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
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ID: aiam2220OpenMs. Diane Bortle, Executive Secretary, VIRACON, Inc., 800 Park Drive, Industrial Park, Owatonna, MN 55060; Ms. Diane Bortle Executive Secretary VIRACON Inc. 800 Park Drive Industrial Park Owatonna MN 55060; Dear Ms. Bortle: This responds to Viracon's December 13, 1975, and January 28, 1976 requests for a copy of Standard No. 216, *Roof Crush Resistance*, and for a discussion of the distinction under NHTSA regulations between installation of a sunroof before and after 'original sale of the roof.' A copy of Standard No. 216 has already been mailed to Viracon under separate cover.; You suggest that there may be different regulations for installation o a sunroof prior to, and after, the sale of the roof, by which I understand you to mean the sunroof. The NHTSA does not regulate sunroofs as such, but it does regulate the roof strength of most passenger cars (Standard No. 216), and conformity with this standard can be affected by installation of the sunroof.; Section 108(a) (1) (A) of the National Traffic and Motor Vehicle Safet Act (15 U.S.C. S 1397(a) (1) (A)) prohibits, among other things, the sale of a motor vehicle that does not comply with all applicable standards. Anyone that modifies a passenger car roof by the addition of your product would be responsible for compliance with Standard No. 216 at the time of sale. This would include alterations of the type made to a vehicle that has been certified by the manufacturer (49 CFR Part 567). This prohibition does not apply (except in cases of importation) after the first purchase of the vehicle in good faith for purposes other than resale (15 U.S.C. S 1397(b) (1)).; The Act also prohibits, except in the process of repair, manufacturer, distributor, dealer, or repair business from knowingly rendering inoperative, in whole or part, any device or element of design installed in a motor vehicle in compliance with applicable standards (15 U.S.C. S 1397(a) (2) (A)). This means that these classes of persons may not install one of your products, even after the first retail sale, if the installation takes the vehicle out of conformity with Standard No. 216 or any other applicable Federal motor vehicle safety standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2670OpenMr. M. J. Denholm, Director of Engineering, Power Controls Division, Midland-Ross Corporation, 490 South Chestnut Street, Owosso, MI 48867; Mr. M. J. Denholm Director of Engineering Power Controls Division Midland-Ross Corporation 490 South Chestnut Street Owosso MI 48867; Dear Mr. Denholm: This responds to Midland-Ross' July 8, 1977, request for confirmatio that the requirement that '[e]ach service reservoir system shall be protected against loss of air pressure. . .by check valves or equivalent devices' in S5.1.2.3 and S5.2.1.5 of Standard No. 121, *Air Brake Systems*, permits small losses of air pressure through the check valve of up to 2 psi per minute without constituting noncompliance.; The requirement for protection against 'loss of air pressure' doe permit a small amount of leakage, in recognition of the fact that no fitting can be perfectly air tight. While the standard does not presently specify a rate of permissible air loss in S5.1.2.3 or S5.2.1.5, the agency has adopted a maximum loss of 10 psi in 10 minutes as meeting the requirement for protection against loss of air pressure. The agency is considering adding such a specification to the standard in the future by interpretive amendment.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3962OpenMs. Virginia Walborn, Pennsylvania Bureau of Motor Vehicles, Room G-112, Transportation and Safety Building, Harrisburg, PA 17122; Ms. Virginia Walborn Pennsylvania Bureau of Motor Vehicles Room G-112 Transportation and Safety Building Harrisburg PA 17122; Dear Ms. Walborn: After the promulgation of the Federal odometer disclosure requirements 49 CFR Part 580, the State of Pennsylvania requested from the National Highway Traffic Safety Administration, approval to use the certificate of title in lieu of a separate odometer disclosure statement. The Agency granted that request.; It has come to our attention that some dealers have purchased vehicles altered the odometer reading on the title and subsequently reassigned the title, without signing it and without listing their address. While the Pennsylvania title provides a space for the purchaser's address and signature, the information is apparently furnished only when the buyer applies for title. Due to the practice of permitting a dealer to reassign titles without applying for them in his own name, it has become necessary for us to qualify our initial determination.; Unless the first buyer applies for title in Pennsylvania, a separat odometer disclosure statement, signed by the buyer and containing his address must be issued and a photostat or other facsimile retained by the transferor. This information is required by 49 CFR 580.4, and must be included upon the certificate of title before that document can be used in lieu of a separate statement. 