, etc." As noted above, NHTSA has used only the Endevco Model 7231c for the thorax and knee impactor accelerometers in the compliance testing to date. Thus, the agency has not made any determination of which accelerometers are equivalent to the Endevco Model 7231c. Until such time as the agency makes a determination about equivalent accelerometers, the issue of equivalency of your EGE-72C-750 model and the specified accelerometer model is a matter to be worked out between your company and prospective users of your company's accelerometers. As long as you can satisfy prospective users about the equivalence of your company's accelerometers, NHTSA will not review the use of any particular accelerometers in certification testing, unless the test results indicate a problem or problems caused by those accelerometers. I hope this information is helpful. If you have any further questions; or need some additional information on this subject, please feel free to contact Steve Kratzke of my staff at this address or by telephone at (202) 366-2992. |
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ID: 17026.drnOpenMr. William Shima Dear Mr. Shima: This responds to your January 22, 1998, request for confirmation that this agency's February 7, 1984, interpretation that the Mercedes-Benz Unimog is not a motor vehicle has not changed. Without information about the Unimog as sold in 1998, I am unable to do so. As you may be aware, the National Highway Traffic Safety Administration (NHTSA) interprets and enforces the laws under which the Federal motor vehicle safety standards are promulgated. NHTSA's statute defines "motor vehicle" as follows:
Whether the agency considers any vehicle to be a motor vehicle depends on its use. Certain types of vehicles are not considered "motor vehicles." These include vehicles 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. Vehicles which frequently use the highway going to and from job sites, and stay at a job site for only a limited time, are "motor vehicles," since the on-highway use is more than "incidental." The February 1984 interpretation letter was based on the then-existing Unimog, fourteen years ago. NHTSA has no information about the features of the 1998 Unimog, or whether the Unimog has significantly changed since 1984. Therefore, if you wish NHTSA to reexamine whether the Unimog is a motor vehicle, please provide us with information about the Unimog's features, as it is sold in 1998. We would need information about the configuration of the 1998 Unimog, and its top speed. As stated in our February 1984 interpretation letter, we would need to know whether the Unimogs are still marketed principally through farm machinery and heavy equipment dealers, and whether the vehicle would have affixed in the cab a label stating that the Unimog is not manufactured for highway use. Please note also that any opinion NHTSA provides on the Unimog affects new Unimogs sold in the United States only. Transport Canada would determine whether Unimogs sold in Canada are considered motor vehicles. I hope this information is helpful. If you have any questions, please contact Dorothy Nakama of my staff at (202) 366-2992. Sincerely, |
1998 |
ID: 15454.ztvOpen Mr. David Hutton Dear Mr. Hutton: Thank you for your FAX of June 24, 1997, informing us of an error in the Code of Federal Regulations. I note that your original FAX that was not answered was dated April 22 and addressed to Richard Carter. Mr. Carter has retired from NHTSA and questions regarding the language of the Federal motor vehicle safety standards or interpretations of them should be addressed to the Chief Counsel. The FAX number of this office is 202-366-3820. Parargraph S7.1 of 49 CFR 571.105 Motor Vehicle Safety Standard No. 105, Hydraulic Brake Systems, as printed in the October 1, 1996 revision of Title 49 Code of Federal Regulations reads: "Each passenger car, multipurpose passenger vehicle, truck, and bus shall be equipped with a headlighting system designed to conform to the requirements of S7.3, S7.4, S7.5, or S7.6." This is incorrect and should be stricken. At one time, the paragraph was correctly S7.1 of 49 CFR 571.108 Motor Vehicle Safety Standard No. 108, Lamps, Reflective Devices and Associated Equipment. However, paragraph S7.1 of Standard No. 108 as it appears in the October 1, 1996 revision of Title 49 is correct as written. The correct language for S7.1 of Standard No. 105 is that appearing in the October 1, 1991 revision of Title 49. This reads: "S7.1 Brake warming. If the initial brake temperature for the first stop in a test procedure (other than S7.7 and S7.16) has not been reached, heat the brakes to the initial brake temperature by making not more than 10 snubs from not more than 40 to 10 mph, at a deceleration not greater than 10 fpsps." I enclose a copy as you requested. When we looked into this matter, we were surprised to find that the incorrect S7.1 appeared in the 1992, 1993, 1994, and 1995 CFR revisions as well as the 1996 one. We have informed the CFR of this error and the correct language is promised for the 1997 revision. This is the second time within a month that you have spotted errors in the CFR that have otherwise escaped detection, and we are very grateful for it. Sincerely, |
