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: aiam2358OpenMr. J. W. Lawrence, Manager, Safety and Environmental Engineering, White Motor Corporation, P.O. Box 91500, Cleveland, OH 44101; Mr. J. W. Lawrence Manager Safety and Environmental Engineering White Motor Corporation P.O. Box 91500 Cleveland OH 44101; Dear Mr. Lawrence: This responds to White Motor Corporation's April 26, 1976, questio whether S5.3.3 and S5.3.4 of Standard No. 121, *Air Brake Systems*, require minimum brake chamber air pressures of 60 psi and 95 psi, respectively, or whether these air pressures are included in the sections only as 'bench marks' on which to base specifications for minimum actuation and release timing in brake systems. Section S5.3.3 specifies in part:; >>>. . .With an initial service reservoir system air pressure of 10 psi, the air pressure in each brake chamber shall, when measured from the first movement of the service brake control, reach 60 psi in not more than 0.45 seconds. . . .<<<; Your understanding that S5.3.3 and S5.3.4 only specify the ai pressures of 60 psi and 95 psi as the basis for timing requirements is correct. Neither value is intended as a requirement that the vehicle be designed to provide a certain level of brake chamber air pressure. The values were based on an understanding of the typical configuration of existing air brake systems at the time the final rule was issued.; In response to your request for interpretation of these sections i view of White's intent to use a lower air pressure than was commonly used in the past, the agency will utilize the stated 60-psi value or a value that is 70 percent of a maximum air pressure (measured by the NHTSA at the brake chamber), whichever is lower. In the case of release, the stated 95-psi value or the value that represents maximum air pressure (measured by the NHTSA at the brake chamber), whichever is lower, will be used. For purposes of this determination, the maximum air pressure in the brake chamber is that obtainable with full brake application when the pressure in the service reservoir is at 100 psi. Use of the maximum air pressure application timing would be unreasonable because of the decreased rate of air pressure build-up that occurs as the brake chambers reach maximum pressure.; The agency will issue an interpretive amendment to S5.3.3 and S5.3.4 t reflect this interpretation.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam0108OpenMr. Stephen E. O'Toole, National Highway Users Conference, National Press Building, Washington, DC 20004; Mr. Stephen E. O'Toole National Highway Users Conference National Press Building Washington DC 20004; Dear Mr. O'Toole:#Thank you for your letter of August 23, to Mr. Georg Nield, concerning the compliance of crane carriers and fire engines with Federal Motor Vehicle Safety Standards 103 and 104.#The crane carrier you have described is a 'motor vehicle' subject to the provisions of the National Traffic and Motor Vehicle Safety Act of 1966. For purposes of the Federal Motor Vehicle Safety Standards the described crane carrier is classified as a 'truck.' Although currently Federal Standards 103 and 104 do not apply to trucks both standards, by amendment, issued April 24, 1968, (33 F.R. 6466-69), will be applicable to trucks manufactured on or after January 1, 1969.#Similarly, a fire truck is a 'motor vehicle' and a 'truck' and subject to all Federal Motor Vehicle Safety Standards applicable to this category of vehicle, including Standards 103 and 104. However, the open cabs found on many fire trucks may make full compliance with Standard 103 impossible. A public docket, Docket No. 24, has been established to receive comments pertaining to the possible classification of fire fighting equipment as a separate vehicle category which might be exempt from certain standards.#Sincerely, Robert M. O'Mahoney, Assistant Chief Counsel for Regulations; |
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ID: aiam4781OpenMr. A. Roger Hirstein Industry Development Center 3M Commercial Graphics Div. 3M Center, BUilding 220-6W-06 St. Paul, MN 55144-1000; Mr. A. Roger Hirstein Industry Development Center 3M Commercial Graphics Div. 3M Center BUilding 220-6W-06 St. Paul MN 55144-1000; Dear Mr. Hirstein: This is in reply to your letter of June 1, l990, t Taylor Vinson of this Office. One of your customers has asked whether 3M's Diamond Grade Reflective Sheeting can be used in a red and white block pattern on the side of a trailer for conspicuity without violating Standard No. 108. Your interpretation is that the Sheeting can be used in addition to devices meeting the requirements of Standard No. 108 but not in place of them. You are essentially correct. However, because we do not know both the pattern and location of the design, whether 'side' includes the front and rear of a trailer, the reflective qualities of your sheeting, who will apply the sheeting, and whether the application will occur before or after delivery of the trailer to its purchaser, we can only provide general guidelines. Under S5.1.3 of Standard No. 108, supplementary