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: nht72-4.12OpenDATE: 03/02/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Nissan Motor Co., Ltd. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of February 11, 1972, in which you requested our interpretation as to how seats with varying numbers of adjustment positions are to be adjusted to the position "midway between the forwardmost and rear most position," as specified in S8.1.2 of Standard 208. The intent of the "midway" provision in S8.1.2 is that the seat must be placed as nearly as possible at the midpoint of its fore and aft travel. Since the standard also provides that the seat is in an adjustment position -- a notch -- there is a possibility that there will not be a notch at the exact center of the range. In such cases, the seat is placed in the notch nearest the midpoint of the seat's travel. In your case A, if the notches are evenly spaced, the middle notch would probably be the nearest to the midpoint and would therefore be used. In your case B, if the two middle notches are not equidistant from the midpoint, the nearest notch would be used. If they are equidistant, the rearmost notch would be used. It is not necessary to make a special notch. |
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ID: nht72-4.13OpenDATE: 02/03/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Toyota Motor Company, Ltd. TITLE: FMVSS INTERPRETATION TEXT: This letter is in response to your inquiry of January 6, 1972, regarding the relationship of Standards No. 208 and No. 216. You interpret Standard 216, paragraph S3. Application, which states that the Standard does not apply to passenger cars "that conform to the rollover test requirements (S5.3) of Standard 208 by means that require no action by vehicle occupants," as follows: 1. From August 15, 1973, the effective date of Standard 216, to August 15, 1977, passenger cars are not required to meet Standard 216 if they conform to the "first option" of Standard 208. 2. For the period of August 15, 1973, through August 14, 1975, passenger cars which are designed to conform to the "second" or proposed "third" option of Standard 208 are not required to meet Standard 216 if they meet the rollover requirements (S5.3) by passive means (when tested under the applicable conditions of S8), even though in Standard 208 the rollover requirement is specified only for "option 1." These interpretations are correct. Please write if we can be of further assistance. |
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ID: nht72-6.24OpenDATE: 11/16/72 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Nippondenso Company, Ltd. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of October 25, 1972, telling us that you have tested turn signal flashers in accordance with Motor Vehicle Safety Standard No. 108a, which you believe is a more severe test than Standard No. 108, and asking our views as to whether you should retest in accordance with Standard No. 108. The important question is not whether one standard establishes a more severe test than another, but whether a flasher meets all performance requirements applicable to it on the date of its manufacture. The legal obligation of a manufacturer is to insure that it does. The requirements currently applicable to flashers are those of Standard No. 108. It is true that Standard No. 108a has been "repealed" and No. 108 "reinstated". The reason for this action is a judicial decision that the NHTSA did not provide adequate public notice and opportunity to comment on the flasher requirements in Standard No. 108a. However, the NHTSA has proposed that the flasher performance requirements of Standard No. 108a be re-adopted, and is offering the public an opportunity to comment. I enclose a copy of the notice for your information. |
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ID: nht72-6.25OpenDATE: 05/31/72 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Rhode Island Consumers' Council TITLE: FMVSS INTERPRETATION TEXT: We have received your letter of March 15, 1972, which was forwarded to us by the Federal Trade Commission, concerning problems experienced by Mr. Ronald Dandeneau regarding a repossessed vehicle he purchased which was equipped with tires marked "NA." Mr. Dandeneau claims he was told by a tire dealer that such tires are considered unserviceable, cannot be repaired, and are unsafe. The sale of these tires by the tire manufacturer (we understand that the practice is not limited to Uniroyal) is not prohibited by the National Traffic and Motor Vehicle Safety Act, and the Federal standard applicable to passenger car tires. The Federal standard applies only to tires before their first sale to a consumer, and does not apply to used tires such as these. We understand that tires marked "NA" are tires that have been adjusted previously, but for reasons that are not considered to affect the safety of the tire. Examples of such reasons are a lack of roundness and uniformity. While these conditions may produce riding qualities which some people find unsatisfactory, we presently have no evidence that such tires cannot be repaired or that they are unsafe. |
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ID: nht73-3.33OpenDATE: 02/22/73 FROM: AUTHOR UNAVAILABLE; C. A. Baker for E. T. Driver; NHTSA TO: Morino and Moore TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of February 1 to Mr. B.M. Crittenden, Regional Administrator, concerning emergency flashers. Effective January 1, 1969, all new automobiles were required to meet Federal Motor Vehicle Safety Standard No. 108, "Lamps, Reflective Devices and Associated Equipment," which in turn required the vehicular hazard warning signal operating unit to meet Society of Automotive Engineers Standard J910, January 1966. Prior to January 1, 1969, automobile were required to meet the standards and regulations of the individual States. Since New York required hazard warning signals (4-way flashers) in 1966, most automobiles manufactured for sale throughout the United States were similarly equipped. SAE J910 did not contain requirements relating the activation of the signal to the position or rotation of the steering wheel. Several States prohibited the operation of the subject signal on a moving vehicle; therefore, on many cars, this signal was cancelled by the rotation of the steering wheel, and consequently could not be activated even with the vehicle stopped with the steering wheel in certain positions. We are unaware of similar complaints on the activation of the hazard warning signals. |
