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: nht87-2.87OpenTYPE: INTERPRETATION-NHTSA DATE: 09/03/87 FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA TO: John Scott Hatt TITLE: FMVSS INTERPRETATION TEXT: Mr. John Scott Hatt 1215 N. Quinn Street, Apt #2 Arlington, VA 22209 This is in reply to your letter of June 8, 1987, to this agency asking about the legality of having "a lighten sign on the side of a car door used for advertising purposes." You have also asked whether such a sign would be a safety hazard to other driver s. There is no Federal prohibition against installation of such a sign. Its legality would be determined under local laws where a vehicle with a lighted sign would be registered and operated. You might wish to seek the advice of Arlington traffic officia ls and the Virginia State Police on this subject. It is not possible to say whether such a sign would be a safety hazard. Unlit advertising signs seem permissible in some areas on the sides of buses. |
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ID: nht94-5.14OpenTYPE: INTERPRETATION-NHTSA DATE: December 21, 1994 FROM: Philip R. Recht -- Chief Counsel, NHTSA TO: R. F. Wareham -- Technical Director, Total Vehicle Security, Ltd. TITLE: None ATTACHMT: ATTACHED TO LETTER DATED 1/26/93 FROM JOHN WOMACK TO DAVID H.B. LEE; ALSO ATTACHED TO LETTER DATED 12/9/94 FROM R. E. WAREHAM TO J. WOMACK (OCC 10573) TEXT: We have received your letter of December 9, 1994, to John Womack, the Acting Chief Counsel who responded to David Lee on January 26, 1993. This will confirm that his opinion regarding the "Third Brake Light Conditions Sensor" remains the official positi on of this agency. We shall be pleased to meet with you when you come to Washington late in January. You may phone Taylor Vinson of this Office to make arrangements (202-366-5263). We will be particularly interested in learning more about how the device "will be marketed as a D.I.Y. installation by the car owner." |
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ID: nht69-1.49OpenDATE: 04/10/69 FROM: AUTHOR UNAVAILABLE; Charles A. Baker; NHTSA TO: Department of California Highway Patrol TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of January 24, 1969, to Dr. William Haddon, Jr., former Director, National Highway Safety Bureau, concerning the installation of front identification lamps on various vehicles manufactured in more than one stage. Motor Vehicle Safety Standard No. 108 specifies that multipurpose passenger vehicles, trucks, truck tractors, and buses of 80 inches or more in overall width shall be equipped with three identification lamps on the front of the completed vehicle. This standard is applicable to the completed vehicle and it is the responsibility of the final assembler to certify that such vehicle conforms to the standard. A manufacturer of a chassis-cab is not required to mount identification lamps on the chassis-cab. However, if he does so, the manufacturer who adds a body to the chassis-cab is not required to add identification lamps to the front of the body. |
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ID: nht79-4.37OpenDATE: 11/29/79 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Mr. B. Stine TITLE: FMVSS INTERPRETATION TEXT: Bennie Stine 1602 Emil Street Madison, Wisconsin 53713 Dear Mr. Stine: This responds to your letter asking whether you may remove the electronic antilock device from your vehicle. You state that the vehicle is unsafe with the antilock device in operation. The National Highway Traffic Safety Administration believes that a properly maintained antilock device can increase the safety of heavy duty vehicles. Accordingly, the agency encourages you to make sure that the antilock device on your vehicle is in the proper working order. However, if you want to remove the device, it is perfectly legal to do so. We suggest that you take the vehicle to its manufacturer or a representative of the manufacturer to be sure that the device is correctly removed and that the remaining braking system is properly adjusted. Sincerely, Frank Berndt Chief Counsel |
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ID: nht71-4.20OpenDATE: 10/14/71 FROM: AUTHOR UNAVAILABLE; C. A. Baker for E. T. Driver; NHTSA TO: Forse Cleanamation TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of September 29, 1971, to Mr. J. E. Leysath of this Office requesting information relative to the lighting requirements applicable to your E - Z Tow towing unit. The E-Z Tow unit is a "motor vehicle" as defined by the National Traffic and Motor Vehicle Safety Act of 1966 since it is a "vehicle . . . drawn by mechanical power manufactured primarily for use on the public streets, roads, and highways." However, since it is designed to "tow" rather than to "carry" property, the E-Z Tow unit is not a "trailer" as defined for purposes of the Federal Motor Vehicle Safety Standards. Since it is an unclassified "motor vehicle," the lighting requirements of Federal Motor Vehicle Safety Standard No. 108 are not applicable; therefore, you need only to comply with the lighting requirements of the States in which you sell or use the unit. |
