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: aiam0343OpenMr. H. William Tanaka, Counsel, Tanaka and Walders, Federal Bar Building West, 1819 H Street, N.W., Washington, DC 20006; Mr. H. William Tanaka Counsel Tanaka and Walders Federal Bar Building West 1819 H Street N.W. Washington DC 20006; Dear Mr. Tanaka: This is in response to your letter of April 19, 1971, in which yo discussed the difficulties that may be caused by State enforcement procedures that require a manufacturer to obtain State approval of products covered by Federal standards before he may sell the products in the State. Your letter was an amplification of the JAMA petition for reconsideration of Standard No. 209, submitted April 3, 1971.; The NHTSA is giving careful consideration to the situation you hav described. We intend to take action to alleviate the problem in the near future.; Sincerely, Lawrence R. Schnider, Acting Chief Counsel |
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ID: aiam5511OpenMr. Mayo D. Tubbs Visionary Lighting Systems 1409 Sweetgum Circle Keller, TX 76248; Mr. Mayo D. Tubbs Visionary Lighting Systems 1409 Sweetgum Circle Keller TX 76248; "Dear Mr. Tubbs: We have received your letter of March 23, 1995, askin for a waiver of 49 U.S.C. 30112(a) which will enable the introduction of a new lighting system that you have developed for large trailers. You envision that this system will eventually be installed on emergency vehicles and school buses. We understand that you wish to market this system as original equipment. You have asked that we 'provide adequate safeguards to prevent unauthorized dissemination of this information.' As Taylor Vinson of this Office explained to you before you wrote, all the agency's letters of interpretation must be made available to the general public, and these letters must include enough information to make the interpretation comprehensible. Mr. Vinson telephoned you on March 30, 1995, and informed you that we proposed, in this instance, to limit the description of the system to the number, location, and quantity of lamps, to withhold the incoming letter with the exception of Attachment A, and to exclude your name and address from the copy made publicly available. You concurred with this treatment of your letter, except that you preferred not to have your name and address withheld in the event a reader might be interested in getting in touch with you. You believe that the current lighting and conspicuity requirements for large trailers are inadequate for safety when compared with your system. This system consists of 18 'strip lights on the side and rear' of large trailers which are 'Aviation Green' in color. The side and rear lighting schemes are depicted on Attachment A to your letter. As we interpret Attachment A, two of the strip lights are mounted in the upper right and left rear corners, while eight lights are on each side of the trailer (four right-angle lights in each upper and lower corner, and four lights deployed at one-third body-length intervals at the top and bottom). Motor Vehicle Safety Standard No. 108 Lamps, Reflective Devices, and Associated Equipment is the Federal regulation that governs original lighting equipment on trailers. These requirements must be met upon the manufacture and sale of trailers. With respect to the rear of a van trailer, your Attachment A depicts only strip lights in the upper right and left corners. This is not permissible under Standard No. 108. The Federal regulation requires the conspicuity treatment specified by S5.7 to be applied in this area, as well as clearance lamps. With respect to the side of a van trailer, Standard No. 108 requires horizontal conspicuity treatment to be applied near the lower edge of the trailer as close to the front and rear as practicable, though it need not be continuous as long as it covers at least half the trailer length. Because of the gaps between the strip lights on the trailer side as depicted in Attachment A, it is possible that conspicuity treatment could be applied between the strips that would total half or more of the trailer length. However, supplementary lighting equipment such as your system is not permissible under Standard No. 108 (paragraph S5.1.3) if it impairs the effectiveness of the lighting equipment required by the standard. Standard No. 108 restricts the color of exterior lights to red, amber, and white, the former two of which are associated with caution. Green is not used as an exterior lighting color because it is the recognized signal to proceed rather than to warn. We believe that use of the color green has the potential to create a measure of confusion rather than caution, thereby affecting the effectiveness of the mandatory side lighting equipment, i.e., amber front side markers, red rear side markers, and red and white conspicuity striping or red reflectors. A vehicle manufacturer may petition for a temporary exemption from a Federal motor vehicle safety standard under the conditions specified in 49 CFR part 555, a copy of which is enclosed. Therefore, a trailer manufacturer interested in using your system could apply for a 2-year exemption on the basis that the exemption would make easier the development or field evaluation of a new motor vehicle safety feature providing a safety level at least equal to the safety level of the standard. The effect of an exemption is to allow the manufacture and sale of a nonconforming vehicle without violating 49 U.S.C. 30112(a). I am sorry to inform you that the exemption is not available to equipment manufacturers. If you have data that sustains your belief that your system enhances safety, our Office of Research and Development would be interested in corresponding with you. The Associate Administrator of that Office is George Parker. If there are other questions you have, Taylor Vinson will be happy to answer them for you. Sincerely, Philip R. Recht Chief Counsel"; |
