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: 24099.ztvOpen Ms. Karen Benedix Dear Ms. Benedix: This is in reply to your letter of February 21, 2002, with reference to Federal stop lamp requirements. You have asked for specific requirements "for the number of brake lamps and also the amount of illumination required for each lamp" on passenger cars. Original and replacement equipment stop lamps must comply with Title 49, Code of Federal Regulations, Section 571.108 (Federal Motor Vehicle Safety Standard No. 108, Lamps, Reflective Devices, and Associated Equipment. Table III of Standard No. 108 requires a vehicle to be equipped with at least two stop lamps, one on each side of the vertical centerline, as far apart as practicable, and a center high-mounted stop lamp. The two lower-mounted stop lamps may be supplemented by additional stop lamps (which must be functionally and operationally similar to the required ones, and must not impair the effectiveness of the required stop lamps). The center high-mounted stop lamp must remain a single lamp and cannot be supplemented with an additional lamp. Table III requires that the lower-mounted stop lamps be designed to conform with SAE Standard J586 FEB84, which has been incorporated by reference into Standard No. 108 and contains photometric requirements for these lamps. Table III requires that the center high-mounted stop lamp be designed to conform with SAE Standard J186a, September 1977, except that the photometric requirements for the center lamp are those of Figure 10 of Standard No. 108. I hope that this answers your question. Sincerely, Jacqueline Glassman ref:108 |
2002 |
ID: 2498yOpen Joseph R. Wheeler, Esq. Dear Mr. Wheeler: This is in response to your letter to Kenneth Weinstein of my staff requesting information about actions by the Secretary of Transportation pursuant to Federal Motor Vehicle Safety Standard No. 208, Occupant Crash Protection (49 CFR 571.208). More specifically, you noted that S4.1.4.1 of Standard No. 208 states that, "Except as provided in S4.1.5 [and another section not relevant to your inquiry], each passenger car manufactured on or after September 1, 1989 shall comply with the [automatic restraint requirements]." S4.1.5 of Standard No. 208 provides that: "If the Secretary of Transportation determines, by not later than April 1, 1989, that state mandatory safety belt usage laws have been enacted that meet the criteria specified in S4.1.5.2 and that are applicable to not less than two-thirds of the total population . . ., [the automatic restraint requirements will not go into effect]." You asked whether the Secretary ever made a determination under S4.1.5 regarding State safety belt use laws. The answer is no. Under S4.1.5, the Secretary was not required to make any determination about any State safety belt laws. In fact, the Secretary never did so. Because no determination was made under S4.1.5, the automatic restraint requirements are now in effect for all passenger cars. This letter expresses no opinion about the implications under Tennessee law of the absence of a determination by the Secretary of Transportation regarding any State's safety belt law. Sincerely,
Paul Jackson Rice Chief Counsel /ref:208 d:6/l4/90 |
1970 |
ID: 3196yyOpen William Engel, Assistant Chief Dear Mr. Engel: This responds to your letter asking whether Federal Motor Vehicle Safety Standard No. 206, Door Locks and Door Retention Components, requires door locks on fire trucks. Safety Standard No. 206, which applies to all passenger cars, multipurpose passenger vehicles and trucks, does not exclude fire trucks. Thus, new fire trucks are covered by the standard's general requirement that "components on any side door leading directly into a compartment that contains one or more seating accommmodations shall conform to this standard." [ S4] Standard No. 206 does not apply, however, to certain types of doors which are often found on fire trucks. Since your letter did not provide any details about the design of the specific doors to which you refer, I am unable to determine whether any of the doors on those fire trucks would be subject to Standard No. 206's requirements. For your information, I have enclosed two letters from this office which discuss the applicability of Standard No. 206 to specific doors on fire trucks in more detail. The two letters are an August 13, 1980 letter to Mr. Steenbock and a February 11, 1988 letter to Ms. Salvio. The National Highway Traffic Safety Administration has not adopted any amendments to Standard No. 206 that affect the accuracy of the information contained in these letters. I have also enclosed a current copy of Standard No. 206. I hope this information is helpful. Please contact Elizabeth Barbour of my staff at this address or by telephone at (202) 366-2992 if you have further questions. Sincerely,
Paul Jackson Rice Chief Counsel Enclosures /ref:206 d:ll/7/9l |
1970 |
