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: aiam1578OpenMr. R. L. Limbaugh, General Manager, Rite-Way Inc. of Indiana, 4301 Bluffton Road, Fort Wayne, IN 46809; Mr. R. L. Limbaugh General Manager Rite-Way Inc. of Indiana 4301 Bluffton Road Fort Wayne IN 46809; Dear Mr. Limbaugh: This responds to your July 29, 1974, request for a copy of ou temporary exemption regulations, and for information on the effective date of Standard No. 121, *Air brake systems*, as it applies to vehicles with a driven front axle. I have enclosed a copy of NHTSA's 'Temporary Exemption' regulations, Part 555 of Title 49, the Code of Federal Regulations.; Standard No. 121 applies to trucks manufactured on or after March 1 1975, with only limited exceptions. Fire trucks are excluded from regulation until September 1, 1975, and vehicles with an overall width of 108 inches or more or a gross axle weight rating for any axle of 24,000 pounds or more, are excluded until September 1, 1976.; In addition, a truck manufactured before September 1, 1975, that has front steerable axle with a gross axle weight rating of 16,000 pounds or more, or a front steerable drive axle, is exempt from some of the stopping distance requirements if its brakes conform to a certain retardation force and values. Aside from these exemptions, any truck with a front steerable drive axle must meet all other requirements of the standard.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam2906OpenMr. T. F. Brown, Mack Trucks, Inc., P.O. Box 1761, Allentown, PA 18105; Mr. T. F. Brown Mack Trucks Inc. P.O. Box 1761 Allentown PA 18105; Dear Mr. Brown: This responds to your October 10, 1978, letter asking whether you ar permitted to mark the certification documents of some of your incomplete vehicles as MACK TRUCKS, INC./RVI. These incomplete vehicles will be manufactured abroad by Renault Vehicules Industriels and imported in the United States by Mack Trucks, Inc.; Part 568, *Vehicles Manufactured in Two or More Stages*, requires a incomplete vehicle manufacture to furnish with the incomplete vehicle certification its name and mailing address. Section 102(5) of the National Traffic and Motor Vehicle Safety Act states that the term manufacturer includes any person importing motor vehicles or motor vehicle equipment. Since your company will be importing these incomplete vehicles and an importer may be considered a manufacturer, it is permissible for you to label incomplete vehicles assembled by Renault with the MACK TRUCKS, INC./RVI designation.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam1629OpenMr. Phil Hooley, Federal Codes and Standards Engineer, Starcraft Company, 3010 College Avenue, Goshen, IN 46526; Mr. Phil Hooley Federal Codes and Standards Engineer Starcraft Company 3010 College Avenue Goshen IN 46526; Dear Mr. Hooley: This is in reference to your defect notification campaign (NHTSA No 74-0170) concerning some camper trailers which may have incorrect inner wheel bearing grease seals installed.; The letter which you have sent to the owners of the subject trailer does not completely meet the requirements of Part 577 (49 CFR), the Defect Notification regulation. Specifically, your letter does not provide an estimate of the day by which dealers will be supplied with parts and instructions for correcting the defect as required by Part 577.4(e)(1). Your statement that the inspection and repair procedure 'should not take very long,' is too vague to qualify as an estimate of the time reasonably necessary to perform the necessary labor as required by Part 577.4 (e)(1). The second sentence of your letter is also incorrect in that where the vehicle manufacturers are concerned, the defect should be described as existing in the vehicle itself rather than a specific part or component of the vehicle.; Since the discrepancies in your notification letter do not appear t discourage owner response in this case, mailing of a revised letter will not be required. It is, however, expected that all future defect notification campaigns will conform completely with the applicable regulations.; Although it may be desirable to issue a service bulletin as soon a possible, we do not believe that justification exists for delaying the submission of a defect report beyond the five working days time limit specified by Part 573 (49 CFR). It is therefore expected that all future reports will be submitted on a timely basis.; Copies of Part 577 and Part 573 of the regulations are enclosed. Sincerely, Andrew G. Detrick, Acting Director, Office of Defect Investigation, Motor Vehicle Programs; |
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ID: aiam3614OpenMr. Shizuo Suzuki, Nissan Motor Co., Ltd., Suite 707, 1919 Pennsylvania Avenue, N.W., Washington, DC 20037; Mr. Shizuo Suzuki Nissan Motor Co. Ltd. Suite 707 1919 Pennsylvania Avenue N.W. Washington DC 20037; Dear Mr. Suzuki: This is in response to your September 23, 1982, letter regarding th applicability of Federal Motor Vehicle Safety Standard No. 118, *Power-Operated Window Systems*, to power sunroofs. The agency apparently has never previously addressed this question.; Standard 118 specifies requirements only for power-operated window an partition systems. A power sunroof would be considered neither a 'window' nor a 'partition,' and therefore would not be subject to the standard. Our standard was intended to apply to the typical power side windows and the power tailgate windows of station wagons. The reference to 'partitions' in the standard was adopted as part of the July 23, 1970, final rule establishing Standard 118 and was intended to assure that power-operated interior partitions, such as might be used in a taxi or a limousine, would comply.; Although Standard 118 does not apply to power sunroofs, we strongl recommend that safety precautions along the lines of those established in that standard be incorporated in power sunroof designs. It appears possible that the types of accidents which the standard was intended to prevent could also occur as a result of the unsupervised operation of power sunroofs.; If you have any further questions on this matter, please contact us. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0891OpenMr. Francois Louis, Manager, Technical Standards Department, Renault, Inc., 100 Sylvan Avenue, Englewood Cliffs, NJ 07632; Mr. Francois Louis Manager Technical Standards Department Renault Inc. 100 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Louis: This is in reply to your letter of October 16, 1972, concerning th seat adjustment procedures of S8.1.2 of Motor Vehicle Safety Standard No. 208.; As described in your letter, some models manufactured by Renault hav front seats that can be adjusted to an extreme forward position to allow the reclining seat back to be fully lowered. You imply that this position cannot be used for driving the vehicle, and ask whether the 'forwardmost' position referred to in S8.1.2 could be interpreted to be the forwardmost *driving* position.; The purpose of S8.1.2 is to specify an adjustment position that i appropriate for the 50th percentile adult male occupant used in the standard's barrier tests. If the adjustment range is determined by using the extreme forward position you describe, the midway point would no longer be appropriate for the 50th percentile adult male size. It is therefore consistent with the purpose of S8.1.2 to exclude the extreme, non-driving positions in determining the midway adjustment position.; However, despite the references in some parts of the standard to a occupant of the 5th percentile adult female size, the adjustment range specified in S8.1.2 does not refer to this or any other size of occupant and we are of the opinion that no occupant size specification can be read into the section.; We would consider a position to be outside the range used to determin the midway point of S8.1.2 if it cannot reasonably be used for driving and if it is separated from other positions by a distance greater than the normal distance between positions. It would appear that the position described in your letter meets these criteria and that it should therefore be excluded in determining the midway position under S8.1.2.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1783OpenMr. J. L. Chancey, Trail-O-Matic, Inc., P.O. Box 2367, Jacksonville, FL 32203; Mr. J. L. Chancey Trail-O-Matic Inc. P.O. Box 2367 Jacksonville FL 32203; Dear Mr. Chancey: This responds to Trail-O-Matic's January 21, 1975, question whether trailer manufactured from the running gear and suspension of an existing trailer and a newly- fabricated frame and upper structure would qualify as a rebuilt vehicle that would not have to be certified as conforming to the requirements of Standard No. 121, *Air brake systems*.; The answer to your question is no. In determining that a buildin operation constitutes the repair of an existing vehicle, and not the manufacture of a new vehicle, the NHTSA requires that, as a minimum, the running gear and frame of the existing vehicle be used in the building operation. For your information, I have enclosed a letter which discusses a similar operation in the trailer industry.; Standard No. 121, therefore, applies to the manufacture of trailer described in your letter.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1279OpenMr. D. P. Peck, Technical & Safety Manager, Triumph Motors, British Leyland UK Limited, Conley, Coventry, 0V4 9DB, England; Mr. D. P. Peck Technical & Safety Manager Triumph Motors British Leyland UK Limited Conley Coventry 0V4 9DB England; Dear Mr. Peck:#This is in reply to your letter of September 11, 1973 asking whether a console-mounted diagram depicting proper placement of heating controls to activate the defrost mode is a 'symbol' within the meaning of Standard No. 101 and whether it is therefore prohibited.#We do not consider the diagram a symbol since it does not itself identify a control, but depicts only how that control is to be placed in a certain mode. Its use is therefore permitted.#Yours truly, Richard B. Dyson, Assistant Chief Counsel; |
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ID: aiam4581OpenMr. Keith A. McDowell Vice President - Engineering Transportation Products Group American Seating Company 901 Broadway, N.W. Grand Rapids, MI 49504; Mr. Keith A. McDowell Vice President - Engineering Transportation Products Group American Seating Company 901 Broadway N.W. Grand Rapids MI 49504; "Dear Mr. McDowell: This responds to your recent letter asking thi agency to 'provide guidelines for the design and installation of seat belt assemblies on large buses (over 10,000 pounds GVW).' You explained that you were interested in this information for passenger seats of large buses used in transit service, not as school buses. I am happy to be able to explain our requirements to you. Standard No. 208, Occupant Crash Protection (49 CFR /571.208) sets forth the crash protection requirements applicable to most vehicle types. Section S4.4 of that standard sets forth the requirements applicable to large buses other than school buses. That section requires large buses to have either a complete automatic protection system for the bus driver's seating position, or a seat