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: nht81-1.22OpenDATE: 03/03/81 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Carbonneau & Turgeon Inc. TITLE: FMVSS INTERPRETATION TEXT: Mar 3, 1981 NOA-30 Mr. Wilfrid Carbonneau President Carbonneau & Turgeon Inc. 4E, Ave Centre Industriel St-Romuald, CTE Levis, P.Q. Dear Mr. Carbonneau: In response to your recent letter, to Mr. Schwartz of my office, I have enclosed a copy of U.S. Federal Motor Vehicle Safety Standard No. 115, and two recent amendments. The Canadian authority for the issuance of the three or six character manufacturer identifier is: MVMA of Canada Suite 1602 25 Adelide Street E. Toronto, Ontario MSC-1Y7 ATT: Mr. Brian Hickey Phone: 416-364-9333 Sincerely, Frank Berndt Chief Counsel Enclosures ST-ROMUALD, le, 6 fevrier 1981 M. Frederic Schwartz, junior National Highway Traffic Safety Administration 400, Seventh Street, S.W. Washington, D.C., 20590 U.S.A. Monsieur, Auriez-vous l'obligeance de m'envoyer de plus amples details au sujet de la nouvelle norme americaine, la FMVSS 115. Vous remerciant a l'avance de votre attention, veuillez agreer, Monsieur, l'expression de nos sentiments les meilleurs. Bien a vous, CARBONNEAU & TURGEON INC. Par: Wilfrid Carbonneau President WC/cc |
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ID: nht68-1.37OpenDATE: 01/11/68 FROM: AUTHOR UNAVAILABLE; Robert M. O'Mahoney; NHTSA TO: United States Auto Club TITLE: FMVSR INTERPRETATION TEXT: Secretary Boyd has asked that we reply to your letter of November 27, 1967. Your letter raises questions concerning joint regulations to be issued by the Department of the Treasury and the Department of Transportation governing the importation of motor vehicles and motor vehicle equipment subject to motor vehicle safety standards. You are correct in your understanding that the Act was not intended to apply to vehicles prepared for auto racing or race tracks and not intended for use on the public streets or highways. The question you raised concerning the use of the words "by bona fide auto vehicle manufacturers" has also been raised by others who have commented on the proposed regulations. Accordingly, you will note that the regulations, a copy of which is attached, have been changed so as to eliminate this phraseology and make it clearer that vehicles intended for "competition" and which "will not be sold or licensed for use on the public roads" may be admitted. This provision will not require an affidavit on the part of the importer but merely a declaration to this effect. We believe that the regulations, as amended, will provide for the unhampered entry of foreign built race cars for the Indianapolis 500 race and other USAC sanctioned events. |
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ID: nht92-6.40OpenDATE: May 22, 1992 FROM: Jerry Ralph Curry -- Administrator, NHTSA TO: Dan Glickman -- House of Representatives COPYEE: Washington Office TITLE: None ATTACHMT: Attached to letter dated 4/29/92 from Dan Glickman to Andrew Card, Secretary, U.S. DOT (OCC 7273) TEXT: Thank you for your letter to the Department of Transportation on behalf of your constituent, Mr. David Lourana. Secretary Card has asked me to explain our regulations about motor vehicle fuel tanks to you. Specifically, Mr. Lourana asked for information about requirements pertaining to the accuracy of gasoline tank capacity. He was concerned that, absent such regulations, a consumer would not know whether he or she is receiving the proper amount of gasoline. I am pleased to have this opportunity to respond to you. By way of background, the National Highway Traffic Safety Administration (NHTSA) is authorized to issue Federal Motor Vehicle Safety Standards that apply to the manufacture of new motor vehicles and items of motor vehicle equipment. One such standard, Standard No. 301, Fuel System Integrity, applies to motor vehicle fuel tanks. This standard specifies requirements for the integrity of motor vehicle fuel systems. The purpose of Standard No. 301 is to reduce deaths and injuries occurring from fires that result from fuel spillage during and after motor vehicle crashes. However, neither Standard No. 301, nor any other of our standards, regulate the accuracy of the gasoline tank capacity. Even though our Federal Motor Vehicle Safety Standards do not address measuring a fuel tank's accuracy, Mr. Lourana may wish to contact the State government in Kansas. Some States make sure that service station fuel pumps are accurate. We hope that this information is helpful. |
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ID: nht71-1.9OpenDATE: 03/09/71 FROM: AUTHOR UNAVAILABLE; R. H. Compton; NHTSA TO: Truck Body and Equipment Association, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of February 23, 1971, to Mr. Julian B. Leysath of this office requesting an interpretation on the mounting location of rear clearance lamps on slant-sided beverage truck bodies. Rear clearance lamps mounted on the outermost top corners of the body, as indicated on the TBEA diagram, adequately meet the location requirements of Federal Motor Vehicle Safety Standard No. 108. |