reflective devices, i.e., devices other than those required by the standard, may be installed and present on vehicles at the time of their first sale as long as they do not impair the effectiveness of lamps and reflectors required by the standard. The initial determination of whether there is impairment is to be made by the manufacturer who certifies that the vehicle complies with all applicable Federal motor vehicle safety standards. If that decision appears incorrect to the agency, NHTSA will advise accordingly. After the initial sale, the supplementary reflective devices may be installed by a manufacturer, dealer, distributor, or motor vehicle repair business subject to the limitation in section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act that such installation not 'render inoperative in whole or in part' any of the lighting equipment required by Standard No. 108. There is no statutory prohibition under the Act against owner modifications, even if they involve impairing or removing devices required by Standard No. 108. However, the trailer would still remain subject to the laws of the individual States in which the trailer is registered and operated, and (if applicable), to the regulations of the Office of Motor Carrier Standards of the Federal Highway Administration. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam2933OpenLori Malinovsky, Gladiator Southeast, 1250 8th Street, Jacksonville, FL 32205; Lori Malinovsky Gladiator Southeast 1250 8th Street Jacksonville FL 32205; Dear Ms. Malinovsky: This is in response to your letter of October 30, 1978, requestin information on the Federal Odometer Mileage Statement. Section 580.5(b) of Title 49 Code of Federal Regulations provides; >>>A transferor of a new vehicle prior to its first transfer fo purposes other than resale need not disclose the vehicle's odometer mileage.<<<; Manufacturers of vehicles fall within this section and are exempt fro the disclosure requirements because they sell vehicles to dealers who intend only to resell the vehicles. Since Gladiator, Inc. purchased the vans new with the intent to resell them and since the vans are being sold to dealers only who also intend only to resell them, Gladiator is likewise exempt from the disclosure requirements. The dealerships, however, will be selling the vans to customers who will use them for some purpose other than resale. Consequently, the dealerships are required to issue disclosure statements each time they sell a van.; Sincerely, John Womack, Assistant Chief Counsel |
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ID: aiam2585OpenMr. E. C. Elliott, Engineer, Product Safety and Environment, Sullair Corporation, 3700 East Michigan Boulevard, Michigan City, IN 46360; Mr. E. C. Elliott Engineer Product Safety and Environment Sullair Corporation 3700 East Michigan Boulevard Michigan City IN 46360; Dear Mr. Elliott: This responds to your April 1, 1977, question whether your company' wheel mounted portable air compressors qualify as motor vehicles under the National Traffic and Motor Vehicle Safety Act, as amended, (15 U.S.C. S 1381, *et. seq*.).; The answer to your question is yes. Section 102(3) of the Act define motor vehicle as:; >>>any vehicle driven or drawn by mechanical power manufacture primarily for use on the public streets, roads, and highways, except any vehicle operated exclusively on a rail or rails.<<<; Thus, a motor vehicle is a vehicle which the manufacturer expects wil use the public highways as part of its intended function. Vehicles which use the highway on a necessary and recurring basis to move between work sites are motor vehicles. Since your portable air compressors are used in this manner they qualify as motor vehicles. For purposes of regulating motor vehicles, the National Highway Traffic Safety Administration (NHTSA) established vehicle catagories (sic) within that class. Your portable air compressors meet the definition of one of those catagories (sic), trailers.; The following safety standards are applicable to the manufacture o trailers: Safety Standard No. 108, *Lamps, Reflective Devices, and Associated Equipment*, Standard No. 121, *Air Brake Systems*, and Standard No. 106-74, *Brake Hoses* (in the case of trailers equipped with air brakes), and Standard No. 120, *Tire Selection and Rims for Vehicles Other Than Passenger Cars*.; You will have to certify the compliance of your trailers to thes safety standards. Part 566, *Manufacturer Identification* (49 CFR Part 566), specifies identification information which must be submitted to the NHTSA by manufacturers of vehicles and equipment that are regulated by our safety standards. Part 567, *Certification* (49 CFR Part 567, (sic) specifies the content and location of the certification label or tag that must be attached to motor vehicles regulated by our standards.; Sincerely, Joseph J. Levin, Jr. Chief Counsel |