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ID: nht73-4.34OpenDATE: 07/19/73 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Kysor of Cadillac TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of June 22, 1973, concerning the applicability of section S5.1.4, Pressure gauge, of Standard No. 121, to an electronic gauge that displays the air pressure under normal conditions only when the driver pushes a switch but that provides continuous display at pressures below 70 p.s.i. Section S5.1.4 requires a pressure gauge to be "readily visible." Used in this context, "readily visible" means visible whenever the driver wants to see it. It does not mean that the air pressure level should be continuously visible. As we understand your system, the driver could determine the air pressure at any time by pushing the "air pressure" button. We have concluded that this operation satisfies the intent of S5.1.4 and that your system would be permissable under that section. The low pressure warning signal is required by section S5.1.5 and must be separate from the pressure gauge. You state that you provide a flashing red light and an audible alarm, in addition to providing continuous readout of air pressure below 60 p.s.i. This would appear to conform to S5.1.5. |
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ID: nht92-6.2OpenDATE: June 22, 1992 FROM: Trevor J. Buttle -- Project P4 TO: Office of Chief Council, U.S. DOT TITLE: Our Ref 1547; Your Fax No. 0101 202 366 2106; Re: FMVSS 102, Transmission Lever Shift Sequences ATTACHMT: Attached to letter dated 8/1/92 (est) from Paul J. Rice to Trevor Buttle (A39; Std. 101; Std. 102) TEXT: I am responsible for certification of a passenger vehicle being developed with a view to U.S.A. export in 2-3 years. Could you please advise on the following concern relating to S3.1.4 of the above standard: o The (transmission shift lever position) information is to be "displayed in view of the driver". - S3.1.4.1. I believe this relates to the 95% eye range contour, hence requiring a display on or near to the instrument binacle. Is this correct, or (as seems to be the current practice for some auto makers) is the floor shift identification sufficient? This query relates to auto and manual transmission. o Could you also clarify whether the display should be permanently illuminated for night usage (again, some auto makers have opted to make this facility switchable). Your assistance with these issues would be greatly appreciated. |
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ID: nht89-1.19OpenTYPE: INTERPRETATION-NHTSA DATE: 02/10/89 FROM: ROLF DUERR -- NOITH TRANSMISSIONS PROJECT ENGINEER TO: U.S. DEPARTMENT OF TRANSPORTATION OFFICE OF CHIEF COUNCIL TITLE: DOT APPROVAL OF SWAGELOK FITTING ATTACHMT: LETTER DATED 08/23/89 FROM STEPHEN P. WOOD -- NHTSA TO ROLF DUERR -- VOITH TRANSMISSIONS; REDBOOK A34[2]; FMVSS 106 TEXT: To Whom It May Concern: Enclosed, please find the fitting used on our product, the Voith VHBK-120 Driveline Brake Retarder. We are a European manufacturer of brake retarders and wish to make our product more adaptable to the American market. We are doing this by converting ou r metric air fittings to DOT approved fittings. Most of the air fittings we required were offered by Parker. The enclosed swagelok fitting will replace the enclosed DIN metric fitting as a positionable 90 degrees elbow. Swagelok, as you may know, has no DOT designation standard on the fitting. Thus your approval is theoretically needed if it is attached to the air braking system of a truck. In our case, the air supply line to the retarder is tapped off of the auxiliar y air brake tank/system. Attached you will find technical specs on this swagelok fitting which we would like to use. I have also enclosed some literature on our product. Your prompt response will be greatly appreciated. Regards, |
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ID: nht89-1.45OpenTYPE: INTERPRETATION-NHTSA DATE: 03/20/89 FROM: M. IWASE -- TECHNICAL ADMINISTRATION DEPT. KOITO MFG. CO., LTD. TO: ERIKA Z. JONES -- CHIEF COUNSEL NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION TITLE: NONE ATTACHMT: ATTACHED TO LETTER DATED 06/19/89 FROM ERIKA Z. JONES -- NHTSA TO M. IWASE; REDBOOK A33; STANDARD 108 TEXT: Dear Ms. Jones, Koito would like to confirm the following prescription of license plate lamp in Table II and IV of FMVSS No. 108. TABLE II - LOCATION OF REQUIRED EQUIPMENT Location on Height above Item Multipurpose passenger Trailers road surface vehicles, trucks, and busses measuredLicense At rear license plate, to At rear license plate, to No plate illuminate the plate from the illuminate the plate from requirement lamp top or sides. the top or sides. TABLE IV - LOCATION OF REQUIRED EQUIPMENT Location on Height above Item Passenger cars, multipurpose Motorcycles road surface passenger vehicles, measuredLicense At rear license plate, to At rear license plate No plate illuminate the plate from the requirementlamp top or sides. We interpret that the license plate lamp is not permitted to illuminate the plate from the bottom (except Motorcycle). We would greatly appreciate if you would kindly and promptly give us your confirmation as to whether the illumination from the bottom be permissible. Sincerely yours, |
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ID: nht76-1.26OpenDATE: 01/28/76 FROM: AUTHOR UNAVAILABLE; Mark I. Schwimmer; NHTSA TO: File TITLE: FMVSS INTERPRETATION TEXT: On January 23, 1976, I received a telephone call from Mr. Walt Robbins (750-2600) concerning the interpretation letter mailed from this office to him on January 20, 1976. (The subject of that letter was the application of Standard No. 109's labeling requirements to a "Radial, Bias Ply Tire".) Mr. Robbins asked three questions: 1) Were the four labeling examples set out in the letter intended to be restrictive or merely a model, with respect to the cord materials used in the tires (e.g. would a similar label that specified "3 PLIES 2 POLYESTER BIAS PLIES 1 POLYESTER RADIAL PLY" instead of an aramid radial ply also be permissible)? I explained that, in that respect, the examples were merely a model, so that his suggested alternative would be permissible. 2) When would the rule that was discussed in the letter be issued? I declined to give a prediction, explaining generally the uncertainties in the rulemaking process. 3) What was the real reason for inclusion of the suggestion that he consult the FTC concerning advertising of the tires in question? I explained that he could take the sentence on its face and that the NHTSA was not, in the letter, taking any position on the use of the word "radial" in the advertising of such tires. |
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.