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ID: nht67-1.21OpenDATE: 05/15/67 FROM: AUTHOR UNAVAILABLE; George C. Nield; NHTSA TO: Fire Apparatus Manufacturers Association, Inc. TITLE: FMVSS INTERPRETATION TEXT: Your March 7, 1967, letter to Dr. William Haddon, Jr., requested that you be advised regarding the applicability of lighting requirements, as spacified in the Initial Motor Vehicle Safety Standards to fire apparatus. With exception as noted in Section 255.7, page 2409 of the Federal Register, Volume 32, Number 23, dated February 3, 1967 (copy enclosed), the lighting requirements will be applicable to fire apparatus. Initial Standard No. 108 covers lighting requirements for vehicles (as specified therein) that are 80 or more inches wide overall and becomes effective January 1, 1968. A Notice of Proposed Rule Making (see page 2418) of enclosed Federal Register includes a Proposed Amendment to Standard No. 108 and a Proposed Initial Standard No. 112, covering vehicles (as specified therein) that are less than 80 inches wide overall. It is anticipated that the proposed Amendment and Initial Standard No. 112 will also become effective on January 1, 1968. Thank you for your interest in the Motor Vehicle Safety Standards. FIRE APPARATUS MANUFACTURERS ASSOCIATION, INC. March 7, 1967 Dr. WILLIAM HADDON, JR. -- NHTSA We have an inquiry from one of our members as to whether or not all of the lighting standards under the Initial Federal Motor Vehicle Safety Standards as published in the Federal Register Volume 32, Number 23, Part II dated Friday, February 3, 1967 will apply to fire apparatus. Will you please advise us on this matter so that we may inform our members. Thank you for your prompt attention. C. L. Koepenick Secretary-Treasurer |
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ID: nht76-5.28OpenDATE: 01/07/76 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Wisconsin Trailer Company Inc. TITLE: FMVSR INTERPRETATION TEXT: This responds to your November 26, 1975, request for confirmation that the NHTSA permits the establishment of gross axle weight ratings (GAWR) for trailer axles based on use at a speed of less than 60 mph. Your interpretation is incorrect. In the April 28, 1975, interpretation letter to Mr. James Srch that was enclosed in the NHTSA's recent letter to you, it was stated that ". . . NHTSA has found it necessary to specify that GAWR's and GVWR's be calculated on the basis of highway speeds and not qualified by reduced speed ratings . . . ." Since the NHTSA's November 20, 1975, letter to you, the agency has published a proposal that would amend the definition of GAWR to conform to this interpretation. A copy is enclosed for your information. YOURS TRULY, WISCONSIN TRAILER COMPANY, INC. November 26, 1975 Frank A. Berndt Acting Chief Counsel U.S. Department of Transportation National Highway Traffic Safety Adm. Reference: N40-30 I have your letter of November 20th, in which you discussed Gross Axle Weight Rating and Gross Vehicle Weight Ratings at an attainable speed of 60 miles per hour. Enclosed is a copy of amendments to Title 49, which became effective October 1, 1975 . . . with exceptions as provided. It is our interpretation that trailer manufacturers are permitted to rate their product at a speed lesser than 60 miles per hour. Are we correct in our interpretation? Your early reply would be appreciated. LeRoy E. Mueller President |
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ID: nht72-6.19OpenDATE: 09/06/72 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: University of Puerto Rico TITLE: FMVSR INTERPRETATION TEXT: This is in response to your letter of July 20, 1972, requesting that we obtain for you vehicle identification numbers for vehicles involved in certain defect notification campaigns. At present, manufacturers are not required to furnish vehicle identification numbers to the NHTSA. While they are required to compile them for their own purposes as part of their Owner Lists, as we indicated in our letter to you of July 5, 1972, we do not consider your request to be a justifiable reason for requesting this information from manufacturers. We appreciate your efforts with regard to the survey