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ID: aiam2627OpenMr. John B. White, Engineering Manager, Technical Information Dept., Michelin Tire Corporation, New Hyde Park P.O., P.O. Box 3467, New York, New York 11040; Mr. John B. White Engineering Manager Technical Information Dept. Michelin Tire Corporation New Hyde Park P.O. P.O. Box 3467 New York New York 11040; Dear Mr. White: This responds to Michelin's March 23, 1977, letter concerning it February 20, 1976 petition for reconsideration of Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*. Your petition for reconsideration was responded to on February 7, 1977 (42 Fr 7140). By this letter, you attempt to resubmit your petition for reconsideration.; Petitions for reconsideration must be received by the agency within 3 days of the publication of a notice. Since the resubmission of your petition is untimely, it has been considered a petition for rulemaking as required by Part 553,35 of our regulations (Code of Federal Regulations, Volume 49). The National Highway Traffic Safety Administration (NHTSA) denies your requested rulemaking.; Your petition suggests that consumers will be confused by the tir label information if the vehicle is not equipped with the tires identified on the label. The agency has determined that confusion will be minimized by the use if the optional heading 'Suitable Tire-Rim Choice.'; Your petition raises a second problem concerning tires of identica size designations manufactured by different companies. These tires may have different inflation pressures even though their sizes are identical. The agency understands that this difference in inflation pressure could result in confusion. Manufacturers, however, con avoid this problem through the use of the manufacturers's name on the tire information label as part of the tire information. Use of the manufacturer's name on the label should distinguish between two otherwise similar tires.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam2199OpenMr. Jackson Decker, Chief Product Engineer, E. D. Etnyre & Co., 200 Jefferson Street, Oregon, IL 61061; Mr. Jackson Decker Chief Product Engineer E. D. Etnyre & Co. 200 Jefferson Street Oregon IL 61061; Dear Mr. Decker: This responds to your letter of January 5, 1976, requesting informatio as to the criteria used to distinguish between a 'new' or a 'used' chassis, in regard to the certification requirements of 49 CFR Part 567 and 49 CFR Part 568.; You described a situation in which a chassis-cab comes to you 'from th field,' lacking both a certification label and an incomplete vehicle manual, under the claim that it is used, with the absence of a certification label explained by a statement that 'a previous body was mounted and removed by the customer and the vehicle was not presented for resale by a distributor or dealer.' You also add that 'the vehicle reportedly has had extremely limited or no use.'; It seems to us that the facts you are describing constitute a fairl obvious misrepresentation by your customer in order to circumvent the requirements of the standards. Even if the implausible allegation that the customer 'mounted and removed' a body were true, it would not remove the requirement for the vehicle to bear a certification label. Our regulations do not limit the labeling requirement to the narrow language of section 114, any vehicle upon completion must be permanently labeled.; Furthermore, for a vehicle to be 'used' today, it must be titled an registered under the laws of some State. Your letter does not discuss this, but we would assume that any vehicle whose owner cannot produce title and registration as a completed vehicle was never completed and used within the meaning of our regulations.; For these reasons, we would expect you as a final-stage manufacturer t treat as new a chassis-cab brought to you for completion under the conditions you described. If the chassis-cab were properly certified in a manner that evidenced prior use, or the customer were able to produce legitimate title/registration documentation showing significant previous use as a completed vehicle, the answer would of course be different.; Please let us know if we can be of further assistance. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4875OpenMr. Chris Lawrence Chang & Lawrence P.O. Box 105-55 Taipei Taiwan R.O.C.; Mr. Chris Lawrence Chang & Lawrence P.O. Box 105-55 Taipei Taiwan R.O.C.; "Dear Mr. Lawrence: This responds to your letter of April 10, 1991 asking for an amplification of my letter of March 21, with reference to the mounting of an electric sign board in the rear window area, or on the rear, of a passenger car. You have asked whether we would 'object to mounting the board in a side window.' Although the only required lighting equipment mounted on the side of vehicles are side marker lamps and reflectors, the most likely place a vehicle will be seen only from the side is when it is crossing an intersection, at a 90-degree angle to the observer. At other times, in the flow of traffic, the side of the vehicle will be viewed obliquely, whether the driver of another vehicle is approaching it from the front or from the rear. Thus, a side mounted electronic sign board may have an even greater potential for impairing the effectiveness of the required front and rear