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: aiam1166OpenMr. Ray Hartman, Vice President-Engineering, Crown Coach Corporation, 2500 East Twelfth Street, Los Angeles, CA 90021; Mr. Ray Hartman Vice President-Engineering Crown Coach Corporation 2500 East Twelfth Street Los Angeles CA 90021; Dear Mr. Hartman: This is in reply to your letter of June 1, 1973, concerning Standar No. 217, Bus Window Retention and Release.' You raise two questions regarding the standard: the first concerns the incompatibility of the standard with buses designed to transport convicts or other persons under physical restraint, the second, the possibility that the standard may preclude the use of a push-button release mechanism for emergency exits which you apparently presently use in many buses you manufacture.; We have received other communications regarding the incompatibility o Standard No. 217 with buses designed to transport convicts and are presently considering requests that these buses be exempted from the standard.; With respect to the use of push-button emergency exit releas mechanisms, Standard No. 217 does not specify the design of the emergency exit release mechanisms but, rather, specifies requirements which these release mechanisms, regardless of design, are required to meet. These requirements essentially specify the magnitude and direction of release forces necessary to operate the emergency exit release mechanism. If these requirements do preclude the use of a push-button release mechanism you wish to use, the appropriate procedure for you to follow is to petition for rulemaking to amend the standard, in accordance with NHTSA regulations (49 CFR SS553.31 *et seq.*, copy enclosed). We recommend that you include detailed information on the type of release you wish to use as part of any such petition.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3659OpenMr. Jack Garvin, Vice President-Operations, Garvin-Fram, Inc., 817 Albion Avenue, Schaumburg, IL 60193; Mr. Jack Garvin Vice President-Operations Garvin-Fram Inc. 817 Albion Avenue Schaumburg IL 60193; Dear Mr. Garvin: This responds to your recent letter to Mr. Kratzke of my staf requesting information concerning any regulations applicable to the salvage and sale of farm implement tires exposed to a warehouse fire. This agency has no such regulations, and I am not aware of any other Federal regulations applicable to this situation.; The National Traffic and Motor Vehicle Safety Act, as amended 1974 (1 U.S.C. 1381 *et* *seq*.), gives this agency authority to regulate motor vehicles and motor vehicle equipment. Tires for use on motor vehicles are subject to regulation as motor vehicle equipment. Section 102(3) of the Safety Act (15 U.S.C. 1391(3)) defines a motor vehicle as 'any vehicle driven or drawn by mechanical power manufactured primarily for use on the public streets, roads, and highways...' Farm implements have been determined not to be motor vehicles, because they are not manufactured primarily for use on public roads. Therefore, tires for use on farm implements are not considered motor vehicle equipment, and are not regulated by this agency. The inventory sheet attached to your letter shows that these tires are of a size and strength that were designed for use on farm implements. Accordingly, you may conduct the salvage and sale of these farm implement tires as you wish without violating any of this agency's regulations.; In your telephone conversation with Mr. Kratzke, you mentioned tha some tires for use on passenger cars were also involved in the fire and asked about any agency requirements for subsequent sale of these tires. With respect to those tires, the manufacturer that has certified the tires as complying with our safety standards (by molding the letters 'DOT' on the sidewall) must make a determination of whether the certification is still valid. If the manufacturer determines that the certification is still valid, the tires may be sold. If, on the other hand, the certification is not still valid, the manufacturer must remove its DOT symbol from the sidewall of the tires, and those tires could not be sold. The means by which the manufacturer determines whether or not its certification is still valid is left completely to the discretion of the individual manufacturer. I have enclosed a 1981 interpretation explaining this more fully.; I appreciate your concern for tire safety and for complying with ou safety regulations.