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: nht70-2.26OpenDATE: 09/21/70 FROM: AUTHOR UNAVAILABLE; D. W. Toms; NHTSA TO: Donald O'Neill TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of August 17, 1970, concerning Mr. George R. Smith's comments on the energy-absorbing steering system in response to my interview in your August issue. I did not mean to imply that energy-absorbing steering systems were not installed by some manufacturers, such as General Motors, prior to the effective date of our Federal Motor Vehicle Safety Standard No. 203 - Impact Protection for the Driver from the Steering Control System. Mr. Smith is correct in noting that Standard No. 203 does not require collapsible steering columns. It was intentionally written in performance terms rather than as a design specification. Most manufacturers chose the collapsible steering column to meet the standard, hence the common use of the term "collapsible column" to refer to our requirement. However, it should be noted that the standard is also being complied with by steering control systems employing other methods of energy-absorption including energy-absorbing rims and a collapsible bellows located forward of the steering wheel hub. Regarding your request for a copy of the National Highway Safety Bureau "Program Plan for Motor Vehicle Safety Standards," this plan is a working document and represents the presently scheduled rulemaking actions to be issued by our Motor Vehicle Programs activity during the period of 1970-1972. I am pleased to enclose a copy as you requested. I appreciate the opportunity to clarify some of my interview remarks and I enjoyed reading Mr. Smith's comments. ENCLOSURE |
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ID: nht70-2.31OpenDATE: 10/23/70 FROM: AUTHOR UNAVAILABLE; R. H. Compton; NHTSA TO: American Motors Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of October 12, 1976, to Mr. Charles A. Baker of this office in which you requested an interpretation of the phrase "affective projected illuminated area." Class A turn signal lamps are required by Section S3.1 of Federal Motor Vehicle Safety Standard No. 108, which references SAE Standard J588d in Tables I and III for there lamps. The requirements for the illuminated area of a turn signal lamp are specified in J588d as follows: "The effective projected illuminated area measured on a plane at right angles to the side of the lamp must not be less than 12 sq. in. for Class A and 36 sq/ in. for Class B." In the 45 degree visibility requirements, this standard further states "To be considered Visible, the lamp must provide an instructed projected illuminated area of outer less surface, excluding reflex, . . .". Our interpretation of affective projected illuminated area follows; The affective projected illuminated area is that area of the lent measured on a plane as that angles to the axis of the lamp, excluding reflex reflector, noted is not obstructed by an opaque object such as a mounting(Illegible Words) The above interpretation allows the area of rings or other configurations ((Illegible Word) portions) applied in the lane to be considered part of the total effective from, even if this area does not contribute significantly to the total light output. |
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ID: nht70-2.8OpenDATE: 05/05/70 FROM: AUTHOR UNAVAILABLE; R. A. Diaz; NHTSA TO: D. F. Clausen TITLE: FMVSS INTERPRETATION TEXT: Your postcard of March 9, 1970, to the Chicago Regional Office of the Interstate Commerce Commission has been forwarded to this office by Mr. F. B. Farrell, Regional Administrator for Region 4, Federal Highway Administration. In your card, you request a copy of I.C.C. requirements for a camping trailer you intend to build. The I.C.C. regulations concerning equipment for trailers are now administered by the Bureau of Motor Carrier Safety, Federal Highway Administration, Department of Transportation. These regulations apply only to vehicles used in interstate commerce for commercial purposes. If you intend to build a camping trailer for your personal use, these regulations would not be applicable to it. Should this not be the case, however, I am enclosing a copy of these requirements for your information. Federal motor vehicle safety standards, which are issued by the National Highway Safety Bureau pursuant to National Traffic and Motor Vehicle Safety Act of 1966, do apply to manufacturers of camping trailers which will be towed on public highways. At present, the only Federal standard applicable to trailers is Standard No. 108, "Lamps Reflective Devices and Associated Equipment", and your trailer must conform to its requirements. I enclose a copy of this standard as amended, and a copy of the above mentioned Act. I suggest you also consult state and local authorities for possible other requirements which they may impose on trailers. If I may be of further assistance, please contact me. ENCLOSURES |
