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: nht94-7.38OpenDATE: March 17, 1994 FROM: Eric T. Stewart -- Engineering Manager, Mid Bus TO: Office of Chief Counsel, NHTSA TITLE: Reference: Amendment to FMVSS 571.217 published in the Federal Register November 11, 1992 (Docket 88-21 notice No. 3) ATTACHMT: Attached to letter dated 4/1/94 from John Womack to Eric T. Stewart (A42; Std. 217); Also attached to letter dated 7/7/93 from John Womack to Thomas D. Turner TEXT: The background to this amendment indicates that the "final rule requires a minimum of 1 inch wide retro-reflective tape ...." (page 49421). The actual amendment reads that the retro-reflective tape is to be "a minimum 3 centimeters wide". (page 49425) (CFR571.217 S 5.53(c)). These two dimensions are not the same since 1.00 inch is equal to 2.54 centimeters. I believe that the intent of this rule making was to make the retro-reflective tape 1.00 inch wide and an error has taken place in converting the dimension to metric units. I am requesting written clarification indicating how wide NHTSA wants the retro-reflective tape around the outside perimeter of a school bus emergency door. If you have any questions, please call me at (419) 221-2525. |
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ID: nht70-2.35OpenDATE: 11/12/70 FROM: AUTHOR UNAVAILABLE; R. H. Compton; NHTSA TO: Department of California Highway Patrol TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of October 21, 1970, to the National Highway Safety Bureau, concerning environmental tests for sealed beam headlamps used on motocycles and motor-driven cycles. Federal Motor Vehicle Safety Standard No. 108 requires that motorcycle and motor-driven cycle headlamps conform to SAE Standard J584. This SAE Standard, in turn, permits optional use of "one 7-in. sealed beam unit or one 5 3/4-in. Type 1 and one 5 3/4-in. Type 2 sealed beau units meeting the requirements of SAE J579". Therefore, unsealed motorcycle and motor-driven cycle headlamps must conform to the vibration, moisture, dust and corrosion test requirements of SAE J584. Glass sealed beau motocycle and motor-driven cycle headlamps, which are designed specifically to conform to the requirements of SAE J584 (including photometric values), and which are not intended for use on other vehicles, must conform to the vibration, moisture and corrosion test requirement of SAE J584. Such test requirements would not, however, be applicable if a manufacturer elected to provide optional headlamps meeting the requirements of SAE J579a. |
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ID: 77-2.9OpenTYPE: INTERPRETATION-NHTSA DATE: 04/13/77 FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA TO: Dennis J. Mahr; Attorney at Law TITLE: FMVSR INTERPRETATION TEXT: This responds to your February 23, 1977, letter asking whether Ford Motor Company's record keeping practices conform to the regulations of the National Highway Traffic Safety Administration (NHTSA). Your letter refers to material allegedly destroyed by Ford pertaining to accident and recall information involving headlamp concealment devices in 1967 Mercury Cougars. The NHTSA is unable to ascertain from the information that you have submitted whether or not Ford's record keeping violates our requirements. The NHTSA implemented on August 20, 1974, a regulation requiring manufacturers to retain for a period of 5 years records generated or acquired after August 15, 1969, concerning motor vehicle malfunctions that may be related to motor vehicle safety (49 CFR 576, Record Retention). Since the recall to which you refer occurred prior to this regulation, it is possible that the identified records were generated of acquired prior to the promulgation of the regulation, and therefore, the destruction of these records would not necessarily mean that Part 576 was violated. The NHTSA has a public file concerning the headlamp concealment devices referred to in your letter. This file containing 26 pages of information will be sent to you by our Technical Reference Branch under separate cover. |
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ID: nht95-6.3OpenTYPE: INTERPRETATION-NHTSA DATE: August 8, 1995 FROM: Nancy Tavarez -- Bietrix Industries, Inc. TO: John Walmack -- Chief Council ATSA TITLE: NONE ATTACHMT: ATTACHED TO 08/30/95 LETTER FROM JOHN WOMACK TO NANCY TAVAREZ (REDBOOK 2; STD. 108) TEXT: Dear Mr. Walmack: We are currently importing Phoenix Halogen Auto Bulbs H4 series, H3, H1 and 9000 series-HBI for the USA market. Mr. Taylor Benson recently informed us that these lights required DOT approval. We request you to please inform via fax the procedure to follow in order to obtain DOT approval for our automotive lights. We greatly appreciate your cooperation in this matter. |
