
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: nht68-4.15OpenDATE: 09/11/68 FROM: AUTHOR UNAVAILABLE; Robert M. O'Mahoney; NHTSA TO: Ashton Martin Lagonda Ltd. TITLE: FMVSR INTERPRETATION TEXT: This is in response to your letter of August 27 and your cable of September 5. You have written me with respect to the possibility of crash-testing an Aston Martin with weight added to the 6 cylinder engine so as to approximate the weight of a V8 engine which you may introduce in the future. I am puzzled by your opening statement "We are arranging . . . to crash one of our DBS cars . . . on your instructions and as we previously agreed to do . . .." A review of the correspondence between the Federal Highway Administration/National Highway Safety Bureau and Aston Martin Lagonda does not disclose either our instructing you or you agreeing, to crash test any motor vehicle. Generally, this correspondence has concerned the limited production vehicle problem and Public Law 90-283. Since the demonstration procedure set forth in certain of the standards involves a crash test, an actual crash test seems the best way for a manufacturer to verify conformance with these standards. The standards, however, do not per se require a crash test, and 23 C.F.R. @ 255.11 specifically states that "As approved equivalent may be substituted for any required destructive demonstration procedure." With respect to your planned test for September 13, our engineers do not view the 40 pound weight differential as significant, and, assuming no further modifications to the DBS, crash testing a 6 or a V8 simulation would be sufficient to demonstrate compliance for the current 6 or projected V8 model. I understand your concern with the "thought of having to smash cars every time there is a change in specification", but you will have to face this issue every time a new Federal standard appears with a crash demonstration procedures. You may not know of newly issued Standard No. 212 (Windshield Mounting - Passenger Cars), requiring a barrier collision test, and I enclose a copy for your information. Robert M. O'Mahoney, Esq., Assistant Chief Counsel, US Department of Transportation, August 27, 1968 We are arranging very shortly to crash one of our DBS cars in 6 cylinder form, on your instructions and as we previously agreed to do, and this will be done during mid September. As if this is not worrying enough, we are wondering if we may get some concession or help on a further aspect which could cause much financial calamity later on. This is that we may, in the future at a date not yet decided, be in the position to offer an alternative engine capacity of V8 formation in the same chassis. Basically, this engine will only weigh 40 lbs more than the existing 6 cylinder installation and all mounting points and other fittings will be, to all intents and purposes, identical. Could you please let me know, as soon as possible, whether or not this alternative will make it necessary for us to crash yet another car; or can it be considered that the minor weight variation would not affect the aspects for which the crash has been organised, i.e. the steering wheel penetration and fuel tank installation. As a further alternative, might it be possible for us to add this extra weight, in some form to be defined by you, to the existing 6 cylinder engine on our forthcoming crash test in September. We would be grateful if this particular concession could be made, as quite frankly we had serious thoughts about continueing with the US market when it came to smashing one car, which represents our profit margin for a complete year. The thought of having to smash cars every time there is a change in specification is horrifying and would mean financial penalties which are too heavy for us to bear. Could I please trouble you for a very prompt reply in view of the possibility of the extra weight 'concession' we have requested to simulate the V8 unit, and the time needed to organise this prior to the crash test of the 6 cylinder car. D.C. Gerston. Director of Engineering ASTON MARTIN LAGONDA LTD. |
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ID: nht68-4.16OpenDATE: 09/16/68 FROM: AUTHOR UNAVAILABLE; Robert M. O'Mahoney; NHTSA TO: Messrs. O'Donohue and O'Connor TITLE: FMVSR INTERPRETATION TEXT: In your letter of August 15 you ask for a copy of regulations issued under the National Traffic and Motor Vehicle Safety Act of 1966 which might apply to "a small refuse-carrying three-wheeled vehicle" which is being designed by one of your clients. I enclose a copy of all Federal Motor Vehicle Safety Standards which have been issued to date. You will note in 23 C.F.R. @ 255.3(b) that the definitions of "truck" and "motorcycle" or "motor driven cycle" appear to apply to the vehicle you have described. In order to make a definite classification we need more information such as 'a photograph of the vehicle and a technical specification sheet'. However, if the vehicle is classified as a "truck", 23 C.F.R. @ 255.7(a) provides that the Federal Standards will not apply if its curb weight