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: aiam0385OpenMr. Nathan Sagan, 949 Central Avenue, Albany, NY (sic); Mr. Nathan Sagan 949 Central Avenue Albany NY (sic); Dear Mr. Sagan: This is in further reply to your request made to the Regiona Administrator of the National Highway Traffic Safety Administration concerning the applicability of the Tire Identification and Record Keeping regulation (49 CFR Part 574) to tires on Cushman golf carts.; As we indicated in our letter of June 23, golf carts are not considere to be motor vehicles within the meaning of the regulation or the National Traffic and Motor Vehicle Safety Act. Therefore, the regulation is not applicable to tires sold with or for golf carts.; Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam2212OpenMr. Tommy Watson, Engineer of Codes and Standards, Leisure Time Products, Inc., P.O. Box 232, Nappanee, Indiana 46550; Mr. Tommy Watson Engineer of Codes and Standards Leisure Time Products Inc. P.O. Box 232 Nappanee Indiana 46550; Dear Mr. Watson: This is in response to your letter of January 29, 1976, requesting a interpretation of the requirements of S.6 of Federal Motor Vehicle Safety Standard No. 111 , *Rearview Mirrors*, as they apply to the manufacture of mobile homes with a GVWR of greater than 10,000 pounds.; The standard requires that these vehicles be equipped with outsid mirrors of unit magnification, *each with not less than 50 square inches of reflective surface*, on both sides of the vehicle. While you are free to provide additional mirrors, the standard clearly requires two mirrors each of which has at least 50 square inches of reflective surface. Substitution of a number of small mirrors for one or both of the 50 square inch mirrors is impermissible, even if a total reflective area of 50 square inches is provided.; If you require any further assistance, do not hesitate to write. Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4796OpenMr. Satoshi Nishibori Vice President Industry-Government Affairs 750 17th Street, NW Suite 902 Washington DC 20006; Mr. Satoshi Nishibori Vice President Industry-Government Affairs 750 17th Street NW Suite 902 Washington DC 20006; "Dear Mr. Nishibori: This responds to your request for a interpretation of Standard No. 114, Theft Protection (49 CFR 571.114). You were uncertain whether your shift lock emergency override system, your emergency key release, and your transmission park lock system comply with S4.2 and S4.3, as amended by a May 30, 1990 final rule (55 FR 21868). On June 29, 1990, you submitted a petition for reconsideration which the agency is currently considering. Under the revised requirements, section S4.2 provides that: 'Each vehicle shall have a key-locking system that, whenever the key is removed, prevents: (a) the normal activation of the vehicle's engine or motor, and (b) either steering or forward self-mobility of the vehicle or both. For a vehicle equipped with an automatic transmission with a 'park' position, the key-locking system shall prevent removal of the key unless the transmission or transmission shift lever is locked in 'park' or becomes locked in 'park' as the direct result of removing the key.' As explained below, we have made the following interpretations concerning your systems based on our understanding of them from your petition for reconsideration, your July 25, 1990 letter, and your discussions with agency staff. By way of background, the National Traffic and Motor Vehicle Safety Act, ('Vehicle Safety Act,' 15 USC 1381 et seq.) requires every new motor vehicle sold in the United States to be certified as complying with all applicable Federal motor vehicle safety standards. The Vehicle Safety Act specifies that the manufacturer must certify that each of its vehicles complies with all applicable safety standards in effect on the date of manufacture. Because of this statutory requirement, this agency does not approve any manufacturer's vehicles or offer assurances that the vehicles comply with the safety standards. Any person violating the Vehicle Safety Act by manufacturing or selling new noncomplying vehicles may be liable for potential penalties of $1,000 per violation up to $800,000. Shift Lock Emergency Override You explained that your shift lock emergency override system is operable by depressing a button on the lower, rear portion of the shift lever. By depressing the button, the transmission may be shifted out of 'park,' independent of the ignition key position or the key being in the ignition switch. You expressed your opinion that the transmission remains 'locked' in 'park' until it is 'unlocked,' either by turning the ignition key to the 'on' position and depressing the brake pedal or by operating the emergency shift release override. This led you to conclude that your emergency shift override would be permissible under S4.2(b). We disagree with your suggested interpretation. Under S4.2(b), the key-locking system must prevent removal of the key unless the transmission or transmission shift lever is locked in 'park' or becomes locked in 'park' as the direct result of removing the key. Given the presence of the emergency shift release