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ID: nht71-1.5OpenDATE: MAY 28, 1971 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: Boise Cascade Recreational Vehicles TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of May 14, 1971, on the subject of the effective date of the requirements for seat belts and seat belt anchorages in multipurpose passenger vehicles. You have been correctly informed by RVI that the seat belt installation standard (No. 208), and the seat belt anchorage standard (No. 210) are effective July 1, 1971, with respect to trucks and multipurpose passenger vehicles. The amendment to Standard No. 208 issued September 30, 1970, required seat belts effective July 1, 1971. That standard will be superseded by the new occupant crash protection standard on January 1, 1972, but it is in full effect from July 1, 1971, to January 1, 1972. We regret any confusion that may have arisen as the result of the issuance of the occupant crash protection standard. The requirements for seat belt anchorages have not been affected in any way by the occupant crash protection rule and it is therefore suprising to find that the effective date of the anchorage standard has also been misunderstood. We would hope that the changes in procurement schedule to which you refer would not result in inability to conform to the standard by July 1, 1971. On the basis of the information presently available to us there does not appear to be sufficient cause to postpone the effective dates of Standards No. 208 and 210. |
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ID: nht72-1.24OpenDATE: 09/28/72 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Associate Mgt. Services, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of August 22, 1972, concerning the recently issued amendment to Standard No. 109 (37 F.R. 16604, August 7, 1972) prohibiting the sale of "reclassified" tires. You indicate that you agree with the amendment that such tires should be allowed to be sold as scrap, but suggest that it be only after they are (Illegible Word) completely inoperable for any vehicular use. The amendment to the standard prohibits, in effect, the distribution by a manufacturer of any tire does not conform to the standard, unless it is impossible that the tire (Illegible Word) be used or be repaired for use as motor vehicle equipment (see paragraph S2, Application, of the enclosed copy). Whether cutting the bead on a tire meets this requirement is for each individual manufacturer to determine. We have received some reports that it is possible to repair the bead of a tire so that the tire can still be used on a motor vehicle. If this is the case, cutting a tire's bead may not be sufficient to allow the tire to be sold as scrap under the National Traffic and Motor Vehicle Safety Act. The amendment, then, does achieve the result you suggested in that it does require a noncomplying tire to be "completely inoperable for any vehicular use" before it can be sold as scrap. We appreciate your continued efforts for motor vehicle safety. Enclosure |
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ID: nht72-1.40OpenDATE: 08/16/72 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Nissan Motor Company, Ltd. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letters of July 25 and 28, 1972, on the subject of the positioning of seat backs for the purposes of testing under Standards No. 208 and 210. The "nominal design riding position" specified in Standard 208 and formerly employed in Standard 210 is the position considered by the manufacturer as that most likely to be used by vehicle occupants. In our compliance tests, we ask the manufacturer of each vehicle to be tested to advise us of the correct position. The term "most upright position" used in Standard 210 was adopted in part to avoid the need to go to the manufacturers for advice each time we tested a vehicle's seats. Under S4.3.2 of the standard, the seat back is adjusted to the position which places the seating surface most nearly in a vertical position. There have, however, been difficulties with the use of the "most upright position", in cases where that position is not the same as the position used by the manufacturer to establish the seating reference point. Because S4.3.2 also calls for the positioning of the SAE J826 mannikin on the seating reference point, there is a possibility that the manikin cannot be correctly positioned. This does not appear to be a serious discrepancy, but it is one that should be resolved, and we intend to do so by appropriate amendment in the Federal Register. |
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ID: nht72-2.24OpenDATE: 05/09/72 FROM: AUTHOR UNAVAILABLE; D. W. Toms; NHTSA TO: Department of California Highway Patrol TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of April 18, 1972, requesting an interpretation of the requirements of Federal Motor Vehicle Safety Standard No. 108 which relates to the use of mechanical aimers on headlamps. Standard No. 108 references, in Tables I and III, SAE Standard J580a. As stated in your letter, SAE J580a specifies in part that "Headlamps shall be designed so that they may be checked by mechanical aimers without the removal of any ornamental trim rings or other parts." The language in this requirement, and that contained in other referenced and subreferenced SAE standards, does not specifically identify the design or complete dimensional details of "mechanical aimers." Therefore, the use of any mechanical aimer, including those fitted with special adapters for specific vehicles, would be permitted under the above stated requirement. Specifically, you asked, "If a vehicle is so designed that the headlamps cannot be checked with mechanical aimers of the type now commonly available without the removal of ornamental trim rings or other parts, does it meet the requirements of Federal Standard 108?" A "commonly available" aimer is defined as one that is manufactured and offered for sale, including an aimer with adapters for special applications. A vehicle which is so designed that the headlamps cannot be checked with mechanical aimers as thus defined, without the removal of ornamental trim rings or other parts, would not meet the requirements of Standard No. 108. |