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ID: aiam1801OpenMr. Fred W. Cords, Minnesota Automotive, Inc., Box 2074, North Mankato, MN 56001; Mr. Fred W. Cords Minnesota Automotive Inc. Box 2074 North Mankato MN 56001; Dear Mr. Cords: This is in reply to your letter of January 6, 1975, requesting a opinion on whether a person who installs a Mico Brake Lock device on a new vehicle before its sale to the first purchaser is required to affix an alterer label in accordance with 49 CFR SS 567.7 and 568.8. You state that you believe the device, which serves as a hydraulic parking brake, is readily attachable because it can be installed in a minimum amount of time and does not in any way alter the operation of the vehicle's original brake system.; The NHTSA will generally abide by a good faith determination on th part of a manufacturer that a device is readily attachable. Such a decision should be based primarily on the intricacy of the installation of the device. Simple tools, a relatively short installation time, and the ability to install the device without extensively modifying the vehicle would all be factors pointing to a decision that a component is readily attachable. You should note that section 567.7 of the Certification regulations also requires an alterer label when the installation of a component invalidates a vehicle's existing weight ratings, whether or not the component is readily attachable. On the basis of your letter, however, it appears to us that this would not occur as a result of installation of the Mico Brake Lock device.; If your device meets these criteria, no additional labeling will b required.; Yours truly, James C. Schultz, Acting Chief Counsel |
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ID: aiam0713OpenMr. Satoshi Nishibori, Nissan Motor Company, Ltd., 560 Sylvan Avenue, Englewood Cliffs, NJ 07632; Mr. Satoshi Nishibori Nissan Motor Company Ltd. 560 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Nishibori: This is in reply to your letter of May 9, 1972, in which you agai raise the problem of where to place the seat in tests for which Standard 208 specifies that the seat is to be at the midway position but the seat track has no adjustment position that coincides with the midway point.; Our reply of March 2, 1972, stated that when the midway point i exactly halfway between two adjustment notches, the seat should be placed in the rear notch. You are correct in pointing out that if the notches were on the upper seat rail the seat would be moved forward if these instructions were followed. It was our intent to specify rearward seat movement in each case in which the midway point on the track fell exactly between two notches. In Case (2) of your letter, therefore, it will be our practise (sic) to move the seat rearward from the position shown in red until the next notch is reached.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3095OpenMr. David H. Lewis, Tiger Trading Corporation International, 1706 Broadway, Suite 401, Oakland, California 94612; Mr. David H. Lewis Tiger Trading Corporation International 1706 Broadway Suite 401 Oakland California 94612; Dear Mr. Lewis: This responds to your letter of July 26, 1979, concerning an 'afte market' motor vehicle accessory you plan to distribute. You describe the accessory as an item of clear plastic that affixes to the inside of the rear window 'to greatly improve the rear vision of the driver of a passenger vehicle.'; Standard No. 111, *Rearview Mirrors*, established performanc requirements for rearview mirror systems. The standard only applies to mirror installed as original equipment in motor vehicles and does not apply to replacement equipment such as the aftermarket accessory you intend to distribute. However, since the device you plan to distribute is an item of motor vehicle equipment, the recall and remedy provisions of the National Traffic and Motor Vehicle SAfety Act (the Act), as amended, (15 U.S.C. 1411-1420) would apply to any safety-related defect in your mirror accessory. A copy of the Act is enclosed.; If you have any further questions, please let me know. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4750OpenMr. John W. Garringer 158 E. Center Street Shavertown, Pennsylvania 18708; Mr. John W. Garringer 158 E. Center Street Shavertown Pennsylvania 18708; "Dear Mr. Garringer: This responds to your letter asking whethe Federal law permits the installation of tinted plastic film on the bottom of motor vehicle windshields. The purpose of this film would be to reduce glare for the driver and any front seat passengers. I am pleased to have this opportunity to explain how our laws and regulations apply to such a product. Our agency is authorized under the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq., the Safety Act) to issue safety standards applicable to new motor vehicles and new items of motor vehicle equipment. NHTSA, however, does not approve or certify any vehicles or items of equipment, nor do we endorse any commercial products or processes. Instead, the Safety Act specifies that each manufacturer itself must certify that its products meet all applicable safety standards. The agency periodically tests vehicles and items of equipment for compliance with the standards, and also investigates alleged defects related to motor vehicle safety and alleged violations of other statutory provisions. Pursuant to this authority, NHTSA has issued Standard No. 205, Glazing Materials (49 CFR 571.205), which sets forth performance requirements for windows and other glazing items installed in motor vehicles. Among the requirements set forth in Standard No. 205 are specifications for minimum levels of light transmittance. A minimum of 70 percent light transmittance is required in glazing areas requisite for driving visibility, which includes all windows in passenger cars. In trucks and buses, the windshield and windows to the immediate right and left of the driver and the rearmost window, if the latter is used for driving visibility, are considered to be requisite for driving visibility, and therefore subject to the 70 percent minimum light transmittance requirement. Your letter did not provide any information on the light transmittance that would be measured through glazing with your Hood Glare product installed on it. The combination of the glazing material and your tinting film must allow at least 70 percent light transmittance to comply with the requirements of Standard No. 205. No manufacturer or dealer would be permitted to install your tinting film on the glazing materials on new vehicles, unless the manufacturer or dealer certifies that the vehicle continues to comply with the 70 percent minimum light transmittance and other requirements of Standard No. 205. After a vehicle is first sold to a consumer, modifications to the vehicle are affected by section 108(a)(2)(A) of the Safety Act (15 U.S.C. 1397(a)(2)(A)). That section prohibits any manufacturer, dealer, distributor, or repair business from 'rendering inoperative' any device or element of design installed in a vehicle in compliance with any safety standard. This provision of the law means that no manufacturer, dealer, distributor, or repair business could install tinting film if the addition of the tinting film to the glazing would result in a light transmittance of less than 70 percent, or otherwise cause the vehicle to no longer comply with the applicable requirements of Standard 205. Violations of this 'render inoperative' prohibition can result in Federal civil penalties to the manufacturer, dealer, distributor, or repair business of up to $1000 for each noncomplying installation. Section 108(a)(2)(A) of the Safety Act does not affect vehicle owners. Hence, vehicle owners themselves may install tinting film or any other product on the glazing of their vehicle, regardless of whether the installation causes the vehicle to no longer comply with Standard No. 205. Individual States have the authority to regulate the operational use of vehicles by their owners, and, therefore, have the authority to regulate or preclude individual owner modifications to the glazing of their vehicles. I have enclosed an information sheet that summarizes the relationship between Federal auto safety laws and motor vehicle window tinting. I hope this information is helpful. If you have any further questions or need any additional information about this topic, please feel free to contact Dorothy Nakama 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: aiam1552OpenMr. Thomas S. Pieratt, Jr., Executive Director, Distributors Association, 602 Main Street, Cincinnati, OH 48202; Mr. Thomas S. Pieratt Jr. Executive Director Distributors Association 602 Main Street Cincinnati OH 48202; Dear Mr. Pieratt: This is in reply to your letter of May 30, 1974, asking whether final-stage manufacturer or vehicle alterer may use the incomplete vehicle's gross vehicle weight rating on the certification label when he adds a third axle. You point out that the manufacturer thereby increases the vehicle's actual capacity and could increase the vehicle's gross vehicle weight rating if he so desired, but he does not do so because the vehicle may not conform to applicable standards (mentioning specifically Standard No. 121) at the higher weight rating. It does conform, however, at the weight rating of the incomplete vehicle.; Although, as you point out, gross vehicle weight rating is establishe by the manufacturer, it must be based on a good faith attempt on the part of the manufacturer to conform to its definition. Gross vehicle weight rating is defined as '. . . the value specified by the manufacturer as the loaded weight of a single vehicle.' A manufacturer is generally free to rate his vehicle at less than full loaded weight, and we would support such a policy where the purpose is to provide a reasonable safety margin. However, we would not consider as made in good faith a gross vehicle or axle weight rating that is so unrelated to vehicle capacity that it suggests a motive such as avoidance of an applicable standard. If it could be shown that this was the manufacturer's intent, he could be subject to civil penalties and other sanctions provided in the National Traffic and Motor Vehicle Safety Act for the issuance of a false and misleading certification, and to the responsibilities incident to a finding of a safety-related defect.