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: aiam0570OpenMr. Vincent G. Grey, Engineering Manager, Truck Trailer Manufacturers Association, 1413 K Street, N.W., Washington, DC 20005; Mr. Vincent G. Grey Engineering Manager Truck Trailer Manufacturers Association 1413 K Street N.W. Washington DC 20005; Dear Mr. Grey: This is in reply to your letter of December 20, 1971, asking whethe the Certification regulations (Docket Nos. 70-6, 70-8, 70-15) apply to pole trailers. The Docket numbers you refer to also include the regulations concerning 'Vehicles Manufactured in Two or More Stages.'; As there are no motor vehicle safety standards presently applicable t pole trailers, neither the Certification regulations (49 CFR Part 567) nor the regulations governing 'Vehicles Manufactured in Two or More Stages' (49 CFR Part 568) apply to them. As you were informally informed, however, pole trailers manufactured on or after January 1, 1973, that are equipped with air brake systems would be required to comply with Motor Vehicle Safety Standard No. 121, and their manufacturers would be required to comply with the Certification regulations and, where applicable, the regulations governing Vehicles Manufactured in Two or More Stages.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5288OpenMr. Lloyd Boshaw M&L Auto Trim P.O. Box 822 Poway, CA 92074; Mr. Lloyd Boshaw M&L Auto Trim P.O. Box 822 Poway CA 92074; Dear Mr. Boshaw: We have received your letter of January 28, 1993 asking whether you must disconnect an original equipment center highmounted stop lamp when you add an aftermarket spoiler to the deck lid that incorporates such a lamp. I enclose a copy of an interpretive letter we sent David Holscher on August 31, 1990, which remains our position today. In brief, a spoiler lamp will supersede the original equipment center lamp. When the spoiler is installed, Federal law does not dictate whether the original lamp must be disconnected or remain usable. That question is answerable under State law, and we suggest that you consult the Department of California Highway Patrol for its views. If California has no regulation bearing on this problem, we assume that you may either disconnect the original lamp or leave it connected, as your customers desire. Sincerely, John Womack Acting Chief Counsel Enclosure; |
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ID: aiam2222OpenMr. Phil Schneider, PTV Project Supervisor, Steam Power Systems, 7617 Convoy Court, San Diego, CA 92111; Mr. Phil Schneider PTV Project Supervisor Steam Power Systems 7617 Convoy Court San Diego CA 92111; Dear Mr. Schneider: This is in response to your letter of January 22, 1976, requestin confirmation that your company's Paratransit Vehicle would be classified as a 'multipurpose passenger vehicle' for purposes of the Federal motor vehicle safety standards and regulations.; Your letter states that the Paratransit Vehicle is designed primaril to carry wheel-chair- confined passengers in a Dial-a-Ride or jitney type of service, and that the vehicle is of the forward control configuration, constructed with a custom chassis-body structure.; Based upon the facts presented in your letter, the description an specifications contained in the attached SAE design paper, and the National Highway Traffic Safety Administration's previous interpretation of the classification, we would conclude that the Paratransit Vehicle does qualify as a 'multipurpose passenger vehicle.'; Please contact us if we can be of any further assistance. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3960OpenMr. H. Moriyoshi, Executive Vice President and General Manager, Mazda (North America), Inc., 24402 Sinacola Court, Farmington Hills, MI 48018; Mr. H. Moriyoshi Executive Vice President and General Manager Mazda (North America) Inc. 24402 Sinacola Court Farmington Hills MI 48018; Dear Mr. Moriyoshi: This is in reply to your letter of June 3, 1985, asking for a interpretation of Motor Vehicle Safety Standard No. 108 regarding requirements for the center high- mounted stop lamp.; You reference an agency letter of July 30, 1980, to Volkswagen o America in which the Chief Counsel concluded that placement of the stop lamps and taillamps on the deck lid could be viewed as a defect in performance requiring notification and remedy. You have asked, in essence, how this relates to Standard No. 108's present allowance of a center high- mounted stop lamp mounted on a vehicle's decklid, hatch, or tailgate.; The assumption underlying the agency's 1980 letter was that a defec could exist if all a vehicle's stop lamps and taillamps were mounted on the decklid, where their signals could be unobserved or obscured if the lid were in any position other than closed. The center high-mount stop lamp, on the other hand, while an item of required equipment, is nevertheless a supplementary stop lamp. Even if the deck, hatch, or tailgate upon which it is mounted should be open, following drivers may still observe the signals