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
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ID: aiam3826OpenMr. Fred J. Clark, Vintage Cars & Restoration Center, 560 N.E. F Street, Grants Pass, OR 97526; Mr. Fred J. Clark Vintage Cars & Restoration Center 560 N.E. F Street Grants Pass OR 97526; Dear Mr. Clark: This is in response to your letter of March 5, 1984 in which yo request the opinion of the National Highway Traffic Safety Administration (NHTSA) regarding whether you are permitted, under the Federal Odometer law (Title IV of the Motor Vehicle and Cost Savings Act, 15 U.S.C. S1981, *et seq*.), to turn the odometers, on the restored vintage automobiles which you sell, back to zero. It is the opinion of this agency that you may not.; Section 404 of the Act, 15 U.S.C. S1984, makes it unlawful for an person to 'disconnect, reset, or alter or cause to be disconnected, reset, or altered, the odometer of any motor vehicle with intent to change the number of miles indicated thereon.' The term odometer means an instrument for measuring and recording the actual distance a motor vehicle travels while in operation. Although each motor vehicle which you sell has been restored and although each may be, as you claim, 'better than it was as a new car', the odometers must continue to reflect the actual miles which these vehicles have travelled.; The Federal odometer law also requires that a written disclosure of th mileage registered on the odometer by provided by the seller of a motor vehicle to the purchaser at the time ownership of the vehicle is transferred. If the odometer mileage is incorrect, the Act requires that the purchaser be furnished with a written statement to that effect. 15 U.S.C. 1988, 49 C.F.R. S580.4. All dealers and distributors of motor vehicles are required to retain a copy of each odometer disclosure statement which they issue or receive. These statements are to be retained for four years at their principal place of business. 49 C.F.R. S580.7.; NHTSA found, however, that the value of antique vehicles is determine not by the number of miles travelled by such vehicles, but rather by their age, condition and scarcity. The Agency therefore exempted from the odometer disclosure requirements of section 580.4, vehicles which are 25 years old or older. 49 C.F.R. S580.5(a)(3). NHTSA also exempted from these requirements, vehicles having a gross vehicle weight rating (GVW) of more than 16,000 pounds, S580.5(a)(1), and vehicles which are not self- propelled, S580.5(a)(2). Please note that these are exemptions from the odometer disclosure requirements only. They do not permit tampering with the odometer.; Before you decide whether or not to issue odometer disclosur statements for the 25 years old and older vehicles which you sell, however, you should consider that at least two Federal District Courts have declared the exemptions to be void. The courts found that NHTSA had exceeded its authority in fashioning exemptions to the odometer disclosure requirements. *Lair v. Lewis Service Center*, 428 F.Supp. 778 (D.Neb. 1977), *Davis v. Dils Motor Company*, 566 F.Supp. 1360 (S.D.W.Va. 1983). These cases did not address the validity of the exemption of 25 year old and older vehicles. They addressed instead the validity of the exemption of vehicles having a GVW of more than 16,000 pounds. Their finding, however, that the Agency lacked authority to create the exemptions, may equally apply to this case.; Their findings are not binding on other courts, and the Agenc continues too believe that the exemptions it created are valid. It is important that you consider these decisions, however, since another court could find them well-reasoned or persuasive, and follow the findings that they reached.; If you have additional questions regarding the requirements of th Federal odometer law, please call Heidi Lewis Coleman of my staff at (202) 426-2992 or write to her attention.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1548OpenLee and Winnie Jones, District Directors, National Campers & Hikers Assoc., Virginia Avenue, Sturgis, Michigan 490091; Lee and Winnie Jones District Directors National Campers & Hikers Assoc. Virginia Avenue Sturgis Michigan 490091; Dear Lee and Winnie Jones: This is in response to your letter of June 27, 1974, objecting to th use of extension mirrors on automobiles when a trailer is not in tow.; Although we fully appreciate the possible dangers inherent in the us of extension mirrors, this agency has no authority to regulate the use of such equipment. The authority that Congress has conferred upon the National Highway Traffic Safety Administration relates to the safe manufacture of motor vehicles and motor vehicle equipment, and not directly to its use. Therefore. unless some showing can be made that the design of the mirrors is dangerous, we have no authority to deal with the problem you describe.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3575OpenCarolyn L. Carter, Esq., The Legal Aid Society of Cleveland, Law Reform Office, 1223 West Sixth Street, Cleveland, OH 44133; Carolyn L. Carter Esq. The Legal Aid Society of Cleveland Law Reform Office 1223 West Sixth Street Cleveland OH 44133; Dear Ms. Carter: This is in response to your letter of May 4, 1982, concerning whethe the odometer disclosure form on the Ohio certificate of title has been approved for use in lieu of the Federal odometer disclosure statement. The odometer disclosure statement on the Ohio certificate of title has been approved by the agency for use in lieu of the Federal form.; As requested in your letter, I am enclosing a copy of the agency' letter to the Ohio Bureau of Motor Vehicles approving their form as a substitute for the Federal form.; If you have any further questions, please do not hesitate to write. Sincerely, David W. Allen, Assistant Chief Counsel |