is 1,000 pounds or less. If the vehicle is classified as a "motorcycle" or "motor driven cycle", Federal Standard No. 108 effective January 1, 1969, will be the only Standard applicable to this category of vehicle. If there is any further assistance I can give you I shall be happy to do so. O'DONOHOE AND O'CONNOR August 15, 1968 National Highway Safety Bureau It is our understanding that under the President's Executive Order of June 6, 1967, your Bureau is charged with the carrying out of the principles of the Highway Safety Act. This firm represents a small local corporation which is engaged in the design for marketing of a small refuse-carrying three-wheeled vehicle, to be primarily used in combination with a larger packer truck. Could you please forward to the undersigned copies of such bulletins or regulations as you have promulgaged with reference to required safety features in this particular type of vehicle. The vehicle will be three wheeled, operate with hydrostatic drive, and will have a dump box at the front. As stated above, it's main purpose will be to pick up from trash cans in alley ways and up driveways and then to deposit its load when full in the larger packer truck. We will be glad to supply added details for your use in determining what regulations would be applicable;but frankly, right now, having just read the bare bones of the statute, I am at a loss to know what you will need to proceed. We would appreciate it if you would send us such materials as you have on hand. James E. O'Donohoe |
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ID: nht68-4.17OpenDATE: 09/17/68 FROM: AUTHOR UNAVAILABLE; William Haddon, Jr.; NHTSA TO: Chrysler Corporation TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of September 11, 1968, to Mr. J.E. Leysath of this Bureau, concerning the Chrysler Super Lite which you intend to offer as an optional supplemental light on some of the Chrysler 1969 car lines. You are correct in your understanding that a supplemental light of this type is not required by Federal Motor Vehicle Safety Standard No. 108. Standard No. 108 does, however, specify, in Paragraph S3.1.2, that no additional lamp, reflective device, or associated equipmont shall be installed if it impairs the effectiveness of the required equipment. On the basis of our review of your technical literature on the Super Lite and our observation of limited field demonstrations of the light, it does not appear that the Super Lite will impair the effectiveness of the lighting equipment required by Standard No. 108. It should be noted, however, that, while the incorporation of this lamp in your 1969 automobiles would not be precluded by the Federal Standard, the various States may interpose restrictions as to this lamp. With respect to the requirements of Standard No. 108, I must point out that this Bureau does not issue approvals on items of lighting equipment or on vehicle designs incorporating this equipment. Therefore, the above comments are for your information only and in no way relieve the vehicle manufacturer from his responsibility for certifying that the assembled vehicle meets the requirements of the standard. |
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ID: nht68-4.18OpenDATE: 09/18/68 FROM: AUTHOR UNAVAILABLE; Eugene B. Laskin; NHTSA TO: Department of California Highway Patrol PAR=LOCATION TITLE: FMVSR INTERPRETATION TEXT: Your letter of August 19, 1968, addressed to Mr. David A. Fay, of the National Highway Safety Bureau has been forwarded to my office for reply. The original list of definitions of vehicles was published in the Federal Register as part of a Notice of Proposed Rule Making dated December 3, 1966. Comments were requested from interested parties. Subsequently, the definition of a multipurpose vehicle as added to the Federal Motor Vehicle Safety Standards in response to a number of comments received from industry requesting a different category for certain utility vehicles. Under the previous classification, there were a number of special purpose vehicles which did not fit into any single category. It was agreed that certain types of motor vehicles, such as Dune Buggies, the Carryall, Travelall, Compact Van, Jeep Wagoneer, Ford Bronco, and Scout type vehicles comprised a hybid class of motor vehicle which possessed the characteristics of more than one of the motor vehicle categories previously established. The "special features" include such items as 4-wheel drive amphibious equipment. Due to the differences in body construction, load time requirements, and general vehicle purpose, it was not considered reasonable to require those dual purpose vehicles designed to carry ten persons or less to meet all of the passenger car requirements, as would have been required by the Notice. For those reasons, the new category of "multipurpose passenger vehicle" use added to Section 245(b). Your interest in the automotive safety program of the Federal Highway Administration is greatly appreciated. |
