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: nht76-1.33OpenDATE: 04/07/76 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Trans-Continental Tire Sales, Inc. TITLE: FMVSS INTERPRETATION TEXT: I am writing to confirm your March 19, 1976, telephone conversation with Mark Schwimmer of this office concerning Federal Motor Vehicle Safety Standard No. 119, New Pneumatic Tires for Vehicles Other than Passenger Cars. Standard No. 119 requires that the symbol "DOT" appear on the sidewall of a non-passenger car tire, as a certification that the tire meets all of the standard's performance and labeling requirements. Assuming that the tire in question does meet those requirements and is so certified, there is no prohibition in the standard against additional labeling such as "Blem" or "A.B.O." I hope this clarifies the status of your tires. Sincerely, ATTACH. March 9, 1976 Frank Berndt -- Acting Chief Counsel, N.H.T.S.A. Dept. of Transportation Re: Federal Motor Vehicle Safety Standards Sec. 119. Dear Mr. Berndt, Can you clarify that truck tires marked "A.B.O." or "Blem" are safe for highway use on the front end of commercial over the road vehicles? The tires in question do meet D.O.T. highway specifications for manufacturers safety, in so for as they are free from defects in workmanship and materials. Please rush clarification as soon as possible. Thank You. Respectfully Yours, Raymond Oleisky, Operations Manager |
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ID: nht79-3.35OpenDATE: 07/17/79 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Paul Schuil TITLE: FMVSS INTERPRETATION TEXT: This responds to your recent letter asking whether smoked, tinted and mirrored windows may legally be used on vehicles operating on U.S. highways. The Federal requirements for glazing materials on motor vehicles are set forth in the Federal Motor Vehicle Safety Standard No. 205 (49 CFR 571.205). This standard specifies performance requirements for the various types of glazing and also the locations in vehicles in which each glazing type may be used. Smoked, tinted and mirrored glazing may be used in certain vehicles in certain locations. For example, smoked glass may be used in side windows of trucks and buses. However, glazing material for use in any vehicle at levels requisite for driving visibility (e.g., windshields) must have a luminous transmittance of at least 70 percent. Most smoked glass would not pass this requirement. I am enclosing a copy of Safety Standard No. 205 for your information. If you have any questions after reviewing the standard, contact Hugh Oates of my office (202-426-2992). SINCERELY, HADCO ALUMINUM & METAL CORPORATION DEAR SIRS, I would like to know if smoked or tinted, & mirrored windows are legal on U.S. highways. I am talking about all four sides of a vehicle. Please send a response to: HADCO ALUMINUM AND METAL CORPORATION PAUL SCHUIL |
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ID: nht81-3.47OpenDATE: 11/30/81 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: G & C Mills Plastics, Inc. TITLE: FMVSS INTERPRETATION TEXT: It has come to our attention that you are distributing auxiliary wind deflectors for use on motor vehicles which may not be in compliance with Federal Motor Vehicle Safety Standard No. 205, Glazing Materials. You received a letter from this agency dated July 13, 1979, and a later letter from the Department of Commerce which may have misled you concerning your responsibilities for complying with Standard No. 205. This matter was brought to our attention by Mr. Paul Hingtgen who told the agency you had shown him the correspondence referred to above. I am enclosing copies of two letters we sent to Mr. Hingtgen which explain why and how the previous letter to you from this agency was misleading. From those letters, you will see that auxiliary wind deflectors are considered to be pieces of "motor vehicle equipment" and, as such, they must be made from glazing materials that are in compliance with Standard No. 205. We hope you will ensure that any wind deflectors you sell or distribute are in compliance with the standard, since you could be subject to substantial civil penalties if you fail to do so. I am also enclosing a copy of Standard No. 205. If after reviewing the enclosed letters you have any questions, please contact Mr. Hugh Oates of my staff (202-426-2992). ENCLS. |