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ID: aiam1118OpenProfessor Dr.-Ing. L. Meckel, Fachgruppe 3.2, Bundesanstalt fur Materialprufung (BAM), Unter Den Eichen 87, 1 Berlin 45, West Germany; Professor Dr.-Ing. L. Meckel Fachgruppe 3.2 Bundesanstalt fur Materialprufung (BAM) Unter Den Eichen 87 1 Berlin 45 West Germany; Dear Professor Dr. Meckel: This is in reply to your question regarding Standard No. 302 'Flammability of Interior Materials,' in your March 15, 1973, letter to Dr. John D. Hoffman, that has been forwarded to this office. You ask whether the test cabinet described in the standard in the 'only right one'.; While the test cabinet described in Standard No. 302 is not the onl test cabinet that could be used for testing under the standard, whether a material complies with the standard will be determined by the National Highway Traffic Safety Administration by means of this described cabinet. The only requirement of the standard is that the material must be capable of meeting the requirements when tested in the described cabinet. Accordingly, any test results derived from the use of a different cabinet should be correlated with the results that would be obtained from the test cabinet described in the standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3125OpenMr. Thomas F. Brown, Executive Engineer, Vehicle Regulations and Standards, Engineering Division, Mack Trucks, Inc., P.O. Box 1761, Allentown, PA 18105; Mr. Thomas F. Brown Executive Engineer Vehicle Regulations and Standards Engineering Division Mack Trucks Inc. P.O. Box 1761 Allentown PA 18105; Dear Mr. Brown:#I regret the delay in responding to your letter of Jul 19, 1979, which requested an interpretation of Federal Motor Vehicle Safety Standard 101-80, *Controls and Displays*. You asked whether placing the turn signal symbol on the turn signal control shown in your illustration so that the arrows are vertical would comply with the standard.#The answer is no. Section 5.2.1 of the standard requires that the turn signal symbol appear perceptually upright to the driver. The purpose of that requirement is to ensure quick and accurate indentification (sic) of the vehicle controls. The upright position of a symbol is determined by referring to column 3 of Table 1 of Safety Standard 101-80. That table shows that the upright position for the turn signal symbol is with the arrows pointing horizontally. Thus, the arrows must point essentially horizontally in the motor vehicle.#Since the symbols required by Safety Standard 101-80 were selected in order to facilitate international standardization and harmonization, it is important that they not be significantly altered from one vehicle to another. This is particularly important in order to ensure that drivers become familiar with the meaning of various symbols including the turn signal symbol.#However. Safety Standard 101-80 does permit manufacturers to supplement the symbols designated in Table 1 of the standard with additional words or symbols for the purpose of clarity. Therefore, nothing in the standard would prevent your company from adding additional symbols, such as curved thinner arrows next to the turn signal symbol, to indicate mode of operation.#Sincerely, Frank Berndt, Chief Counsel; |
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ID: aiam3430OpenH. A. Kendall, Ph.D, Executive Secretary, United Sidecar Association, Inc., 1621 Palomino Lane, Kingwood, Texas 77339; H. A. Kendall Ph.D Executive Secretary United Sidecar Association Inc. 1621 Palomino Lane Kingwood Texas 77339; Dear Dr. Kendall: This responds to you letter of May 4, 1981, requesting information o the applicability of Federal Motor Vehicle Safety Standard to motorcycles and sidecars.; You should note that this agency's current definition of the ter 'motorcycle' (which is relevant to determination of the applicability of safety standards) includes motorcycle-sidecar combinations. The current definition, as set forth in Title 49 of the Code of Federal Regulations, Section 571.3, is as follows:; >>>'Motorcycle' means a motor vehicle with motive power having a sea or saddle for the use of the rider and designed to travel on not more than three wheels in contact with the ground.