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 |
|---|---|
ID: aiam1555OpenMr. Y. Takami, Technical Representative, Toyo Rubber Industry Company, Ltd., 3136 East Victoria Street, Compton, California 90221; Mr. Y. Takami Technical Representative Toyo Rubber Industry Company Ltd. 3136 East Victoria Street Compton California 90221; Dear Mr. Takami: This responds to your July 8, 1974, question whether publication of brochure that lists the rims that may be used with the tires produced by Toyo Tire Corporation would meet the requirements of S5.1 of Standard No. 119, *New pneumatic tires for vehicles other that passenger cars.*; Publications of such a brochure would meet the requirement of S5.1 s long as the tires ar listed in accordance with S5.1(ak), that is by manufacturer name or brand name, followed by a listing of rims that may be used with each tire listed. The brochure would have to be supplied to dealers of the manufacturer's tires, to any person upon request, and in duplicate to: Tire Division, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
|
ID: aiam1479OpenMr. Charles R. Richards, Superior Trailer Works, 1430 East Washington Boulevard, Los Angeles, CA 90021; Mr. Charles R. Richards Superior Trailer Works 1430 East Washington Boulevard Los Angeles CA 90021; Dear Mr. Richards: This responds to your April 22, 1974, question concerning th certification responsibility of a small manufacturer of trailers that must conform to Standard No. 121, *Air brake systems*. You ask if road testing of any or all vehicles produced would be necessary to satisfy the requirements.; A manufacturer must 'exercise due care' in certifying that the vehicle manufactured by him comply with the applicable standards (National Traffic and Motor Vehicle Safety Act of 1966, S 108(b)(2), 15 U.S.C. S 1392(b)(2)). What constitutes due care in a particular case depends on all relevant facts, including such things as the time to elapse before a new effective date, the availability of test equipment to small manufacturers, the limitations of current technology, and above all the diligence evidenced by the manufacturer.; A small manufacturer of standard and custom trailers might fulfill hi due care responsibility to assure that each of his trailers is capable of meeting the standard in several ways. For example, he could establish categories of models which share a common brake and axle system and certify them all on the basis of tests on the most adverse configuration in the category. Calculations should be written down in such a case to establish that reasonable care was taken in these decisions.; Alternatively, joint testing might be undertaken with a trad association or with a major supplier of brake and axle components. In the case of standard models, you might be able to rely on the supplier's warranty of his products' capacities.; Neither of these methods would require road testing of each vehicl manufactured, nor would every model have to be road tested. A manufacturer must simply satisfy himself that the trailer is capable of meeting the stopping performance requirements if it were tested by the NHTSA.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
|
ID: aiam4670OpenMr. W. Marshall Rickert Motor Vehicle Administrator Maryland Department of Transportation 6601 Ritchie Highway Glen Burnie, MD 21062; Mr. W. Marshall Rickert Motor Vehicle Administrator Maryland Department of Transportation 6601 Ritchie Highway Glen Burnie MD 21062; "Dear Mr. Rickert: Thank you for your letter seeking this agency' opinion as to whether the State of Maryland may amend its motor vehicle regulations to permit the installation of aftermarket tinting on motor vehicle windows, for individuals who may desire this for medical reasons. I am pleased to have this opportunity to describe the legal principles that relate to your question. The National Highway Traffic Safety Administration ('NHTSA') is responsible for issuing Federal motor vehicle safety standards that impose requirements for specific levels of safety performance for new motor vehicles and motor vehicle equipment. Federal Motor Vehicle Safety Standard No. 205, Glazing Materials (49 CFR 571.205), which has been in effect since 1968, imposes a minimum level of light transmittance of 70 percent in all areas requisite for driving visibility (which includes all windows on passenger cars). The purpose of this requirement is to ensure adequate visibility through the windows, thereby reducing the risk of a motor vehicle crash. Although Federal motor vehicle safety standards apply directly only to new vehicles and equipment, Federal law also imposes limits on the addition of tinting materials to motor vehicle glazing after vehicles have been purchased by consumers. Pursuant to section 108(a)(2) of the National Traffic and Motor Vehicle Safety Act, 15 U.S.C. 1397(a)(2), manufacturers, distributors, dealers, or motor vehicle repair businesses may not 'render inoperative' any equipment or element of design installed in compliance with a Federal safety standard. Thus, those businesses may not install tinting that reduces the