lighting equipment by its potential to distract other drivers from the signals sent by the front and rear lamps when they and the sign board are operated simultaneously. As I explained on March 21, this might also create a partial inoperability of lighting equipment within the meaning of the prohibition discussed in the letter of August 17, l989, that I enclosed. Whether there is an impairment is determined in the first instance by the manufacturer of the vehicle, if it is the installer, or by the dealer, if it performed such work. If a negative determination appears clearly erroneous, NHTSA will inform the manufacturer or dealer responsible for the determination. You have also asked as to other regulatory bodies that need to be consulted before product marketing for a side mounted sign board can begin. This question appears based on the premise that there would be no Federal objection to the side mounted sign. If you choose to sell this device, its use will be subject to the laws of the States in which it is employed. We are unable to advise you on State laws. The American Association of Motor Vehicle Administrators may be able to assist you. The address is 4600 Wilson Boulevard, Arlington, Va. 22203. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam1714OpenMr. David D. Anderson, Chairman, ASTM Subcommittee E17.24, Tire and Slider characteristics, General Motors Proving Ground, Milford, Michigan 48042; Mr. David D. Anderson Chairman ASTM Subcommittee E17.24 Tire and Slider characteristics General Motors Proving Ground Milford Michigan 48042; Dear Mr. Anderson: This is in reply to your letters of October 25, and November 5, 1974 requesting our opinion on whether a tire recently approved by ASTM for special purpose highway and airport runway skid resistance tests must conform to Motor Vehicle Safety Standard No. 109 (49 CFR S 571.109), and whether it may be used for skid resistance testing on highways and airport runways. You describe the tire as a G778-15 of bias-belted construction (2-ply polyester sidewall and 2 fiberglass belts), having a tread with no grooves or sipes. You indicate that due to the tread configuration the tire will not meet the high speed performance requirements (S4.2.2.6) of Standard No. 109.; Standard No. 109 applies according to its terms to '...tires for use o passenger cars...' We believe it reasonable to distinguish these ASTM test tires from tires subject to Standard No. 109. While physically similar to passenger car tires, these tires are manufactured purely as test devices, and for test purpose. We conclude, therefore, that they are not 'for use on passenger cars' within the meaning of Standard No. 109. These tires should be distinguished from experimental program for passenger car tires, which we have found to be subject to Standard no. 109.; Because of this conclusion, there are no NHTSA prohibitions on th tires' use as test tires. They may be used for testing purposes on public highways and airport runways if that testing can be conducted in a safe manner. You should, however, check State and local laws in any area in which you which to conduct testing to see that those laws permit testing if this type. Because the tires are not subject to Standard No. 109 we believe it would be preferable if they did not contain the nomenclature required by Standard No. 109 except insofar as that nomenclature relates to their safe use in testing. This would reduce the chance that they may be used on passenger cars for other than test purposes. We also believe a stronger warning against general use would be proper. We have in mind Something like 'CAUTION: NOT FOR GENERAL HIGHWAY USE - DO NOT USE EXCEPT FOR SPECIAL TEST PURPOSES.'; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam2403OpenMr. Donald I. Reed, Executive Secretary, Trailer Manufacturers Association, 401 North Michigan Avenue, Chicago, IL, 60611; Mr. Donald I. Reed Executive Secretary Trailer Manufacturers Association 401 North Michigan Avenue Chicago IL 60611; Dear Mr. Reed: This is in reply to your letter of September 9, 1976, asking for a interpretation of two provisions of Motor Vehicle Safety Standard No. 108.; You have informed us that 'some manufacturers are mounting lamps usin lock washers and wing nuts rather than conventional nuts to facilitate the installation of lamps when boat trailers are assembled at the dealer level.' S4.3.1 of Standard No. 108 requires that lamps 'shall be securely mounted . . . .' and you asked whether wing nuts, used as you described, provide a mounting that complies with S4.3.1. The answer is that this would appear to provide a secure mounting within the intent of Standard No. 108.; S4.3.1.3 requires that front side marker lamps for trailers be locate as far to the front as practicable, exclusive of its tongue. You ask whether 'the tongue is considered to start where the trailer frame begins to angle inward from its parallel sides . . . .' The answer is yes.; I hope this clarifies Standard No. 108 for you and your members. Yours truly, Frank Berndt, Acting 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.