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: aiam4111OpenMr. Marshall D. Carter, Whisper Electric Car AS, 87 Hadsundve, Als, DK-9560 Hadsund, Denmark; Mr. Marshall D. Carter Whisper Electric Car AS 87 Hadsundve Als DK-9560 Hadsund Denmark; Dear Mr. Carter: This is in reply to your letter of February 18, 1986, asking tw questions with respect to the Federal motor vehicle safety standards.; With respect to electric vehicles, you have asked 'is there a standar regulating the minimum length of time that the hazard light must be able to function at a minimum intensity, on the service battery alone?' There is no such standard. The vehicle must be equipped with a hazard warning signal operating unit designed to conform to SAE J910, January 1966, and a hazard warning signal flasher designed to conform to SAE J945, February 1966, but there is no requirement in the Federal motor vehicle safety standard on vehicle lighting, Standard No. 108, that the hazard warning signal flashers perform for a minimum specified period of time in service.; You have also asked 'Is there a requirement that the vehicle b equipped with an illuminated display, indicating gear selection?' We are unable to confirm your conclusion that there is no such requirement under Standard No. 101. Paragraph S3.2 of Standard No. 102 requires that identification of shift lever positions or patterns be permanently displayed in front of the driver. Paragraph S5.3.1 of Standard No. 101 requires illumination of the 'gauges' listed in Column 1 of Table 2 that are accompanied by the word 'Yes' in Column 5. The last 'gauge' listed is 'Automatic gear position', and the word 'Yes' appears in Column 5. The automatic gear position is a 'gauge' as defined by paragraph S4 of Standard No. 101, 'a display that is listed in ...Table 2 and is not a telltale'. Thus the Federal standards do require illumination of the gear positions of automatic transmissions, but not of manual ones.; I hope that this responds to your questions. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1313OpenMr. Gordon M. Bradford, Vice President, Corporate Development, American Safety Equipment Corporation, 16055 Ventura Boulevard, Encino, CA 91316; Mr. Gordon M. Bradford Vice President Corporate Development American Safety Equipment Corporation 16055 Ventura Boulevard Encino CA 91316; Dear Mr. Bradford: This is in reply to your letter of October 5, 1973, concerning you proposed use of a tension reliever device in a seat belt retractor. As we understand the concept of the tension reliever, it allows a small amount of slack to be introduced into the webbing by a mechanism roughly similar to that of a window shade. If the webbing is pulled smoothly back and forth, the retractor exerts a normal retractive force. If, however, the retraction is halted at a certain point, as when the belt comes to rest against an occupant's shoulder, the reliever engages and the occupant is relieved of the active pull of the retractor until he moves forward by an inch or two and disengages the reliever.; Your initial question is whether a reliever-equipped retractor will b considered to meet the retraction force requirements of S4.3(j)(6) of Motor Vehicle Safety Standard No. 209. You state that it will meet the test so long as the procedures of S5.2(j) are strictly observed and no oscillations are introduced by the test apparatus. If the facts are as you state, it is our opinion that the retractor would meet S4.3(j)(6).; Your other question, as clarified by telephone on November 1, 1973, i whether we have reservations about the concept of a tension reliever that would lead us to bar its use through amendment of Standard No. 209. Based on the information presently available, we have no such reservations.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3284OpenCharles M. Kneip, Vehicle Services Division, Department of Motor Vehicles, Lincoln, NE 68509; Charles M. Kneip Vehicle Services Division Department of Motor Vehicles Lincoln NE 68509; Dear Mr. Kneip: This is in response to your letter of May 7, 1980, in which you aske whether the proposed Nebraska certificate of title may be used as a substitute for the Federal odometer disclosure form required by 49 CFR Part 580.; The Nebraska title differs from the minimum Federal requirements i that there is no certification that the odometer reading reflects the actual mileage or the mileage over 99,999 miles, or is not the actual mileage. The buyer is not required to sign the Nebraska title as he is the Federal form (sic). In addition, your title does not refer to the legal consequences of a false disclosure. If you can make these additions, the Nebraska title will satisfy the Federal requirements.; For your information, I have enclosed a copy of the *Federal Register notice which discusses the short form odometer disclosure that States may use on their titles to satisfy Federal requirements, a letter to Maryland in which we indicate that formal approval by NHTSA is not necessary if the title contains the specified information, and sample titles that the NHTSA has approved.; If you need any further inforamtion, please do not hesitate to contac us.; Sincerely, John Womack, Assistant Chief Counsel |