light transmittance of windows covered by Standard 205 to a level below the Federal requirement of 70 percent, since that would make the windows 'inoperative' within the meaning of Standard 205. This Federal prohibition is similar to that imposed by section 22-104 of the Maryland Vehicle Law, which provides: A person may not willfully or intentionally remove or alter any safety device or equipment that has been placed on any motor vehicle . . . in compliance with any law, rule, regulation, or requirement of . . . the United States or of this State . . . unless the removal or alteration is permitted by rule or regulation adopted by the Maryland Motor Vehicle Administrator. The 'render inoperative' provision of Federal law does not apply to actions by individual vehicle owners. Therefore, each State may regulate the extent to which aftermarket tinting may be applied by vehicle owners to their own vehicles. Thus, although section 22-104 appears to preclude aftermarket tinting by any person if the result would be to reduce the level of light transmittance below 70 percent, Maryland may amend its rules or regulations to permit such tinting by individuals, for medical or any other reasons deemed valid by the State. However, Maryland has no authority to grant any exemptions, including medical exemptions, from the 'render inoperative' prohibition of Federal law that applies to commercial entities. Hence, regardless of any provisions of Maryland law, no manufacturer, distributor, dealer, or motor vehicle repair business may legally install window tinting film on a vehicle, unless the vehicle continues to comply with the Federal light transmittance requirements. In adopting Standard 205, NHTSA determined that a minimum light transmittance of 70 percent is necessary to meet the need for motor vehicle safety. This is the same level of light transmittance contained in the Safety Code of the American National Standards Institute. If, as your letter suggests, Maryland is considering permitting vehicle owners to modify their vehicles such that their windows will have a lower level of light transmittance, we would urge you to carefully consider the safety consequences of such an exemption. Please let me know if you need any further information on this subject. Sincerely, Paul Jackson Rice Chief Counsel"; |
|
ID: aiam1735OpenMr. Robert A. Danis, Carlton Manufacturing Company, 1152 High Street, Central Falls, Rhode Island 02863; Mr. Robert A. Danis Carlton Manufacturing Company 1152 High Street Central Falls Rhode Island 02863; Dear Mr. Danis: This is in response to your letter of October 23, 1974, requesting ou comments on your West Coast type mirror (which includes a ground-in convex spot mirror) and information on Federal regulations for spot mirrors in general.; Standard No. 111, *Rearview Mirrors*, provides minimum performanc requirements for rearview mirrors on passenger cars and multipurpose passenger vehicles. According to the standard, the outside rearview mirror required to be placed on the driver's side of the vehicle must be furnish the driver with a specified field of view to the rear of substantially unit magnification. As long as the mirror is capable of satisfying these field view requirements, the inclusion of a convex spot mirror no the plane mirror (as with the West Coast mirror) is not prohibited by the standard. If your West Coast type mirror is capable of providing the required view of substantially unit magnification independent of its convex spot mirror, it will comply with the standard.; The recent notice proposing to amend the rearview mirror standard (Ma 1, 1974, 39 FR 15143), does not alter the above described permissible use of West Coast type mirrors. No requirements for spot mirrors are contained in the Federal motor vehicle safety standards.; We appreciate your interest. Yours truly, Richard B. Dyson, Acting Chief Counsel |
|
ID: aiam3996OpenMr. H. Miroyoshi, Executive Vice President and General Manager, Mazda (North America), Inc., 24402 Sinacola Court, Farmington Hills, MI 48018; Mr. H. Miroyoshi Executive Vice President and General Manager Mazda (North America) Inc. 24402 Sinacola Court Farmington Hills MI 48018; Dear Mr. Miroyoshi: Thank you for your letter of July 2, 1985, requesting an interpretatio of Federal Motor Vehicle Safety Standard No. 201, *Occupant Protection in Interior Impact*. You specifically asked whether a design alternative you are considering for an interior storage compartment would have to meet the requirements of S3.3 of the standard. As explained below, we would consider your design to be an interior compartment door assembly and thus subject to the requirements of S3.3 of the standard.; You described your design as an interior surface with an integrate map/magazine compartment. Your proposed design consists of a compartment with a rigid exterior surface that remains open at a fixed width. You said that when a motorist wanted to stow a thicker package in the compartment, the opening could be expanded to a greater width. The drawing accompanying your letter shows that the exterior surface (i.e., the surface nearest to a vehicle occupant) is hinged, the movement of the hinged surface is restricted by a spring. It appears from your drawing that if the spring broke or otherwise became disengaged in a crash, the exterior surface of the compartment would swing open on its hinge and be struck by a vehicle occupant. Such an action is similar to what could happen with the conventional hinged glovebox or other doors in a vehicle. We would therefore consider your proposed design to be an interior compartment door assembly.; I hope this information is of assistance to you. If you have furthe questions, please let me know.; Sincerely, Jeffrey R. Miller, Chief Counsel |