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ID: nht80-3.1OpenDATE: 06/11/80 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Kelsey-Hayes Company TITLE: FMVSS INTERPRETATION TEXT: This responds to your December 7, 1979, letter to Docket No. 79-03; Notice 2 on Heavy Duty Vehicle Brake Systems. That letter was in part a comment to the docket and in part a request for an interpretation of Standard No. 121, Air Brake Systems. The points raised in your comment to the docket will be considered in our final rule on the issues proposed in Notice 2. This letter responds to your interpretive question whether your trailer emergency valve is permitted in accordance with the requirements of section 5.2.1.1 of the standard. The answer to your question is no. Section 5.2.1.1 of the standard requires that vehicles be equipped with a reservoir that is capable of releasing the parking brakes when the air in the service brake system fails. The valve that you suggest would not provide such a reservoir but would merely reroute air from the trailer air supply system which would be used to release the parking brakes. The agency does not believe that this complies with the requirement that a reservoir be provided. Recently, the Berg Manufacturing Company has petitioned the agency to amend the standard in a manner that would permit the type of system that you suggest. The agency is now evaluating that petition and will issue a notice in the near future addressing this issue. We suggest that you closely follow this rulemaking action. |
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ID: nht81-1.41OpenDATE: 03/16/81 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Columbia Manufacturing Company TITLE: FMVSS INTERPRETATION TEXT: MAR 16 1981 NOA-30 Mr. David R. Stevens Quality Control Manager Columbia Manufacturing Company Westfield, Massachusetts 01085 Dear Mr. Stevens: In response to your recent letter, this is to advise you that the 4 mm height requirement for vehicle identification numbers (VIN) does not apply to mopeds (S4.3.1, Federal Motor Vehicle Safety Standard No. 115, 49 CFR 571.115). The letters and number used must be clear, however (S4.3). You should also be aware that if the VIN is to appear on the certification label, it must be at least three thirty-seconds of an inch high (49 CFR 567.4(g)). Sincerely, Frank Berndt Chief Counsel December 29, 1980 NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION 400 Seventh Street, S. W. Washington, D. C. 20590 Attn: Mr. Fred Schwartz Dear Mr. Schwartz: This is to confirm our phone conversation in that we may use a 3/32 character height for our V.I.N., and that the 4 mm character height doesn't apply to mopeds. Please find enclosed a sample of cur new V.I.N. Sincerely, David R. Stevens Quality Control Manager DRS/aco Enc. |
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ID: nht73-6.5OpenDATE: 11/14/73 FROM: E. T. DRIVER -- NHTSA; SIGNATURE BY CHARLES A. BAKER TO: Browning-Ferris Industries, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of October 26 to Mr. J. E. Leysath of this office concerning marker and signal lights on your Mack trucks. Federal Motor Vehicle Safety Standard No. 108 requires that front clearance and identification lamps be located as close as practicable to the top of the vehicle. Mounting these lamps on the top of the vehicles described in your letter does not appear to be practicable because of possible damage to the lamps. If mounting the lamps on the front vertical surface near the top is, in your determination, "as close to the top as practicable," then you have met the requirements of Standard No. 108. Mounting an additional side marker lamp (which you have identified as a corner clearance lamp) on each side of the cab, near the front and top of the cab, would not be prohibited by Standard No. 108. Turn signal lamps and hazard warning signal lamps mounted on the rear of the vehicle may be either red or amber. The color of these lamps was addressed in a Notice of Proposed Rule Making published in the Federal Register on October 25, 1972, (Docket 69-19; Notice 3). It was proposed that amber be eliminated as an optional color for these lamps, but no final decision has been made. |
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ID: nht78-2.28OpenDATE: 01/17/78 FROM: AUTHOR UNAVAILABLE; Joseph J. Levin, Jr.; NHTSA TO: Hendrickson Mfg. Co. TITLE: FMVSS INTERPRETATION TEXT: This responds to your November 21, 1977, letter asking whether a school bus that is propelled by a propane-fueled engine is required to comply with Federal Motor Vehicle Safety Standard No. 301-75, Fuel System Integrity (49 CFR 571.301-75). Paragraph S3 of Safety Standard No. 301-75 specifies that the standard applies to school buses that have gross vehicle weight ratings greater than 10,000 pounds and use fuel with a boiling point above 32 degrees F. Since the boiling point of propane is below 32 degrees F, Safety Standard No. 301-75 would not be applicable to a school bus propelled by a propane engine. Please contact us if you have any further questions. SINCERELY, November 21, 1978 Chief Counsel National Highway Traffic Safety Administration Ref: 571.301 Standard No. 301: Fuel system integrity Dear Sir: Hendrickson Manufacturing Company, as a manufacturer of custom school bus chassis over 10,000 GVWR pounds, requests a ruling that would determine if a school bus propelled by a propane fueled engine is required to comply with Standard 301, fuel system integrity. HENDRICKSON MFG. CO. Kenneth R. Brennan Engineer Mobile Equipment Division CC: M. A. SIGNA; T. F. CRAMER; A. TABB |