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ID: aiam4541OpenMr. Gerald Peterson Taraco Enterprises Inc. Empire Plaza 23 Empire Drive St. Paul, MN 55103; Mr. Gerald Peterson Taraco Enterprises Inc. Empire Plaza 23 Empire Drive St. Paul MN 55103; "Dear Mr. Peterson: This responds to your May 17, 1988 letter to m asking for 'information on petitions filed, concerning the safety problems on trucks.' You also enclosed for the agency's information materials on the product you manufacture called a 'Truk-Hedrest.' According to the brochures you sent, the Truk-Hedrest attaches to the rear window of a vehicle by means of velcro and 'is designed to help protect the head of the driver and passenger of a truck or van in an accident when their head is snapped back against the rear window or bulkhead of a vehicle.' You also enclosed a copy of an August 28, 1987 letter which Mr. Carl Clark of this agency sent you regarding your product. The latter part of this letter addresses statements in your brochures relating to our regulations and the Truk-Hedrest. The National Highway Traffic Safety Administration (NHTSA) shares your concern for light truck safety and is currently reviewing a number of actions intended to improve the protection for occupants of such vehicles. This review has been described in detail in the enclosed reports to Congress issued by NHTSA in May 1987 ('Light Truck and Van Safety') and April 1988 ('Safety Programs for Light Trucks and Multipurpose Passenger Vehicles'). Among the rulemaking activities considered by NHTSA for light trucks is a possible extension of Safety Standard No. 202, Head Restraints, to those vehicles. The agency is presently reviewing petitions for rulemaking on this subject from Mr. Dale T. Fanzo of Bethel Park, Pennsylvania and Mr. Mark E. Goodson of Lewisville, Texas. I have enclosed copies of these petitions for your information. With regard to the brochures and materials you sent on your product, I would like to first to make it clear that Mr. Clark's letter on the Truk-Hedrest only expressed his personal opinions and interests concerning your product. His letter does not represent any official agency position regarding light truck safety in general or regarding your product in particular. Mr. Clark's letter was neither an approval nor endorsement of your product by this agency. NHTSA does not approve motor vehicles or motor vehicle equipment, nor do we endorse any commercial products. In addition, the agency cannot as a matter of law and will not as a matter of policy determine the extent, if any, of the occupant protection provided by any commercial product apart from the context of an actual enforcement proceeding. Thus, the agency does not concur in any manner with Mr. Clark's assessement that the Truk-Hedrest 'does indeed provide excellent head protection' or with any other statement as to the effectiveness of your product. Second, your brochures imply that the Truk-Hedrest has been shown to help protect against possible neck and head injuries when tested to 'NHTSA guidelines.' NHTSA has neither adopted or even developed guidelines for testing the Truk-Hedrest. Again, in his letter to you Mr. Clark provided only his personal opinion on certain aspects of your product testing program. He expressed no agency recommendations or 'guidelines' for testing a product such as yours 'for rear end collisions up to 50 MPH,' or with bowling balls, since no such guidelines exist. My final clarification concerns the statements in your brochures that the Truk-Hedrest 'Passes MVSS-302 Test for fire and toxic fumes.' Please note that Standard No. 302, Flammability of Interior Materials, addresses only the flammability resistance of vehicle components and not the toxicity of gases from burning materials. With respect to your statement about meeting the FMVSS 302 requirements regarding fire, please note that if the Truk-Hedrest did not in fact meet those requirements and were installed in a vehicle by a motor vehicle manufacturer, distributor, dealer or repair business, there could be a violation of the National Traffic and Motor Vehicle Safety Act. Section 108(a)(2)(A) of the Act prohibits those persons from rendering inoperative any device or element of design installed pursuant to the Federal motor vehicle safety standards. Installation of rapidly burning materials could vitiate the compliance of the materials which were present in the vehicle at the time of its sale to the first consumer and were certified as meeting FMVSS 302. To repeat, in his letter to you Mr. Clark was only expressing his personal opinions and interests concerning your product and made no statements that should be construed as official agency positions. NHTSA does not endorse the Truk-Hedrest nor do we make any determination on the extent, if any, of the occupant protection provided by your product. I regret any confusion that may have resulted from Mr. Clark's letter to you on the Truk-Hedrest. Please contact my office if you have further questions. Sincerely, Erika Z. Jones Chief Counsel Enclosures"; |