ID: 3197yyOpen Mr. Marc M. Baldwin Dear Mr. Baldwin: This responds to your September 25, 1991, letter in which you asked "the specific date when 2-point seatbelts were outlawed." Lap, or 2-point, belts have never been outlawed by this agency. Rather, 3-point, or lap/shoulder belts have been required at certain seating positions in certain vehicles. Lap belts are still permitted as the only occupant restraint at a seating position in all vehicles at some seating positions. Such seating positions include all seating positions that are not outboard seating positions and all seating positions that are not forward-facing. Your letter mentioned that you are specifically interested in this information for pending litigation regarding a 1984 passenger car convertible. Passenger car convertibles manufactured in 1984 were permitted to have lap belts installed at all seating positions. The following discussion should clarify NHTSA regulations regarding safety belts. S4.1.2 of Standard No. 208 gives vehicle manufacturers a choice of three options for providing occupant crash protection in passenger cars. Option 1, set forth in S4.1.2.1, requires vehicle manufacturers to provide automatic protection at the front outboard seating positions, lap or lap/shoulder safety belts at all other seating positions, and either meet the lateral crash protection and rollover requirements by means of automatic protection systems or have manual safety belts at the front outboard seating positions such that those positions comply with the occupant protection requirements when occupants are protected by both the safety belts and the automatic protection. Option 2, set forth in S4.1.2.2, requires vehicle manufacturers to provide a lap or lap/shoulder safety belt at every seating position, have automatic protection for the front outboard seats, and have a warnin |
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ID: 3201yyOpen William Engel, Assistant Chief Dear Mr. Engel: This responds to your letter asking whether Federal Motor Vehicle Safety Standard No. 206, Door Locks and Door Retention Components, requires door locks on fire trucks. Safety Standard No. 206, which applies to all passenger cars, multipurpose passenger vehicles and trucks, does not exclude fire trucks. Thus, new fire trucks are covered by the standard's general requirement that "components on any side door leading directly into a compartment that contains one or more seating accommmodations shall conform to this standard." [ S4] Standard No. 206 does not apply, however, to certain types of doors which are often found on fire trucks. Since your letter did not provide any details about the design of the specific doors to which you refer, I am unable to determine whether any of the doors on those fire trucks would be subject to Standard No. 206's requirements. For your information, I have enclosed two letters from this office which discuss the applicability of Standard No. 206 to specific doors on fire trucks in more detail. The two letters are an August 13, 1980 letter to Mr. Steenbock and a February 11, 1988 letter to Ms. Salvio. The National Highway Traffic Safety Administration has not adopted any amendments to Standard No. 206 that affect the accuracy of the information contained in these letters. I have also enclosed a current copy of Standard No. 206. I hope this information is helpful. Please contact Elizabeth Barbour of my staff at this address or by telephone at (202) 366-2992 if you have further questions. Sincerely,
Paul Jackson Rice Chief Counsel Enclosures /ref:206 d:ll/7/9l |
1970 |
ID: 3271yyOpen Mr. John H. Heinrich Re: Case No. 92-2704-00015 Dear Mr. Heinrich: This responds to your letter of December 5, 1991, enclosing a petition for relief from the forfeiture of "200 Spinner Wheel Nuts" seized by the Customs Service as violative of 49 CFR Sec. 571.211. The petitioner expresses the opinion that the wheel nuts should be exempt from DOT regulations, stressing safety considerations and the need to replace worn parts on vehicles manufactured in the l950's. You have also enclosed a copy of the petitioner's own parts list that identifies the wheel nuts as part of a conversion kit, intended to replace disc wheels with wire wheels. Federal Motor Vehicle Safety Standard No. 211, Wheel Nuts, Wheel Discs, and Hub Caps, 49 CFR 571.211, precludes, for use on passenger cars, wheel nuts that incorporate winged projections. The chrome wheel nuts depicted in the Moss Motors catalogue page which you enclosed (Parts Nos. 200-210 and 200-220) clearly incorporate winged projections, and are the type of wheel nuts that Standard No. 211 addresses and prohibits. As such, they may not be imported for sale in the United States. We have discounted petitioner's safety arguments. This is the first allegation in the nearly 24 years that the standard has been in effect that the spinners are required to replace original equipment, implying that there is no acceptable substitute that would conform with Standard No. 211. In our view, no justification has been shown for granting the petition. Sincerely,
Paul Jackson Rice Chief Counsel /ref:2ll d:l/9/92 |
1970 |
ID: nht80-2.4OpenDATE: 04/17/80 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Sholz Oldsmobile, John Galotti TITLE: FMVSS INTERPRETATION ATTACHMT: 8/17/79 letter from Frank Berndt to Mike Champagne TEXT: Mr. John B. Galotti Service Manager Sholz Oldsmobile 35 West Post Road White Plains, New York 10606 Dear Mr. Galotti: This responds to your recent letter requesting information concerning the legal requirements applicable to the installation of fuel separators and auxiliary fuel tanks in motor vehicles. I am enclosing a copy of a letter the agency issued last year which discusses the Federal requirements and implications that would be involved with such activities. That discussion should answer all of your questions. If, however, you require further information, please contact Hugh Oates of my office at 202-426-2992. Sincerely, Frank Berndt Chief Counsel Enclosure [8/17/79 letter from Frank Berndt to Mike Champagne omitted here.] March 10, 1980 NHTSA Office of Chief Counsel NOA 30 Re; Installation of Diesel engine fuel and dirt separators and auxiliary Diesel fuel tanks in trunks of passenger cars. Dear Sir; We have received many requests and inquires from car owners concerning the installation of Fuel separators and Auxiliary fuel tanks in their vehicles. Before we oblige them we would like to know officially what difficulties and liabilities we might run into as far as Federal Laws are concerned. Any assistance you may give us pertaining to this matter will be greatly appreciated. Thank you. Sincerely, John B. Galotti Service Manager |