override, we do not believe the transmission or transmission shift lever would ever be 'locked' in park, since it could be released without regard to the key used to operate the vehicle's key-locking system. Your alternative shift lock system in which the manual override would be operable only after removing a cover over the override lever would also not appear to comply with S4.2 because the presence of a cover would not affect one's ability to release the transmission shift lever without regard to the key used to operate the vehicle's key-locking system. Emergency Key Release You explained that your emergency key release system facilitates removal of the ignition key in the event of an electrical system failure. That system permits overriding the ignition key lock, so that the ignition key can be removed from the vehicle and the driver can lock the vehicle. You explained that the emergency key release override is activated by removing a cover over the ignition switch and then using a screw driver to activate a hidden lever located inside the exposed ignition switch compartment. We do not concur with your suggested interpretation of S4.2. That requirement provides that 'the key-locking system shall prevent removal of the key unless the transmission or transmission shift lever is locked in 'park.' The regulatory text does not refer to alternative methods of key removal such as the procedure you describe. While you state that virtually any key locking system can be overriden through some form of lock disassembly and associated procedures, we do not consider the simple override you describe to be similar to lock disassembly. Therefore, an emergency key release system in which the key could be removed in a position other than 'park' would not comply with S4.2, regardless how the key could be removed. Nevertheless, such an emergency key release would be permissible if it were operable only while the transmission or transmission shift lever were locked in the 'park' position. You should be aware that we are evaluating such systems in our review of the petitions for reconsideration to the final rule. Park Lock System You explained that your park lock system prevents drivers from inadvertently depressing the accelerator pedal rather than the brake pedal when shifting out of 'park'. This is accomplished by permitting the transmission lever to be moved out of 'park' only if the ignition key is in the 'on' position and the brake pedal is depressed. You further explained that if the transmission is placed in 'park,' the shift lever locks in that position when the ignition key is turned to the 'off' position. You expressed your belief that your park lock system complies with S4.3, as amended. I agree that your park lock system appears to comply with S4.3. That provision requires that the prime means for deactivating the vehicle's engine or motor, typically the ignition key, shall not activate the key-locking system described in S4.2(b). Based on our understanding of your key-locking system, it appears to comply with S4.3 because that provision refers to the key-locking system and not a transmission shift lock. As you correctly note, the purpose of S4.3 is to prevent the potentially dangerous situation in which the ignition key of a moving vehicle is turned to the 'off' position causing the steering column to lock. You asked that we continue to consider your petition for reconsideration, if, as we have done, we concluded that some of your suggested interpretations were incorrect. We will notify you of our response to that petition as soon as we complete our review of it. I hope this explanation is helpful. Please contact Mr. Marvin Shaw of my staff at (202) 366-2992 if you have any further questions. Sincerely, Paul Jackson Rice Chief Counsel Enclosure"; |
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ID: aiam3053OpenMr. Stephen E. Mulligan, International Harvester, Law Department, 401 North Michigan Avenue, Chicago, IL 60611; Mr. Stephen E. Mulligan International Harvester Law Department 401 North Michigan Avenue Chicago IL 60611; Dear Mr. Mulligan: This responds to your June 4, 1979, letter asking several question relating to manufacturer's responsibilities to maintain first purchaser lists and to certify vehicles in compliance with the safety standards.; Your first question asks whether a manufacturer is permitted to replac its first purchaser lists with lists of most recent purchasers when that information comes to a manufacturer's attention. You point out that Part 577, *Defect and Noncompliance Notification*, requires manufacturers to notify vehicle owners or the most recent purchaser known to the manufacturer.; The National Traffic and Motor Vehicle Safety Act of 1966 (as amended (15 U.S.C. 1381 *et seq*.) requires in section 158 (15 U.S.C. 1418) that manufacturers maintain lists of first purchasers of their vehicles. The purpose of this requirement is to facilitate the issuance of defect and noncompliance notifications to vehicle owners. Lists of the most recent purchasers of a manufacturer's vehicles would be even more efficient for recall purposes than would first purchaser lists. Accordingly, the