1997 |
ID: nht94-4.42OpenTYPE: INTERPRETATION-NHTSA DATE: October 1, 1994 EST FROM: Womack, John -- Acting Chief Counsel, NHTSA TO: Littler, C. N. -- Motor Coach Industries, Administrator Regulatory Affairs, Winnipeg, Manitoba, Canada TITLE: NONE ATTACHMT: Attached To 1/6/94 Letter From C. N. Littler To Mary Versailles TEXT: This responds to your letter concerning whether a New York State law addressing the in-use stopping ability of privately owned motor coaches is preempted by Federal law. I apologize for the delay in our response. The New York law states that a vehicle must be capable of stopping "at a rate of deceleration equivalent to a stop within 22.2 feet from a speed of 20 miles per hour." You believe that @103 (d) of the National Traffic and Motor Vehicle Safety Act ("Safety Act") preempts the New York law, sinc e the state law is not identical to Federal motor vehicle safety standard No. 121, Air Brake Systems. Please note that the Safety Act has been codified at 49 U.S.C. 30101 et seq. and that the citation for 103(d) is now 49 U.S.C. @ 30103. As explained below, Standard No. 121 currently does not have stopping distance requirements in effect; therefore, the New York law is not currently preempted by a Federal safety standard. Nevertheless, the agency has issued a proposal to reinstate stopp ing distance requirements in Standard No. 121. (58 FR 11003, February 23, 1993). If the agency issues a final rule to reinstate stopping distances, then any more stringent requirements in the New York law (addressing the same aspects of performance as Standard No. 121) would be preempted. Title 49 U.S.C. @ 30103 states: Whenever a Federal motor vehicle safety standard . . . is in effect, no State or political subdivision of a State shall have any authority either to establish, or to continue in effect, with respect to any motor vehicle or item of motor vehicle equipm ent any safety standard applicable to the same aspect of performance of such vehicle or item of equipment which is not identical to the Federal standard. 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. If you wish to contact someone in the Federal Highway Administratio n's Office of Chief Counsel concerning the motor carrier standards, please call Charles Medalen at (202) 366-1354. |
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ID: nht88-4.53OpenTYPE: INTERPRETATION-NHTSA DATE: 12/30/88 EST FROM: ERIKA Z. JONES -- NHTSA CHIEF COUNSEL TO: C. I. NIELSEN III -- VICE PRESIDENT/GENERAL SALES MANAGER, WESBAR CORPORATION TITLE: NONE ATTACHMT: MEMO DATED 11-11-88, TO ERIKA 2. JONES, FROM C.I. NIELSEN III -- WESBAR, OCC-2789. TEXT: This is in reply to your letter of November 11, 1988, asking for an interpretation of Motor Vehicle Safety Standard No. 108. Specifically, you find unclear the "minimum square inches required of a turn signal lens for a trailer/vehicle, 80" or more in o verall with, using a single compartment lamp assembly". As you stated, the applicable standard is SAE J588e Turn Signal Lamps, September 1970. This standard does not set minimum area requirements per se for turn signal lenses, but it does specify minimum requirements for "effective projected luminous areas" o f turn signal lamps. With respect to a single compartment turn signal lamp, section 3.2 of J588e requires this area, when measured on a plane at right angles to the axis of the lamp, to be at least 8 square inches for a rear lamp, and at least 3.5 squar e inches for a front lamp. As you are probably aware, on September 9 of this year the agency proposed adopting SAE J1395 APR85 Turn Signal Lamps for Use on Motor Vehicles 2032mm or More in Overall Width. Its section 5.3.2 requires "the functional lighted lens area of a single lam p" to be at least 75 square centimeters (12 square inches). The agency is currently reviewing the comments received on the proposal. I hope that this clarifies the matter for you. |