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ID: nht78-3.1OpenDATE: 04/27/78 FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA TO: Bureau of Transportation - L.A., CA TITLE: FMVSS INTERPRETATION TEXT: This responds to your March 10, 1978, question whether Standard No. 121, Air Brake Systems, applies to a device that automatically applies to vehicle's service brakes when a sensing bumper mounted at the rear of the vehicle is tripped by contact with an object during a backing maneuver. For purposes of your question, I assume that the vehicle, whether new or used, has been certified to comply with Standard No. 121 prior to installation of the device. The answer to your question is no. Paragraph S3 (Applicability) of Standard No. 121 states that the standard applies to trucks, buses, and trailers equipped with air brake systems (with some specified exceptions). The standard therefore applies only to vehicles, and does not apply to motor vehicle equipment such as the braking actuator you describe. The vehicle must, of course, conform to Standard No. 121 following installation of the device, if the installation occurs prior to the first purchase in good faith for purposes other than resale. After the first retail sale, $ S 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act (the Act) (15 U.S.C. $ S 1397(a)(2)(A)) prohibits, with one exception, manufacturers, distributors, dealers, and repair businesses from knowingly rendering inoperative devices or elements of design installed in satisfaction on a safety standard such as Standard No. 121. |
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ID: nht78-3.16OpenDATE: 11/09/78 FROM: AUTHOR UNAVAILABLE; Joan Claybrook; NHTSA TO: Hon. Bob Wilson - H.O.R. TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of October 17, 1978, concerning a telephone call from your constituent, Mr. Stefan Dagrowski, urging standardization of the type of release on seat belts. Federal Motor Vehicle Safety Standard No. 208, Occupant Crash Protection, issued March 10, 1971 (36FR4600), required that effective January 1, 1972, passenger car seat belt assemblies would be released at a single point by push button action. To that extent, the type of release on seat belts is standardized since our standards are primarily performance oriented, and the manufacturers are free to design however they wish to meet those performance requirements. I hope this information is sufficient to satisfy Mr. Dagrowski's interest in standardized seat belt releases. SINCERELY, Congress of the United States House of Representatives October 17, 1978 Dear Ms. Claybrook: I recently received a telephone call from a constituent, Mr. Stefan Dagrowski, urging standardization of the type of release on seat belts. Your advice and counsel as to anything currently underway in this regard, which I can pass along to Mr. Dagrowski, will be greatly appreciated. Thank you for your attention to this matter and kind regards. Bob Wilson Member of Congress Honorable Joan Claybrook National Highway Traffic Safety Administration |
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ID: nht78-3.7OpenDATE: 01/26/78 FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA TO: Oklahoma Department of Public Safety TITLE: FMVSS INTERPRETATION TEXT: This responds to your letter of December 9, 1977, asking whether the recent amendment of Safety Standard No. 205, Glazing Materials, permits the use of plastic glazing in school buses. The answer to your question is yes. Safety Standard No. 205, as amended December 5, 1977 (42 FR 61465), allows the use of rigid plastic glazing in doors and windows of all buses, including school buses. Please note, however, that plastics cannot be used for bus windshields or in doors or windows to the immediate right or left of the driver. Sincerely, ATTACH. Oklahoma Department of Public Safety December 9, 1977 Hugh Oates -- National Highway Traffic Safety Administration Dear Mr. Oates: RE: Motor Vehicle Safety Standard #205 as amended by the Federal Register Docket #71-1, Notice #6, published 12-5-77 On December 5, 1977, a notice was published in the Federal Register amending Motor Vehicle Safety Standard #205, glazing material, which added to the list specified in ANS Z26, items 4 and 5 allowing the use of plastics in the side windows of buses. My question is, does this also include the use of items 4 and 5 of the ANS Z26 Standard in school buses. Sincerely, Joe Wall, Asst. Director -- Vehicle Inspection Division |
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.