belt assembly that conforms with Standard No. 209 at the driver's seating position. Standard No. 208 does not specify any requirements for either an automatic protection system or seat belt assemblies to be installed at any other seating positions in large buses. Standard No. 210, Seat Belt Assembly Anchorages (49 CFR /571.210) also includes requirements applicable to the anchorages for any belt assemblies installed at the driver's seating position on large buses. Specifically, section S4.1.2 of Standard No. 210 provides that: 'Seat belt anchorages for a Type 1 or Type 2 seat belt assembly shall be installed for each designated seating position, except a passenger seat in a bus or a designated seating position for which seat belt anchorages for a Type 2 seat belt assembly are required by S4.1.1.' As with Standard No. 208, Standard No. 210 exempts passenger seats in large buses from its requirements. Finally, Standard No. 209, Seat Belt Assemblies (49 CFR /571.209) sets forth requirements applicable to all seat belt assemblies for use in motor vehicles, including large buses. Thus, any seat belt assembly installed at the driver's position in a large bus would have to be certified as complying with Standard No. 209, as would any seat belt assembly voluntarily provided by a manufacturer for passenger seating positions in a large bus. In short, our standards do not require seat belt assemblies to be installed in passenger seats of large buses, but any seat belt assemblies that are installed at those positions would have to comply with Standard No. 209. Your letter indicated that you were generally aware of the fact that seat belt assemblies were not required to be installed at passenger seating positions of large buses. Nevertheless, you asked us to provide you with 'guidelines' for such installations, in response to the continuing demand for such installations by your company's customers. As a policy matter, NHTSA does not provide the sort of guidelines you have requested. The National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq.) sets forth certain specific requirements that must be satisfied by each of the Federal motor vehicle safety standards established by this agency. Among these requirements are that each safety standard shall be practicable, meet the need for motor vehicle safety, and be stated in objective terms (section 103(a) of the Safety Act) and each standard shall be reasonable, practicable, and appropriate for the particular type of vehicle for which it is prescribed (section 103(f)(3) of the Safety Act). NHTSA has determined that the current requirements of Standards No. 208 and 210, which do not apply to passenger seats in large buses, meet all of the statutory criteria. The issuance of 'guidelines' specifying measures beyond those required by our standards could readily be misinterpreted as an agency decision that these additional measures are necessary to satisfy the criteria of the Safety Act, or indirectly force manufacturers to comply with the 'guidelines,' in addition to the standards issued under the Safety Act. Either or both of these results would be inappropriate for passenger seats on large buses, because the information currently available to NHTSA indicates that no additional requirements are necessary in this area. Indeed, if the agency were to learn of additional information suggesting the current requirements no longer meet all the statutory criteria, and that requirements for the installation of seat belt assemblies at passenger seats of large school buses would meet all the statutory criteria, we would have an obligation to consider changing the applicable standards. Any such change would be required to be made through the ordinary, notice-and-comment rulemaking process, rather than through issuance of supplemental guidelines. I hope this information is helpful. Sincerely, Erika Z. Jones Chief Counsel"; |
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ID: aiam3244OpenMr. Robert G. Szabo, Van Ness, Feldman & Sutcliffe, Suite 500, 1220 Nineteenth Street, N.W., Washington, D.C. 20036; Mr. Robert G. Szabo Van Ness Feldman & Sutcliffe Suite 500 1220 Nineteenth Street N.W. Washington D.C. 20036; Dear Mr. Szabo: This responds to your recent letter requesting information concernin the legal ramifications of converting motor vehicles fuel systems to operate on both gasoline and compressed gas. I am enclosing a copy of a letter the agency issued last year which discussed the Federal law concerning auxiliary gasoline tanks and the conversion of gasoline-powered vehicles to propane. The discussion in that letter should answer all of your questions. If, however, you require more information, please contact Hugh Oates of my office at 202-426-2992.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2005OpenGerhard P. Reichel, Volkswagen of America, Inc., Englewood Cliffs, N.J. 07632; Gerhard P. Reichel Volkswagen of America Inc. Englewood Cliffs N.J. 07632; Dear Mr. Reichel: Please forgive the delay in responding to your letter of April 10 1975, requesting an interpretation of S4.3, the placarding requirements, of Federal Motor Vehicle Safety Standard No. 110, *Tire Selection and Rims--Passenger Cars.; You have proposed a format for presenting vehicle capacity weight which is designed to accommodate, with a single placard, several different model configurations. The NHTSA has not objection to this format, provided that the weights listed are correct.; Sincerely, Frank Berndt, Acting Chief Counsel |
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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.