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ID: nht74-1.22OpenDATE: 04/16/74 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Trelleborgs Gummifabriks Aktiebolag TITLE: FMVSS INTERPRETATION TEXT: This responds to your February 20, 1974, request for a determination of whether two of your motorcycle treadwear indicator designs conform to the S6.4 requirements of Standard 119, New pneumatic tires for vehicles other than passenger cars. The treadwear indicator requirements have been amended by deleting all of that portion of S6.4 that begins "The indicators shall, as a minimum". This means that the manufacturer determines for himself the location and design of the six treadwear indicators required (three in the case of motorcycle tires). He must assure himself that when the indicator is reached, the tread at that point on the tire is worn to a depth of one-sixteenth of an inch (or one-thirty-second of an inch in the case of motorcycle tires). Yours truly, ATTACH. U.S. Department of Transportation, att: Asst Chief Counsel Richard Dyson -- National Highway Traffic Administration FMVSS-119 Motorcycle Tires Dear Mr Dyson. Trelleborg Gummifabriks AB has exported motorcycle tires to U.S.A. for a couple of years. With referens to FMVSS-119, S 6.4 Tread Wear Indicators. We have a little question: If you look on the two enclosed drawings, G-3053-2, you find two different designs for treadwears: "Forslag I" and "Forslag II". Please, inform me if you think the one or both of the two designs are in accordance with your stipulations. Yours sincerely TRELLEBORGS GUMMIFABRIKS AKTIEBOLAG -- Tire Department; Erik Sundelin |
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ID: nht79-4.51OpenDATE: 01/01/79 EST FROM: NHTSA TO: DIETMAR K. HAENCHEN -- ADMINISTRATOR, VEHICLE REGULATIONS VOLKSWAGEN OF AMERICA, INC. TITLE: A78; STANDARD 115 TEXT: Dear Mr. Haenchen: This is in response to your letter of September 25, 1979, requesting an interpretation of the term "restraint system type" as contained in Table I of S4.5.2 of Federal Motor Vehicle Safety Standard No. 115. In addition, this is in confirmation of Volkswagen's statement of the conclusions reached in the meeting with Messrs. Carson, Parker and Schwartz of the National Highway Traffic Safety Administration. The agency has carefully considered your request that "restraint system type" not be interpreted to require a distinction between active and passive belt systems. The agency must deny your request. As the introduction of mandatory passive restraints approaches, information concerning restraint system type is of exceptional importance to the agency. It is important not only to evaluate the overall effectiveness of passive restraints, but also to determine the effectiveness of the various types of passive restraint system types. Consequently, it is necessary that passive belt systems be differentiated from other restraint system types by decoding the vehicle identification number (VIN). The agency has also considered the alternative Volkswagen suggested which is to submit this information separately to the agency on a magnetic tape. Motor vehicle safety research is carried out by many organizations aside from the NHTSA, however, and Standard No. 115 is intended to make information available to these other researchers as well. Consequently, the agency can not accept the alternative you suggest.
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ID: nht80-1.1OpenDATE: 01/03/80 FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA TO: Mr. Glen Brinks TITLE: FMVSR INTERPRETATION TEXT: This responds to your recent letter requesting information concerning the Federal safety regulations applicable to motorcycle fuel tanks and motorcycle trailers. The Federal Motor Vehicle Safety Standard regarding fuel system intergrity, Standard No. 301-75, currently does not apply to motorcycles. Two safety standards would be applicable to the manufacture of motorcycle trailers: Safety Standard No. 108, Lamps, Reflective Devices, and Associated Equipment and Safety Standard No. 120, Tire Selection and Rims for Vehicles Other Than Passenger Cars. The manufacturer of a trailer, including a motorcycle trailer, would have to certify the compliance of the trailer to these two safety standards. Part 566 of our regulations, Manufacturer Identification (49 CFR 566), specifies information which must be submitted to the NHTSA by manufactures of motor vehicles, including trailers. Part 567, Certification (49 CFR 567), specifies the content and location of the certification label or tag that must be attached to motor vehicles regulated by our standards. I am enclosing an information sheet that explains where you can obtain copies of these safety standards and regulations. ENC. November 23, 1979 Joseph Levin NHTSA Dear Mr. Levin; Some time ago, you were a big help to me when I was working on a kit car article for Road & Track magazine. Currently, I am working on another project requiring a knowledge of NHTSA regulations and I wonder if you could help out again. Could you send me a copy of the NHTSA regulations relating to 1) motorcycle fuel tank construction, type of fittings required, fuel lines, etc. and 2) motorcycle trailers? Thank you very much for your consideration. Glenn Brinks |
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.