49 CFR 480.4(f)(1) (sic). The Agency finds the buyer's signature to be of utmost importance. The signature serves as an acknowledgement that the purchaser was aware of the mileage. It prevents the buyer from later alleging that he was not informed of the mileage or that the mileage was different from that appearing on the odometer. Likewise, the address of an intervening dealer-owner is important, should subsequent investigation or enforcement actions become necessary. You may find it feasible to change the format of Pennsylvania's title to include the purchaser's address and signature on the assignment or reassignment space.; If I can be of further assistance, do not hesitate to contact me or Ms Judith Kaleta of my staff at (202) 426-1834.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam5320OpenMr. Marc D. Marutani National Truck Sales Manager ARI 9000 Midlantic Dr. P.O. Box 5039 Mt. Laurel, NJ 08054; Mr. Marc D. Marutani National Truck Sales Manager ARI 9000 Midlantic Dr. P.O. Box 5039 Mt. Laurel NJ 08054; "Dear Mr. Marutani: This responds to your letter of January 31, 1994 requesting an interpretation of whether a 15-passenger Ford Econoline Wagon would be considered a school bus. 'The client requesting the vehicle is a mental health and substance abuse facility handling adolescents on a full-time on-site basis. There is a school located on the premises, since the children reside at the location. The vehicle's purpose would primarily be used for miscellaneous transportation of juvenile patients and facility personnel, both on and off campus, as opposed to providing commuting services to and from home.' I am pleased to have this opportunity to clarify our requirements for school buses. The National Highway Traffic Safety Administration (NHTSA) has the authority under the National Traffic and Motor Vehicle Safety Act (the Act) to issue motor vehicle safety standards that apply to the manufacture and sale of new motor vehicles, including new school buses. NHTSA defines 'school bus' as a motor vehicle designed for carrying 11 or more persons, including a driver, which 'is likely to be significantly used for the purpose of transporting primary, preprimary, or secondary school students to or from such schools or events related to such schools.' It is a violation of Federal law for any person to sell or lease any new vehicle that does not comply with all school bus safety standards if they are aware that the purchaser intends to use the vehicle as a school bus. Whether you are required to sell or lease a certified school bus to your client depends on the anticipated use of the vehicle. The mental health and substance abuse facility operated by your client is not a school, however, it does operate a school on the premises. If your client were to purchase or lease a new bus to be used solely for transporting students to athletic events at other schools, it would be a violation of Federal law for you to sell or lease them a new vehicle that is not a school bus. This is because the vehicle would clearly be significantly used as a school bus. On the other hand, it is not a violation of Federal law for you to sell or lease them a new vehicle that is not a school bus if your client will use the vehicle for general purposes, even though such vehicles may be used occasionally to transport students to school-related events. Your letter states that the vehicle would be used for 'miscellaneous transportation.' If a significant portion of that use would not be transportation of students to school-related events, you are not required to sell or lease a school bus. I hope you find this information helpful. If you have any other questions, please contact us at this address or by phone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam0122OpenMr. Praxl, Chief of Series Design and Development, NSU Motorenwerke Aktiengesellschaft, 7107 Neckarsulm, Germany; Mr. Praxl Chief of Series Design and Development NSU Motorenwerke Aktiengesellschaft 7107 Neckarsulm Germany; Dear Mr. Praxl: Thank you for your letter of October 8, 1968, to Mr. Eugene Laskin Acting Director, Office of Standards Preparation, concerning reflex reflectors.; The use of two Class B reflectors combined with the tail lamps on th rear of your vehicles will not impair the effectiveness of the two Class A red reflex reflectors required in Motor Vehicle Safety Standard No. 108. These devices are therefore in accordance with Standard No. 108, including paragraph S3.1.2.; Since this Bureau does not issue approval on items of lightin equipment or on vehicle designs incorporating this equipment, the above comments are for your information only, and in no way relieve the vehicle manufacturer from his responsibility for certifying that the assembled vehicle meets the requirements of Standard No. 108.; Sincerely, Charles A. Baker, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service; |
