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: aiam1913OpenMr. Danny J. Lanzdorf, Supervising Engineer, Oshkosh Truck Corporation, P.O. Box 560, Oshkosh, WI 54901; Mr. Danny J. Lanzdorf Supervising Engineer Oshkosh Truck Corporation P.O. Box 560 Oshkosh WI 54901; Dear Mr. Lanzdorf: This responds to your April 1, 1975, request for confirmation that th emergency braking stopping distance requirements in S5.7.2.3 of Standard No. 121, *Air brake systems*, specify that, when stopped six times for each configuration of weight and speed specified in S5.3.1.1 on a road surface with a skid number of 75 (with a single failure introduced in the service brake system), the vehicle must stop at least once within the distances specified in Column 3 of Table II and no part of the vehicle must leave the 12-foot roadway. You also request confirmation that modulation of the service brake control during the stop is not prohibited.; With certain exceptions, the statements in your letter are correct Your interpretation only sets out the basic stopping distance requirements for those vehicles which the manufacturer has chosen to make conform to S5.7.2 of the standard. Thus, your interpretation does not include any of the requirements of the emergency braking capability option found in S5.7.1. Additionally, your interpretation does not include the requirements for a truck-tractor at unloaded vehicle weight plus 500 pounds, or for the trucks and buses which qualify for the interim requirements of S5.7.2.3.1 and S5.7.2.3.2.; Section S5.7.2 does not prohibit modulation of the emergency brakin capability, and modulation by means of the service brake control is therefore permissible.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1460OpenMr. Charles E. Park, President, Intermodal Services, Inc., P.O. Box 111, 4 Lavista - Perimeter Park - Suite 130, Tucker, GA 30084; Mr. Charles E. Park President Intermodal Services Inc. P.O. Box 111 4 Lavista - Perimeter Park - Suite 130 Tucker GA 30084; Dear Mr. Park: This responds to your April 8, 1974, request for a waiver from Standar 121, *Air brake systems*, to permit the manufacturer of semi-trailers which do not comply with the standard after its effective date.; Our authority to enforce standards under S108(a)(1) of the Nationa Traffic and Motor Vehicle Safety Act of 1966 prohibits the sale of a vehicle which does not comply with applicable standards. We are unable to permit by regulation what is prohibited by this section of the law.; We do have under consideration petitions to delay the effective date o Standard 121 as it applies to trailers.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3148OpenMr. William Shapiro, Volvo of America, Rockleigh, NJ 07647; Mr. William Shapiro Volvo of America Rockleigh NJ 07647; Dear Mr. Shapiro: This is in response to the questions that you addressed to Mr. Hug Oates over the telephone with regard to auxiliary fuel tanks. I have enclosed a copy of a letter which was sent to a company that planned to manufacture auxiliary fuel tanks for passenger cars and to do some installation. The principles enunciated in that letter are applicable to auxiliary fuel tanks intended for use in all types of motor vehicles except motor carriers in interstate commerce. If you have any further questions after reading the enclosed letter please feel free to contact Ms. Debra Weiner of my office who is familiar with the issues arising from the manufacture and use of auxiliary fuel tanks.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1175OpenMr. Edward W. Gaylord, Vice President, Gaylord Products, Inc., 1918 Prairie Avenue, Chicago, IL 60616; Mr. Edward W. Gaylord Vice President Gaylord Products Inc. 1918 Prairie Avenue Chicago IL 60616; Dear Mr. Gaylord: This is in reply to your letter of June 26, 1973, to Mr. Vinson of thi office, enclosing the proposed Panther certification label, and asking whether it conforms to our requirements. The label is arranged as a narrow horizontal strip with two lines of type.; The label contains the required statements in the required order, an thus fulfills the requirements.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4377OpenMr. John Scott Hatt, 1215 N. Quinn Street, Apt #2, Arlington, VA 22209; Mr. John Scott Hatt 1215 N. Quinn Street Apt #2 Arlington VA 22209; Dear Mr. Hatt: This is in reply to your letter of June 8, 1987, to this agency askin about the legality of having 'a lighted sign on the side of a car door used for advertising purposes.' You have also asked whether such a sign would be a safety hazard to other drivers.; There is no Federal prohibition against installation of such a sign Its legality would be determined under local laws where a vehicle with a lighted sign would be registered and operated. You might wish to seek the advice of Arlington traffic officials and the Virginia State Police on this subject. It is not possible to say whether such a sign would be a safety hazard. Unlit advertising signs seem permissible in some areas on the sides of buses.