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: aiam2815OpenColonel James C. Crawford, Chief, Minnesota State Patrol, Department of Public Safety, Saint Paul, MN 53155; Colonel James C. Crawford Chief Minnesota State Patrol Department of Public Safety Saint Paul MN 53155; Dear Col. Crawford: Jim Downey of our regional office has forwarded for reply your lette of May 3, 1978, in which you asked whether a single beam headlighting system is permissible on mopeds.; The answer is yes. The portion of SAE Standard J584 that you hav quoted only establishes an option to the specific requirements of J574. Table 1 of J584 permits motor driven cycles to be equipped with a single (upper) beam headlamp. We consider mopeds to be 'motor driven cycles' as defined by 49 CFR 571.3(b) and J584 as they are invariably powered by a motor developing less than 5 horsepower.; I hope this answers your question. Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam0379OpenGerhard P. Riechel, Esq., Volkswagen of America, Inc., Englewood Cliffs, NJ 07632; Gerhard P. Riechel Esq. Volkswagen of America Inc. Englewood Cliffs NJ 07632; Dear Mr. Riechel:#This is in replay to your letter of June 2 requestin confirmation of certain matters concerning compliance of the 1973 model Volkswagen Type I (Beetle) and Type II (Station Wagon) vehicles with Motor Vehicle Safety Standard No. 101.#We confirm that the arrangement, identification, and illumination of the heater and defroster controls as described at the meeting of May 25 between representatives of this agency and Volkswagen, and as presented in your letter of June 2, appear to meet the intent of Standard No. 101. Specifically, the requirement of paragraph S4.3 that control identification 'shall be illuminated whenever the headlamps are activated' does not necessarily require the installation of a separate light source to illuminate the identification of each control. Thus, if the ambient illumination emanating from the dash panel provides sufficient illumination to identify heater and defroster controls mounted on the drive shaft tunnel, then the illumination requirement would appear to be met. We agree that the use of contrasting lettering on the control knobs increases the likelihood that this method of compliance would meet the intent of Standard No. 101.#Sincerely, Robert L. Carter, Acting Associate Administrator, Motor Vehicle Programs; |
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ID: aiam0380OpenGerhard P. Riechel, Esq., Volkswagen of America, Inc., Englewood Cliffs, NJ 07632; Gerhard P. Riechel Esq. Volkswagen of America Inc. Englewood Cliffs NJ 07632; Dear Mr. Riechel:#This is in replay to your letter of June 2 requestin confirmation of certain matters concerning compliance of the 1973 model Volkswagen Type I (Beetle) and Type II (Station Wagon) vehicles with Motor Vehicle Safety Standard No. 101.#We confirm that the arrangement, identification, and illumination of the heater and defroster controls as described at the meeting of May 25 between representatives of this agency and Volkswagen, and as presented in your letter of June 2, appear to meet the intent of Standard No. 101. Specifically, the requirement of paragraph S4.3 that control identification 'shall be illuminated whenever the headlamps are activated' does not necessarily require the installation of a separate light source to illuminate the identification of each control. Thus, if the ambient illumination emanating from the dash panel provides sufficient illumination to identify heater and defroster controls mounted on the drive shaft tunnel, then the illumination requirement would appear to be met. We agree that the use of contrasting lettering on the control knobs increases the likelihood that this method of compliance would meet the intent of Standard No. 101.#Sincerely, Robert L. Carter, Acting Associate Administrator, Motor Vehicle Programs; |
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ID: aiam0543OpenMs. Reva B. Fuhrmann, Bookkeeper, Pioneer Machinery, Inc., 1725 Silverton Road, N.E., Salem, OR 97303; Ms. Reva B. Fuhrmann Bookkeeper Pioneer Machinery Inc. 1725 Silverton Road N.E. Salem OR 97303; Dear Ms. Fuhrmann: In your letter of September 15, 1972, you ask for clarification of th records that Pioneer Machinery, Inc., as a manufacturer and installer of truck hoists and racks, is required to keep.; There are several regulations issued by the National Highway Traffi Safety Administration that could apply to Pioneer. The first of these is 49 CFR Part 566, *Manufacturer Identification*. Under this regulation manufacturers of vehicles and equipment to which a Federal motor vehicle safety standard applies must file certain information with the NHTSA. Although Pioneer may not manufacture equipment subject to a standard, it could be a final-stage manufacturer, as defined by 49 CFR Part 568, *Vehicles Manufactured in Two or More Stages*, and subject to both these regulations. I enclose a copy of each. If Pioneer determines it is a 'final-stage manufacturer' then it would also be subject to the obligations of Part 568 (S 568.6) and the requirements of Part 567 (S 567.5) *Certification*, copy enclosed.; If Pioneer is a 'final-stage manufacturer,' it must file quarterl reports of production figures pursuant to 49 CFR Part 573, (S 573.5 (b)) *Defect Reports*. I have also enclosed a copy of this regulation for your review.