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3910OpenMr. Gordon Bonvallet, Manager, Photometric Division, ETL Testing Laboratories, Inc., P.O. Box 2040, Cortland, NY 13045- 2040; Mr. Gordon Bonvallet Manager Photometric Division ETL Testing Laboratories Inc. P.O. Box 2040 Cortland NY 13045- 2040; Dear Mr. Bonvallet: This is in reply to your letter of February 4, 1985, asking for a interpretation of the humidity testing procedure for replaceable bulb headlamps.; Paragraph S6.8 of Motor Vehicle Safety Standard No. 108 states i pertinent part that after completion of the test cycle in which the headlamp shall have been in an environment of 100 degrees Fahrenheit with a relative humidity of 90 *+* 10 percent, it shall then be in an environment with a temperature of 73 degrees Fahrenheit and relative humidity of 30 *+* 10 percent before removal for photometric testing. You believe that this implies an instantaneous transition in temperature/humidity conditions which, in your view, is 'impossible to achieve.' You have set forth three alternative procedures and ask which is the most acceptable to this agency.; Under your first alternative, the temperature and humidity in th humidity chamber would be reduced to 73 degrees Fahrenheit-43 percent, requiring about an hour, whereupon the headlamp would be removed to a 'dry box' chamber of the requisite temperature/humidity before photometric testing. In the second alternative, there would be no such removal before the photometric testing. In the third alternative, the headlamp would be removed from the humidity chamber and immediately carried to a 'dry box' with the requisite temperature/humidity, however, in your test set up this would require three to five minutes elapsed time between chambers.; Paragraph S6.8 does not specify a humidity of 43 percent in any of it test conditions, and a procedure incorporating the first and second alternatives clearly would not be in accordance with paragraph S6.8. That paragraph, however, does not specify that the temperature/humidity sequences must occur in the same chamber but it does imply that the lower temperature/humidity soak should take place directly following the higher temperature/humidity one. Therefore, your third alternative is the one that meets the intent of paragraph S6.8. To insure consistency of results, we recommend that no transfer period exceed three minutes and that the headlamp be exposed as briefly and as little as possible to the ambient temperature/humidity of the test laboratory.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam4722OpenMr. J. Douglas Smith Engineering Manager Duralite Truck Body and Container Corp. 1300 Bush Street Baltimore, MD 21230; Mr. J. Douglas Smith Engineering Manager Duralite Truck Body and Container Corp. 1300 Bush Street Baltimore MD 21230; Dear Mr. Smith: This is in reply to your letter to Taylor Vinson o this Office. I regret the delay in responding. You have asked for an interpretation of Motor Vehicle Safety Standard No. 108 as it pertains to the location of clearance lamps. You stated your understanding that 'if a chassis cab is equipped with clearance and marker lamps, it is not necessary to add a second set of two lamps to act as clearance lamps to the front wall of the truck body.' This is not correct. A chassis cab is an incomplete motor vehicle, and not required to comply with Standard No. 108. However, when the chassis cab is completed, the completed vehicle must comply, and be certified by its final-stage manufacturer as complying, with Standard No. 108 (and all other applicable Federal motor vehicle safety standards). Standard No. 108, in pertinent part, requires front clearance lamps to be mounted to indicate the overall width of the vehicle, and as near the top as practicable. This means that if clearance lamps have been mounted on the chassis cab, and if in that location they do not indicate the overall width of the completed motor vehicle and are not as near the top of the completed motor vehicle as practicable, the final stage manufacturer must add a set of clearance lamps to the front of the truck body to meet that requirement. In this event, the cab-mounted clearance lamps may be disconnected or removed. However, this is not true with respect to the mounting of identification lamps on chassis cabs. Standard No. 108 allows them to be mounted as close as practicable to the top of the cab as an alternative to the top of the vehicle. Further, on truck tractors, clearance lamps mounted on the cab may be located to indicate the width of the cab rather than the overall width of the vehicle. I hope this has answered your question. Sincerely, Stephen P. Wood Acting Chief Counsel /; |
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ID: aiam4920OpenMr. Robert W. Smith President Auto Safety Corporation Box 424 Middletown, Delaware 19709; Mr. Robert W. Smith President Auto Safety Corporation Box 424 Middletown Delaware 19709; Dear Mr. Smith: This responds to your letter of October 14, 1991, t Taylor Vinson of this Office, asking for a confirmation of your interpretation of Motor Vehicle Safety Standard No. 108, based upon a meeting with Mr. Vinson on August 15, l990. You are developing a license plate frame that incorporates a 'flashing/steady burning stop lamp', for use on passenger cars and motorcycles, and 'an auxiliary flashing/steady burning stop lamp' for use on vans, minivans, and pickup trucks. You cite a letter of this agency to Bettie Lou Simcox, dated October 24, 1986, as authority for your understanding that Standard No. 108 allows the use of a flashing, steady burning stop lamp. Standard No. 108 covers original motor vehicle lighting equipment, and lighting equipment that is intended to replace the original lighting equipment. It does not cover supplementary or novelty lighting equipment offered in the aftermarket. Mrs. Simcox asked us about the acceptability of an aftermarket stop lamp which, when the brake is applied, pulses before going into a