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: aiam3061OpenHonorable Mark Marks, 108 Federal Court House, Erie, Pennsylvania 16501; Honorable Mark Marks 108 Federal Court House Erie Pennsylvania 16501; In response to the request of Ms. Chris Anderson of your office, I hav enclosed a copy of a letter which I recently wrote detailing the National Highway Traffic Safety Administration (NHTSA) regulations pertinent to the manufacture of trailers. Please note the reference on page 2 of the letter concerning the 'Manufacturer Identification' requirements. These requirements are independent of those pertinent to the Vehicle Identification Numbers.; Under current regulations (49 CFR Part 571.115), manufacturers o trailers are not subject to the Vehicle Identification Number requirements. However, pursuant to recent amendments (see enclosed copy), a manufacturer of trailers will be required to affix a Vehicle Identification Number to every Trailer manufactured on or after September 1, 1980. Although, the Vehicle Identification Number will not have to be affixed until this date, certain reports will be required in advance. Any trailer manufacturer who begins production before September 1, 1979, must report to NHTSA by that date the characters that he will include in his Vehicle Identification Numbers to uniquely identify himself, the make and the type of vehicle he produces. A manufacturer beginning production after September 1, 1979, must submit this information at least 60 days before he begins affixing the Vehicle Identification Numbers to vehicles.; I hope that this information will be helpful to you and you constituent. I will be happy to answer any further questions that you may have.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1036OpenMr. Sanford Davis, Corporate Flammability Coordinator, BASF Wyandotte Corporation, Wyandotte, MI, 48192; Mr. Sanford Davis Corporate Flammability Coordinator BASF Wyandotte Corporation Wyandotte MI 48192; Dear Mr. Davis: This is in reply to your letter of February 20, 1973, asking for a interpretation of the self-extinguishing test in the burn- rate requirement of Paragraph S4.3 of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials'. You ask whether both the 60- second as well as the 2-inch criterion must be satisfied in order to meet this self-extinguishing test. The answer to your question is yes. Both criteria must be met before any material shall be considered to have satisfied the burn-rate requirement.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1120OpenMr. W. H. Blaine, Manager, Southern California Edison Company, Automotive; Mr. W. H. Blaine Manager Southern California Edison Company Automotive; Dear Mr. Blaine: This is in response to your letter of April 13, 1973, in which you as whether the installation of a truck body or derrick on a new chassis-cab by your company for its own use makes it a final-stage manufacturer subject to the identification and certification provisions implementing the Highway Traffic and Motor Vehicle Safety Act, Public Law 89- 563.; The answer to your question is yes. The completion of a motor vehicl by a manufacturer for its own use does not relieve it of responsibility for certification.; As a final-stage manufacturer, you are required to submit th information specified in 49 CFR Part 566, Manufacturer Identification. I am enclosing a copy of Part 566 for your information. No specific format is required, and a letter report will suffice.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1121OpenMr. W. H. Blaine, Manager, Southern California Edison Company, Automotive; Mr. W. H. Blaine Manager Southern California Edison Company Automotive; Dear Mr. Blaine: This is in response to your letter of April 13, 1973, in which you as whether the installation of a truck body or derrick on a new chassis-cab by your company for its own use makes it a final-stage manufacturer subject to the identification and certification provisions implementing the Highway Traffic and Motor Vehicle Safety Act, Public Law 89- 563.; The answer to your question is yes. The completion of a motor vehicl by a manufacturer for its own use does not relieve it of responsibility for certification.; As a final-stage manufacturer, you are required to submit th information specified in 49 CFR Part 566, Manufacturer Identification. I am enclosing a copy of Part 566 for your information. No specific format is required, and a letter report will suffice.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2737OpenMr. Joe Wall, Assistant Director, Vehicle Inspection Division, Oklahoma Department of Public Safety, 3600 North Eastern, P.O. Box 11415, Oklahoma City, OK 73111; Mr. Joe Wall Assistant Director Vehicle Inspection Division Oklahoma Department of Public Safety 3600 North Eastern P.O. Box 11415 Oklahoma City OK 73111; Dear Mr. Wall: This responds to your letter of December 9, 1977, asking whether th recent amendment of Safety Standard No. 205, *Glazing Materials*, permits the use of plastic glazing in school buses.; The answer to your question is yes. Safety Standard No. 205, as amende December 5, 1977 (42 FR 61465), allows the use of rigid plastic glazing in doors and windows of all buses, including school buses. Please note, however, that plastics cannot be used for bus windshields or in doors or windows to the immediate right or left of the driver.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam1658OpenMr. P. K. Kamath, Oshkosh, P.O. Box 2566, Oshkosh, WI 45901; Mr. P. K. Kamath Oshkosh P.O. Box 2566 Oshkosh WI 45901; Dear Mr. Kamath: This responds to your October 8, 1974, question whether a front axl automatic pressure limiting valve may be removed during the burnish procedure to permit effective burnish of the front brakes.; The answer to your question appears in Notice 6 to Docket 74-10 i response to a similar inquiry from International Harvester. A copy of that notice is enclosed for your information. It amends S6.1.8.1 to require that any automatic pressure limiting valve be in use except in the case where the temperature of the hottest brake on a rear axle exceeds the temperature of the hottest brake on a front axle by more than 125 degrees F. A bypassed valve is reconnected if the temperature of the hottest brake on a front axle exceeds the temperature of the hottest brake on a rear axle by 100 degrees F.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam3005OpenMr. D. L. Haines, BFGoodrich Company, Dept. 7089, Bldg. 24C, 500 South Main Street, Akron, OH 44318; Mr. D. L. Haines BFGoodrich Company Dept. 7089 Bldg. 24C 500 South Main Street Akron OH 44318; Dear Mr. Haines: This responds to a January 15, 1979, request from Mr. A. J. Burt t permit adjustment of foundation brakes during the burnish procedures in S6.1.8 and S6.2.6 of Standard No. 121, *Air Brake Systems*, for any reason. At present, such adjustments can only be made to control brake temperature, as stated in our January 24, 1979, letter to Mr. Burt.; The National Highway Traffic Safety Administration is unaware of reason other than control of brake temperature which would justify adjustments during burnish. Accordingly, we decline to grant your request. The NHTSA would, of course, be willing to consider any data or other information you have which would indicate that the present interpretation of burnish procedures may be too narrow in this respect.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2095OpenMr. James E. Harris, President, Willamette, Wheel Inc., 1235 Se. E. Grand, Portland, OR 97214; Mr. James E. Harris President Willamette Wheel Inc. 1235 Se. E. Grand Portland OR 97214; Dear Mr. Harris: This is in response to your letter of September 22, 1975, askin whether you are required to have a 'manufacturers number' as a result of modification work you perform on Datsun pickups.; It appears from your letter that you are a vehicle alterer as define in 49 CFR 567.7 (copy enclosed). As an alterer, you are not necessarily a manufacturer and are not required to file the identifying information required by 49 CFR Part 566 (copy enclosed). However, as an alterer, you must affix a label to the vehicle stating that as altered, the vehicle conforms to applicable Federal motor vehicle safety standards. The label described in your letter does not meet the requirements of 49 CFR 567.7.; If you have any further questions, please let us know. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1557OpenMr. P.K. Kamath, Senior Safety Engineer, Oshkosh Truck Corporation, P.O. Box 2566, Oshkosh, WI 54901; Mr. P.K. Kamath Senior Safety Engineer Oshkosh Truck Corporation P.O. Box 2566 Oshkosh WI 54901; Dear Mr. Kamath:#This is in reply to your letter of July 9, 1974 asking whether Standard No. 101 requires identification and illumination of an emergency engine stop control, in addition to the engine stop control intended for normal use.#The 'engine stop' control referred to in Standard No. 101 means any control used to stop the engine, and would include the emergency control. If it is important for the normal control to be identified and illuminated, it is all the more important that a control intended for emergency use meet the requirements of the standard. Identification such as 'emergency engine stop' would be acceptable under Standard No. 101. Illumination, of course, must meet the requirements of the standard, but since you have not described the emergency system or its location we cannot offer a more precise comment.#Yours truly, Richard B. Dyson, Acting Chief Counsel; |
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ID: aiam1395OpenMr. W. G. Milby, Project Engineer, Blue Bird Body Company, P.O. Box 937, Fort Valley, GA, 31030; Mr. W. G. Milby Project Engineer Blue Bird Body Company P.O. Box 937 Fort Valley GA 31030; Dear Mr. Milby: This is in reply to your letter of January 15, 1974, asking whether school bus rear lighting system is permissible that activates the back-up lamps and flashes four red stop lamps when the gearshift is in reverse.; The system of supplemental school bus warning lamps you describe is on that is not specified by Standard No. 108. Although S4.6(b) states that 'All . . . lamps [other than those specified in S4.6(a)] shall be steady burning. . . ,' we interpret this requirement as covering only the systems specified by the standard. Therefore there is no Federal prohibition against your installation of such a system. However, the system would be subject to regulation by the individual States, some of which may have restrictions on the use of flashing lights.; Yours truly, Richard B. Dyson, Assistant 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.