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ID: nht68-4.19OpenDATE: 09/19/68 FROM: AUTHOR UNAVAILABLE; Howard A. Heffron; NHTSA TO: Government of the Virgin Islands of the United States TITLE: FMVSR INTERPRETATION TEXT: This is in response to your letter of June 10 to the Federal Highway Administrator with reference to implementation of 19 C.F.R. S12.80, in the Virgin Islands. You have informed us that your analysis of S12.80(b)(1) which begins "Any vehicle or equipment item offered for importation into the customs territory of the United States. . . ." leads you to believe that these regulations are not applicable to the Virgin Islands, which are not within the customs territory of the United States. These regulations were issued jointly by the Department of the Treasury and the Department of Transportation pursuant to section 108 of the National Traffic and Motor Vehicle Safety Act of 1966. Section 102 (8) of this Act specifically includes the Virgin Islands in the definition of "State" so that the Act applies to the Islands. Since the Act applies, regulations issued under the Act also apply by their own force. It is our understanding that these regulations have been implemented in AmericanSamoa and Guam, also outside the customs territory of the United State by Executive Order of the respective governors. We believe that Governor Palewonsky should do the same, substituting the word "Virgin Islands" for "customs territory", and an Island enforcement agency in lieu of the Bureau of Customs, and making such other minor changes as appear called for by local conditions. The alternative, of course, is for the Secretary of Transportation to issue a separate set of regulations applicable only to the Virgin Islands. We would appreciate knowing what action will be taken by Governor Paiswonsky, and which Island agency will be responsible for enforcing the regulations. |
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ID: nht68-4.2OpenDATE: 08/20/68 FROM: AUTHOR UNAVAILABLE; Charles A. Baker; NHTSA TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of July 24, 1968, to Mr. George C. Nield, concerning the method of operating school bus signal lamps as required by Motor Vehicle Safety Standard No. 108. Paragraph S3.1.3.2(b)(2) of Standard No. 108 requires that the system of red and amber signal lamps shall be wired so that the red signal lamps are automatically energized, and the amber signal lamps are automatically de-energized, when the bus entrance door is opened. Paragraph S3.1.2 of the standard does not permit the installation of an additional lamp, reflective device or associated equipment if it impairs the effectiveness of the required equipment. Therefore, the criteria for determining the compliance of an additional manual switch for controlling operation of the signal lamps is whether or not the manual switch would impair the effectiveness of the required automatic entrance door switch. A manual switch which overrides the entrance door switch only while the entrance door is closed does not appear to impair the effectiveness of the required automatic switch. However, a manual switch which controls operation of the signal lamps while the entrance door is open would definitely impair the effectiveness of the automatic switch. With respect to the requirements of Standard No. 108, I must point out that this Bureau does not issue approvals on items of lighting equipment or on vehicle designs incorporating this equipment. Therefore, the above comments are for your information only and in no way relieve the vehicle manufacturer from his responsibility for certifying that the assembled vehicle meets the requirements of the standard. Thank you for writing. |
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ID: nht68-4.20OpenDATE: 08/21/68 FROM: AUTHOR UNAVAILABLE; Robert M. O'Mahoney; NHTSA TO: Bugetta Inc. TITLE: FMVSR INTERPRETATION TEXT: With reference to your letter of August 14 and its enclosed specification sheet covering the Bugetta, this vehicle appears to be a "multipurpose passenger vehicle" for purpose of the Federal motor vehicle safety standards since it is constructed with features for ocasional off road use. Your understanding of the applicability of standards to multi-purpose passenger vehicles is correct. We concur with your view that compliance with Standard No. 103 (Windshield Defrosting and Defogging) is a meaningless requirement for a vehicle with no top or windows. BUGETTA INC. August 14, 1968 U.S. Department of Transportation Federal Highway Administration Attention: Robert M. O'Mahoney Responding to letter of July 31st from Mr. David Schmeltzer, we enclose general specifications and line drawing of the vehicle which is constructed with racing components and aircraft quality fittings throughout. The special features of this motor vehicle that are contained for occasional off-road operations are: a. Telescopic shocks which can raise chassis approximately 18" off the ground to traverse rough terrain, water, etc. b. Removable fiberglass body (8 pit pins) for use in mud, etc. Vehicle completely functionable with body removed. c. Metal protective covering under entire vehicle for deflecting rocks, twigs, etc. d. Off highway tires as standard item. e. Roll bar for off highway and racing protection. Safety Standards complied with: 102, 104, 106, 107, 108, 109, 111, 205, 209, 211. It was felt that the following standards did not apply primarily due to the multipurpose classification or for additional reasons given: 101 - Not applicable. 