of the primary stop lamps remaining on the body.; You have asked that we also discuss the implications of a stop lamp an taillamp constructed so that a portion is fixed to the body of the vehicle adjacent to the decklid opening and the remaining portion is mounted on the outboard area of the decklid.; Compliance of a vehicle is determined with respect to its norma driving position, that is to say, with the tailgate, hatch, or decklid closed. However, in order to obviate any possibility of the existence of a safety-related defect, we recommend that the portion of the lamp that is mounted on the body itself comply with the minimum requirements of Standard No. 108 for a single compartment stop lamp or taillamp.; I hope that this answers your questions. Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam2672OpenMr. J. Shillinger, Project Engineer, AM General Corporation, 32500 Van Born Road, Wayne, MI 48184; Mr. J. Shillinger Project Engineer AM General Corporation 32500 Van Born Road Wayne MI 48184; Dear Mr. Shillinger: This responds to AM General Corporation's July 18, 1977, request fo confirmation that certain aspects of the M.A.N. articulated transit bus conform to the requirements of Standard No. 121, *Air Brake Systems*, and Standard No. 124, *Accelerator Control Systems*. In an October 3, 1977, telephone call with Mr. Herlihy of this office, it was determined that the request for interpretation is now limited to confirmation that the four-way pressure protection valve described in M.A.N.'s June 22, 1977, letter would meet the location and functional requirements of S5.1.2.3 of Standard No. 121. Section S5.1.2.3 specifies--; >>>S5.1.2.3 Each service reservoir shall be protected against loss o air pressure due to failure or leakage in the system between the service reservoir and its source of air pressure by check valves or equivalent devices.<<<; I am enclosing prior interpretations of the location requirement o S5.1.2.3. While the agency cannot 'approve' systems based on schematic drawings, it appears that the location of the four-way protection valve in the M.A.N. drawings does not violate the provisions contained in S5.1.2.3.; As we understand the description and capabilities of the four-wa valve, it appears to be a pressure protection device that is 'equivalent' to the check valve otherwise required by S5.1.2.3.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam2388OpenMr. Bing Johnson, 135 Jade Cove Drive, Roswell, Georgia 30075; Mr. Bing Johnson 135 Jade Cove Drive Roswell Georgia 30075; Dear Mr. Johnson: This is in reply to your letter of August 16, 1976 in which you ask about our regulations concerning the modification of 'vans' to make them suitable for camping. The modifications you propose to make include the installation of plumbing, water, electricity, and additional seating.; The National Traffic and Motor Vehicle Safety Act (15 U.S.C. SS 1381 *et seq.*) prohibits the manufacture, offer for sale, sale, introduction in interstate commerce or importation of a motor vehicle that does not comply with all applicable standards in effect on the date of its manufacture. This prohibition does not apply (except for importation) after the first purchase of the vehicle in good faith for purposes other than resale. Under these provisions, you are responsible for the compliance of any vehicle that you modify up to and including the time of first purchase for purposes other than resale.; The manufacturer must comply with all applicable safety standard established by the National Highway Traffic Safety Administration (NHTSA). His certification appears on a completed vehicle. It would be your responsibility to ensure that the vehicle continues to comply with all applicable safety standard after your modifications. Under Part 567 of our regulations, you must attach a label to the vehicle that states that, as altered, the vehicle continued to conform to the standards.; From the description of the modification you describe, it appears tha you might affect the compliance of the vehicle with the following standards: Standard No. 207, *Seating Systems*, Standard No. 208, *Occupant Crash Protection*, Standard No. 210, *Seat Belt Assembly Anchorages*, and Standard No. 302, *Flammability of Interior Materials*. It should be noted that any additional weight created by your modifications or a change in the distribution of weight could also affect the vehicle's compliance with other safety standards whose test procedures required a barrier crash test.; We also would point out that if you modify a Ford 'Econoline' in al probability you would change the vehicle classification from a truck to a multipurpose passenger vehicle. This should be noted on the certification label that you attach to the vehicle. I have enclosed an information sheet that explained where you may obtain copies of these regulations.