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0551OpenMs. Reva B. Fuhrmann, Bookkeeper, Pioneer Machinery, Inc. 1725 Silverton Road, N.E., Salem, OR 97303; Ms. Reva B. Fuhrmann Bookkeeper Pioneer Machinery Inc. 1725 Silverton Road N.E. Salem OR 97303; Dear Ms. Fuhrmann: In your letter of September 15, 1972, you ask for clarification of th records that Pioneer Machinery, Inc., as a manufacturer and installer of truck hoists and racks, is required to keep.; There are several regulations issued by the National Highway Traffi Safety Administration that could apply to Pioneer. The first of these is 49 CFR Part 566, *Manufacturer Identification*. Under this regulation manufacturers of vehicles and equipment to which a Federal motor vehicle safety standard applies must file certain information with the NHTSA. Although Pioneer may not manufacture equipment subject to a standard, it could be a final-stage manufacturer, as defined by 49 CFR Part 568, *Vehicles Manufactured in Two or More Stages*, and subject to both these regulations. I enclose a copy of each. If Pioneer determines it is a 'final-stage manufacturer' then it would also be subject to the obligations of Part 568 (S 568.6) and the requirements of Part 567 (S 567.5) *Certification*, copy enclosed.; If Pioneer is a 'final-stage manufacturer,' it must file quarterl reports of production figures pursuant to 49 CFR Part 573, (S 573.5 (b)) *Defect Reports*. I have also enclosed a copy of this regulation for your review.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0545OpenMs. Reva B. Fuhrmann, Bookkeeper, Pioneer Machinery, Inc. 1725 Silverton Road, N.E., Salem, OR 97303; Ms. Reva B. Fuhrmann Bookkeeper Pioneer Machinery Inc. 1725 Silverton Road N.E. Salem OR 97303; Dear Ms. Fuhrmann: In your letter of September 15, 1972, you ask for clarification of th records that Pioneer Machinery, Inc., as a manufacturer and installer of truck hoists and racks, is required to keep.; There are several regulations issued by the National Highway Traffi Safety Administration that could apply to Pioneer. The first of these is 49 CFR Part 566, *Manufacturer Identification*. Under this regulation manufacturers of vehicles and equipment to which a Federal motor vehicle safety standard applies must file certain information with the NHTSA. Although Pioneer may not manufacture equipment subject to a standard, it could be a final-stage manufacturer, as defined by 49 CFR Part 568, *Vehicles Manufactured in Two or More Stages*, and subject to both these regulations. I enclose a copy of each. If Pioneer determines it is a 'final-stage manufacturer' then it would also be subject to the obligations of Part 568 (S 568.6) and the requirements of Part 567 (S 567.5) *Certification*, copy enclosed.; If Pioneer is a 'final-stage manufacturer,' it must file quarterl reports of production figures pursuant to 49 CFR Part 573, (S 573.5 (b)) *Defect Reports*. I have also enclosed a copy of this regulation for your review.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1806OpenMr. Tatsuo Kato,Staff, Safety,Nissan Motor Co., Ltd.,P.O. Box 1606,Englewood Cliffs, New Jersey 07632; Mr. Tatsuo Kato Staff Safety Nissan Motor Co. Ltd. P.O. Box 1606 Englewood Cliffs New Jersey 07632; Dear Mr. Kato:#This responds to your December 18, 1974, Questio whether the test procedure in S7.11.2.1 of Standard No. 105-75, *Hydraulic brake systems*, that specifies 'Accelerate immediately...After each stop' can be interpreted to permit a maximum rate of acceleration to the initial test speed of 60 mph. You also ask whether, in the case of a vehicle incapable of attaining 60 mph, the S5.1 requirement that it be tested 'at the highest speed attainable in the time or distance interval specified' can also be interpreted to permit a maximum rate of acceleration.#Both of these specifications permit acceleration at maximum speed. As in the case of any performance requirement, when a test procedure is not specified, a manufacturer must only 'exercise due care' to assure himself that each of his vehicles meets the requirement, by selecting a reasonable test procedure to demonstrate compliance. In fact the NHTSA has consistently started that, even when a test procedure is started, a manufacturer may use a different procedure, so long as it is calculated, in the exercise of due care, to demonstrate that the vehicle would comply if tested in accordance with the procedure.#Because the NHTSA has chosen not to specify an acceleration rate in S7.11.2.1 for fade tests, the manufacturer may reasonably choose the maximum or near maximum acceleration rate which ensures the greatest cooling effect in the brake assembly. This interpretation is also true for vehicles which are unable to attain 60 mph and must therefore reach their 'highest speed' under S5.1 prior to braking.#Therefore, in both cases cited, you may interpret the procedures to permit acceleration at 'maximum rate' as specified in S7.11.3.1.#Yours truly,Richard B. Dyson,Acting Chief Counsel; |
