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: nht73-5.13OpenDATE: 09/25/73 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Taylor Machine Works TITLE: FMVSR INTERPRETATION TEXT: This is in reply to your letter of August 6, 1973, in which you ask whether a sample certification label you enclosed will conform to NHTSA Certification regulations (49 CFR Part 567). We assume from the weight ratings specified in the sample that the trailer is a semitrailer. As we indicated to you in our letter of June 26, 1973, the regulations do not provide for the listing of inflation pressure with the tire size designation, and the inflation pressure you have included should not appear in its present location on the label. You may, if you wish, include it following all the required information. Apart from this item, a label similar to that you have submitted, affixed in both an appropriate manner and location, will conform to Part 567. We are happy to have been of assistance. |
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ID: nht68-4.14OpenDATE: 09/11/68 FROM: AUTHOR UNAVAILABLE; Robert M. O'Mahoney; NHTSA TO: Meyer Products, Inc. TITLE: FMVSS INTERPRETATION TEXT: I regret the delay in responding to your letter of April 23, in which you provided certain certification information and details on your wheeled spreaders. The wheeled spreaders attached to a towing vehicle are considered motor vehicles under the National Traffic and Motor Vehicle Safety Act of 1966, and have been categorized as "trailers". Federal Motor Vehicle Safety Standard No. 108 is currently the only Standard applicable to trailers, specifically those 80 inches and more in overall width. This Standard will also apply to trailers of lesserwidth manufactured after December 31, 1968. Accordingly Meyer Products is required to certify compliance in accordance with section 114 of the Act. I enclose for your guidance copies of the Act, Federal Standard No. 108, and the certification Notice currently in effect. |
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ID: nht75-3.18OpenDATE: 10/03/75 FROM: AUTHOR UNAVAILABLE; Frank A. Berndt; NHTSA TO: Charter Arms Corporation TITLE: FMVSR INTERPRETATION TEXT: This is in response to your letter of September 16, 1975, inquiring whether approval from the Federal Government is necessary before selling motorcycles manufactured by you. No approval is necessary in order to market your motorcycles. However, you should be aware of the regulations governing manufacturer identification and vehicle certification. Each manufacturer who begins to manufacture motor vehicles must submit certain information to the National Highway Traffic Safety Administration describing the type of motor vehicle manufactured (49 CFR Part 566, copy enclosed). In addition, each vehicle must be certified as being in compliance with all applicable Federal Motor Vehicle Safety Standards in effect at the time of manufacture (49 CFR Part 567, copy enclosed). If you have any further questions, please contact us. |
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ID: 27124.ztvOpenMr. Dennis G. Moore Dear Mr. Moore: This is in reply to your letter of May 25, 2000, asking for an interpretation of Standard No. 108 as it concerns Light-Emitting Diode (LED) lamps. You believe that the agency is allowing manufacturers of LED lamps to "violate" the requirements of Federal Motor Vehicle Safety Standard No. 108 with respect to the "effective projected luminous lens area" specifications. As you know, the agency has been engaged for some time in rulemaking to adapt Standard No. 108 to accommodate LED technology. In the Notice of Proposed Rulemaking that established Docket No. NHTSA-98-3967, we asked for comments on the issue that you raise. This issue will be discussed in the preamble to the final rule presently being prepared. In the meantime, I am sending your letter to this docket as a comment to be considered. Thank you for your interest in motor vehicle safety. Sincerely, |
2000 |
ID: nht93-4.47OpenDATE: June 25, 1993 FROM: Ernest Farmer -- Director, Pupil Transportation, Tennessee State Department of Education, Office of Commissioner TO: Chief Counsel COPYEE: Wayne Qualls TITLE: None ATTACHMT: Attached to letter dated 7-13-93 from John Womack (signature by Stephen P. Wood) to Ernest Farmer (Std. 108; VSA 108(a)(2)(A)) TEXT: We are interested in conducting a "controlled" experiment involving a substitution of strobe lights for the traditional incandescent lights currently used in the eight light overhead warning system on school buses. Would this experiment, in your opinion, conflict with the provisions of FMVSS 108? An early reply would be appreciated since the retrofitting of these three buses (one bus in each of three school systems) is scheduled during the month of July. |