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ID: nht90-3.81OpenTYPE: Interpretation-NHTSA DATE: September 4, 1990 FROM: Hiroshi Kato -- Vice President, Mitsubishi Motors America, Inc. TO: Jack Rice -- Chief Counsel, NHTSA TITLE: None ATTACHMT: Attached to drawing of proposed illumination on rear panel garnish and photo of 1988 Pontiac Fiero (graphics omitted); Also attached to letter dated 9-26-90 from P.J. Rice to H. Kato (A36; Std. 108) TEXT: This letter serves to request an interpretation of FMVSS 108, Lights and Relectors. S.5.1.3 of Standard 108 states that "no additional lamp, reflective device, or other motor vehicle equipment shall be installed that impairs the effectiveness of lightin g equipment required by this standard." We are considering lighting the rear panel garnish of a vehicle to illuminate the word "MITSUBISHI" at 0.1 cd (0.02 cd/in) when the vehicle headlamp system is turned on. This illumination would not be lighting required by FMVSS 108. The enclosed page s hows the proposed illumination and specifications. A similar illumination on the 1988 model year Pontiac Fiero is also shown. We would like your determination as to whether the illumination described above would be considered impairment of the effectiveness of required lighting as described in S.5.1.3. If the described illumination is considered an impairment due to the candela power, we would like to know what candela would be acceptable. Also, we would like to confirm that if the center of the rear panel garnish was illuminated as a supplemental tail lamp and the word "MITSUBISHI" was not illuminated, this type of lighting would be allowed under FMVSS 108. Your prompt response would be appreciated. Enclosure Drawing of proposed illumination on rear panel garnish and photo of 1988 Pontiac Fiero (graphics omitted). |
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ID: nht89-2.11OpenTYPE: INTERPRETATION-NHTSA DATE: 06/19/89 FROM: STEPHEN P. WOOD -- NHTSA ACTING CHIEF COUNSEL TO: ROD WILLAREDT -- PRESIDENT DIAMOND CROSS LIGHTS TITLE: NONE ATTACHMT: LETTER DATED 05/17/89 FROM ROD WILLAREDT TO TAYLOR VINSON -- NHTSA; LETTER DATED 04/18/88 FROM ERIKA Z. JONES -- NHTSA TO WAYNE APPLE; STANDARD 108; LETTER DATED 02/19/88 FROM ERIKA Z. JONES -- NHTSA TO CHARLES WILSON -- CONGRESS; STANDARD 108; LETTER DATED 07/11/88 FROM ERIKA Z. JONES -- NHTSA TO WILLIAM J. STEPHENSON; STANDARD 108 TEXT: Dear Mr. Willaredt: This is in reply to your letter to Taylor Vinson of this Office, received by FAX on May 17, 1989. You have developed a "safety light" that displays right and left turn signals, "and when the caution light/emergency light appears, the formation of such l ights indicate a diamond". The device appears intended for installation on large trucks or trailers. The turn signal lamps are supplementary to a vehicle's original equipment turn signal lamps. I assume that the caution/emergency lamp to which you ref er is what we call a hazard warning signal, sometimes known as a 4-way flasher. You have asked for written approval of this device. This agency has no authority to "approve" or "disapprove" any motor vehicle or item of equipment. We can, however, advise as to the relationship of equipment to applicable Federal motor vehicle safety standards. I enclose copies of representatives lett ers covering other auxiliary rear lighting for large trucks, such as wide-turn and U-turn indicators, and their relationship to Motor Vehicle Safety Standard No. 108, the National Traffic and Motor Vehicle Safety Act, and State law. These principles ar e applicable to your safety light as well. If you have any further questions, we shall be happy to answer them. Sincerely, ENCLOSURES |
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ID: 77-3.46OpenTYPE: INTERPRETATION-NHTSA DATE: 08/04/77 FROM: AUTHOR UNAVAILABLE; Joseph J. Levin Jr.; NHTSA TO: Humanoid Systems TITLE: FMVSR INTERPRETATION TEXT: This responds to your June 3, 1977, request for confirmation that @ 572.7(b) of Part 572, Anthropomorphic Test Dummy (49 CFR 572), specifies a minimum time period during which the pendulum used in testing may not reverse direction rather than an exact time. Your interpretation is correct. The specification that the pendulum "shall not reverse direction until T=123 ms" means that reverse travel must not occur earlier than 123 milliseconds after chordal displacement begins. The agency believes that this language can be improved and intends to clarify it at the next opportunity. |
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ID: nht92-1.33OpenDATE: December 8, 1992 FROM: Vasant Jinwala -- Consumer Testing Laboratories, Inc. TO: Marvin Shaw -- Department of Transportation TITLE: Flammability for Comfort Cushions ATTACHMT: Attached to letter dated 1/22/93 from John Womack to Vasant Jinwala (A40; Std. 302; VSA 102(4)) TEXT: We have received a comfort cushion for testing. The sample does not conform to DOT 302 flammability requirements. The manufacturer claims that the DOT 302 standard is only applicable to a car's original equipment and NOT for auto accessories. Your input in this matter is appreciated. Please see the attached copy of packaging. The packaging clearly indicates the intended CAR use. (Comfort Cushion brochure omitted.) |
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ID: nht71-3.5OpenDATE: 05/20/71 FROM: AUTHOR UNAVAILABLE; R. B. Dyson for L. R. Schneider; NHTSA TO: Boise Cascade Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of April 29, to Mr. Charles West, on the subject of air brake systems on mobile structure trailers. The standard to which you refer does not require air brakes to be installed on trailers, as your associates seem to fear. However, if your company decides on its own initiative to install air brakes on its mobile structure trailers, such brakes must conform to the air brake standard if the trailer is built on or after the effective date of the standard, January 1, 1973. Please advise us if further clarification is needed. |
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ID: nht73-5.36OpenDATE: 10/31/73 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Motor Coach Industries, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of September 5, 1973, to Mr. Schneider asking whether you may furnish side turn signal lamp for inter-city buses at the rear wheels, and if so, the required color. It is correct that there are no Federal safety requirements for side turn signal lamps. Therefore, there is no Federal prohibition against your providing such a lamp, and such restrictions as may exist would be those imposed by the States. Rear mounted turn signal lamps under Federal Standard No. 108 may be either red or amber. |
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.