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ID: 3327oOpen Mr. C. I. Nielsen III Dear Mr. Nielsen: This is in reply to your letter of November ll, l988, asking for an interpretation of Motor Vehicle Safety Standard No. l08. Specifically, you find unclear the "minimum square inches required of a turn signal lens for a trailer/vehicle, 80" or more in overall with, using a single compartment lamp assembly". As you stated, the applicable standard is SAE J588e Turn Signal Lamps, September 1970. This standard does not set minimum area requirements per se for turn signal lenses, but it does specify minimum requirements for "effective projected luminous areas" of turn signal lamps. With respect to a single compartment turn signal lamp, section 3.2 of J588e requires this area, when measured on a plane at right angles to the axis of the lamp, to be at least 8 square inches for a rear lamp, and at least 3.5 square inches for a front lamp. As you are probably aware, on September 9 of this year the agency proposed adopting SAE J1395 APR85 Turn Signal Lamps for Use on Motor Vehicles 2032mm or More in Overall Width. Its section 5.3.2 requires "the functional lighted lens area of a single lamp" to be at least 75 square centimeters (12 square inches). The agency is currently reviewing the comments received on the proposal. I hope that this clarifies the matter for you. Sincerely,
Erika Z. Jones Chief Counsel ref:l08 d:l2/30/88 |
1988 |
ID: nht73-2.21OpenDATE: 04/07/73 FROM: AUTHOR UNAVAILABLE; David Schmeltzer; NHTSA TO: Arthur H. Davis TITLE: FMVSR INTERPRETATION TEXT: This is in reply to your letter which we received April 5, 1973, which asks if you, as a dealer of tires, may register all new and retreaded tires sold to first purchasers on a single form and send that form to a tire registry service. Under the Tire Identification and Record Keeping regulation (49 CFR Part 574) dealers selling cars to first purchasers must record the sale and forward the required information to the manufacturer or his designee. Therefore, you can only record all the tire sales from various manufacturers and retreaders on a registry service form if that registry service is the designee of all of the manufacturers and retreaders whose tires you sell. For your information we have enclosed a copy of the Tire Identification and Record Keeping regulation (Notice No. 5) and a copy of an interpretation of the regulation dealing with the question of manufacturers' designees (Notice No. 10). Thank you for your interest in auto safety. Sincerely, Enclosures Sir RE: D.O.T Registration I am in the wholesale tire business. It has come to my attention twice that a dealer may register all this not only mine but all this on one simple registration form. That being Axican Systems hire. Can a dealers register all new turn' and all retracks on the form that Axican Systems he use, mail it to Axican and be legally within the bainclouir of the federally law. Sincerely, (Illegible Word) -- RFD 2 Box 174A.,(Illegible Word). Mc 04401 |
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ID: nht79-2.13OpenDATE: 02/13/79 FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA TO: Nissan Motor Co., Ltd. TITLE: FMVSR INTERPRETATION TEXT: FEB 13 1979 NOA-30 Mr. Hisakazu Murakami Staff, Safety Nissan Motor Co., Ltd. P.O. Box 1606 560 Sylvan Avenue Englewood Cliffs, New Jersey 07632 Dear Mr. Murakami: This responds to your January 9, 1979, letter concerning a mistake on the certification labels of approximately 2000 Datsun trucks. You stated that the vehicles, although manufactured in 1979, were incorrectly dated on their certification labels as being manufactured in 1978. You propose to remedy the affected vehicles by crossing out the incorrect date and inserting the correct information. Your proposed correction is acceptable to the National Highway Traffic Safety-Administration. As long as all other information on the certification label is correct, your modification of existing certification labels will comply with the agency's regulations. Sincerely, Joseph J. Levin, Jr. Chief Counsel NOA-30 January 9, 1979 Mr. Roger S. Tilton Office of Chief Council National Highway Traffic Safety Administration 400 Seventh Street, S.W. Washington, D.C. 20590 Dear Mr. Tilton: This is to confirm our telephone conversation of January 9th regarding the following problem. We mistakenly attached the certification label (required by Part 567) on which "78" was printed in the space of year for FMVSS certification statement to the rear bodies of our DATSUN Pick-Up (620) manufactured in 1979. Approximately 2,000 vehicles are involved. The method of correction which we are now planning to do is to cross out the digits "78" and add the digits "79" directly below as follows: XX 79 During our conversation I requested your interpretation on whether our method of correction will be accepted by your office and your reply was yes. We will be able to submit the list of VIN of the vehicles (DATSUN Pick-Up) which are involved in the problem within the next couple of weeks. Very truly yours, NISSAN MOTOR CO.,LTD. Hisakazu Murakami Staff, Safety HM:mh |