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ID: aiam0088OpenMr. R. M. Thurber, Western Body and Hoist Company, 8901 Juniper Street, Los Angeles, CA 90002; Mr. R. M. Thurber Western Body and Hoist Company 8901 Juniper Street Los Angeles CA 90002; Dear Mr. Thurber: Thank you for your letter of April 9, 1968, to the Federal Highwa Administration, in which you requested clarification of the requirements for amber side marker lamps and amber side reflectors.; A copy of presently applicable standards, and some proposed standard are enclosed. Note that Federal Motor Vehicle Safety Standard 108, effective January 1, 1968, requires amber front side marker lamps, and amber front side reflectors for vehicles of less than 30 feet overall length, and 80 or more inches in overall width. When the overall vehicle length is less than 30 feet and the front side marker lamps and front side reflectors have been mounted on the cab by the chassis-cab manufacturer, an additional set of the foregoing lamps and reflectors is not required on the body when it is installed.; With respect to the requirements of Standard No. 108, I must point ou that this Bureau does not issue approvals on items of lighting equipment or on vehicle designs incorporating this equipment. Therefore, the above comments are for your information only and in no way relieve the vehicle manufacturer from his responsibility for certifying that the assembled vehicle meets the requirements of the standard.; I trust this answers your questions. Sincerely, Joseph R. O'Gorman, Acting Director, Office of Performanc Analysis, Motor Vehicle Safety Performance Service; |
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ID: aiam4862OpenMr. David E. McAllister Manufacturers Representative 442 Robin Hill Road Wayne, PA . 19087; Mr. David E. McAllister Manufacturers Representative 442 Robin Hill Road Wayne PA . 19087; "Dear Mr. McAllister: This responds to your letter of March 14, l99l 'as a supplier to the U.S. Postal Service for lights', asking whether it is 'legal' for the center high mounted stop lamp to flash. We understand that the new postal service vehicles are trucks. Under Federal Motor Vehicle Safety Standard No. 108, the center highmounted stop lamp is required only on passenger cars. When installed as original equipment on a passenger car, it is required to be steady-burning when the brake pedal is applied. However, since Standard No. 108 does not require center highmounted stop lamps on motor vehicles other than passenger cars, any such lamps would not be required to be steady-burning. Thus, the current requirements of Standard No. 108 would permit a center lamp on a postal truck to flash. Supplementary lighting equipment, i.e., lighting equipment that is not required by Standard No. 108, is subject to Standard No. 108's general prohibition that such not impair the effectiveness of the lighting equipment required by the standard. The determination of impairment is to be made by the manufacturer of the vehicle before it certifies compliance with all applicable Federal motor vehicle safety standards. If it appears to be clearly erroneous, NHTSA will review the determination. With respect to the present case, it is theoretically possible that a flashing center stop lamp could 'impair the effectiveness' of the truck's two steady-burning primary stop lamps by sending a confusing signal. However, given the lamp's location on the vertical centerline of the vehicle, and the public recognition of the function of the center lamp on passenger cars, we do not believe it is likely that the public would be confused. We would like to advise you that the agency has proposed that trucks be equipped with steady-burning center lamps, and that it has announced that a final rule will be issued during the first half of 1991. If the final rule applies to postal trucks, then a flashing center lamp could not be installed on postal trucks manufactured on and after the rule's effective date. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam0572OpenMr. Bob Lockwood, Enterprise Sky Park, Tarmac Road, Redding, California 96001; Mr. Bob Lockwood Enterprise Sky Park Tarmac Road Redding California 96001; Dear Mr. Lockwood: This is in reply to your letter of January 20, 1972, regardin standards for retreaded automobile and truck tires.; Federal motor vehicle safety standards do not apply to aircraft o aircraft equipment.; Standard No. 117 entitles 'Retreaded Pneumatic Tires - Passenger Cars, does not apply to the retreading of aircraft tires and does not supersede Advisory Circular 43.13-1. A copy of the standard is enclosed.; We do not have a safety standard for retreaded truck tires at thi time.; Thank you for your inquiry. Sincerely, E.T. Driver, Director, Office of Operating systems, Moto Vehicle Programs; |