steady burning mode. We informed Mrs. Simcox that her lamp was unacceptable as replacement equipment because Standard No. 108 requires original equipment stop lamps, and lamps designed to replace that equipment, to be steady burning in use, but that it would be permissible under Standard No. 108 as a supplementary stop lamp. For the same reason, your invention would not be prohibited by Standard No. 108 if it is offered in the aftermarket as a supplementary stop lamp, which we understand is your intent. You should be aware that Standard No. 108 specifically requires motor vehicles to be equipped with one or more license plate lamps. We are uncertain of the effect, if any, that the installation of your combination license plate frame/supplementary stop lamp would have upon conformance of a vehicle's license plate lamp(s) with the requirements of Standard No. 108. We therefore remind you of the prohibition in the National Traffic and Motor Vehicle Safety Act that a manufacturer, distributor, dealer or motor vehicle repair business may not render inoperative, in whole or in part, a device such as the license plate lamp that has been installed in accordance with a safety standard such as Standard No. 108. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam0848OpenMr. Gorou Utsunomiya, Chief, Liaison Engineer in U.S., 23777 Greenfield Road, Suite 462, Southfield, MI 48075; Mr. Gorou Utsunomiya Chief Liaison Engineer in U.S. 23777 Greenfield Road Suite 462 Southfield MI 48075; Dear Mr. Utsunomiya: This is in reply to your letter of August 8, 1972, enclosing sketche of motor vehicles and asking into which vehicle category under the motor vehicle safety standards they fall. The numbered paragraphs below correspond to those in your letter.; >>>1. Figures 1, 2, and 3 illustrate trailers under the standards Trailers are presently subject only to Motor Vehicle Safety Standard No. 108, 'Lamps, Reflective Devices, and Associated Equipment.' Trailers equipped with air brakes and manufactured after September 1, 1974, will be required to conform to Standard No. 121, 'Air Brake Systems.' It is unlikely that many camping or recreational trailers will be subject to these requirements.; 2. Figure 4 illustrates two pickup trucks equipped with slide-i campers. Pickup trucks must conform to all standards applicable to trucks. The campers must conform, as you state, to Motor Vehicle Safety Standard No. 205, 'Glazing Materials.' Both pickup trucks and slide-in campers will be required to conform to a new Standard No. 126, 'Truck- Camper Loading,' when that standard becomes effective. A copy of the standard is enclosed.; 3. In referring to the illustrations of the pickup trucks equipped wit slide-in campers, you ask whether the requirements applicable to the trucks when combined with a camper are different from those applicable when the truck is not so equipped. The answer is no. The standards applicable to pickup trucks (those that are applicable to 'trucks') are the same whether or not the pickup is equipped with a camper.; 4. The requirements for pickup trucks and slide-in campers do no differ if both components are manufactured by the same company.; 5. Wagon campers and motor homes are considered to be multi-purpos passenger vehicles when constructed on truck chassis. The illustrations you enclose appear to us to represent vehicles manufactured on truck chassis.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0849OpenMr. Gorou Utsunomiya, Chief, Liaison Engineer in U.S., 23777 Greenfield Road, Suite 402, Southfield, Michigan 48075; Mr. Gorou Utsunomiya Chief Liaison Engineer in U.S. 23777 Greenfield Road Suite 402 Southfield Michigan 48075; Dear Mr. Utsunomiya: This is in reply to your letter of August, 1972, enclosing sketches o motor vehicles and asking into which category under the motor vehicles safety standards they fall. The numbered paragraphs below correspond to those in your letter.; >>>1. Figures 1,2, and 3 illustrate trailers under the standards Trailers are presently subject only to Motor Vehicle Safety Standard No. 108, 'Lamps, reflective Devices, and Associated Equipment.' Trailers equipped with air brakes and manufactured after September 1, 1974, will be required to conform to Standard No. 121, 'Air Brake Systems.' It is unlikely that manu camping or recreational trailers will be subject to these requirements.; 2. Figure 4 illustrates two pickup trucks equipped with slide-i campers. Pickup trucks must conform to all standards applicable to trucks. The campers must conform, as you state, to Motor Vehicle Safety Standard No. 205, 'Glazing Materials.' Both pickup trucks and slide-in campers will be required to conform to a new Standard No. 126, 'Truck-Camper Loading,' when that standard becomes effective. A copy of the standard is enclosed.; 3. In referring to the illustrations of the pickup trucks equipped wit slide-in campers, you ask whether the requirements applicable to the trucks when combined with a camper are different from those applicable when the truck is not so equipped. The answer is no. The standards applicable to pickup trucks (those that are applicable to 'trucks') are the same whether or not the pickup is equipped with a camper.; 4. The requirements for pickup trucks and slide-in campers do no differ if both components are manufactured by the same company.; 5. Wagon campers and motor homes are considered to be multi-purpos passenger vehicles when constructed on truck chassis. The illustration you enclose appear to us to represent vehicles manufactured on truck chassis.