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4300OpenMr. Paul B. Krieger, Director of Marketing, Sky-Top Sunroofs Ltd., 4700 Le Bourget Drive, St. Louis, MO 63134; Mr. Paul B. Krieger Director of Marketing Sky-Top Sunroofs Ltd. 4700 Le Bourget Drive St. Louis MO 63134; Dear Mr. Krieger: This responds to your letter of November 4, 1986, in which yo requested that this agency amend Federal motor vehicle safety standard (FMVSS) 118, *Power Operated Window Systems*.; In your letter, you mentioned an electronic touchpad, known as th DOORMAN keyless entry system, and stated that it is designed to be used by someone outside a vehicle to operate your power sunroof. You requested that this agency amend paragraph S3(c) of the standard, which currently permits the operation of power windows and vehicle exterior, to permit the operation of a sunroof by means of an electronic touchpad system.; There is no need to amend Standard 118 to permit the use of you touchpad since the reference in Standard 118 to power-operated window and partition systems does not include sunroofs. Windows include the typical power windows on the sides of many vehicles and to the power tailgate windows on station wagons. Partitions refer to movable surfaces, such as those found inside some taxicabs and limousines, which separate different portions of the vehicle interior from one another.; Since there is no need to amend Standard 118, we are treating you letter as a request for interpretation and trust that it is fully answered by this response.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1102OpenMr. Thomas B. Mitchell, 707 East Queen Street, Hastings, New Zealand; Mr. Thomas B. Mitchell 707 East Queen Street Hastings New Zealand; Dear Mr. Mitchell: Thank you for your letter of March 27, 1973, requesting informatio concerning Federal Motor Vehicle Safety Standards with special emphasis on those standards pertaining to fuel systems.; Enclosure 1 is a brochure which gives a brief summary of all safet standards issued through June 1972, and a subscription Order Form, should you wish to purchase a complete edition of the standards from the Superintendent of Documents on a subscription basis.; Enclosure 2 is a copy of Federal Motor Vehicle Safety Standard No. 301 'Fuel Tanks, Fuel Tank Filler Pipes, and Fuel Tank Connections - Passenger Cars.' This standard is currently undergoing amendment that will include rollover and rear-end impact requirements in addition to the fixed barrier collision which is currently required.; The Bureau of Motor Carrier Safety regulates vehicular interstat commerce. Enclosure 3 is an Advanced Notice of Proposed Rule Making concerning plastic fuel tanks (*Federal Register,* Volume 36, No. 178, September 14, 1971) which was recently issued by this Bureau. Further information may be obtained by contacting this Bureau as follows:; >>>Director, Bureau of Motor Carrier Safety, Department o Transportation, 400 Seventh Street, S.W., Washington, D.C. 20590<<<; In response to your question: 'I particularly wish to know if th relevant Safety Standard in force in America requires the fuel tanks to be located outside the main body shell of the vehicles or if it is permissible under this Safety Standard for fuel tanks to be situated in the interior of the vehicles,' the standards as written do not specifically require that the fuel system be external to the passenger compartment. These standards, in accordance with Public Law 89-563 which authorized their development, emphasize performance rather than design considerations.; Another standard which may be of interest to you is Standard No. 302 'Flammability of Interior Materials in Passenger Cars, Multipurpose Passenger Vehicles, Trucks and Buses,' which was effective September 1, 1972. Enclosure 4 is a copy of this standard along with two proposed amendments.; We trust your inquiry has been satisfactorily answered. If there ar any other questions or we can be of further service, please do not hesitate to contact this office. I am also returning the amount you enclosed for postage, etc.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam1417OpenMr. W.T. Little,Vice President,General Manager,Lufkin Trailer Division,Lufkin Industries, Inc,P.O. Box 848,Lufkin, Texas 75901; Mr. W.T. Little Vice President General Manager Lufkin Trailer Division Lufkin Industries Inc P.O. Box 848 Lufkin Texas 75901; Dear Mr. Little:#This responds to your January 30, 1974, request fo inclusion in Standard 106, *Brake Hoses*, of J1402 type A and B hose and J844 (nylon type 3) hose.#Standard 106 has already been amended by addition of 3/8-in and 1/2-in special sizes to the list of hose sizes which may be used with reusable fittings, and this addition permits continues use of commonly utilized types of A and B hose.#The nylon 3 hose to which you refer is not excluded from use under the Standard. Several of its manufacturers have indicated that it does conform to the requirements of the standard, which have been modified to reflect the lower tensile strength valves needed when used at non-articulating points in the system.#Yours truly,Richard B. Dyson,Assistant 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.