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 |
|---|---|
ID: 9838Open The Honorable Doug Bereuter Dear Mr. Bereuter: Thank you for your letter concerning a rulemaking 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 ref:303 d:4/12/93 |
1993 |
ID: nht89-3.51OpenTYPE: INTERPRETATION-NHTSA DATE: 12/08/89 FROM: HOWARD KOSSOVER -- CMI TRAILER DIVISION TO: TAYLOR VINSON -- LEGAL COUNCIL - FMVSS - 108 N.H.T.S.A. TITLE: NONE ATTACHMT: ATTACHED TO LETTER DATED 01/09/90 FROM STEPHEN P. WOOD -- NHTSA TO HOWARD KOSSOVER -- CMI TRAILER DIVISION; REDBOOK A35; STANDARD 108 TEXT: Dear Mr. Vinson: I am writing to you in regard to the FMVSS Lighting Code. We are in process of building a semi-trailer for highway use and would like to know if we are in violation of the code with respect to the location of the rear stop, turn & tail lights. This unit is a Rear Discharge trailer designed to haul hot mix asphalt. As the asphalt is discharged out it tends to build up on the rear components. We have recessed the lights approximately 27" from the rear so they will stay clean. I have enclosed some pictures. Does this violate the lighting code? Please let me know. Thank you, PHOTOGRAPHS OMITTED |
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ID: nht93-1.23OpenDATE: 01/29/93 FROM: BEVERLEY SILVER-CORBER TO: U.S. DEPARTMENT OF TRANSPORTATION -- NHTSA TITLE: NONE ATTACHMT: ATTACHED TO LETTER DATED 2-19-93 FROM JOHN WOMACK TO BEVERLEY SILVER-CORBER (A40; PART 591) TEXT: I am the owner of a 1992 Accord purchased in Canada. My husband has been accepted into Graduate Studies at Temple University in Philadelphia for the fall term. We understand from Honda (a copy of their letter to us is enclosed) that our vehicle meets EPA standards but does not have a passive restraint system and cannot be modified. We were planning to bring this car with us for our own personal use during the two years my husband will be studying. Please advise whether we would qualify for an exemption and be allowed to import the car for the two years of study and under what conditions, if any. Thanking you in advance for a prompt response to our enquiry, ATTACHMENT LETTER DATED 1-13-92 FROM VERNELL WOODS (HONDA) TO B. CORBER (TEXT OMITTED) |
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ID: nht76-2.4OpenDATE: 02/25/76 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: General Motors Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of February 10, 1976, concerning the definition of "daylight opening" (DLO) as specified in Motor Vehicle Safety Standard No. 219, Windshield Zone Intrusion, 49 CFR 571.219, and concerning the procedure used by General Motors to determine DLO. Your letter states that General Motors is concerned about the definition of DLO as stated in Standard No. 219, and "believes that the wording is not easily understood." The definition of DLO as stated in the Standard is based upon the definition found in paragraph 2.3.12 of Section E, Ground Vehicle Practice, SAE Areospace Automotive Drawing Standards, September, 1963. The SAE definition was slightly modified to reflect the particular characteristics of Standard No. 219. The last phrase of the SAE definition was changed to read "as measured parallel to the outer surface of the glazing material," because there was concern that there might be some confusion if the definition directed measurement by means of a "vertical projection". Your letter describes General Motors' procedure for obtaining DLO, and asks if this procedure is consistent with the definition of DLO as specified in Standard No. 219. The answer to your question is yes. Your illustration (Figure 1) shows that you are measuring "parallel to the outer surface of the glazing material". Your Figure 1 is a simplified illustration, of course, since nearly all windshields are curved. Please contact us if we can be of any further assistance. |
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ID: nht74-3.23OpenDATE: 10/02/74 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Bendix Home Systems Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of August 21, 1974, asking whether the terms "loaded vehicle weight" or "rated cargo load" include the liquid for both water potable tanks and waste holding tanks in the case of motor homes and multipurpose passenger vehicles. You indicated in a phone conversation with Mike Peskoe of this office on September 4, 1974, that the purpose of your question is to determine whether the weight of this liquid would be included in a manufacturer's computation of gross vehicle weight rating. You also ask for definitions of "loaded vehicle weight" and "rated cargo load." It is not required that a determination of gross vehicle weight rating include the weight of a full amount of liquid in both the potable and the waste holding tanks on the assumption, stated in your letter, that in actual use the holding tank is empty when the potable tank is filled, and the liquid is drawn gradually from one tank to the other. It should be placed in the potable tank for determining GVWR, for this more closely reflects a new vehicle configuration. The term "loaded vehicle weight" is not defined in the Federal motor vehicle safety standards or regulations nor are we aware of its use therein. A related term, "maximum loaded vehicle weight," is defined in Motor Vehicle Safety Standard No. 110 (49 CFR 571.110), but this definition is not applicable to your question. "Rated cargo load" is also not specifically defined, but is used in the requirements for gross vehicle weight rating in 49 CFR 567 and as a test condition in Motor Vehicle Safety Standard No. (Illegible Word) It is intended to mean the manufacturer's good faith rating of the weight of a vehicle's full cargo. |
