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: aiam0155OpenMr. J. Wuddel, Ing., Westfalische Metall Industrie, Hueck and Company, 4780 Lippstadt, Germany, Federal Republic; Mr. J. Wuddel Ing. Westfalische Metall Industrie Hueck and Company 4780 Lippstadt Germany Federal Republic; Dear Mr. Wuddel: Thank you for your letter of March 22, 1969, requesting a clarificatio of the location requirements for license plate lamps as specified in Federal Motor Vehicle Safety Standard No. 108.; As you indicated, Standard No. 108 currently references SAE Standar J587B and also permits the location of license plate lamps at the top, side or bottom of the license plate. The latest revision of SAE Standard J587 (J587c) is (sic) no way changes the location provision of Standard No. 108. Therefore, a license plate lamp assembly may be tested according to SAE Standard J587b and Standard No. 108 when the license plate is illuminated from the bottom.; Section 103(d) of the National Traffic and Motor Vehicle Safety Act o 1966 states: 'Whenever a Federal motor vehicle safety standard established under this title is in effect, no State or political subdivision of a State shall have any authority either to establish, or to continue in effect, with respect to any motor vehicle or item of motor vehicle equipment any safety standard applicable to the same aspect of performance of such vehicle or item of equipment which is not identical to the Federal standard.' Therefore, any State regulations on the location of license plate lamps should be identical to the requirements of Standard No. 108 on and after the effective date of the standard.; Sincerely, Charles A. Baker, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service; |
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ID: aiam2626OpenMr. H. K. Scheller, Project Engineer, AM General Corporation, 32500 Van Born Road, Wayne, MI 48184; Mr. H. K. Scheller Project Engineer AM General Corporation 32500 Van Born Road Wayne MI 48184; Dear Mr. Scheller: This is in reply to your letter of June 10, 1977, petitioning fo temporary exemption, on behalf of an electric truck, from Federal Motor Vehicle Safety Standards Nos. 102 and 301.; Your petition is inadequate for consideration at this time. manufacturer may apply for temporary exemption upon only one basis, while AM General's petition is an attempt to apply both on grounds of hardship (49 CFR 555.6(a)) and of low- emissions vehicle development (555.6(c)). On either basis the petition lacks the full complement of information required by Part 555.; In view of the fact that AM General has previously received a exemption (NHTSA Exemption No. 74-4) under 555.6(c) I suggest that you reapply on that basis, using the company's previous petition as a guide. Your present petition is inadequate under 555.6(c) because it does not provide 'reasons why the failure to meet the standard does not unreasonably degrade the safety of the vehicle' (555.6(c)(2)(iv)). It also does not supply the results of tests conducted on conforming vehicles to substantiate certification to Standards Nos. 102 and 301-75 (555.6(c)(2)(ii)), you have merely stated that AM General manufactures vehicles that meet these standards.; Under our general requirements for petitions, AM General must als provide its views why the granting of the petition would be in the public interest and consistent with the objectives of the National Traffic and Motor Vehicle Safety Act (555.5(b)(7)).; We shall be pleased to consider your petition further when you hav furnished the information requested.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam1718OpenMr. Newman V. Gill, Marketing Manager, Barns (sic) Lumber and Manufacturing Co., 2813 Lombardy Lane, P.O. Box 20160, Dallas, TX 75220; Mr. Newman V. Gill Marketing Manager Barns (sic) Lumber and Manufacturing Co. 2813 Lombardy Lane P.O. Box 20160 Dallas TX 75220; Dear Mr. Gill: This responds to your November 21, 1974, request for a determinatio that the Barnes Models RTY, RT-XF, RTDF, RTCF, RTA, and GWPHD trailers all qualify as 'Heavy hauler trailers' and, as such, are not required to meet the requirements of Standard No. 121, *Air brake systems, until September 1, 1976.; 'Heavy hauler trailer' is defined in the standard as follows: >>>'Heavy hauler trailer' means a trailer with one or more of th following characteristics:; (1) Its brake lines are designed to adapt to separation or extension o the vehicle frame, or; (2) Its body consists only of a platform whose primary cargo-carryin surface is not more than 40 inches above the ground in an unloaded condition, except that it may include sides that are designed to be easily removable and a permanent 'front-end structure' as that term is used in S 393.106 of this title.<<<; The TRY, (sic) RT-XF, RTDF, RTCF, and RTA models appear to have brak lines that are designed to adapt to extension of the vehicle frame.; We would consider the cargo-carrying surface to the GWPHD to be th horizontal portion of the frame rails, and that it therefore would have a bed-height of less than 40 inches.; I would like to emphasize that your vehicles appear to qualify for thi exemption, but that it exists only until September 1, 1976. Each vehicle manufactured after that date must conform to the requirements of the standard.