103 - Impossible requirement without top and side windows to vehicle. 105 - Not applicable. 110 - Not applicable. 112 - Not applicable. 113 - No hood, therefore not applicable. 114 - Not applicable. 201 - Not applicable. 202 - Not applicable. 203 - Not applicable. 204 - Not applicable. 206 - Not applicable. No doors. 207 - Not applicable. 208 - Not applicable. 210 - Not applicable. 301 - Not applicable. Please review and let us know if further information is desired. R. J. Hart Enclosure |
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ID: nht68-4.21OpenDATE: 11/18/68 FROM: AUTHOR UNAVAILABLE; R. Brenner for William Haddon, Jr., M.D.; NHTSA TO: General Motors Corporation TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of September 25, 1968, regarding Federal Motor Vehicle Safety Standard No. 211 and the use of hexagonal wheel nuts. The requirement of this standard that wheel nuts, hub caps and wheel dirce "shall not incorporate vinged projections" apparently applied to all wheel nuts, whether hexagonal or otherwise. I agree that clarification of the standard is needed, but the method of accomplishing this is yet to be resolved. I have asked the Motor Vehicle Safety Performance Service to look into this problem immediately and to take the neccessary steps to relieve any undue burdens. |
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ID: nht68-4.22OpenDATE: March 1, 1968 FROM: George C. Nield -- Acting Deputy Director, Motor Vehicle Safety Performance Service TO: Earl Allgaier -- Manager, Driver Education Division, Traffic Engineering and Safety Department, American Automobile Association TITLE: None ATTACHMT: Attached to letter from Joseph R. O'Gorman to A. Nathan Darby (Std. 101); Also attached to letter dated 3-14-91 from Paul Jackson Rice to George Smyth (A37; Std. 101); Also attached to letter dated 7-30-75 from Richard B. Dyson (signed by Z. Taylor Vinson) to Bryon A. Crampton; Also attached to letter dated 8-27-68 from Eugene B. Laskin to Barry G. Seitz (Std. 203; Std. 204) TEXT: Thank you for your letter of February 16 concerning the installation of dual controls and handicapped controls on passenger cars. In general, your evaluation of the effect of installing dual controls for driver training or controls for handicapped persons by dealers is correct. The present Federal motor vehicle safety standards do not prohibit the installation of these controls provided none of the requirements specified by the standards are eliminated or adversely affected by such installation. I am enclosing a complete set of standards now in effect for your information. In the event that dual steering controls and other controls are provided on driver training vehicles, the applicability of the appropriate standards is confined to the primary controls. For example, under Standard No. 101 the person seated behind the secondary steering control need not be able to reach all controls. Should you have any further questions on this matter, I would be most happy to have you again contact me. |
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ID: nht68-4.23OpenDATE: 01/01/68 EST FROM: Joseph R. O'Gorman -- Acting Director, Office of Performance Analysis, Motor Vehicle Safety Performance Services TO: A. Nathan Darby TITLE: None ATTACHMT: Attached to letter dated 3-14-91 from Paul Jackson Rice to George Smyth (A37; Std. 101); Also attached to letter dated 7-30-75 from Richard B. Dyson (signed by Z. Taylor Vinson) to Byron A. Crampton; Also attached to letter dated 8-27-68 from Eugene B. Laskin to Barry G. Seitz (Std. 203; Std. 204); Also attached to letter dated 3-1-68 from George C. Nield to Earl Allgaier TEXT: Thank you for your letter of December 17, 1967, to the National Highway Safety Bureau, concerning the installation of dual controls on passenger cars. The present Federal Motor Vehicle Safety Standards do not prohibit the installation of dual controls provided none of the requirements specified by the standards are eliminated or adversely affected by such installation. In other words, if a dealer or manufacturer modifies a conforming vehicle, then he assumes the responsibility for the vehicle's certification. We enclose a complete set of standards now in effect for your information. In the event that dual steering controls and other controls are provided on driver training vehicles, the applicability of the appropriate standards is confined to the primary controls, For example, under Standard No. 101, the person seated behind the secondary steering control need not be able to reach all controls. We trust this information will be of assistance to you in your desire to comply with existing safety standards. |
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.