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ID: aiam1743OpenMr. John Massey, Fontaine Truck Equipment Co., 9051 Sorenson Avenue, Santa Fe Springs, CA 90670; Mr. John Massey Fontaine Truck Equipment Co. 9051 Sorenson Avenue Santa Fe Springs CA 90670; Dear Mr. Massey: Mr. S. G. Holder of the Fontaine Truck Equipment Company asked th National Highway Traffic Safety Administration to explain for your benefit the requirements of Standard No. 121, *Air brake systems*, for alteration of wheelbase and installation of a liftable axle on incomplete or complete vehicles by a dealer like yourself.; I have enclosed a copy of the standard as requested. It lists severa requirements which would be affected by the addition of an additional axle. These changes can be complex, and we believe that some assistance from the manufacturer of the axle may be necessary to assist a final-stage manufacturer or vehicle alterer like yourself in meeting the certification requirements. I enclose a letter to a liftable axle manufacturer which explains the responsibilities of the various parties to each other.; Standard No. 121 was issued in February 1971 in part to reduce th incompatibility in brake performance between the larger air-braked vehicles on the highway and other highway users. Its provisions substantially improve the stopping distance performance and other braking characteristics of air-braked vehicles. To meet these requirements, chassis-cab and other vehicle manufacturers have limited the modifications which may be made to their brake system design so that a vehicle will remain in compliance.; It is for this reason that final-stage manufacturers and vehicl alterers are more limited than previously in the modifications which they can undertake. Wheelbase alteration is an example of the type of modification which seriously affects brake system performance. We expect experience with Standard No. 121 will justify greater freedom in the future for such modifications as wheel base alteration.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam0851OpenR. F. Tifft, Purchasing Agent, Bunker Ramo, Borg Instruments Division, 902 Wisconsin Street, Delavan, WI, 53115; R. F. Tifft Purchasing Agent Bunker Ramo Borg Instruments Division 902 Wisconsin Street Delavan WI 53115; Dear Mr. Tifft: This is in reply to your letter of September 6, 1972, inquiring abou the applicability of Federal Motor Vehicle Safety Standard (FMVSS) No. 302 to the lens or crystal of automobile clocks installed in the instrument panel of a car.; The lens or crystals of automobile clocks are not included unde paragraph S4.1 as interior components subject to the standard, and, accordingly, they do not have to meet the requirements of FMVSS No. 302.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam1893OpenMr. Frazer F. Hilder, General Counsel, General Motors Corporation, General Motors Building, 3044 West Grand Boulevard, Detroit, MI 48202; Mr. Frazer F. Hilder General Counsel General Motors Corporation General Motors Building 3044 West Grand Boulevard Detroit MI 48202; Dear Mr. Hilder: This is in response to your letter of March 21, 1975, inquiring as t the effect of Federal Motor Vehicle Safety Standard No. 121 on Massachusetts and New Jersey State laws relating to air brake performance.; As you are aware, section 103(d) of the National Traffic and Moto Vehicle Safety Act of 1966 (15 U.S.C. 1392(d)) provides that no state or political subdivision of a State may promulgate or continue in effect standards applicable to an aspect of motor vehicle or motor vehicle equipment performance which is covered by a Federal motor vehicle safety standard, unless the standards are identical.; Standard No. 121 includes provisions relating to truck and bus brak performance, including requirements for stopping distances. A more restrictive State brake requirement than that specified in Standard 121 is voided by S 103(d) since the Federal standard is intended to cover all aspects of air brake performance.; The Federal requirements must be regarded as conclusive with regard t service, emergency, and parking braking capabilities in order to maintain the