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 |
|---|---|
ID: aiam1583OpenMr. Paul D. Carfagna, Technical Representative, Plastics Department, E. I. DuPont de Nemours & Company, Incorporated, Wilmington, DE 19898; Mr. Paul D. Carfagna Technical Representative Plastics Department E. I. DuPont de Nemours & Company Incorporated Wilmington DE 19898; Dear Mr. Carfagna: This is in reply to your letter of August 2, 1974, asking for th appropriate method for bending plastic material over the mandrel as specified in Test No. 22 of ANS Z26.1-1966, which is incorporated into Federal Motor Vehicle Safety Standard No. 205 (49 CFR 571.205). You indicate that the test procedure does not specify either the bending force, or whether mechanical means for bending are allowed.; Paragraph 5.22.2 of Test 22 states, in part, as follows: >>>After conditioning, the test specimens shall be immediately ben over a mandrel so that either the entire length of the specimen shall conform to the surface of the mandrel or that it be bent 180 degrees over the mandrel, with the longitudinal axis of the specimen normal to the axis of the mandrel. (emphasis added)<<<; As the procedure does not specify the bending force, or the method i which it is to be applied, the NHTSA would consider as appropriate any force or method of application that would permit the plastic to be bent immediately after conditioning. There is nothing to prohibit the use of hand or mechanical pressure, but it must be applied in such a way that an immediate bending takes place.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam0657OpenAnil Chudgar, Project Engineer, Synthetic Products Department, Imperial Eastman Corporation, 1440 North 24th Street, Manitowoc, WI, 54220; Anil Chudgar Project Engineer Synthetic Products Department Imperial Eastman Corporation 1440 North 24th Street Manitowoc WI 54220; Dear Mr. Chudgar: Thank you for your letter of March 16, 1972, to Miss Grace Robinson inquiring about the possible noncompliance of air brake tubing and hose with Federal Motor Vehicle Standard No. 302.; A copy of Standard No. 302 is enclosed for your information. Paragrap S4.1 lists the materials applicable to this standard. Air brake tubing and air brake hose are not included in the requirements for flammability performance. We trust this information will answer your questions, but if further information is needed, please do not hesitate to contact this office.; Sincerely, Robert L. Carter, Acting Associate Administrator, Moto Vehicle Programs; |
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ID: aiam1026OpenMr. Joseph R. Radzius, Food and Drug Counsel, Dow Corning Corporation, Midland, Michigan 48640; Mr. Joseph R. Radzius Food and Drug Counsel Dow Corning Corporation Midland Michigan 48640; Dear Mr. Radzius: This is in reply to your letter of February 26, 1973, in which yo inquired whether our brake fluid standard, No. 116, has preempted State regulation with respect to silicone-based fluids.; As you know, Standard No. 116 does not presently contain an performance requirements for silicone-based brake fluids. The recent amendment of January 31, 1973 (38 FR 2981) only establishes labeling requirements for these fluids.; Section 103(d) of the National Traffic and Motor Vehicle Safety Act, 1 U.S.C. 1392(d), states that no State shall have a safety standard 'applicable to the same aspect of performance' as a Federal standard that is not identical to the Federal standard. In this case, no 'aspects of performance' at all, other than labeling, are covered by the Federal standard, so the State performance standards other than labeling cannot be said to cover the same aspects of performance. For these reasons the State performance requirements are not preempted by Standard No. 116. To hold otherwise would have the effect of voiding all State regulation of this product, leaving nothing in its place, until a Federal standard came into effect. No such results were intended by the issuance of the labeling amendment.; Work is in process to propose performance standards for silicone-base brake fluids, and we plan to have requirements in effect before very much more time passes. At that time, of course, all State regulations will have to be identical to the Federal standard.