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: aiam5304OpenMs. Angela R. Caron 892 Murray Rd. Meridian, MS 39305; Ms. Angela R. Caron 892 Murray Rd. Meridian MS 39305; "Dear Ms. Caron: This responds to your letter asking about the safet of aftermarket belt positioning devices. The devices you ask about alter the positioning of vehicle lap and shoulder belts, for the advertised purposes of improving the fit of the belts on children and small adults. Although NHTSA understands your view that safety belts should be comfortable for the wearer, we have significant concerns about aftermarket belt positioning devices. The following discussion explains those concerns and the effect of our regulations on such products. By way of background information, the National Traffic and Motor Vehicle Safety Act (the Safety Act) gives this agency the authority to issue safety standards applicable to new motor vehicles and new items of motor vehicle equipment. This agency does not have a safety standard that directly applies to belt positioning devices. Our safety standards for 'Occupant Crash Protection,' (Standard No. 208) and 'Seat Belt Assembly Anchorages' (Standard No. 210) apply to new, completed vehicles. In addition, our safety standard for 'Seat Belt Assemblies' (Standard No. 209) applies to new seat belt assemblies. Because a belt positioning device is neither installed as part of a completed vehicle nor as part of a seat belt assembly, none of these regulations apply to belt positioning devices. While none of these standards applies to a belt positioning device, the manufacturer of the product is subject to the requirements of the Safety Act concerning the recall and remedy of products with defects related to motor vehicle safety. To date, there have been no defect proceedings concerning these products. In addition, while it is unlikely that a belt positioning device would be installed by a motor vehicle manufacturer, distributor, dealer or repair business, the Safety Act prohibits those businesses from installing the device if the installation 'rendered inoperative' compliance with any safety standard. Belt positioning devices raise safety concerns you should consider in deciding whether to use these products. These devices could be used in a way that significantly affects crash forces on the occupant. Standard No. 208 includes requirements that have the effect of ensuring that the lap and shoulder belts distribute the crash forces to the occupant's skeletal structure, a part of the body that can better withstand the forces. For example, Standard No. 208 requires the shoulder belt and the lap belt to intersect off of the abdominal area. A device that moved that intersection from the side to the middle of the abdomen could greatly increase the loading on the occupant's abdomen. An increase in abdominal loading could have serious safety implications for the wearer of the belt. There are other concerns about these devices. The realigning of the shoulder belt could increase the likelihood that the wearer would twist toward the middle of the vehicle in a crash, so that the person could be partially or completely unrestrained by the shoulder belt. In addition, if the device introduced excessive slack into the belt system, the occupant's head would be more likely to contact the vehicle interior. Also, slack in the belt system generally introduces higher crash forces, which increase the risk of injury. We urge you to consider these factors when deciding whether to use a belt positioning device, or the manner in which to use one. You also asked whether a 'travel vest' can be used with your two and a half year old son, in place of a child seat. The travel vest is a 'child restraint system' and is thus subject to our safety standard for child restraints (Standard No. 213). The manufacturer of the travel vest (which the standard refers to as a 'harness') is responsible for determining the conformance of the vest to the requirements of Standard No. 213, and certifying that the vest so conforms. This agency periodically tests products for compliance with Standard No. 213. When properly used, harnesses that comply with Standard No. 213 provide good protection in a crash, similar to that provided by child seats. You should always follow the manufacturer's instructions for using the child restraint system, including the specifications for the weight of the child for whom the restraint is recommended. I hope this information is helpful. If you have further questions, please feel free to contact Mary Versailles of my staff at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam0556OpenMr. David J. Humphreys, RVI Washington Counsel, Recreational Vehicle Institute, Inc., Suite 406, 1140 Connecticut Avenue, N.W., Washington, DC 