uniformity necessary in a Federal regulatory scheme. This was affirmed in a recent decision rendered in a case brought by the Motorcycle Industry Council, Inc. against the State of California in the United States District Court for the Eastern District of California concerning the preemption of a California State requirement that motorcycle headlamps be wired to operate when the engine is running. The Court held that the California requirement is preempted by the Federal Motor Vehicle Safety Standard No. 108 since the National Highway Traffic Safety Administration intended to cover all aspects of performance directly involving motorcycle headlamps.; Therefore, requirements such as those described in your letter would b preempted by Standard 121 since the aspects of performance that would be affected are covered by the Federal standard. You should note that this discussion of State 'requirements' only refers to rules of general applicability within a State or municipality. It does not refer to purchase specifications that may be imposed by any person or organization, including a State or municipality, with respect to vehicles purchased for the person or organization's own use. Such specifications are not limited by Federal law, and in the case of governmental bodies are specifically allowed by S103(d), although of course they cannot alter a manufacturer's duty to conform to Federal standards.; Sincerely, James C. Schultz, Chief Counsel |
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ID: aiam0781OpenMr. Thomas S. Pieratt, Jr., Executive Secretary, Truck Equipment & Body Distributors Association, 602 Main Street, Cincinnati, OH 45202; Mr. Thomas S. Pieratt Jr. Executive Secretary Truck Equipment & Body Distributors Association 602 Main Street Cincinnati OH 45202; Dear Mr. Pieratt: This is in reply to your letter of June 16, 1972, requestin information on steps to be taken under the Certification regulations when a manufacturer considers a fifth wheel to be a 'readily attachable component,' and certifies the vehicle as a complete vehicle before the attachment of the fifth wheel. You ask what responsibilities apply to the person who ultimately attaches the fifth wheel when that person also affixes other components to the vehicle. You list as other components a third axle, the substitution of an air ride suspension for the regular suspension, and the addition of a 'drum' unit (we assume that this is a dromedary unit).; The situations you have listed appear to resemble situations similar t those involving the possible use of the 'altering distributor label' which we discussed in our letter to you of June 20. We said in that letter that if a person altering a completed vehicle does not make changes significant enough to make him a remanufacturer, he may satisfy the requirements by allowing the existing label to remain in place. If he does make significant changes, however, he must recertify the vehicle, but he may rely on the previous manufacturer's certification for those aspects of performance that are not affected by his alterations.; We would consider the addition of a third axle to be remanufacturing and you were correct in advising your member to recertify the vehicle, utilizing the information on the existing label except as to the third axle. Strictly speaking, however, your member as the remanufacturer is responsible for the conformity of the entire vehicle. While he may rely on the information on the original label, if a noncompliance were discovered the burden in the first instance would be on him to show that his alterations were not responsible.; We cannot determine from the information you provide whether th 'substitution of an air ride suspension' would constitute remanufacturing. You can probably infer the answer based on your own knowledge of what is involved.; With reference to the drum unit, we advised you by letter of March 24 1972, that we consider the addition of a dromedary unit to be remanufacturing. A person who installs such a component on a new vehicle would be required to recertify the entire vehicle as a final-stage manufacturer. He may also rely on the previous certification for those aspects of performance which he does not affect.; You also ask whether, if the installation of the fifth wheel alters component covered by a safety standard, the installer should recertify the vehicle. As you are assuming that the fifth wheel is a 'readily attachable component,' no further certification is necessary. However, the person installing the fifth wheel must ensure that the vehicle conforms to all standards when the work is completed.