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3518OpenMr. David Traxler, 147 King George Way, Columbia, SC 29210; Mr. David Traxler 147 King George Way Columbia SC 29210; Dear Mr. Traxler: This is to follow-up your telephone call of October 29, 1981, askin whether any Federal motor vehicle safety standards apply to 'hatchback' door latches.; Safety Standard No. 206, *Door Locks and Door Retention Components* includes requirements for side door latches. We have enclosed a copy of that standard for your convenience.; There are no Federal motor vehicle safety standards applicable to th rear latch of a hatchback. However, even in the absence of a safety standard, the defect provisions of the National Traffic and Motor Vehicle Safety Act may be applicable. Sections 151 *et seq*. of the Act provide that manufacturers of motor vehicles and motor vehicle equipment must notify owners of vehicles and equipment with safety-related defects and remedy those defects free of charge.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1525OpenMr. J. W. Kennebeck, Manager, Emissions, Safety & Development, Volkswagen of America, Inc., Englewood Cliffs, NJ 07632; Mr. J. W. Kennebeck Manager Emissions Safety & Development Volkswagen of America Inc. Englewood Cliffs NJ 07632; Dear Mr. Kennebeck: This responds to your May 22, 1974, question whether Volkswagen' passive belt system may be equipped with a 'comfort clip,' and whether an optional Type I lap belt may be offered in conjunction with the passive system. Your passive system consists of an upper torso restraint and, in place of a lap belt, knee padding under the dashboard.; A vehicle which satisfies Standard No. 208, *Occupant cras protection*, may be equipped, at the option of the manufacturer, with additional safety belts which conform to Standard No. 209, *Seat belt assemblies*. Additional belts, like any required belt, must conform to the S7.2 requirements for latch mechanisms.; >>>S7.2 *Latch mechanism*. A seat belt assembly installed in passenger car shall have a latch mechanism --; (a) Whose components are accessible to a seated occupant in both th stowed and operational positions,; (b) That releases both the upper torso restraint and the lap bel simultaneously, if the assembly has a lap belt and an upper torso restraint that require unlatching for release of the occupant, and; (c) That releases at a single point by a push-button action.<<< This requirement assures that the occupant crash protection provide under Standard No. 208 is not diminished by a complicated and slow series of belt latch mechanisms which could otherwise be introduced into the vehicle.; Volkswagens' passive upper torso restraint and a separate active la belt do not violate S7.2(b) in combination. Simultaneous release is required only 'if the assembly has a lap belt and an upper torso restraint that require unlatching for release of the occupant.' As described, Volkswagen's upper torso restraint does not require unlatching for release of the occupant.; With regard to our regulation of 'comfort clips', we approved the us of a clip in a March 9, 1973, letter to General Motors, to relieve belt tension in limited circumstances. A copy of that letter is enclosed. In that case, the lap belt provided could be independently and firmly adjusted to limit occupant movement, providing protection in the event of lateral and rollover crashes. Until we have further details on the functioning of the Volkswagen clips, however, which we urge you to submit, we are unable to determine whether it would conform to the adjustment requirements of S7.1.1 of Standard No. 208, *Occupant crash protection*.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam4727OpenMs Margaret Schmock Dept K2/ELE2 Robert Bosch GmbH Postfach 42 7410 Reutlingen W. Germany; Ms Margaret Schmock Dept K2/ELE2 Robert Bosch GmbH Postfach 42 7410 Reutlingen W. Germany; Dear Ms Schmock: This is in reply to your FAX of March 6, l990, wit respect to the relationship between Federal Motor Vehicle Safety Standard No. 108, and 'CAC Title 13, Article 9'. You have indicated that CAC requires a headlamp adjustment range in the horizontal of at least +/- 4 degrees, whereas Standard No. 108 requires a horizontal adjustment range of not less than 2.5 degrees. You have asked whether Bosch headlamps still must have an adjustment range of +/-4 degrees in the horizontal although Standard No. 108 has been changed. We understand that 'CAC' refers to 'California Administrative Code'. The effect of the preemption provisions of the National Traffic and Motor Vehicle Safety Act is to prohibit California from adopting and enforcing a minimum horizontal headlamp adjustment range greater or less than 2.5 degrees. Thus, a State requirement that a headlamp have a horizontal range of +/- 4 degrees is invalid because it differs from a corresponding Federal requirement. We are unable to answer your further questions with respect to the California code, and suggest that, for further information you write Department of Motor Vehicles, State of California, 2415 First Avenue, Sacramento, California 95818, ATTN: Mr. A. A. Pierce, Director (FAX 916-732-7854). Sincerely, Stephen P. Wood Acting Chief Counsel; |