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ID: 11308Open Mr. A.D. Fisher Dear Mr. Fisher: This is in reply to your letter of October 11, 1995, asking for our comments on the relationship of your lighting invention, "The Enlightener," to Federal Motor Vehicle Safety Standard (FMVSS) No. 108. The Enlightener is intended to replace the center highmounted stop lamp. The lens has two colors, divided between amber at the top and red at the bottom. The amber portion is lit in a steady burning mode when both the accelerator and brake are not depressed, and in a flashing mode when the transmission lever is in Reverse. The red portion is lit when the brake pedal is depressed and amber is extinguished. This device would not be permissible under FMVSS No. 108. The center highmounted stop lamp must stand alone; the lamp cannot serve another function, and paragraph S5.4(a) prohibits combining it with any other lamp. In addition, the backup function on motor vehicles is furnished by a steady burning white lamp, required by FMVSS No. 108. The presence of a flashing amber lamp operating simultaneously would impair the effectiveness of the backup lamp by sending a conflicting signal. I am sorry that we cannot provide you a more positive response. If you have any questions, you may refer them to Taylor Vinson of this office by calling (202) 366-5263. Sincerely,
Samuel J. Dubbin Chief Counsel ref:108 d:11/21/95 |
1995 |
ID: nht76-1.33OpenDATE: 04/07/76 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Trans-Continental Tire Sales, Inc. TITLE: FMVSS INTERPRETATION TEXT: I am writing to confirm your March 19, 1976, telephone conversation with Mark Schwimmer of this office concerning Federal Motor Vehicle Safety Standard No. 119, New Pneumatic Tires for Vehicles Other than Passenger Cars. Standard No. 119 requires that the symbol "DOT" appear on the sidewall of a non-passenger car tire, as a certification that the tire meets all of the standard's performance and labeling requirements. Assuming that the tire in question does meet those requirements and is so certified, there is no prohibition in the standard against additional labeling such as "Blem" or "A.B.O." I hope this clarifies the status of your tires. Sincerely, ATTACH. March 9, 1976 Frank Berndt -- Acting Chief Counsel, N.H.T.S.A. Dept. of Transportation Re: Federal Motor Vehicle Safety Standards Sec. 119. Dear Mr. Berndt, Can you clarify that truck tires marked "A.B.O." or "Blem" are safe for highway use on the front end of commercial over the road vehicles? The tires in question do meet D.O.T. highway specifications for manufacturers safety, in so for as they are free from defects in workmanship and materials. Please rush clarification as soon as possible. Thank You. Respectfully Yours, Raymond Oleisky, Operations Manager |
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ID: nht95-3.23OpenTYPE: INTERPRETATION-NHTSA DATE: June 22, 1995 FROM: Douglas Miyashiro -- ATTB System Engineering, Northrop Grumman TO: Dorothy Nakama -- NHTSA TITLE: Clarification of Title 49, Part 581 ATTACHMT: ATTACHED TO 7/13/95 LETTER FROM JOHN WOMACK TO DOUGLAS MIYASHIRO (A43; REDBOOK 2; PART 581) TEXT: Dear Ms. Nakama, Thank you for your recent help in providing clarification on a previous issue regarding the FMVSS title 49 part 571. Currently, our system engineering department is defining design requirement for the Northrop Grumman Advance Technology Transit Bus (ATT B) program working in conjunction with the Federal Transit Authority. We have been researching bumper safety standard concerning any applicable federal regulation for transit buses. Title 49, part 581 is the only reference on the subject of bumper stan dard and it states the following: Title 49, Part 581.3 states, "This standards applies to passenger motor vehicles other than multipurpose passenger vehicle." We are requesting clarification regarding the word "passenger motor vehicles." We feel that this pertains only to a passenger car but request clarification if a bus is inclusive in the definition of a "passenger motor vehicle." We have reviewed all the d efinitions listed in the FMVSS (title 49 part 571) for all different variation to the specific types of vehicle. We would appreciate a written response clarifying the word "passenger motor vehicle" in order to determine what our design requirements are. |
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ID: nht71-2.11OpenDATE: 03/01/71 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: Recreational Vehicle Institute Inc. TITLE: FMVSR INTERPRETATION TEXT: This is to confirm your interpretation of the Tire Identification and Record Keeping Regulations as expressed in your letter of February 18, 1971. The vehicle manufacturer is responsible for the retention of records of tires shipped "in or on" a new vehicle. However, if the vehicle is used to transport extra tires, the manufacturer is not obliged to retain records of those tires, but rather, the vehicle dealer will be responsible for communicating the appropriate information to the tire manufacturer in accordance with either section 574.8 or section 574.9 of Part 574. |
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ID: nht71-2.48OpenDATE: 05/12/71 FROM: AUTHOR UNAVAILABLE; L. R. Schneider; NHTSA TO: Mercedes-Benz of North America, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of May 3 asking for confirmation of your understanding with Mr. Vinson of my staff that the "optical horn" lighting feature is not prohibited by paragraph S4.6(b) of Motor Vehicle Safety Standard No. 108. Paragraph S4.6(b) which states in part that "means may be provided to flash headlamps . . . for signaling purposes" allows the use of an automatic device for headlamp flashing, and it follows that a non-automatic system, such as the "optical horn" incorporates, is also permissible. |
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.