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ID: aiam3143OpenMr. M. Ogata, Branch Manager, Toyo Kogyo U.S.A., 23777 Greenfield Road, Suite 462, Southfield, Michigan 48075; Mr. M. Ogata Branch Manager Toyo Kogyo U.S.A. 23777 Greenfield Road Suite 462 Southfield Michigan 48075; Dear Mr. Ogata: This letter is in response to your October 19, 1979, request for an interpretation of the requirements of Federal Motor Vehicle Safety Standard No. 110 and 49 CFR Part 575. Specifically, you inquired if it is permissible for Mazda to place information concerning the 185SR13 tire size on the tire placard, as required by section 4.3(d) of Standard No. 110, and in the consumer information booklet, as required by 49 CFR S 575.102(c)(2), for vehicles which may have 185HR13 tires installed by dealers at a customer's request. This would be permissible.; A 185SR13 tire and a 185HR13 tire are the same size and have the sam load-carrying capacity. The 'S' and 'H' only denote different high-speed capabilities for what are, otherwise, identical tires.; This agency requires the manufacturer to list recommended tire sizes o the tire placard and in the consumer information booklet for two reasons. First, the information is required to ensure that any replacement tires installed on the vehicle will be a proper size for the rims mounted on that vehicle. Second, the information helps to ensure that the tires installed on the vehicle will have sufficient load-carrying capacity to be used safely on that particular vehicle. Neither of these safety concerns would be frustrated by a manufacturer putting information on the placard and in the booklet about a tire with a lower speed rating. Therefore, your proposed plan would not violate any of our consumer information regulations.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1246OpenMr. Pundalik K. Kamath, P.O. Box 560, Oshkosh, WI 45901; Mr. Pundalik K. Kamath P.O. Box 560 Oshkosh WI 45901; Dear Mr. Kamath: This is in reply to your letters of August 7 and August 23, 1973 concerning the conformity to Standard No. 121 of certain features in air brake systems submitted to you by suppliers.; Your first question is whether the volume of a supply reservoir tha lacks a check valve is to be included in arriving at the required reservoir volume of 12 times the full-travel service brake chamber volume. Our reply is that S5.1.2.1 includes the volume of all service and supply reservoirs, regardless of valving, and that the volume of the supply reservoir in question would therefore be included in the combined reservoir volume.; You next ask whether a system that has no isolated emergency reservoi can rely on its service reservoirs to provide air for the two emergency stops proposed as S5.7.3 by Docket No. 73-13, Notice 1 (38 F.R. 14963). Under this proposal, the stops would have to be accomplished with a single failure of a part (other than a common valve, manifold, brake fluid housing or brake chamber housing) designed to contain compressed air or brake fluid. If the system is designed so that no single failure, other than a valve, manifold, or housing failure, will cause a loss of air in both tanks, it would seem to be capable of meeting the proposed requirement even though it does not have an isolated emergency reservoir. However, if a single failure in a brake line would deplete the air in both service reservoirs, the system would be unable to meet S5.7.3 unless an emergency isolated reservoir were provided.; In answer to your last question, the emergency stops proposed in S5.7. would be conducted from an initial pressure in excess of the compressor cut-in pressure. The reservoirs would not be depleted by prior stops.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3145OpenMr. William E. Barry, Chief, Cleveland Fire Department, 1645 Superior Avenue, Cleveland, OH 44114; Mr. William E. Barry Chief Cleveland Fire Department 1645 Superior Avenue Cleveland OH 44114; Dear Mr. Barry: This is in response to your letter of July 2, 1979, in which you aske for copies of any current or recommended standards concerning the use of plastic auxiliary fuel tanks. May I apologize for the delay in this response.; I have enclosed a copy of a letter, which was sent to a company whic planned to manufacture auxiliary fuel tanks and to do some installation, that details the ways in which the safety standards and statutes administered by this agency apply to the manufacture of auxiliary fuel tanks of all types. In addition, I have enclosed a copy of an advance notice of proposed rulemaking that this agency issued with respect to a proposal to issue performance standards applicable to nonmetallic fuel tanks.; At this time the agency does not have any standards applicable to th use of auxiliary fuel tanks. However, several months ago we issued a consumer advisory warning against carrying fuel in portable containers in the trunks of cars. We consider this advisory applicable not only to portable containers but to any fuel container mounted in an area not normally consigned to such use. I have enclosed a copy of this advisory for your information. In addition, we are planning to issue a press release in the near future specifically addressed to the dangers of using auxiliary fuel tanks.; If you have any reports, case histories, photographs, or other materia concerning any fires or fire problems caused by the use of auxiliary fuel tanks we would be most grateful if you would allow us to examine them. Your concern in this area of vehicle safety is deeply appreciated.; Sincerely, Frank Berndt, 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.