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam3433OpenMs. Nancy Avery, Calesco, Inc., 5620 Glenridge Drive, N.E., P.O. Box 5041, Atlanta, GA 30302; Ms. Nancy Avery Calesco Inc. 5620 Glenridge Drive N.E. P.O. Box 5041 Atlanta GA 30302; Dear Ms. Avery: This is in response to your letter of November 11, 1980, concerning th application of the Federal odometer disclosure requirements. We regret our delay in responding. The answers to your specific questions are as follows:; 1. Are we required to give the purchaser an odometer statement in th states (such as Massachusetts, Pennsylvania, and Ohio) where the mileage at the time of the vehicle transfer is recorded on the Certificate of Title?; The odometer Disclosure Requirements (49 CFR Part 580) provide that th transferor of a vehicle may substitute the state certificate of title for the Federal odometer disclosure statement, if the state title contains essentially the same information found in the Federal statement. Where the state certificate of title can be substituted for the Federal form, there is no requirement that a separate Federal odometer disclosure statement be issued to the purchaser. However, if the information contained in the state certificate of title varies from that required in the Federal form, the state must obtain the approval of this agency before its certificate of title can be used as a substitute for the Federal form.; In order to spare states the burden of an approval process, the agenc has indicated that certain variations from the Federal form are acceptable. In the *Federal Register* notice of August 1, 1977, which amended the disclosure regulation, we gave examples of shortened forms that would be acceptable. A state title can be considered to be approved for use as a full disclosure statement if it varies from the Federal form in only those aspects noted in the August 1 notice, a copy of which is enclosed.; 2. If we sell a vehicle in Canada or Puerto Rico, is this la applicable?; For purposes of the Motor Vehicle Information and Cost Savings Act, a amended, 15 U.S.C. 1901 *et seq.*, Puerto Rico is a state. Therefore, the Federal odometer disclosure requirements are applicable to the sale of a vehicle in Puerto Rico. However, the agnecy has no jurisdiction over the sale of a vehicle in Canada.; 3. On the odometer statements, is the signature of the purchase required?; The Odometer Disclosure Requirements (49 CFR Part 580.4(e)) provid that the transferee (buyer) shall acknowledge receipt of the disclosure statement by signing it.; 4. If the vehicle is sold as salvage, are we required to give th purchaser an odometer statement?; The Federal odometer disclosure laws are not applicable to vehicle that are sold for salvage. The agency has determined that for purposes of the Federal odometer laws a vehicle is salvage if it is so badly damaged that it cannot be returned to the road. However, if the vehicle is repairable and will subsequently be used as a motor vehicle, disclosure has to be made.; Sincerely, David W. Allen, Assistant Chief Counsel |
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ID: aiam3063OpenMr. John Riccardo, Chairman of the Board, Chrysler Corporation, P.O. Box 1919, Detroit, MI 48321; Mr. John Riccardo Chairman of the Board Chrysler Corporation P.O. Box 1919 Detroit MI 48321; Dear Mr. Riccardo: This responds to your letter about Chrysler's general need for relie from Federal regulations and the denial of its petition for a one-year exemption from the automatic restraint requirements for Chrysler 1982-model full- size cars. There are several statements by Chrysler regarding the petition denial that you wish placed in the public record. Accordingly, your letter has been placed in the public docket on occupant crash protection (74-14, General Reference).; This agency is fully appreciative of the significance of Chrysler' circumstances and needs. Where relief can be considered consistent with the spirit and provisions of the laws we administer, we will do so. This willingness was amply demonstrated by my recent action in reducing the 1981 fuel economy standard for light trucks. Chrysler's automatic restraint petition presented us with a substantially different situation. Under our statutory authority, the only way we could have exempted Chrysler's large-size 1982 model from compliance with the automatic restraint requirements would have been to classify that vehicle as a unique type of car under our existing authority. Clearly, such a classification would have been challenged in court, and we believe it would not have been sustained. Indeed, such an action would severely strain our credibility with the court which just recently reviewed that very issued. (sic); Regarding your statements about the safety issues associated with th denial, the agency agrees that some safety belt reminder systems can be effective in encouraging belt use. We do not believe, however, that most simple warning systems can equal the life-saving potential of automatic restraints. Further, the NHTSA has no authority under the National Traffic and Motor Vehicle Safety Act to require ignition interlock systems, which are probably the most effective systems for encouraging use of manual belts.; In this particular matter, the law precludes us from granting th relief you seek. I regret that we are unable to assist you under these circumstances.; Sincerely, Joan Claybrook |