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ID: aiam4531OpenMr. Paul A. Reneau 9261 North 60th Street Brown Deer, WI 53223; Mr. Paul A. Reneau 9261 North 60th Street Brown Deer WI 53223; "Dear Mr. Reneau: This is a response to your undated letter which thi agency received in January 1988. I apologize for the delay in this response. In your letter, you presented a schematic and an engineering explanation of a power window system design and operation, and asked whether the system meets Federal safety standard 118, Power-operated Window Systems (49 CFR 571.118). Based on my understanding of the information enclosed with your letter, it appears that your power window system would comply with Standard 118. As I understand your system description, there are two electrical circuits that control power window operations. In the principal circuit, when the vehicle ignition key system is in the 'ON' or 'ACCESSORY' position, the power windows are operable. In most power-operated window systems, turning the ignition key to the 'OFF' position means that the power windows no longer are operable. However, in your system, a second, parallel circuit connects to the power window motor, and provides an energy source to allow an operator to close a power window when the ignition key is in the 'OFF' position. The parallel energy source permits operation only for a limited time period controlled by the electronic circuitry. My understanding is that with your design, the parallel circuit includes door switches which stop power window operation irrespective of the ignition key system position, whenever either vehicle front door is opened during the window closing sequence. According to your diagram and explanation, in such a circumstance, an operator must close the door, and return the ignition key to the 'ON' or 'ACCESSORY' position to reactivate the power window system. Paragraph S3 of Standard 118 specifies that power window systems may be closed only under certain listed conditions. One of those conditions is when the ignition key is in the 'ON' or 'ACCESSORY' position, as specified in S3(a). When the ignition key is in the 'OFF' position, the power windows may be closed only under the conditions described in S3(b) (by muscular force unassisted by a vehicle power source), S3(c) (upon activation of a key-locking system on the exterior of the vehicle), or S3(d). Paragraph S3(d) reads as follows: During the interval between the time the locking device which controls the activation of the vehicle's engine is turned off and the opening of either of a two-door vehicle's doors or, in the case of a vehicle with more than two doors, the opening of either of its front doors. Based on my understanding of the information you supplied, the only time the power windows in your system can be closed with the ignition key in the 'OFF' position is during the interval between engine deactivation and opening of either of the vehicle's front doors. Standard 118 expressly permits this, so your system appears to comply with that standard. I hope you find this information helpful. If you have further questions, please contact Joan F. Tilghman of my staff at this address or by telephone at (202) 366-2992. Sincerely, Erika Z. Jones Chief Counsel"; |
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ID: aiam1733OpenMr. J.B. Markovich, General Manager, Utility Trailer Sales Co., Railroad and Orange Ave., P.O. Box 3258, Fresno, CA 93776; Mr. J.B. Markovich General Manager Utility Trailer Sales Co. Railroad and Orange Ave. P.O. Box 3258 Fresno CA 93776; Dear Mr. Markovich: This responds to your December 6, 1974, request for a determinatio whether a bulk transport trailer designed for transporting farm commodities from the field to processing plants over private and public roads, qualifies for exemption from Standard No. 121, *Air brake systems*, as an agricultural vehicle.; The vehicle you describe does not qualify as an agricultural vehicl that is excepted from Federal motor vehicle safety standards. The National Traffic and Motor Vehicle Safety Act of 1966 defines motor vehicle as follows:; >>>'Motor vehicle' means any vehicle driven or drawn by mechanica power manufactured primarily for use on the public streets, roads, and highways, except a vehicle operated exclusively on a rail or rails.<<<; We have interpreted this language to mean that a motor vehicle is vehicle which the manufacturer expects to be used on the public highways as part of its intended function. This would include most agricultural vehicles. However, the legislative history of the original Safety Act and S 301 indicate that congress did not intend agricultural machinery to be subject to the safety standards. We have interpreted agricultural machinery to include only vehicles designed as 'implements of husbandry' to perform strictly agricultural functions on farmland. The category does not extend to all vehicles engaged in transporting agricultural products.; The bulk transport trailer you describe appears designed expressly t rransport (sic) the product of an agricultural machine from the field to processing plants over the highways. It does not, therefore, qualify as an agricultural machine.; To expedite any questions you may have regarding the procedure fo temporary exemption, I would advise you to call Mr. Taylor Vinson of this office at (202)426-9511.; Yours truly, Richard B. Dyson, Acting 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.