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ID: aiam1876OpenMr. Owen R. Hildreth, Owen's International Inc., 16725 Van Dam Road, South Holland, IL 60473; Mr. Owen R. Hildreth Owen's International Inc. 16725 Van Dam Road South Holland IL 60473; Dear Mr. Hildreth: This responds to your March 14, 1975, question whether a truck deale or his customer may modify the brake system on a vehicle which is manufactured in conformity with Standard No. 121, *Air brake systems*, after the first purchase of the vehicle in good faith for purposes other than resale.; The National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1391 e seq.) requires that a vehicle meet all applicable safety standards at the time of sale. Conformity is not required, however, after the first purchase of the vehicle in good faith for purposes other than resale. In answer to your second question, therefore, the vehicle becomes 'used' after its first purchase in good faith for purposes other than resale. 'Good faith' means that the purchaser could not purchase the vehicle before an agreed-on modification simply to avoid the effect of the standard. Your modifications can be undertaken only on a vehicle which has already been purchased in good faith.; As for modification that you or your customer might wish to undertake he may himself make whatever changes he cares to, subject to State or motor carrier regulations. The Act does, however, prohibit manufacturers, distributors, dealers, or motor vehicle repair businesses from knowingly rendering inoperative any device or element of design installed on a motor vehicle in compliance with an applicable safety standard (except during repairs). Thus you could not modify the 121 system to render it inoperative.; As long as you and customer do not violate these provisions, the futur sale of a modified vehicle would not be in violation of the Act.; Sincerely, James C. Schultz, Chief Counsel |
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ID: aiam0764OpenMr. T. F. Cathey, Director of Research and Development, Raybestos-Manhattan, 61 Willett Street, Passaic, NJ 07055; Mr. T. F. Cathey Director of Research and Development Raybestos-Manhattan 61 Willett Street Passaic NJ 07055; Dear Mr. Cathey: In your letter of June 30, 1972, you raised two questions that touch o the responsibility of manufacturers who produce components, such as brake blocks, that affect the ability of a vehicle to meet a motor vehicle safety standard.; Motor Vehicle Safety Standard No. 121, Air Brake Systems, the standar of concern to you, regulates vehicles equipped with air brakes, but it does not regulate the brakes or their components as separate items of equipment. As a component manufacturer, your company is therefore not required by our regulations to certify its products as conforming to Standard 121. This is not to say that your customers will not be concerned about the performance of your products, but only that you have no direct responsibility under the standard.; A vehicle manufacturer who intends to use your brake blocks on a ne vehicle will probably try to get as much test data from you as he can. His vehicle will have to conform to the standard. If our tests disclose a shortcoming in the brakes, he will have to show that he exercised due care in the manufacture of the vehicle and the data he obtains from you may be an important part of his case. Whether you supply him with dynamometer data or complete road test data is a matter to be arranged privately, however, and the subject is not regulated by our rules.; A brake block or other brake component sold as a replacement part i not at this time subject to regulation under Standard 121. A truck owner will presumably want to obtain components that are compatible with the rest of the brake system.; You have also asked for information about agencies equipped to ru tests in accordance with Standard 121. At this time we have not compiled a list of test facilities, but we expect that such information will become widely available in the next few months.; Sincerely, Elwood T. Driver, Director, Office of Operating Systems |
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.