National Highway Traffic Safety Administration has determined that maintaining lists of most recent purchasers of a manufacturer's vehicles satisfies the statutory requirement to maintain first purchaser lists.; In your second question, you ask about the labeling requirements o individuals that modify incomplete vehicles. IN the fact situation you present, International Harvester (IH) certifies a chassis-cab in accordance with the agency's certification regulations and transfers it to an IH dealer who performs some minor modifications on the chassis-cab prior to its delivery to a final-stage manufacturer. The IH dealership is either owned or controlled by IH. You ask what type of certification label the IH dealer should attach.; You suggest that an alterer's label might be the appropriate label t use. The other possibilities that you recommend are the use of an intermediate manufacturer's label or merely removing and amending the chassis-cab label attached to the incomplete vehicle. You suggest that the latter is more appropriate since the dealer modifying the chassis-cab is owned by IH, and therefore, it constitutes the same manufacturer that constructed the chassis- cab. You state further that to require an intermediate manufacturer's label appears to be inappropriate since that label would show that the chassis-cab and the intermediate manufacturer are both the same corporation.; Alterer's labels are only used by individuals or businesses modifyin vehicles that have been certified by a final-stage manufacturer. Therefore, an alterer's label would be inappropriate in this instance since the chassis- cab has not been certified as a completed vehicle.; The agency concludes that in the case where a manufacturer's wholl owned dealership is modifying a certified chassis, the label on the chassis-cab should be removed and a correct label should be added. In these instances, the chassis-cab is still within the control of the original manufacturer. Therefore, it is appropriate for that manufacturer to assume the responsibility for the modification made by its dealers. The dealer is not an independent business of the type that must attach an intermediate manufacturer's label. Accordingly, your dealer may amend the incomplete vehicle label as a result of its modifications.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1594OpenMr. A.J. Burt, Sales Engineer, Highway Products, B.F. Goodrich Aerospace and Defense Products, P.O. Box 340, Troy, OH 45373; Mr. A.J. Burt Sales Engineer Highway Products B.F. Goodrich Aerospace and Defense Products P.O. Box 340 Troy OH 45373; Dear Mr. Burt: This responds to your June 4 and June 20, 1974, letters asking if parking brake system which locks mechanically after the brake is applied by any emergency air supply acting through the service air brake chamber would comply with Standard No. 121, *Air brake systems*. The parking brake provisions require in part:; >>>S5.6.3 *Application and holding*. The parking brake shall be applie by an energy source that is not affected by loss of air pressure or brake fluid pressure in the service brake system. Once applied, the parking brakes shall be held in the applied position solely by mechanical means.<<<; The arrangement described would not meet this requirement because th energy source to apply the brakes (the emergency air supply) would be affected by loss of air pressure in the service brake system. For example, any failure in the service brake piston diaphragm would cause a loss of air pressure that would in turn 'affect' the energy source that applies the parking brakes. The brake chamber housing assembly is an element which is not considered to be part of the service brake system for this requirement.; I would like to point out that the provisions of Standard No. 121 d not apply to trailers manufactured before January 1, 1975.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam3403OpenMr. James E. Gregory, Gregory Equipment & Manufacturing Co., 1314 17th Street, Fort Madison, IA 52627; Mr. James E. Gregory Gregory Equipment & Manufacturing Co. 1314 17th Street Fort Madison IA 52627; Dear Mr. Gregory: This is in reply to your letter of April 13, 1981, with respect t placement of identification lamps on the boat trailer you wish to manufacture.; You have informed us that the trailers are not built for transportin boats on the highways and your sales sheet reiterates that point: 'These trailers are for in marina use only. Not for over the road use.' Under the National Traffic and Motor Vehicle Safety Act, a vehicle that is not manufactured primarily for use on the public roads is not a vehicle subject to our regulations. From your letter and advertising enclosure, it appears that your intent is to build a vehicle that will be used primarily on private property. Therefore, our lighting requirements would not apply to it.; I hope that this answers your question. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1449OpenMr. R.O. Sornson,Manager,Environmental and Safety Relations, Chrysler Corporation,Detroit, Michigan 48231; Mr. R.O. Sornson Manager Environmental and Safety Relations Chrysler Corporation Detroit Michigan 48231; Dear Mr. Sornson:#This is in response to your March 13, 1974, reques for confirmation that the intake manifold connector and the brake booster check valve used in connecting the engine intake manifold and the vacuum power brake booster are not subject to Standard No. 106, *Brake hoses*.#A brake hose and fitting is defined in Standard 106 as 'a coupler other than a clamp, designed for attachment to the end of a brake hose.' As pictured in your schematic, the couplers are the clamps, and the intake manifold connection and brake booster check valve are engine components to which the brake hose has been attached by clamp couplers. Therefore your interpretation is correct that neither component is subject to Standard 106.#Sincerely,Lawrence R. Schneider,Chief Counsel; |
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ID: aiam3474OpenMr. T. Takano, Chief of Development Dept., Meiji Rubber & Chemical co., Ltd., Kojima Building, 10-2, Nishishinjuku, 1-Chome, Shinjuku-Ku, Tokyo, Japan; Mr. T. Takano Chief of Development Dept. Meiji Rubber & Chemical co. Ltd. Kojima Building 10-2 Nishishinjuku 1-Chome Shinjuku-Ku Tokyo Japan; Dear Mr. Takano: This responds to your recent letter regarding the use of flexible nylo tubes in vacuum braking systems. You ask whether such plastic hoses would qualify as 'vacuum tubing connectors' for purposes of Safety Standard No. 106, *Brake Hoses*.; We recently received a letter asking this identical question from Toka Rubber Industries of Japan. I am enclosing a copy of that letter for your information. I believe that it will answer all of your questions. You will see from the letter that these nylon tubes cannot qualify as 'vacuum tubing connectors' and must comply with the requirements of Safety Standard No. 106.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1019OpenMr. W. S. Magenau, President, Chesapeake Marine Products, Route 456, Deale, MD 20751; Mr. W. S. Magenau President Chesapeake Marine Products Route 456 Deale MD 20751; Dear Mr. Magenau: This is in response to your letter of February 5, 1973, in which yo suggested, with reference to a previous interpretation, that boat trailer assemblers be allowed to use the 'altering distributor' certification of 49 CFR S 567.6, rather than certifying the vehicle as the manufacturer under S 567.4.; The altering distributor label was not designed to deal with assembler of vehicles, but with persons who alter vehicles that have already been completed and assembled. A basic prerequisite to its use is that there be a vehicle that already has been certified. I take it that your suggestion really amounts to requiring the supplier of the unassembled parts to certify the vehicle.; We are unwilling to do this on the basis of our present information. I is true that a boat trailer is among the simplest vehicles on the road, but considering vehicles generally, we must consider a vehicle as a functioning whole, not as a group of parts. There may easily be problems caused by the way in which it is assembled, and we do not consider it reasonable to require a manufacturer of parts, against his will, to take responsibility for the final assembly. Although it is conceivable that such a scheme could work with very simple vehicles, it certainly could cause large problems with more complex ones.; We permit the unassembled parts manufacturer to certify if he wishes Furthermore, the person who assembles the vehicle can require a written commercial warranty that the vehicle will conform if properly assembled, which will protect him in certifying the vehicle. I recommend one of these courses of action as a matter of good business practice.; If the unassembled parts manufacturer does certify the package i accordance with S 567.4(g)(1)(ii), then it would be permissible for a distributor to use S 567.6 where he deviates from the certifier's instructions.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3024OpenMr. Myles Robert Lee, P.O. Box 1344, Gloucester, MA 01930; Mr. Myles Robert Lee P.O. Box 1344 Gloucester MA 01930; Dear Mr. Lee: This responds to your May 12, 1979, letter asking how to determine th correct date of manufacture of your motor home. You indicate that the chassis was constructed in 1977 and the body in 1978. The manufacturer apparently classified the vehicle as a 1978 model.; The National Highway Traffic Safety Administration has a regulatio governing the date of manufacture of vehicles for the application of safety standards. Part 568, *Vehicles Manufactured in Two or More Stages*, of our regulations states that a manufacturer may choose as the date of manufacture of a vehicle the date of manufacture of the chassis, the date of manufacture of the completed vehicle, or any date between those two dates. However, the vehicle must comply with all of the applicable safety standards in effect on the chosen date. Since the body of your vehicle was manufactured in 1978, we assume that the vehicle was completed in 1978. Therefore, the manufacture could legally call your vehicle a 1978 model, at least for the purposes of our safety program.; Sincerely, Frank Berndt, 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.