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5079OpenMichael J. Vacanti 7533 W. 112th Street Bloomington, MN 55438; Michael J. Vacanti 7533 W. 112th Street Bloomington MN 55438; "Dear Mr. Vacanti: This responds to your letter seeking information o how the laws and regulations administered by this agency would apply to a device you have designed. According to your letter, this device is an aftermarket accessory. The accessory is a polyurethane device that latches onto the lap/shoulder belt and changes the angle at which the shoulder belt crosses a child's torso. The device is intended to improve shoulder belt fit for children that have outgrown child safety seats. I am pleased to have this chance to explain our laws and regulations to you. The National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq., the Safety Act) authorizes this agency to issue motor vehicle safety standards for new motor vehicles and new items of motor vehicle equipment. We have exercised this authority to establish Standard No. 208, Occupant Crash Protection (49 CFR 571.208). This standard requires new motor vehicles to be equipped with safety belts and requires that those belts meet specified fit and comfort requirements, as set forth in S7 of the standard. However, Standard No. 208 does not apply to aftermarket items that seek to alter belt fit and/or comfort. Hence, you are not required to certify that this device complies with Standard No. 208 before offering the device for sale. In addition, you are not required to get some sort of 'approval' from this agency before offering this device for sale. NHTSA has no authority to 'approve' motor vehicles or motor vehicle equipment, nor do we endorse any commercial products. Instead, the Safety Act establishes a 'self- certification' process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. As stated above, this device is not subject to any safety standard, so you do not have to make any certification. Although none of our safety standards directly apply to this device, there are several provisions in the Safety Act that are relevant. Manufacturers of motor vehicle equipment such as your belt positioning device are subject to the requirements in sections 151-159 of the Safety Act (15 U.S.C. 1411-1419) concerning the recall and remedy of products with defects related to motor vehicle safety. In addition, use of your product could be affected by section 108(a)(2)(A) of the Safety Act (15 U.S.C. 1397(a)(2)(A)). That section prohibits manufacturer, distributors, dealers, and repair shops from knowingly 'rendering inoperative,' in whole or in part, any device or element of design installed on or in a vehicle in compliance with an applicable safety standard. There are two elements of design in a vehicle that might be 'rendered inoperative' by the use of your belt positioning device. One is the occupant protection afforded by belts that meet the specified fit and comfort requirements. The other element of design that could be rendered inoperative by the use of your belt positioning device is the burn resistance required by Standard No. 302, Flammability of Interior Materials (49 CFR 571.302). The materials used in the interior of vehicles, including the seat belts, seat backs and cushions, trim panels, and headliner must comply with the burn resistance requirements of Standard No. 302 to reduce deaths and injuries in the event of a fire in the vehicle's interior. If your belt positioning device renders inoperative the belt fit and comfort requirements specified in Standard No. 208 or does not comply with burn resistance requirements, it could not be installed in a vehicle by any manufacturer, distributor, dealer, or repair shop. I have enclosed a general information sheet for new manufacturers that gives a thumbnail sketch of NHTSA's regulations and provides information on how to obtain copies of those regulations. I hope that this information is helpful. If you have any further questions or need some additional information, please feel free to contact Steve Kratzke of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosure "; |
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ID: aiam5583OpenMr. Douglas Helbig Vice President Spencer Testing Services P.O. Box 429 Spencer, WV 25276; Mr. Douglas Helbig Vice President Spencer Testing Services P.O. Box 429 Spencer WV 25276; Dear Mr. Helbig: It has come to my attention that Spencer Testin Services is advertising its inspection procedure as 'NHTSA approved.' This representation is incorrect. NHTSA has not approved this or any other inspection procedure. Therefore, I must insist that this language be immediately removed from the advertisement and that you refrain from making such representations in any other format. Please send me a copy of the corrected advertisement without reference to the inspection procedure being NHTSA approved. Thank you for your immediate attention to this matter. Sincerely, John Womack 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.