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ID: aiam3599OpenMr. Robert P. Donley, President, Weldon Incorporated, 2000 South High Street, Columbus, OH 43207; Mr. Robert P. Donley President Weldon Incorporated 2000 South High Street Columbus OH 43207; Dear Mr. Donley: This is in reply to your letter of December 10, 1981, regardin continuing compliance of lighting equipment after repairs.; You have asked the following questions: '1. If the original lens is replaced during a field repair by one no manufactured by the original manufacturer, would the lamp's original certification with FMVSS 108 be nullified?'; Repair of a vehicle in service is irrelevant to its certification Certification is the assurance given by the manufacturer to distributors, dealers, and purchasers, that Federal standards are met by his product upon its sale when new. There is no requirement that the certification be valid for the life of the product.; '2. Must a lamp in use remain in conformance with FMVSS 108 after suc repair is made?'; This is a good question, and the answer is no. When repairs ar necessary there is no Federal legal requirement that the lamp remain in conformance afterwards. However, manufacturers, distributors, dealers, and motor vehicle repair businesses may not alter fully functional lamps in a manner that renders them nonconforming, or substitute nonconforming equipment. This prohibition does not apply to the vehicle owner, his modifications are subject only to State and local restrictions.; '3. If the lamp must remain in conformance with FMVSS 108 after suc repair is made, who is responsible for certifying same?'; As I stated earlier, repairs of used vehicles and equipment are no subject to conformance or certification. However, if a lamp is replaced in its entirety, the manufacturer of the replacement lamp is responsible for certifying conformity to Standard No. 108 because that standard covers replacement equipment of the types you mentioned ('e.g., stop lamp, turn signal lamp, school bus warning lamp, marker lamp').; I hope this answers your questions. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4749OpenMr. Douglas Mayes President Creative Products, Inc. Number One Carissa Littleton, CO 80127; Mr. Douglas Mayes President Creative Products Inc. Number One Carissa Littleton CO 80127; "Dear Mr. Mayes: This responds to your letter asking questions i relation to your product called 'gyroscopic wheel covers.' We apologize for the delay in our response. According to your letter and accompanying information, you claim that use of 'gyroscopic wheel covers' can reduce stopping distance. You stated that Dr. Carl Clark of this agency suggested that you request this office to provide a letter specifically outlining the requirements of the agency's braking test, and a list of the various testing facilities used by the agency when testing a product for this purpose. You then asked for a letter stating the 'stopping distance test guidelines' of Safety Standard No. l05, Hydraulic Brake Systems,' and a list of laboratories acceptable to DOT that could be used to test your product. You also asked whether an SAE standard is a proper example of a stopping distance test. You stated that it is your intention to use these testing standards and one of the acceptable laboratories so as to properly document your product's test results in compliance with the DOT testing standards. By way of background information, the National Highway Traffic Safety Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its products meet applicable standards. Safety Standard No. l05, Hydraulic Brake Systems, applies to passenger cars and other motor vehicles. The standard specifies, among other things, a number of stopping distance tests that each motor vehicle must meet. I have enclosed a copy of the standard for your information. I note that Standard No. l05 was not designed for the purpose of evaluating whether a product such as yours can improve stopping distance. We are unable to offer an opinion as to the appropriateness of using Standard No. l05's stopping distance tests for that purpose, or how such a test program would best be carried out. This agency does not provide recommendations or endorsements for particular testing laboratories. I have, however, enclosed a list of the independent laboratories conducting compliance tests for NHTSA's Office of Vehicle Safety Compliance during the current fiscal year. I have also enclosed a copy of an information sheet we have prepared which provides information for new manufacturers of motor vehicles and motor vehicle equipment. I hope this information is helpful. Sincerely, Paul Jackson Rice 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.