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ID: nht68-2.34OpenDATE: 10/18/68 FROM: AUTHOR UNAVAILABLE; Robert M. O'Mahoney; NHTSA TO: Citroen Cars Corporation TITLE: FMVSS INTERPRETATION TEXT: By your letter of October 8, 1968 you ask if the glazing material in the rear window of passenger cars can be 4 millimeters thick and be in compliance with Federal Motor Vehicle Standard No. 205; Glazing Materials - Passenger Cars, Multipurpose Passenger Vehicles, Motorcycles, Trucks, and Buses. Standard No. 205 requires that glazing materials conform to the ASA Standard Z26.1-1966. The ASA standard Z26.1-1966 does not set forth how thick glazing material must be but requires the glass used to meet certain tests, depending on the type of vehicle the glass is being used in and the location of the glass in that vehicle. |
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ID: nht70-2.32OpenDATE: 10/29/70 FROM: AUTHOR UNAVAILABLE; R. H. Compton; NHTSA TO: Leaseway Transportation Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of October 14, 1970, to Mr. Douglas W. Toms, Director, National Highway Safety Bureau requesting an interpretation on the "marker blink switch" relative to Federal Motor Vehicle Safety Standard No. 108. The use of this switch does not violate the requirements of paragraph S3.5 of Standard No. 108, and is permitted by paragraph S3.1.2. Flashing lights for signaling purposes in a highly controversial subject with many proponents for, and many against, their use. This aspect is being clarified in a soon-to-be-published amendment to Standard No. 108, and will be addressed further in a forthcoming notice of proposed rule making on the same standard. |
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ID: nht72-3.16OpenDATE: 05/08/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Temptation Mfg. Co. TITLE: FMVSS INTERPRETATION TEXT: This is in response to your undated letter, which we received on March 22, 1972, in which you ask what NHTSA requirements are applicable to a truck cover you manufacture, enclosing a picture. The picture appears to show a cover designed for installation over the back of a pickup truck. If this unit is not designed to carry persons when the truck is in motion, there are no requirements applicable to it. If, however, it is designed to transport persons, the glazing materials (glass and plastics) used in it must conform to Motor Vehicle Safety Standard No. 205, "Glazing Materials," (copy enclosed). In addition, the unit must also be certified as conforming to the standard in accordance with section 114 of the National Traffic and Motor Vehicle Safety Act and the enclosed NHTSA notice of November 4, 1967. The ASA Test 226.1-1966 that is incorporated into Standard No. 206 can be obtained from the American National Standards Institute, 1430 Broadway, New York, New York 10018. |
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ID: nht74-3.46OpenDATE: 05/22/74 FROM: AUTHOR UNAVAILABLE; A.G. Detrick; NHTSA TO: Porsche/Audi TITLE: FMVSR INTERPRETATION TEXT: This is in reference to your defect notification campaign (NHTSA No. 73-0229) concerning possible fires resulting from a short in the radiator cooling fan in some Audi 100's. The letter which you have sent to the owners of the involved vehicles does not entirely meet the requirements of 49 CFR Part 577. Specifically, the phrase, "possible hazard that may exist in your vehicle," may be construed as a disclaimer since it tends to discourage vehicle owners from having their vehicles corrected and is therefore not permitted. It is, however, permissible to state that the defect may not be present in every vehicle being campaigned if such a statement is applicable. It will not be necessary to send an additional letter in this instance, but all future defect notifications must comply with the applicable regulation. If you desire further information, please contact Messrs. W. J. Reinhart or James Murray at this office (202) 426-2840. |
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ID: 00183.ztvOpenMr. Don Weidman Re; Number of Identification Lamps Dear Mr. Weidman: This is in reply to your letter of August 20, 2002, asking "how many lamps can be installed as identification lamps on a vehicle . . . and still be in compliance with Standard No. 108." You related that a customer wishes to have a five-lamp array of lamps rather than the cluster of three identification lamps specified in Standard No. 108. It is your opinion that these additional lamps are not allowed because they would detract from the purpose of the three-lamp array to identify a large vehicle in the roadway. We confirm your interpretation. Late in 1973, we were asked by Darrell Gambill of Crane Carrie Company whether a system of four identification lamps would be permissible.I enclose a copy of our response stating that only the three-lamp system specified by Standard No. 108 is permissible. Sincerely, Jacqueline Glassman Enclosure |
2002 |
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.