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam4529OpenAIR MAIL; AIR MAIL; Mr. Mamoru Arisaka Manager, Automotive Lighting Homologation Sect Stanley Electric Co., Ltd. 2-9-13, Nakameguro, Meguro-ku Tokyo 153, JAPAN Dear Mr. Arisaka: This is in reply to your letter of July 7, 1988, with respect to a motorcycle lighting device called the 'rolling headlamp.' The headlamp is designed to have its vertical plane always perpendicular to the ground regardless of the inclination of the motorcycle. You have asked whether such a device is legally permissible. Motor Vehicle Safety Standard No. 108 does not prohibit alteration of the mounting angle of a headlamp. Although paragraph S4.3.1 requires each lamp to 'be securely mounted on a rigid part of the vehicle,' your lamp appears to be 'securely mounted' even if it is able to rotate. I hope this answers your question. Sincerely, Erika Z. Jones Chief Counsel; |
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ID: aiam1914OpenMr. H. (Speedy) Hirai, Technical Representative, Toyo Kogyo Co., LTd. (MAZDA), Representative Office, 23777 Greenfield Road, Suite 462, Southfield, MI 48075; Mr. H. (Speedy) Hirai Technical Representative Toyo Kogyo Co. LTd. (MAZDA) Representative Office 23777 Greenfield Road Suite 462 Southfield MI 48075; Dear Mr. Hirai: In reply to your letter of April 22, 1975, the 'wheel nuts' covered b Motor Vehicle Safety Standard No. 211 are large, center- mounted hub nuts, one to a wheel, that lock the tire to the axle.; They are not the individual nuts, often six to a wheel, that perfor the same function, and which are generally covered by a wheel disc or hub cap.; Your hub nuts and hub bolts therefore need not be marked with manufacturer's identification code.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4530OpenAIR MAIL; AIR MAIL; Mr. Mamoru Arisaka Manager, Automotive Lighting Homologation Sect Stanley Electric Co., Ltd. 2-9-13, Nakameguro, Meguro-ku Tokyo 153, JAPAN Dear Mr. Arisaka: This is in reply to your letter of July 7, 1988, with respect to a motorcycle lighting device called the 'rolling headlamp.' The headlamp is designed to have its vertical plane always perpendicular to the ground regardless of the inclination of the motorcycle. You have asked whether such a device is legally permissible. Motor Vehicle Safety Standard No. 108 does not prohibit alteration of the mounting angle of a headlamp. Although paragraph S4.3.1 requires each lamp to 'be securely mounted on a rigid part of the vehicle,' your lamp appears to be 'securely mounted' even if it is able to rotate. I hope this answers your question. Sincerely, Erika Z. Jones Chief Counsel; |
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ID: aiam5504OpenMr. Malcolm Bricklin President The Electric Bicycle Company 27426 Pacific Coast Highway Malibu, CA 90265; Mr. Malcolm Bricklin President The Electric Bicycle Company 27426 Pacific Coast Highway Malibu CA 90265; Re: Petition for Exemption Dear Mr. Bricklin: We have received you letter of March 20, 1995, asking for an exemption from two provisions of Motor Vehicle Safety Standard No. 123 on the basis that 'compliance with the standards, in this instance, will constitute a greater hazard to the general public and will result in more accidents caused by operator error than the alternatives that we propose.' I am sorry to inform you that we cannot consider your request in its current form. For your guidance, I enclose a copy of our temporary exemption regulation, 49 CFR Part 555. I suggest that the appropriate basis for your petition under that regulation is section 555.6(d): that you are otherwise unable to sell a vehicle whose overall level of safety is the equivalent of, or exceeds, the overall level of safety of a nonexempted vehicle. When you have filed a petition that provides the information required by Part 555, we shall be pleased to consider this matter further. Because of the need to afford the public an opportunity to comment, a decision is rarely reached until three to four months after a petition is received. If you have any questions on the regulation, Taylor Vinson of this Office will be glad to answer them (202-366-5263, FAX: 202-366-3820). Sincerely, Philip R. Recht Chief Counsel Enclosure; |