20006; Mr. David J. Humphreys RVI Washington Counsel Recreational Vehicle Institute Inc. Suite 406 1140 Connecticut Avenue N.W. Washington DC 20006; Dear Mr. Humphreys: This is in response to your letter of December 21, 1971, relating t the upcoming requirements for GVWR and GAWR on the vehicle label, under Part 567 of our regulations.; You discussed the difficulties some of your members have had i arriving at the proper values for gross axle weight ratings. To the extent that your discussion highlights the uncertainty that may in the past have existed with respect to the basic load-carrying capacity of vehicle components, it emphasizes the need for the regulation not only as a matter of information but also to ensure the proper design and selection of safety- related components. You asked specifically 'what NHTSA would consider to be the requisite test factors which should be utilized for determining wheel ratings.' Pending development of performance standards for wheels (or other components), we can only say that the ratings should reflect the manufacturer's own judgement as to the loads that the component can safely carry under the conditions expected to be encountered in use.; The diagrams that you enclosed setting forth basic weighing procedure for determining vehicle and axle loads appear to interpret the regulations correctly.; You mentioned the problem of a possible misunderstanding concerning th measurement of GAWR of a trailer and asked whether the tongue weight may be 'deducted from GVWR in arriving at what GAWR should be.' The answer is yes, since weight that is carried by the towing vehicle will not be carried by the trailer axle. We should add, however, that GAWR is a *rating* and therefore may be greater than the actual weight on the axle system when the vehicle is loaded to capacity.; Finally, you requested an 'extension of the effective date of the GAW and GVWR certification requirements to allow time to be sure the industry is advised of the procedure to follow.' This request is denied. On the basis of the information available to this agency, it has been determined that our procedures, and the lead time between issue and effective date of the regulations, have been fully adequate to allow affected manufacturers to prepare for compliance. Also, by a recent notice published in the Federal Register, we have allowed final-stage manufacturers using incomplete vehicles manufactured before January 1, 1972, for which the weight rating information has not been made available, to omit the GVWR and GAWR values from their labels.; Sincerely, Elwood T. Driver, Acting Associate Administrator, Moto Vehicle Programs; |
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ID: aiam4846OpenMr. Jerry Tassan 177 Airport Blvd San Francisco, CA 94080; Mr. Jerry Tassan 177 Airport Blvd San Francisco CA 94080; "Dear Mr. Tassan: This responds to a telephone inquiry in which yo explained to Mr. Stephen Wood, the Assistant Chief Counsel for Rulemaking, that your truck rental company is considering lowering the Gross Vehicle Weight Rating (GVWR) of some of its used trucks so that a renter need not have a commercial driver's license to operate them. You asked how the regulations of this agency, the National Highway Traffic Safety Administration (NHTSA), would apply to such an action. As explained below, because only a manufacturer can assign a GVWR, any modification of a vehicle's GVWR by parties that are not manufacturers would have no legal effect. By way of background information, NHTSA is authorized by the National Traffic and Motor Vehicle Safety Act ('Safety Act') to issue Federal motor vehicle safety standards that set performance requirements for new motor vehicles and items of motor vehicle equipment. NHTSA is not authorized to certify or approve motor vehicles or motor vehicle equipment for compliance with our Federal safety standards. Instead, under the Safety Act, each manufacturer of motor vehicles and motor vehicle equipment is responsible for certifying that its products meet all applicable safety standards. The Certification requirements in 49 CFR Part 567 require each manufacturer to affix to the vehicle a label containing, among other things, the vehicle's GVWR. Under Part 567, the only parties that can assign or modify a vehicle's GVWR are the original manufacturer (567.4(g)(3)), a final stage manufacturer (567.5(c)(5)), or an alterer (567.7(b)). Modifications of GVWR by any other parties would have no legal effect under Part 567. Accordingly, a vehicle owner that performs no manufacturing operations on a vehicle cannot modify the GVWR of the vehicle. You should also be aware that another Federal authority - the Federal Highway Administration's (FHWA's) Office of Motor