<<<; Thus, unlike the definition you cite in your letter, the curren definition does not exclude vehicles with full or partial passenger enclosures. Therefore, new motorcycle-sidecar combinations sold as a unit must comply with all safety standards applicable to motorcycles. The same standards apply to both domestically produced and imported motorcycles. The definition to which you refer was once proposed by the agency, but the agency has no plans to adopt that definition for the foreseeable future.; On the other hand, sidecars sold independently are treated as 'moto vehicle equipment' by this agency. As such, and since the sidecars will ultimately be used as part of a motorcycle, certain components of the sidecar must meet safety standards.; These components (to the extent they are in fact used) are: brak hoses, which must comply with Standard 106, pneumatic tires, which must comply with Standard 120, and glazing materials, which must comply with Standard 205.; I have enclosed an information sheet which indicates where you ma obtain copies of safety standards. This agency is not responsible for emission or noise standards, however. We have forwarded a copy of you letter to the Environmental Protection Agency so that agency can provide you information on those standards.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3060OpenMr. Donald Beyer, National Service Manager, Vespa of America Corporation, 355 Valley Drive, Brisbane, CA 94005; Mr. Donald Beyer National Service Manager Vespa of America Corporation 355 Valley Drive Brisbane CA 94005; Dear Mr. Beyer: This is in reply to your letter of June 20, 1979, asking for a interpretation of Federal Motor Vehicle Safety Standard No. 108 as it relates to operation of turn signal lamps by alternating current. You have informed us that Vespa wishes to use such a system on its 1980 motor driven cycles, and you have asked what SAE Standard or method must be followed by the lamps to comply.; Table III of Standard No. 108 requires that any motor driven cycles whose speed attainable in 1 mile exceeds 30 mph, be equipped with a turn signal flasher meeting SAE Standard J590b, *Turn Signal Flasher*, October 1965. The scope of this SAE Standard is that the specifications 'are for nominal 12 or 6 v - dc circuits ....' We construe this to mean that the typical electrical system of a motorcycle is designed to utilize direct current (dc), so that the alternate current (ac) flow from the alternator must be rectified (changed) to dc.; We would have no objections, however, to a turn signal system fed b alternating current if Vespa could demonstrate that such turn signal flashers and lamps would meet all performance requirements of SAE Standard J590b, *Turn Signal Flashers*, as well as the other requirements set forth in Standard No. 108.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2221OpenMr. Robert C. Yates, President, Local 178, United Rubber, Cork, Linoleum and Plastic Workers of America, 2209 West Riverview Avenue, Dayton, OH 45407; Mr. Robert C. Yates President Local 178 United Rubber Cork Linoleum and Plastic Workers of America 2209 West Riverview Avenue Dayton OH 45407; Dear Mr. Yates: Your letter of December 1, 1975, to the Federal Trade Commission concerning the dates molded into tires manufactured by the Dayton Tire and Rubber Company, has been forwarded to this agency for further reply.; Motor Vehicle tires are required by S 574.5 of 49 CFR Part 574, *Tir Identification and Recordkeeping*, to be labeled with an identification number containing certain information. A copy of this regulation is enclosed for your convenience. The last three digits of this number indicate the week and year of manufacture of the tire, as follows: the final digit is the last digit of the year, and the preceding two digits represent the week within that year. The numbering of the weeks begins with '01' for the first full calendar week in each year. For example, '016' indicates that a tire was manufactured during the week beginning Sunday, January 4, 1976, and ending Saturday, January 10. While the precise labeling on the tires that you have described is not clear from your letter, it appears that some of the tires do not comply with this labeling requirement, because November 24 and December 1 were not in the same calendar week of 1975.; I have forwarded a copy of your letter to our Office of Standard Enforcement for such further action as may be appropriate.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2671OpenMr. Ray Sizemore, Crane Carrier Company, 1925 N. Sheridan, P.O. Box 51191, Tulsa, OK 74151; Mr. Ray Sizemore Crane Carrier Company 1925 N. Sheridan P.O. Box 51191 Tulsa OK 74151; Dear Mr. Sizemore: This responds to Crane Carrier Corporation's June 8, 1977, questio whether the maximum time limits specified by S5.1.1 of Standard No. 121, *Air Brake Systems*, for build-up of brake system air pressure from 85 to 100 psi includes the time taken to build up air pressure in an accessory reservoir (for an air starter) that is replenished only when the truck is started.; The answer to your question is no. Section S5.1.1 is a performanc requirement that assures that repeated use of the brakes during vehicle operation will not deplete the available air supply because of insufficient air compressor capacity. The purpose of this requirement only indirectly relates to the initial air pressure build-up that occurs when the vehicle is first started.; The agency's existing laboratory procedure for compliance testin provides for fully charging the air brake system (and any accessory reservoirs which charge automatically in the process) before the test is begun. The engine is shut off while brake system air pressure is reduced to a level that permits a subsequent build-up for measurement purposes. In order to properly test vehicles with air starters, the agency is modifying its procedure to keep the engine running throughout the test, so that the air starter reservoir remains fully charged throughout the measurement period.