|
ID: aiam2745OpenMr. James M. Beach, Collins Industries, Inc., P.O. Box 58, Hutchinson, KS 67501; Mr. James M. Beach Collins Industries Inc. P.O. Box 58 Hutchinson KS 67501; Dear Mr. Beach: This responds to your November 15, 1977, letter asking severa questions concerning Standard No. 217, *Bus Window Retention and Release*.; In your first question, you paraphrase the requirements of S5.3. concerning emergency exit force requirements and release motion and ask whether your understanding of the section is correct. Your interpretation of the standard's requirements are accurate.; Second, you enclosed photographs of a manufacturer's rear emergenc door release mechanism and asked whether it complies with the standard's requirements. The force release mechanism shown in the pictures does not comply with the requirements of Standard No. 217. The release mechanism is not located in the high force access region as required by the standard, and the motion required for release of the exit is not upward as required by paragraph S5.3.3.; Finally, you asked whether your enclosed copy of Standard No. 217 whic includes paragraph S5.2.3.1 is up-to-date. The answer to your question is yes. You have been confused by paragraph S5.2.3.1 because it states that a bus must have, at a minimum, one rear emergency door or a side emergency door and a rear push-out window. The requirement for one rear emergency door does not preclude a schoolbus with a 10,000 pound GVWR or less from using two (double) rear emergency doors. Paragraph S5.4.2.2 states '...the opening of the rear emergency door *or doors* shall be ...' (Emphasis added). The use of the term 'doors' in paragraph S5.4.2.2 indicates that double doors are permitted.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
|
ID: aiam5196OpenMr. Ernest Farmer Director, Pupil Transportation Tennessee State Department of Education Office of Commissioner Nashville, TN 37243-0375; Mr. Ernest Farmer Director Pupil Transportation Tennessee State Department of Education Office of Commissioner Nashville TN 37243-0375; Dear Mr. Farmer: We have received your letter of June 25, 1993, wit respect to your plan to retrofit three school buses with strobe lights for 'the traditional incandescent lights currently used in the eight light overhead warning system on school buses.' You ask whether this equipment would 'conflict with the provisions of FMVSS 108.' Yes, the substitute system would not conform to S5.1.4 of Standard No. 108 because it is not a school bus signal lamp system meeting the requirements of SAE J887 School Bus Red Signal Lamps, July 1964. Moreover, section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1392(a)(2)(A)) prohibits a manufacturer, dealer, distributor, or motor vehicle repair business from knowingly rendering inoperative any device or element of design installed in accordance with a Federal motor vehicle safety standard. However, the prohibition does not extend to the vehicle owner. We assume for purposes of this interpretation that the State is the owner of the school buses, and owns the repair facilities where the conversion will occur. Under these circumstances, there is no Federal legal prohibition against the State's conversion to the strobe light system if the work is performed in its own repair shops. Sincerely, John Womack Acting Chief Counsel; |
|
ID: aiam0766OpenMr. Richard L. Curotto, Treasurer, Stutz Motor Car of America, Inc., Time & Life Building, Rockefeller Center, New York, New York 10020; Mr. Richard L. Curotto Treasurer Stutz Motor Car of America Inc. Time & Life Building Rockefeller Center New York New York 10020; Dear Mr. Curotto: This is in reply to your letter of June 21, 1972. As I understand it your company purchases Pontiac Grand Prix models for conversion into vehicles bearing the Stutz nameplate. Your converter, however, has a number of vehicles in stock, the majority of which will not be converted until after September 1, 1972. You ask, in effect, that we require compliance only with those Federal standards in effect on the date of manufacture of the original Pontiac Grand Prix, and that we do not require compliance with standards which may have come into effect after that time and before completion of the Stutz conversion.; The information contained in your letter indicates that the changes yo make to the Grand Prix are confined to cosmetic changes such as alteration of the exterior sheet metal, reupholstering