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: aiam2146OpenMs. Dianne Black, Liaison Engineer, British Leyland Motors Inc., 600 Willow Tree Road, Leonia, NJ 07605; Ms. Dianne Black Liaison Engineer British Leyland Motors Inc. 600 Willow Tree Road Leonia NJ 07605; Dear Ms. Black:#This is in response to your October 20, 1975, lette concerning the status of amendments to Federal Motor Vehicle Safety Standard No. 101, *Control Location, Identification and Illumination*, that were proposed in Notice 10 (Docket 1-18, 38 FR 26940, September 27, 1973).#Although a further proposal on this subject is being considered, no final decision has been made by the National Highway Traffic Safety Administration (NHTSA) concerning action on the outstanding proposal. You should be guided by the standard in its present form. The effective date of any amendments issued by the NHTSA will allow adequate lead time for compliance.#Yours truly, Richard B. Dyson, Assistant Chief Counsel; |
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ID: aiam2516OpenMr. Donald I. Reed, Director of Engineering, Trailer Manufacturers Association, 401 North Michigan Avenue, Chicago, IL 60611; Mr. Donald I. Reed Director of Engineering Trailer Manufacturers Association 401 North Michigan Avenue Chicago IL 60611; Dear Mr. Reed: This is in reply to your letter of December 20, 1976 asking for clarification of the statement in my letter to you dated December 3, 1976, that 'the light emitted by one bulb must not be perceived as performing the function of the other in addition to its design function.'; It is evident from your letter and others that our previou interpretations of the term 'optical combination' have been found to be ambiguous and lacking in the objective criteria that a Federal motor vehicle safety standard must provide. We have reviewed the matter, and now wish to modify our previous interpretation. In our view a lamp is 'optically combined' when the same light source (i.e. bulb) and the same lens area fulfill two or more functions (*e.g.* taillamp and stop lamp, clearance lamp and turn signal lamp). A dual filament bulb would be regarded as the 'same light source'. In determining conformance, the photometric requirements for clearance and taillamp functions, where two bulbs are located in a single compartment, must be met with only the bulb energized that is designed to perform the specific function. But the 15 candlepower maximum under Standard No. 108, however, would be determined with both the taillamp and clearance lamp bulb energized. Further, the lamp must be located to meet requirements for both clearance and taillamps. Our re- interpretation means that the issue of light spill-over from one area of the lamp to another is irrelevant to conformance.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam4211OpenMr. Heinz Huentemann, Vice-President, Spartan Transit Supply Corp., 325 Fairlane Drive, Spartanburg, SC 29302; Mr. Heinz Huentemann Vice-President Spartan Transit Supply Corp. 325 Fairlane Drive Spartanburg SC 29302; Dear Mr. Huentemann: This responds to your letter dated June 17, 1986, asking how ou regulations affect a convex outside mirror manufactured by your company. In your letter, you state that this convex mirror has a reflective surface of 92.5 square inches, and would be used on the curb side of a transit bus. You also state that this convex mirror has a radius of curvature of 94.5 inches. You specifically asked whether this mirror can be used on the curb side of a transit bus.; Standard No. 111, *Rearview Mirrors*, a copy of which is enclosed, set different requirements for buses depending on whether the gross vehicle weight rating (GVWR) is above 10,000 pounds. I believe that the GVWR of a transit bus would exceed 10,000 pounds.; Buses with a GVWR of more than 10,000 pounds must meet S7.1, whic requires buses, other than school buses, to have outside mirrors of unit magnification, each with not less than 50 square inches of reflective surface, installed with stable supports on both sides of the vehicle. These mirrors must also be located so as to provide the driver a view to the rear along both sides of the vehicle and must be adjustable both in the horizontal and vertical directions to view the rearward scene. Although the surface of your convex mirror is close to a plane (flat) surface, due to the 94.5-inch radius of curvature, it is not a unit magnification or plane mirror. Therefore, it does not meet the requirements for rearview mirrors on new buses.; A manufacturer of new transit buses could use your convex mirror on th curb side of the bus *in addition* to a unit magnification mirror which met all applicable requirements of Standard No. 111. However, a commercial business could not substitute your mirror for a complying mirror. Section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act prohibits any manufacturer, distributor, or dealer of motor vehicles or motor vehicle equipment, or any motor vehicle repair business from knowingly rendering inoperative any device or element of design installed on a vehicle in compliance with a safety standard. Thus, a manufacturer, distributor, dealer, or repair business could not remove a unit magnification rearview mirror, installed as original equipment in compliance with our standard, and replace that mirror with a convex mirror.; The sample of your rearview mirror, No. STS-0.253, is being returned t you under separate cover.; I hope this information is helpful to you. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1013OpenMr. F. E. Keith, Keith Motor Company, 4507 East 11th, Tulsa, OK 74112; Mr. F. E. Keith Keith Motor Company 4507 East 11th Tulsa OK 74112; Dear Mr. Keith: This is in reply to your letter of January 30, 1973, concerning th Federal Odometer Disclosure Requirement.; Your questions concerns (sic) the situation in which a person sells vehicle that has had several previous owners. You suggest that, in such a case, the true mileage should be indicated as unknown.; It is our opinion that the language you quote from Section 408(a) o the Act, to the effect that the mileage must be said to be unknown if the odometer reading is known to differ from the actual mileage, does not apply in the situation you describe. A person selling the vehicle in the above situation should not, therefore, indicate that the mileage is unknown, but should rely on the statement by the previous owner.; As you acquire vehicles after March 1, the effective date of th disclosure requirement, you will be obtaining the disclosure statement from each seller. Within a relative (sic) short time, all of the vehicles on your lot will have disclosure statements on which you are entitled to rely in making your disclosure statement upon resale of the vehicle.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3184OpenMr. Jeffrey Libman, President, Edison Rubber Company, P.O. Box 254, Edison, New Jersey 08817; Mr. Jeffrey Libman President Edison Rubber Company P.O. Box 254 Edison New Jersey 08817; Dear Mr. Libman: This responds to your letter of November 9, 19799, inquiring if it i permissible for you suppliers to cut off the DOT serial numbers on used tires before selling those tires to your company. You stated in your letter that your company buys used tires from several companies. These tires generally either have cuts in the tread or sidewalls or are out of round. Your company then resells the tires to another company, which resells the tires to the public.; The answer to your question is no. The presence of the DO identification number on tires is required by several of this agency's regulations. Our tire identification and record keeping regulation (49 CFR Part 574) requires that each manufacturer place the DOT number on at least one sidewall of each tire that it manufactures. The number serves several purposes. It is indispensable in aiding consumers to identify tires subject to a recall campaign for safety defects and noncompliances with the safety standards. It also aids this agency in enforcing its tire safety standards. Federal Motor Vehicle Safety Standards 109 (Passenger car tires, 49 CFR 571.109) and 119 (Tires for vehicles other than passenger cars, 49 CFR 571.119) require that each tire manufacturer certify that its tires conform to all applicable Federal Safety standards by branding or molding the DOT number on the tire.; Section 108(a) (2) (A) of National Traffic and Motor Vehicle SAfety Ac of 1966, as amended (15 U.S.C. 1397(a) (2) (A)), states that, 'No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative, in whole or in part, any device or element of design installed on...an item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard...' By removing the DOT identification number from a tire, the person would be knowingly rendering inoperative an element of design on the tire which is included on the tire for compliance with the requirements of a Federal motor vehicle safety standard. Section 109 of the Act (15 U.S.C. 1398) specifies a penalty of up to $1,000 for each violation of section 108.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4641OpenCONFIDENTIAL; CONFIDENTIAL; Dear: With respect to the interpretation furnished you on July 21 l989, you have requested the following clarification in your letter of the 28th: that the provisions of paragraph S7.4 of Standard No. 108 that relate to filament usage do not apply to the headlamp system previously described. You have also confirmed that this system is designed to conform to all other requirements of Standard No. 108 'including photometric, special wiring, mechanical aim, environmental and marking requirements. Paragraph S7.4 describes a variety of headlighting systems which come under the heading of 'integral beam systems.' The beams in these systems will be produced by 'beam contributors' (S7.4(a)(3)), headlamps containing 'two light sources' (S7.4(b)), or headlamps containing 'a single filament' (S7.4(c)). The arc tubes in the system you describe would appear to be 'beam contributors' within the meaning of S7.4, and the filament language of paragraph S7.4 would not apply to this particular type of integral beam headlighting system. We will honor your continuing request that your name and those of your firm and client be deleted from the copy made publicly available. Sincerely, Stephen P. Wood Acting Chief Counsel; |
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ID: aiam1443OpenMr. Dick Umphrey, Director of Marketing, American Bumper Sales Company, 1150 E. Slauson Avenue, Los Angeles, CA 90011; