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: aiam0804OpenMr. Charles R. Matthews, Sr. Safety Engineer, Oshkosh Truck Corporation, P. O. Box 560, Oshkosh, Wisconsin 54091; Mr. Charles R. Matthews Sr. Safety Engineer Oshkosh Truck Corporation P. O. Box 560 Oshkosh Wisconsin 54091; Dear Mr. Matthews: This is in response to your letter of July 5, 1972, requesting a opinion as to how manufacturers may take into account a vehicle's speed capability in establishing GAWR.; The Certification regulations do not specify particular speed criteri for establishing weight ratings. As a minimum, however, we believe the speed chosen should reflect the maximum speed at which it is reasonable to expect the vehicle to be driven. In the case where a vehicle is subject to some low-speed uses, such as seasonal sue as a snow plow, we believe the figure on the certification label should be based on that use of the vehicle in which its expected speed is greatest. The regulations do not provide for variable ratings based on speed.; Finally, you ask whether cautionary labels dealing with GAWR and GVW figures may be installed in the cab. The NHTSA does not object to the use of such labels. They may be used, as appropriate, to indicate permissible use of higher loads in low-speed applications.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0807OpenMr. Charles R. Matthews, Sr. Safety Engineer, Oshkosh Truck Corporation, P. O. Box 560, Oshkosh, Wisconsin 54091; Mr. Charles R. Matthews Sr. Safety Engineer Oshkosh Truck Corporation P. O. Box 560 Oshkosh Wisconsin 54091; Dear Mr. Matthews: This is in response to your letter of July 5, 1972, requesting a opinion as to how manufacturers may take into account a vehicle's speed capability in establishing GAWR.; The Certification regulations do not specify particular speed criteri for establishing weight ratings. As a minimum, however, we believe the speed chosen should reflect the maximum speed at which it is reasonable to expect the vehicle to be driven. In the case where a vehicle is subject to some low-speed uses, such as seasonal sue as a snow plow, we believe the figure on the certification label should be based on that use of the vehicle in which its expected speed is greatest. The regulations do not provide for variable ratings based on speed.; Finally, you ask whether cautionary labels dealing with GAWR and GVW figures may be installed in the cab. The NHTSA does not object to the use of such labels. They may be used, as appropriate, to indicate permissible use of higher loads in low-speed applications.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1939OpenMr. Bernard R. Weber, Executive Vice President, Wesbar Corporation, P. O. Box 577, West Bend, WI 53095; Mr. Bernard R. Weber Executive Vice President Wesbar Corporation P. O. Box 577 West Bend WI 53095; Dear Mr. Weber: This is in reply to your letter of May 13, 1975, requesting a interpretation of paragraph S4.4.1 of Motor Vehicle Safety Standard No. 108 as it applies to a described lamp design.; In pertinent part, S4.4.1 states that 'no clearance lamp may b combined optically with any taillamp.' The lamp design that interests you has separate compartments for the taillamp and for the clearance lamp. You are concerned that at a distance it will be difficult to distinguish the two lamps, and you feel that this violates the spirit of S4.4.1.; We have no objection to the design of this lamp. Since the clearanc lamp and taillamp are in separate compartments and not optically combined, and since Standard No. 108 does not specify a minimum separation distance between the two lamps, the lamp design foes not violate S4.4.1.; Sincerely, James C. Schultz, Chief Counsel |
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ID: aiam2288OpenMr. Thomas Kupensky, 4136 Loganway, Youngstown, OH, 44505; Mr. Thomas Kupensky 4136 Loganway Youngstown OH 44505; Dear Mr. Kupensky: This is in reply to your letter of April 8 to the Department o Transportation, regarding your CAUTION and THANK YOU signals which would flash simultaneously with the turn signal lamps on trucks and trailers.; Since such signs, flashing CAUTION or THANK YOU when actually 'turn' i intended, may be confusing in many circumstances, they would be prohibited by paragraph S4.1.3 of Federal Motor Vehicle Safety Standard (FMVSS) No. 108, 'Lamps, Reflective Devices and Associated Equipment,' (copy enclosed), because they would appear to impair the effectiveness of the turn signals. If these signs were manually operated by the driver, separately from the turn signals, at appropriate times, whether flashing or steady burning, they would be considered auxiliary devices which did not impair the effectiveness of the turn signals, and would be permitted by Standard No. 108. In this situation, however, they would be subject to the motor vehicle regulation of the individual States.; Sincerely, E. T. Driver, Director, Office of Crash Avoidance, Moto Vehicle Programs; |
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ID: aiam1693OpenMr. W.A. Hertel,Corporate Staff Engineer,Parker-Hannifin Corporation,17325 Euclid Avenue,Cleveland, Ohio 44112; Mr. W.A. Hertel Corporate Staff Engineer Parker-Hannifin Corporation 17325 Euclid Avenue Cleveland Ohio 44112; Dear Mr. Hertel:#Please forgive the delay in responding to your lette of October 28, 1974, enclosing a sample air brake hose assembly and requesting approval of Parker-Hannifin's banding technique to meet the requirements of Federal Motor Vehicle Safety Standard No. 106-74, *Brake Hoses*, for labeling brake hose assemblies.#The NHTSA interprets a band as a label which encircles the hose completely and attaches to itself. To constitute labeling at all, of course, the band must be affixed to the hose in such a manner that i cannot easily be removed.From this discussion, you should be able to determine the compliance of your labeling method with the standard. The NHTSA does not approve specific designs in advance because the material, installation method, and underlying material can significantly affect the quality of specific design.#Yours truly,Richard B. Dyson,Acting Chief Counsel; |
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ID: aiam1433OpenMessrs. Nebe and Gartner, Continental Gummi-Werke, Aktiengeselischaft, Postfach 169, 3 Hannover, Germany; Messrs. Nebe and Gartner Continental Gummi-Werke Aktiengeselischaft Postfach 169 3 Hannover Germany; Gentlemen: This is in reply to your letter of January 29, 1974, raising certai questions about the effective date (September 1, 1974) of the Uniform Tire Quality Grading regulation. You pose two hypothetical questions, asking whether tires must be quality graded when they are to be placed on vehicles manufactured or imported after September 1, 1974. In the first situation, the tires are manufactured in July 1974, while the vehicle is manufactured in August 1974 and imported in October 1974. In the second, the tires are manufactured in August 1974, the vehicle is manufactured in September 1974 and imported in November 1974.; The Quality Grading regulation applies to tires rather than vehicles Its effective date of September 1, 1974, means that all passenger-car tires manufactured on or after that date must be graded in accordance with the regulation. There is no requirement, however, that vehicle manufacturers must use tires manufactured after that date. In each hypothetical question you present, the tires are manufactured before September 1, 1974, and therefore are not required to be graded. The date of manufacture or importation of the vehicle is immaterial.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1430OpenMessrs. Nebe and Gartner, Continental Gummi-Werke, Aktiengeselischaft, Postfach 169, 3 Hannover, Germany; Messrs. Nebe and Gartner Continental Gummi-Werke Aktiengeselischaft Postfach 169 3 Hannover Germany; Gentlemen: This is in reply to your letter of January 29, 1974, raising certai questions about the effective date (September 1, 1974) of the Uniform Tire Quality Grading regulation. You pose two hypothetical questions, asking whether tires must be quality graded when they are to be placed on vehicles manufactured or imported after September 1, 1974. In the first situation, the tires are manufactured in July 1974, while the vehicle is manufactured in August 1974 and imported in October 1974. In the second, the tires are manufactured in August 1974, the vehicle is manufactured in September 1974 and imported in November 1974.; The Quality Grading regulation applies to tires rather than vehicles Its effective date of September 1, 1974, means that all passenger-car tires manufactured on or after that date must be graded in accordance with the regulation. There is no requirement, however, that vehicle manufacturers must use tires manufactured after that date. In each hypothetical question you present, the tires are manufactured before September 1, 1974, and therefore are not required to be graded. The date of manufacture or importation of the vehicle is immaterial.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5337OpenThe Honorable Doug Bereuter U.S. House of Representatives Washington, DC 20515-2701; The Honorable Doug Bereuter U.S. House of Representatives Washington DC 20515-2701; Dear Mr. Bereuter: Thank you for your letter concerning a rulemakin related to compressed natural gas (CNG) vehicle fuel systems and fuel containers. You express concern about the time it is taking to complete the rulemaking. I fully understand your concern over this matter and want to assure you that the agency is working diligently to reach a final decision. The supplemental notice of proposed rulemaking we issued in December 1993 was an essential step toward permitting the use of CNG containers that employ new technologies. We have now reviewed the comments received on this notice and are preparing the final rule. As agency representatives explained when they met with you in December 1993, the final rule will be reviewed by the Office of the Secretary and the Office of Management and Budget. I hope this information is helpful and appreciate your patience in this matter. Sincerely, Christopher A. Hart Acting Administrator; |
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ID: aiam2466OpenMr. William G. Mathews, III, Vice President, Universal Imports, 14622 Southlawn Lane, Rockville, Maryland 20850; Mr. William G. Mathews III Vice President Universal Imports 14622 Southlawn Lane Rockville Maryland 20850; Dear Mr. Mathews: #This is in reply to your November 5, 1976, lette concerning antique tires. You have asked whether it is permissible to import 6.70 x 15 tires, an original equipment size on several classic Mercedes-Benz, that are not marked in accordance with Federal Motor Vehicle Safety Standard No. 109, *New Pneumatic Tires*. #Standard No. 109 applies to 'new pneumatic tires for use on passenger cars manufactured after 1948' (S2). The 6.70 x 15 tire size designation appears in Table I-A of Appendix A of the standard. While this tire may have been original equipment on several classic cars, it is also for use on passenger cars manufactured since 1948. As such, it is subject to all the requirements of Standard No. 109. Therefore, a 6.70 x 15 tire that is not marked according to the standard may not be imported into the United States. #Sincerely, Frank A. Berndt,Acting Chief Counsel; |
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ID: aiam1016OpenMr. J. C. Eckhold, Director, Automotive Safety Office, Ford Motor Company, The American Road, Dearborn, MI 48121; Mr. J. C. Eckhold Director Automotive Safety Office Ford Motor Company The American Road Dearborn MI 48121; Dear Mr. Eckhold: This is in reply to your letter of February 16, 1973, concerning th safety standard applicable to the sling for the upper torso belt used in Ford's 1974 model restraint system.; The schematic drawing attached to your letter shows that the slin attaches to the roof rail and serves the function of an upper torso belt anchorage. We agree with you that the sling is subject to the requirements of Standard No. 210 and not to the requirements of Standard No. 209. Although the sling is made of fabric webbing, its function is that of an anchorage and it is therefore subject to the anchorage standard.; 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.