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ID: nht71-3.19OpenDATE: 06/10/71 FROM: L. R. SCHNEIDER -- ACTING CHIEF COUNSEL, NHTSA; SIGNATURE BY DAVID SCHMELTZER TO: Triplex Safety Glass Co. Ltd. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of May 28, 1971, concerning the marking requirements in the proposed amendment to Standard No. 205, "Glazing Materials" (Docket No. 71-1; Notice 1). These requirements are only proposed at present, as is their effective date, and do not represent the agency's final decision on the matter. If the agency determines to amend the standard, and before any compliance with new requirements is required, a "final rule" will be issued that is based on the proposed rule but may differ in some respects from it. The final rule will specify an effective date for these new requirements which, in this instance, will probably be later than the effective date proposed. You ask whether the effective date of the proposed standard would apply to the manufacture of the glazing, or to the fitting of the material into the vehicle. Standard No. 205 applies to "glazing materials for use in passenger cars, multipurpose passenger vehicles, motorcycles, trucks and buses", and the effective date of any amendment to this standard refers to the date of manufacture of the glazing material, and not to its fitting into the vehicle. Your second question, whether we will accept your marking without a hyphen between the "DOT" symbol and your code mark, has been answered in our letter to you of May 26, 1971. I hope this clarifies the situation. |
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ID: nht71-4.38OpenDATE: 11/02/71 FROM: AUTHOR UNAVAILABLE; R. L. Carter; NHTSA TO: American Motors Corporation TITLE: FMVSS INTERPRETATION TEXT: This is in response to your recent telephone inquiry as to whether the recent amendment of Standard 215, Exterior Protection, requires that vehicles meet the photometric requirements of Standard 108 after being subjected to the Standard 215 impacts. S5.3.1 of Standard 215 reads: "Each lamp or reflective device, except license plate lamps, shall be free of cracks and shall comply with the applicable requirements of Motor Vehicle Safety Standard No. 108." S4.3.1.1 of Standard 108 reads in relevant part: "Each lamp and reflective device shall be located so that it meets the visibility requirements specified in any applicable SAE Standard or Recommended Practice. In addition, no part of the vehicle shall prevent the device from meeting the photometric output at any test point specified in any applicable SAE Standard or Recommended Practice." (Emphasis supplied.) Thus, although the actual photometric tests may be considered "bench tests", that is, tests whose procedures include removing the devices from the vehicle, the above provision of Standard 108 requires that the configuration of the vehicle external to the devices not prevent them from meeting the photometric requirements. The test procedures themselves require the devices to be placed in their actual orientation on the vehicle. Therefore, the provision in Standard 215 that the lamps and reflective devices shall meet all the requirements of Standard 108 after the impacts includes the photometric requirements. |
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ID: nht71-4.9OpenDATE: 09/02/71 FROM: AUTHOR UNAVAILABLE; L. R. Schneider; NHTSA TO: Philadelphia Newspapers, Inc. TITLE: FMVSS INTERPRETATION TEXT: In your letter of August 18 you ask for a ruling on the permissibility of wiring one filement of a clearance lamp on your small delivery truck so that it would function as a stop lamp and turn signal lamp. Federal Motor Vehicle Safety Standard Ho. 108, Lamps, Reflective(Illegible Words), does not prohibit combining a clearance lamp with a stop lamp or a turn signal lamp. However, the maximum allowable mounting height above the road surface for stop lamps is 72 inches measured from the center of the item with the vehicle at curb weight. There is currently no restriction on the maximum allowable mount(Illegible Words) however they may not be amounted higher than(Illegible Word) inches on vehicles manufactured on or after January 1, 1972. These restrictions, however, do not apply to supplemental lamps mounted higher than 72 or 88 inches, as long as a vehicle is equipped with stop lamps and turn signal lamps located within the mounting range prescribed by Standard No. 108,(Illegible Word) inches to 72 or 83 inches, as applicable, above the road surface. The Federal motor vehicle safety standards do not apply to a vehicle "after the first purchase of it for purposes other than resale." If the alterations are to be made to vehicles already in the PHI fleet, the question of the legality of your modifications would be covered by regulations of the Bureau of Motor Carrier Safety, if your vehicles are subject to them, and by State and local laws. |
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.