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ID: aiam3612OpenMr. M. G. Goode, Engineer-Director, State Department of Highways and Public Transportation, Motor Vehicle Division, Austin, TX 78779; Mr. M. G. Goode Engineer-Director State Department of Highways and Public Transportation Motor Vehicle Division Austin TX 78779; Dear Mr. Goode: This is in response to your letter of September 20, 1983, requestin approval for use of the Texas Certificate of Title and disclosure documents in lieu of the Federal odometer disclosure form which is required by 49 CFR Part 580.; The proposed Texas documents do not conform with the regulation' requirements. To conform, the odometer disclosure statements must include the name and address of both the transferee and the transferor, Section 24(a) of the Texas Certificate of Title Act does require their inclusion. It appears, however, that the disclosure statements do not provide a space for the transferor's (seller's) address. Additionally, a space must be provided on the statements for the transferee's (purchaser's) signature. The Agency considers this signature to be essential because it is an acknowledgment that the purchaser was aware of the mileage. The purchaser, when he signs the document, is prevented from later alleging that he was not informed of the mileage or that the mileage was different from that appearing on the title. If these items are added, the Texas forms will satisfy the Federal odometer disclosure statement requirements, and may be used in lieu of a separate Federal form.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2168OpenMr. D. L. Haines, Divisional Manager, Quality Assurance, B. F. Goodrich Engineered Systems Company, 500 South Main Street, Akron, OH 44318; Mr. D. L. Haines Divisional Manager Quality Assurance B. F. Goodrich Engineered Systems Company 500 South Main Street Akron OH 44318; Dear Mr. Haines: This responds to your August 28, 1975, question whether use o compressed air from a trailer air brake system to supply non-brake equipment such as an air suspension would violate the requirements of Standard No. 121, *Air Brake Systems*.; The answer to your question is no. Standard No. 121 does not contain prohibition on the use of air pressure from the air brake system for powering auxiliary devices. 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. For example, the brake actuation timing would still be required to meet S5.3.3 of the standard.; Although not a requirement of the standard, the NHTSA does consider i appropriate that a pressure protective valve be placed in the line to the auxiliary device so that a rupture of an auxiliary line does not cause depletion of air pressure in the brake system.; With respect to your request for approval of four installations o auxiliary equipment, the NHTSA does not issue approvals of specific designs, and therefore cannot state that vehicles modified in the described fashion would or would not be capable of meeting all requirements of the standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2203OpenMr. David E. Martin, Director, Automotive Safety Engineering, General Motors Corporation, General Motors Technical Center, Warren, MI 48090; Mr. David E. Martin Director Automotive Safety Engineering General Motors Corporation General Motors Technical Center Warren MI 48090; Dear Mr. Martin: This is in response to your letter of February 10, 1976, concerning th definition of 'daylight opening' (DLO) as specified in Motor Vehicle Safety Standard No. 219, *Windshield Zone Intrusion*, 49 CFR 571.219, and concerning the procedure used by General Motors to determine DLO.; Your letter states that General Motors is concerned about th definition of DLO as stated in Standard No. 219, and 'believes that the wording is not easily understood.' The definition of DLO as stated in the Standard is based upon the definition found in paragraph 2.3.12 of Section E, Ground Vehicle Practice, SAE Aerospace Automotive Drawing Standards, September, 1963. The SAE definition was slightly modified to reflect the particular characteristics of Standard No. 219. The last phrase of the SAE definition was changed to read 'as measured parallel to the outer surface of the glazing material,' because there was concern that there might be some confusion if the definition directed measurement by means of a 'vertical projection'.; Your letter describes General Motors' procedure for obtaining DLO, an asks if this procedure is consistent with the definition of DLO as specified in Standard No. 219. The answer to your question is yes. Your illustration (Figure 1) shows that you are measuring 'parallel to the outer surface of the glazing material'. Your Figure 1 is a simplified illustration, of course, since nearly all windshields are curved.; Please contact us if we can be of any further assistance. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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.