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam3134OpenMr. J. W. Kourik, Chief Engineer, Brake Products, Wagner Electric Corporation, 11444 Lackland Road, St. Louis, MO 63141; Mr. J. W. Kourik Chief Engineer Brake Products Wagner Electric Corporation 11444 Lackland Road St. Louis MO 63141; Dear Mr. Kourik:This responds to your September 17, 1979, letter askin whether Standard No. 121, *Air Brake Systems*, permits manufacturers to install antilock devices on only one axle of a multi-axle vehicle. The answer to your question is yes.; As you know, the decision in *PACCAR v. NHTSA*, 573 F.2d 632 (9th Cir 1978), *cert. den'd; , 439 U.S. 862 (Oct. 2, 1978) invalidated the antilock requirements a they apply to trucks and trailers. Accordingly, the antilock provisions of the standard no longer apply to those vehicles. A manufacturer that desires to install antilock devices can do so at its own discretion and to any extent that it considers appropriate. This includes the installation of antilock devices on only one axle. Of course, any installation of devices affecting braking must not impair the brake system's compliance with the standard.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1454OpenMr. Robert S. Priver, Law Offices of William and Black, 615 South Flower Street, Suite 1111, Los Angeles, CA 90017; Mr. Robert S. Priver Law Offices of William and Black 615 South Flower Street Suite 1111 Los Angeles CA 90017; Dear Mr. Priver: Thank your for your letter of March 29, 1974, requesting informatio and documentation concerning Fuel System Integrity Standards.; The GSA 515/26 Standard which you mentioned was published July 15 1966, and was effective October 13, 1967. This standard was effectively supplanted by Federal Motor Vehicle Safety Standard No. 301 which was effective January 1, 1968. A copy of this original Standard No. 301 is enclosed for your information along with a recent amendment (F.R. 39, 10586, March 21, 1974) that substantially upgrades the requirements of this standard.; We do not consider it appropriate to give advice concerning privat incidents or controversies, beyond what is contained in our regulations and other public issuances. You may find it helpful to contact private-sector groups such as the Society of Automotive Engineers for further information.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam5367OpenMr. Fred Carr, Engineer Utilimaster 65266 State Road 19 P. O. Box 585 Wakarusa, IN 46573-0585; Mr. Fred Carr Engineer Utilimaster 65266 State Road 19 P. O. Box 585 Wakarusa IN 46573-0585; "Dear Mr. Carr: This responds to your question asking whether Federa Motor Vehicle Safety Standard No. 211, Wheel nuts, wheel discs, and hub caps, applies to 'motor vehicle equipment relating to light duty, medium duty, and heavy duty trucks or truck manufacturers.' As explained below, Standard No. 211 does not apply to trucks, or truck equipment. S2. Application of Standard No. 211 states the following: This standard applies to passenger cars, multipurpose passenger vehicles, and passenger car and multipurpose passenger vehicle equipment. 'Multipurpose passenger vehicle' is defined at 49 CFR 571.3 as a motor vehicle designed to carry 10 persons or less, which is constructed either on a truck chassis or with special features for occasional off-road operation. Since Standard No. 211 applies only to passenger cars, multipurpose passenger vehicles, and their equipment, Standard No. 211 does not apply to trucks, or truck equipment. 'Truck' is defined at 49 CFR 571.3 as a motor vehicle designed primarily for the transportation of property or special purpose equipment. Accordingly, manufacturers of trucks or truck equipment are not required to certify their trucks and truck equipment to the requirements of Standard No. 211. I hope this information is helpful. If there are any further questions, please contact Dorothy Nakama of my staff at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam1961OpenMr. R. J. Reed, V. P., Steer Safe, Inc., Box 149, Deming, NM 88030; Mr. R. J. Reed V. P. Steer Safe Inc. Box 149 Deming NM 88030; Dear Mr. Reed: This is in response to your letter of May 22, 1975, in which yo request a ruling that a person who installs a 'Steer Safe' steering stabilizer is not required to recertify the vehicle in which it is installed. You refer to a letter to Safety Products, Inc., dated August 24, 1972, in which it was stated that we would accept a determination that the installation of a steering stabilizer manufactured by Safety Products did not constitute remanufacturing, and that a person who installed such a device need not recertify the vehicle on which it is installed.; Since that letter, the National Highway Traffic Safety Administratio has issued regulations covering the alteration of completed, certified motor vehicles before their sale to a purchaser for purposes other than resale. These regulations (49 CFR SS 567.7 and 567.8, copy enclosed) supersede opinions such as the one we provided Safety Products, which was based solely on the more general provisions of the National Traffic and Motor Vehicle Safety Act and the certification regulations in effect at that time. Under the new regulations, which were effective February 1, 1974, an alteration which either (1) invalidates a vehicle's existing weight ratings or (2) involves installation of other than 'readily attachable' components gives rise to a responsibility for affixing an alterer label, which identifies the alterer and contains some additional information.; From the description of your device, with the enclosed literature, i appears to require no special expertise or tools to install, and is thus probably readily-attachable. It would also seemingly not affect a vehicle's weight ratings. If this assessment is correct, we would accept as reasonable a manufacturer's determination that it is 'readily attachable', and that an altere label is not required when a 'Steer Safe' steering stabilizer is installed.; Sincerely, James C. Schultz, Chief Counsel |