Carrier Standards - may regulate your attempts to lower a vehicle's GVWR. The FHWA regulates the licensing of operators of 'commercial motor vehicles' under the Commercial Motor Vehicle Safety Act of 1986. I recommend you contact Mr. James Scapellato, Office of Motor Carrier Standards, HCS-1, FHWA, 400 Seventh Street, SW, Washington, D.C. 20590 if you have any further questions about driver licensing. I hope this information is helpful. If you have any further questions about the GVWR assigned to vehicles, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam2091OpenMr. Daniel J. Wahlen, Director-Engines Engineering, Koher Company, Koher, WI 53044; Mr. Daniel J. Wahlen Director-Engines Engineering Koher Company Koher WI 53044; Dear Mr. Wahlen: This is in response to your letter of September 29, 1975, to Senato Proxmire, concerning the regulations governing the production of motor vehicles, a copy of which was referred to this office.; The National Highway Traffic Safety Administration (NHTSA) issue Federal motor vehicle safety standards to which motor vehicles must conform. In addition, the agency requires that the manufacturer certify that the vehicle as completed complies with applicable safety standards. A pamphlet summarizing the Federal motor vehicle safety standards is enclosed, along with a copy of the regulations governing vehicle certification. The safety standards themselves are set forth in their entirety in Part 571 of Volume 49 of the Code of Federal Regulations.; The NHTSA also investigates safety-related defects and noncompliance with safety standards in motor vehicles and items of motor vehicle equipment. If the agency or the manufacturer determine that a safety-related defect or noncompliance exists, the manufacturer is obligated to notify the vehicle owners and remedy the problem without charge. A copy of the provisions of the National Traffic and Motor Vehicle Safety Act of 1966, as amended, which deal with the responsibilities of manufacturers for safety-related defects and noncompliances in their motor vehicles or item of vehicle equipment (15 U.S.C. SS 1411-1420) is also enclosed.; If you have any questions concerning a specific regulation or standard please write.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2838OpenMr. George C. Nield, President, Automobile Importers of America, 900 17th Street, N.W. Suite 100, Washington, DC 20006; Mr. George C. Nield President Automobile Importers of America 900 17th Street N.W. Suite 100 Washington DC 20006; Dear Mr. Nield: This responds to your recent letter asking whether passive safety belt are exempt from the requirements of Safety Standard No. 209, *Seat Belt Assemblies*.; The answer to your question is yes, with one exception. Paragrap S4.5.3.4 of Safety Standard No. 208, *Occupant Crash Protection*, specifies that passive safety belts that are not required for the vehicle to meet the perpendicular frontal crash protection requirements of the standard must meet the requirements of Standard No. 209. Therefore, only passive belts that are installed to meet the frontal crash protection requirements of Standard No. 208 are exempted from the requirements of Standard No. 209.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam0805OpenMr. Rex A. Williams, Ryder System, Incorporated, Post Office Box 816, 2701 South Bayshore Drive, Miami, FL 33133; Mr. Rex A. Williams Ryder System Incorporated Post Office Box 816 2701 South Bayshore Drive Miami FL 33133; Dear Mr. Williams: This is in response to your letter of July 20, 1972, concernin regulations governing the mounting of truck bodies and fifth wheels. Persons who perform these operations on new vehicles are generally considered to be final-stage manufacturers under NHTSA regulations and are required to certify that the completed vehicle conforms to all Federal motor vehicle safety standards.; The requirements for certification are codified at Title 49, Code o Federal Regulations, Parts 567, 568. Copies of these and other NHTSA requirements are available from the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402. The material should be ordered under the title, *Federal Motor Vehicle Safety Standards*. The cost, which must be prepaid, is $8.00, which includes amendments for one year. Checks should be payable to the Superintendent of Documents. Regulations regarding the Certification of completed motor vehicles are found at Parts 567 and 568 of the volume.