<<<; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0107OpenOfficine Alfieri Maserati S.P.A., L'Administratore Delegato, Viale Ciro Menotti, 322, 41100 Modena (Italia); Officine Alfieri Maserati S.P.A. L'Administratore Delegato Viale Ciro Menotti 322 41100 Modena (Italia); >>>Your Ref: Direz. O.O. gb<<< Gentlemen: This is in response to your letter of August 8 with reference t compliance of the Maserati automobile with Federal motor vehicle safety standards.; You have asked first of all whether, as a manufacturer of 620 vehicle in 1967, Maserati may be excused from compliance with some of the Federal standards. The National Traffic and Motor Vehicle Safety Act of 1966, under which Federal standards are issued, was recently amended to authorize a procedure whereby manufacturers of limited production vehicles might petition for exemption from the Federal standards. But this procedure is not available to a manufacturer of more than 500 vehicles a year, no matter how few vehicles of that manufacturer are exported to the United States. Consequently Maserati cannot be exempted from any of the Federal standards.; You have also mentioned the difficulties that a small manufacturer fac in crash-testing vehicles, and have asked whether the photographs you submitted showing several Maserati automobiles which have been involved in front end collisions are acceptable as proof of compliance with Federal standard No. 204 (Steering Control Rear-ward Displacement - Passenger Cars). I hope the following explanation will be of assistance to you. The Federal standards do not require crash-testing of vehicles, nor the submission of any data to the Federal Highway Administration for 'approval'. What is required is that a manufacturer attach a certification plate to his vehicle stating that the vehicle conforms to all applicable Federal standards on the date of the vehicle's manufacture. How the manufacturer satisfies himself that the vehicle conforms in his own affair, he may have non-crash data or other information which indicates conformance. The Federal Highway Administration, however, may request this data if through its own investigation it appears that a certification is false or misleading, and that a vehicle does not actually conform to a standard.; I enclose a copy of the latest Federal standards for your guidance. Sincerely, Robert M. O'Mahoney, Assistant Chief Counsel for Regulations |
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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 |
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ID: aiam3654OpenMr. Thomas A. Kenny, Secretary/Treasurer, Pulse Marketing Group, Inc., P.O. Box 1324, Elkhart, IN 46515; Mr. Thomas A. Kenny Secretary/Treasurer Pulse Marketing Group Inc. P.O. Box 1324 Elkhart IN 46515; Dear Mr. Kenny: This responds to your recent letter requesting information concernin Safety Standard No. 205, *Glazing Materials*. You are considering marketing a fiberglass reinforced plastic part' that would replace rear windows in buses. You ask whether the standard would be applicable.; The answer to your question is yes. Safety Standard No. 205 specifie performance and location requirements for all glazing materials used on motor vehicles, whether as original equipment or replacement parts. As a manufacturer or fabricator of glazing you would have to certify that your fiberglass product complies with all applicable requirements of the standard. Standard No. 205, and the ANS Z26 standard which is incorporated by reference, specifies three types of plastic materials which may be used in the rear windows of buses (including rear side windows). These are Items 4, 5, and 12 glazing materials. Your fiberglass window may only be used in the rear windows of buses if it complies with the performance requirements of one of these glazing types (Items), i.e., if it passes all of the tests specified for one of these Items. The fact that your product is opaque does not preclude its use, since Items 4, 5, and 12 glazing materials do not have to comply with any luminous transmittance requirements.; You also asked if any approvals are necessary before you market thi product. The answer is no. The agency does not grant prior approvals of motor vehicles or motor vehicle equipment. Section 114 of the National Traffic and Motor Vehicle Safety Act provides that it is the responsibility of the glazing manufacturer or fabricator to determine compliance and to certify that its product complies with all applicable requirements of Safety Standard No. 205. The certification and marking requirements are prescribed in paragraph S6 of Standard No. 205. (I am enclosing a copy of section 114 of the Vehicle Safety Act, which is referenced in paragraph S6.); Please contact Hugh Oates of my staff if you have any further question. Sincerely, Frank Berndt, 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.