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ID: aiam3792OpenMr. Bob D. Troxel, Vice President and General Manager, J. F. Enterprises, Inc., Box 583, Wakarusa, IN 46573; Mr. Bob D. Troxel Vice President and General Manager J. F. Enterprises Inc. Box 583 Wakarusa IN 46573; Dear Mr. Troxel: This responds to your recent letter to Mr. Steve Kratzke of my staff asking for a clarification of the requirements of Federal Motor Vehicle Safety Standard No. 302, *Flammability of Interior Materials* (49 CFR S571.302). Specifically, your company manufactures innerspring mattresses, some of which are used in motor vehicles. You noted that the mattress covers on those mattresses for use in motor vehicles must comply with the flammability requirements of Standard No. 302, and that you had interpreted the mattress cover to consist only of the covering applied over the finished mattress. Hence, under your interpretation, Standard No. 302 would not apply to the ticking used as the outside of the mattress. However, you were told by several ticking manufacturers that a recent decision by this agency stated that ticking used on mattresses for use in motor vehicles must also satisfy the flammability requirements of the standard. It is correct that the ticking must satisfy Standard No. 302's flammability requirements.; The mattress cover has been interpreted by this agency to include bot a covering put over a finished mattress and the permanent mattress ticking since Standard No. 302 became effective. Hence, the information that this was a recent decision by this agency is incorrect. For your information, I have enclosed a 1973 letter to the Recreational Vehicle Institute setting forth this interpretation over ten years ago.; Should you have any other questions about the applicability of Standar No. 302 to your products, please do not hesitate to contact Mr. Kratzke at this address or by telephone at (202) 426-2992.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1153OpenMr. Richard T. Ford, Hayden, Smith, Ford & Hays, 1215 Security Bank Building, Fresno, CA 93721; Mr. Richard T. Ford Hayden Smith Ford & Hays 1215 Security Bank Building Fresno CA 93721; Dear Mr. Ford: This is in reply to your letter of May 21, 1973, forwarding to us you second attempt to compose a letter that will conform to Part 577, Defect Notification, for a defect involving the lighting in boat trailers manufactured by V/M Custom Boat Trailers. We responded to an earlier letter from you on May 16, 1973.; Section 577.6 prohibits the making of any statement in the notificatio that either states or implies that the problem discussed is not a defect, or that it does not relate to motor vehicle safety. As we indicated to you in our letter of May 16, we considered your statement, 'The defect on those trailers . . . does not affect the mechanical operation of said trailer except insofar as the lighting is inefficient as installed according to the U.S. Department of Transportation' to be prohibited by section 577.6. The additional phrase, 'This statement is one of fact only and is not intended to be a disclaimer which is prohibited by section 577.6 of the Act', which you have now inserted, does not remedy that deficiency. The regulation states that such a statement may not be made at all, it does not allow it to be made and denied.; Our objection to the statement is with your description of the defec as an 'inefficiency' according to the Department of Transportation. This safety related defect results, rather, from violations of law which require your client's products to meet minimim (sic) safe levels of performance. We recommend that rather than attempt once again to rewrite your statement, and risk violation of the regulation, you delete it entirely, and send the notification to purchasers forthwith.; In other respects your notification appears to conform to Part 577. Sincerely yours, Lawrence R. Schneider, Chief Counsel |
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ID: aiam1903OpenMr. John C. Latzer, Mobilefreeze Co., Inc., P.O. Box 691, Parsons, KS 67357; Mr. John C. Latzer Mobilefreeze Co. Inc. P.O. Box 691 Parsons KS 67357; Dear Mr. Latzer: This responds to your April 15, 1975, question whether the Mobilefreez 'Mark Twain Marine' boat trailer, which consists of a platform whose primary cargo- carrying surface is 18 inches above the ground and supported by two 29-inch-high longitudinal support beams which rise from the outer edges of this surface, would qualify as a heavy hauler trailer. 'Heavy hauler trailer' is defined in S4 of Standard No 121, *Air brake systems*, as follows:; >>>'Heavy hauler trailer' means a trailer with one or more of th following characteristics: (1) Its brake lines are designed to adapt to separation or extension of the vehicle frame, or (2) Its body consists only of a platform whose primary cargo-carrying surface is not more than 40 inches above the ground in an unloaded condition, except that it may include sides that are designed to be easily removable and a permanent 'front-end structure' as that term is used in S 393.106 of this title.<<<; From your description, the 29-inch-high beams do not serve as side from the trailer but simply as longitudinal load-bearing members of the vehicle's cargo-carrying surface. You state that these beams would be placed under the platform except for the necessity that the trailer bed be lower than normal.; If the beams in question do not in fact serve as sides but rather a part of the vehicle frame, the National Highway Traffic Safety Administration concludes that the 'Mark Twain Marine' boat trailer qualifies as a heavy hauler trailer which is not required to conform to Standard No. 121 until September 1, 1976.; 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.