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1717OpenMr. Ronnie H. Walker, Howell, Kirby, Montgomery, D'Aiuto, Dean and Hallowes, Attorneys at Law, P.O. Box 273, Orlando, FL 32802; Mr. Ronnie H. Walker Howell Kirby Montgomery D'Aiuto Dean and Hallowes Attorneys at Law P.O. Box 273 Orlando FL 32802; Dear Mr. Walker: This responds to your November 18, 1974, request for copies of an Federal braking standards for horse trailers.; The National Highway Traffic Safety Administration has responsibilit for the issuance of Federal motor vehicle safety standards, and we have issued only one standard in this area. The standard applies to trailers that are equipped with air brakes (Standard No. 121, *Air brake systems*, 49 CFR 571.121). This standard becomes effective for trailers which are manufactured after January 1, 1975.; Therefore there are no Federal brake standards which apply to the hors trailer you describe.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam4515OpenMs. C. Dianne Black Engineering Manager Jaguar Cars, Inc. 600 Willow Tree Road Leonia, NJ 07605; Ms. C. Dianne Black Engineering Manager Jaguar Cars Inc. 600 Willow Tree Road Leonia NJ 07605; Dear Ms. Black: Thank you for your letter of April l4, l988, providin further information about the Jaguar headlamp levelling system discussed in your letters of June and October l987 to which I responded on February 1, 1988. We support your efforts to call the driver's attention to the fact that the system does not automatically return to the 'zero' position from either of the two adjustment positions when those loading conditions no longer exist. Sincerely, Erika Z. Jones Chief Counsel; |
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ID: aiam1347OpenMr. Peter J. Sferrazza, Staff Counsel, 811 North First Avenue, Wausau, WI 54401; Mr. Peter J. Sferrazza Staff Counsel 811 North First Avenue Wausau WI 54401; Dear Mr. Sferrazza: In response to your request of November 28, 1973, I have enclosed copy of Part 580, *Odometer Disclosure Requirements*, 49 CFR Part 580, which was issued under the authority of the Motor Vehicle Information and Cost Savings Act of 1972, 15 U.S.C. S 1988.; The transferor must disclose the mileage as it is recorded on th odometer, and in addition that he knows that reading to be inaccurate if such is the case. This means that a transferor would check the box indicating that the reading does not reflect the mileage, if he knew that the vehicle had traveled more than 100,000 miles. The buyer would then be on notice to ask why the reading was not accurate and to be told that the vehicle had more than 100,000 miles on it.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2992OpenMr. Hisakazu Murakami, Nissan Motor Co., Ltd., P.O. Box 1606, 560 Sylvan Avenue, Englewood Cliffs, NJ 07632; Mr. Hisakazu Murakami Nissan Motor Co. Ltd. P.O. Box 1606 560 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Murakami: This responds to your letter of January 23, 1979, concerning a ne design belt system for rear seat lap belts that you would like to use in future vehicles. You ask if the proposed design would comply with the requirements of Safety Standard No. 208.; The answer to your question depends in which seating position in th rear seat of the vehicle the proposed belt system would be used. The new design would not comply with paragraph S7.1.1 of Safety Standard No. 208 if installed at outboard designated seating positions in the rear seat. That paragraph requires lap belts to adjust by means of an emergency- locking or automatic-locking retractor to fit persons whose dimensions range from those of a 50th-percentile 6-year-old child to those of a 95th percentile adult male. In some cases your proposed design would not adjust automatically to fit a 95th- percentile adult male.; The proposed design would comply with the standard, however, i installed in the center seating position of the rear seat, since paragraph S7.1.1.2 specifies that a seat belt assembly installed at any designated seating position other than the outboard positions of the front and second seats shall adjust either by a retractor or by a manual adjusting device.; Since your new belt system design would currently be precluded fo outboard designated seating positions, you may wish to petition for amendment of Safety Standard No. 208. Any petition should include an adequate description of the belt design, including: (1) seating positions for which the belt system would be applicable, (2) advantages of the system, (3) size of the belt system hardware, and (4) problems, if any, associated with automatic retraction of the belt system.; The National Highway Traffic Safety Administration hereby grants you request for confidentiality of the new belt system design described in your letter. Please notify us if the design becomes public in the future. Also, please note that if you petition for rulemaking in this area, the details of your belt design would probably have to be disclosed to the public, at least in general terms.; 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.