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ID: nht95-3.39OpenTYPE: INTERPRETATION-NHTSA DATE: July 10, 1995 FROM: John Womack -- Acting Chief Counsel, NHTSA TO: Winston Sharples -- President, Cantab Motors, Ltd. TITLE: NONE TEXT: Dear Mr. Sharples We have received the application of Cantab Motors for temporary exemption from Motor Vehicle Safety Standards Nos. 208 and 214. The application meets our procedural requirements, and a Federal Register notice requesting comment is being prepared for pub lication. We shall inform you when the Administrator has reached a decision on this matter, which we estimate will be between the middle of September and the middle of October. Cantab's previous exemption from Standard No. 208 expired on May 1, 1993. Accordingly, Cantab may be in violation of 49 U.S.C. 30112(a) if it has manufactured for sale and sold vehicles manufactured after that date. Its application states that "[in] the preceding twelve months, Cantab has manufactured nine Morgans for sale in the United States." Within 30 days of your receipt of this letter, please furnish the total number of Morgans that Cantab has manufactured for sale after May 1, 1993, and sold in the United States, between May 1, 1993, and the date of your response. Cantab should be aware that any sales of nonconforming vehicles before a grant of its application may be in violation of 49 U.S.C. 30112(a). If Cantab determines that it has manufac tured and sold noncomplying vehicles, then it is required to notify and remedy the noncompliance according to statute. Alternatively, it may file an application for a determination pursuant to 49 CFR Part 556 that its noncompliance is inconsequential to safety. If this application is granted, Cantab would be excused from the statutory requirement to notify and remedy. As a final matter, the application indicates Cantab's belief that it would be exempt from the phase-in requirements of Standard No. 214 for 1995 since only .75 car would be subject to the requirement. Although .75 car is less than one vehicle, the agenc y rounds up from .50 vehicle in its calculations of compliance. For the same reason, the 1.87 vehicle estimated for 1996 compliance would be two vehicles, not one. The application is sufficient to cover both years. If you have any questions on this matter, you may discuss them with Taylor Vinson of this Office (202-366-5263). |
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ID: nht95-5.18OpenTYPE: INTERPRETATION-NHTSA DATE: July 10, 1995 FROM: John Womack -- Acting Chief Counsel, NHTSA TO: Winston Sharples -- President, Cantab Motors, Ltd. TITLE: NONE TEXT: Dear Mr. Sharples We have received the application of Cantab Motors for temporary exemption from Motor Vehicle Safety Standards Nos. 208 and 214. The application meets our procedural requirements, and a Federal Register notice requesting comment is being prepared for publication. We shall inform you when the Administrator has reached a decision on this matter, which we estimate will be between the middle of September and the middle of October. Cantab's previous exemption from Standard No. 208 expired on May 1, 1993. Accordingly, Cantab may be in violation of 49 U.S.C. 30112(a) if it has manufactured for sale and sold vehicles manufactured after that date. Its application states that "[in] the preceding twelve months, Cantab has manufactured nine Morgans for sale in the United States." Within 30 days of your receipt of this letter, please furnish the total number of Morgans that Cantab has manufactured for sale after May 1, 1993, and sold in the United States, between May 1, 1993, and the date of your response. Cantab should be aware that any sales of nonconforming vehicles before a grant of its application may be in violation of 49 U.S.C. 30112(a). If Cantab determines that it has manufactured and sold noncomplying vehicles, then it is required to notify and remedy the noncompliance according to statute. Alternatively, it may file an application for a determination pursuant to 49 CFR Part 556 that its noncompliance is inconsequential to safety. If this application is granted, Cantab would be excused from the statutory requirement to notify and remedy. As a final matter, the application indicates Cantab's belief that it would be exempt from the phase-in requirements of Standard No. 214 for 1995 since only .75 car would be subject to the requirement. Although .75 car is less than one vehicle, the agency rounds up from .50 vehicle in its calculations of compliance. For the same reason, the 1.87 vehicle estimated for 1996 compliance would be two vehicles, not one. The application is sufficient to cover both years. If you have any questions on this matter, you may discuss them with Taylor Vinson of this Office (202-366-5263). |
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.