the interior, and replacement of the back light with glazing conforming to Standard No. 205. If the converted Grand Prix conforms to those Federal motor vehicle safety standards for which temporary exemption was granted Stutz (Standards Nos. 104, 201, 205, 210 and 212), we will consider it permissible for General Motors to continue to be the 'manufacturer' of the vehicle for certification purposes. In that case, the date of manufacture is considered to be the date of completion by General Motors, and the original certification label should be retained on the car when converted.; The vehicle must nevertheless conform at the time of sale to all safet standards and other regulations (for example, 49 CFR Part 575, Consumer Information) that are applicable on its date of manufacture.; Sincerely, Douglas W. Toms, Administrator |
|
ID: aiam0765OpenMr. Richard L. Curotto, Treasurer, Stutz Motor Car of America, Inc., Time & Life Building, Rockefeller Center, New York, New York 10020; Mr. Richard L. Curotto Treasurer Stutz Motor Car of America Inc. Time & Life Building Rockefeller Center New York New York 10020; Dear Mr. Curotto: This is in reply to your letter of June 21, 1972. As I understand it your company purchases Pontiac Grand Prix models for conversion into vehicles bearing the Stutz nameplate. Your converter, however, has a number of vehicles in stock, the majority of which will not be converted until after September 1, 1972. You ask, in effect, that we require compliance only with those Federal standards in effect on the date of manufacture of the original Pontiac Grand Prix, and that we do not require compliance with standards which may have come into effect after that time and before completion of the Stutz conversion.; The information contained in your letter indicates that the changes yo make to the Grand Prix are confined to cosmetic changes such as alteration of the exterior sheet metal, reupholstering the interior, and replacement of the back light with glazing conforming to Standard No. 205. If the converted Grand Prix conforms to those Federal motor vehicle safety standards for which temporary exemption was granted Stutz (Standards Nos. 104, 201, 205, 210 and 212), we will consider it permissible for General Motors to continue to be the 'manufacturer' of the vehicle for certification purposes. In that case, the date of manufacture is considered to be the date of completion by General Motors, and the original certification label should be retained on the car when converted.; The vehicle must nevertheless conform at the time of sale to all safet standards and other regulations (for example, 49 CFR Part 575, Consumer Information) that are applicable on its date of manufacture.; Sincerely, Douglas W. Toms, Administrator |
|
ID: aiam0121OpenMr. R. Hoffman, Service Department, Rockford Motors, Incorporated, 1911 Harrison Avenue, Rockford, Illinois 61101; Mr. R. Hoffman Service Department Rockford Motors Incorporated 1911 Harrison Avenue Rockford Illinois 61101; Dear Mr. Hoffman: Thank you for your letter of July 30, 1968, in which you reques additional information in regard to certification requirements.; The statement in your letter to the effect that because detailed labe requirements are now being prepared, you are not required to affix a certification label on your motorcycles currently being manufactured is not exactly correct. The 'Certification Requirement Notice,' published in the Federal Register, Volume 32, Number 215, dated November 4, 1967, a copy of which is enclosed, states that a certification label or tag should be affixed to each applicable motor vehicle if manufactured on or after January 1, 1968. In your case the only safety standard that currently involves motorcycles is Number 205, 'Glazing Materials,' pertaining to windshields. On January 1, 1969, another safety standard, Number 108, 'Lamps, reflecting Devices, and Associated Equipment,' will involve motorcycles manufactured on or after that date.; For your immediate information, a copy of the Federal Motor Vehicl Safety Standards with Amendments is enclosed, with particular attention called to Table III, page MVSS 108-18 (1969) and Table IV, page MVSS 108-20 and 21 (1969).; In regard to your question as to whether you have to add the year o manufacture to your serial numbers, this is not a specific requirement, but would be an aid to clarifying the serial numbering system that identifies applicable vehicles as manufactured on or after January 1, 1968.; The study involving the possibility of specific changes t certification requirements is currently in the proposed rule making category and if changes do become finalized they will be published in the Federal Register.; Please furnish this office with the requirements shown in paragraph in the enclosed Certification Requirement Notice at your earliest convenience.; I trust this information will be of assistance to you in regard to you inquiries.; Sincerely, Francis Armstrong, Director, Office of Performance Analysis Motor Vehicle Safety Performance Service; |
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.