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3963OpenMr. Don Benfield, Sales Manager, Express Yourself Company', P.O. Box 2357, Anderson, IN 46018; Mr. Don Benfield Sales Manager Express Yourself Company' P.O. Box 2357 Anderson IN 46018; Dear Mr. Benfield: Thank you for your letter of April 12, 1985, concerning stat regulations that might affect a product you are considering. You explained that your product would fit inside the rear window of a vehicle. While we do not have information on state laws, I can explain the possible effect of Federal law on your potential product. I suggest you contact vehicle safety officials in the states in which you plan to sell your product to learn of their laws.; The National Traffic and Motor Vehicle Safety Act authorizes our agenc to issue Federal Motor Vehicle Safety Standards that apply to new motor vehicles and items of motor vehicle equipment. The agency has issued Federal Motor Safety Standard No. 205, *Glazing Materials*, which sets performance requirements for glazing materials used in new motor vehicles and glazing materials sold as items of replacement equipment, a copy of the standard is enclosed. If your product is mounted on, rather than inside, the rear window, it could be affected by Standard No. 205.; The performance requirements of the standard include ones regulatin the light transmittance and abrasion resistance of glazing. Manufacturers of new vehicles must certify that the glazing in windows requisite for driving visibility conforms with the light transmittance and other requirements of the standard. If a manufacturer or dealer places your product on the rear window in a new vehicle prior to the sale of the vehicle, that person must certify that the glazing continues to be in compliance with the requirements of Standard No. 205.; In 1974, Congress amended the National Traffic and Motor Vehicle Safet Act to address the problems of persons tampering with safety equipment installed on a motor vehicle by adding section 108(a)(2)(A) to the Act. That section provides, in part, that:; >>>No manufacturer, distributor, dealer, or motor vehicle repai business shall knowingly render inoperative, in whole or part, any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor safety standard....<<<; Thus no manufacturer, distributor, dealer, or motor vehicle repai business may add material to the glazing materials of a motor vehicle, if that material would render inoperative the glazing's compliance with Standard No. 205.; Section 108(a)(2)(A) does not establish any limitations on a individual vehicle owner's ability to alter his or her own vehicle. Under Federal law, individual vehicle owners can themselves install any material they want on their vehicles, regardless of whether that material would render inoperative the compliance of the vehicle's glazing with the performance requirements of Standard No. 205.; If your product is not mounted on the window itself, it still may b affected by our standards. Standard No. 111, *Rearview Mirrors*, sets performance requirements for rearview mirrors, a copy of the standard is enclosed. The standard provides that each inside rearview mirror must provide a specified field of view to the rear of the vehicle. If the field of view of the inside mirror in a new vehicle is obstructed by anything other than head restraints or seated occupants, then an outside rearview mirror must be provided on the passenger's side of the vehicle.; Thus, if your product were mounted inside the rear window of a ne vehicle by a manufacturer or dealer at the time of its sale, and if installation of your product would mean that the inside rearview mirror would no longer comply with the applicable field of view requirements, they would have to ensure the vehicle was equipped with the necessary additional mirror required by Standard 111. Just as with Standard No. 205, section 108(a)(2)(A) would apply to the installation of your product in used vehicles by manufacturers, distributors, dealers, and motor vehicle repair shops. Thus, if your product is mounted inside the rear window and its installation would mean that the inside rearview mirror would no longer comply with the applicable field of view requirements, an outside passenger side mirror would have to be installed. Again, section 108(a)(2)(A) does not limit the actions of individual vehicle owners.; If you have further questions, please let me know. Sincerely, Jeffrey R. Miller, 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.