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ID: nht71-5.24OpenDATE: 12/15/71 FROM: AUTHOR UNAVAILABLE; E. T. Driver; NHTSA TO: Mobilefreeze Co., Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of September 7, 1971, to Mr. Stan Haransky, Truck Body and Equipment Association, Inc., concerning the mounting height of lamps and reflectors on your motor-cycle trailers. A copy of Federal Motor Vehicle Safety Standard No. 108, "Lamps, Reflective Devices and Associated Equipment" is enclosed for your information. The minimum mounting height for lamps and reflectors listed in Table IV of this Standard is 15 inches. We do not have the authority to exempt any motor vehicles from meeting these requirements. Enc. |
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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: nht95-3.79OpenTYPE: INTERPRETATION-NHTSA DATE: August 8, 1995 FROM: Nancy Tavarez -- Bietrix Industries, Inc. TO: John Walmack -- Chief Council ATSA TITLE: NONE ATTACHMT: ATTACHED TO 08/30/95 LETTER FROM JOHN WOMACK TO NANCY TAVAREZ (REDBOOK 2; STD. 108) TEXT: Dear Mr. Walmack: We are currently importing Phoenix Halogen Auto Bulbs H4 series, H3, H1 and 9000 series-HBI for the USA market. Mr. Taylor Benson recently informed us that these lights required DOT approval. We request you to please inform via fax the procedure to fol low in order to obtain DOT approval for our automotive lights. We greatly appreciate your cooperation in this matter. |
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ID: nht74-3.26OpenDATE: 09/25/74 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: O'Bannon & Gonce TITLE: FMVSS INTERPRETATION TEXT: In response to your request I have enclosed a copy of Federal Motor Vehicle Safety Standard No. 109, New Pneumatic Tires (49 CFR @ 571.109) as it appears in the current edition of the Code of Federal Regulations. The table listing load and inflation values for the G78-15 tire size designation is Table I-J of Appendix A. Except for the addition of test loads at 16 and 18 psi, the load and inflation information for the G78-15 tire size designation has not changed since the first publication of the information on April 18, 1968 (33 FR 5949), a copy of which is also enclosed. |
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ID: nht72-6.41OpenDATE: 08/09/72 FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA TO: International Housing Inc. TITLE: FMVSR INTERPRETATION TEXT: This is in reply to your letters of June 9 and July 21, 1972 to Mr. E. T. Driver requesting further clarification of the Tire Identification and Recordkeeping regulations (49 CFR 574) concerning the responsibility of vehicle manufacturers and dealers in cases where no agreement can be reached between the two as to the method of recording the required information. Under the circumstances you describe it is the vehicle manufacturer who is ultimately responsible for maintaining the name and address of the purchaser of the vehicle and a record that will supply enough information concerning the tires to enable the manufacturer to conduct a defect notification if the tires are found to be defective. |
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ID: nht75-1.49OpenDATE: 08/25/75 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Pirelli Tire Corporation TITLE: FMVSS INTERPRETATION TEXT: Please forgive the delay in responding to your letter of May 5, 1975, which inquired about the permissibility of iron-branding the letters "N.A." on the sidewall of certain passenger car tires to indicate that they are not adjustable under your warranty. Federal Motor Vehicle Safety Standard No. 109, New Pneumatic Tires -- Passenger Cars, specifies labeling and performance requirements for such tires. The NHTSA has no objection to the provision of additional labeling information such as the "N.A." which you have suggested. However, the tire must continue to be capable of meeting the standard's performance requirements at the completion of the hot-branding process. Sincerely, ATTACH. May 5, 1975 Office of Chief Counsel -- N.H.T.S.A. Att: Mark Schwimmer, attorney Sir: In reference to the phone conversation Friday morning, I am sending you a written request for the following information: We would like to know if there are some objections from your office to iron-brand N.A. (not adjustable) tires which may present possible vibrations, bleeding white sidewall, unbalance or which may not deliver the 40.000 mile guarantee even though they belong to a tire line which has the 40.000 mile guarantee. The tires involved (which are approximately 5000 units) will be sold at a discount of about 50%. Of course such tires have all the safety guarantee as the regular premium ones. Your prompt attention to this matter will be greatly appreciated. Sincerely, PIRELLI TIRE CORPORATION -- G. Buzzi-Ferraris, Technical Manager
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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.