you have to conduct, but we do not believe it appropriate to require manufacturers to prepare and submit information to us purely on the basis of private individual requests. Your letters, and others we have received, however, have demonstrated that a legitimate safety purpose can be served if identification numbers of vehicles involved in campaigns are made available to public and other groups. As a result, the NHTSA has determined to process to amend the Defect Reports regulations to require all manufacturers to supply vehicle identification numbers as part of the information they must submit pursuant to those regulations. Vehicle identification numbers would then be available to the public as a matter of course. We have enclosed copies of quarterly reports which refer to three of the four campaigns you listed (General Motors, campaign number 71-G230: Toyota, campaign number (Illegible Word); and Volkswagen, campaign number 71-0005). Information on the fourth, Ford campaign number 71-0045, was not required to be submitted, and the manufacturer has not voluntarily submitted any to us. |
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ID: 1982-2.31OpenDATE: 08/02/82 FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA TO: The Continental Insurance Companies -- William J. Benzie TITLE: FMVSS INTERPRETATION TEXT:
Mr. William J Benzie Corporate Fleet Coordinator The Continental Insurance Companies Eighty Maiden Lane New York, N.Y. 10038
Dear Mr. Benzie:
This responds to your recent letter asking about Federal regulations pertaining to automotive glass and to windshield repair kits. You are particularly interested in the Novus windshield repair method and ask if it has been approved by the agency.
The agency has issued Safety Standard No. 205, Glazing Materials (49 CFR 571.205), which specifies performance and location requirements for glazing used in motor vehicles. There are no standards or regulations specifically governing Windshield repair methods. However, I am enclosing a letter of interpretation which the agency issued in 1975 regarding the Novus method of windshield repair. I am also enclosing a letter of interpretation which discusses the general responsibilities of persons who modify or repair vehicles, including windshields, under the National Traffic and Motor Vehicle Safety Act, as amended 1974 (15 U.S.C. 1381 et seq.). Please look closely at the third and fourth paragraphs of that letter. Please note that the agency does not grant prior approval of any motor vehicle, motor vehicle equipment or method of vehicle repair. It is the responsibility of the vehicle or equipment manufacturer to certify that its products are in compliance with all applicable safety standards and regulations.
I hope the enclosed information will answer all of your questions. Sincerely,
Original Signed By Frank Berndt Chief Counsel |
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ID: nht90-3.37OpenTYPE: Interpretation-NHTSA DATE: July 31, 1990 FROM: W. Marshall Rickert -- Administrator, Maryland Department of Transportation, Motor Vehicle Administration TO: Chief Counsel, NHTSA TITLE: Re After Market Glazing ATTACHMT: Attached to Maryland Vehicle Law, sections 22-103 and 104, page 320 (text omitted); Also attached to Maryland Vehicle Inspection procedures regarding mirrors and vehicle glazing, pages 227 and 228 (text omitted); Also attached to letter dated 1 0-15-90 from P.J. Rice to W.M. Rickert (A36; Std. 205) TEXT: Section 22-104 of the Maryland Vehicle Law states that a person may not willfully or intentionally remove or alter any safety device or equipment that has been placed on any motor vehicle, trailer, semitrailer, or pole trailer in compliance with any law, rule, regulation, or requirement of any officer or agency of the United States or of this State, if it is intended that the vehicle be operated on highways in this State, unless the removal or alteration is permitted by rule or regulation adopted by the Administrator. Maryland's existing rule and regulation prohibits any type of after market tinting; however, there has been a lot of legislative interest in permitting some form of after market tinting due to medical conditions. We are interested in amending our rule and regulation to permit the installation of after market tinting. If this would create a problem from your standpoint, please advise us on or before October 1, 1990. Attached is a copy of sections 22-103 and 22-104 of Maryland Vehicle Law (text omitted). Also attached is a copy of Maryland vehicle inspections procedures regarding mirrors and vehicle glazing, pages 227 and 228 (text omitted). |
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.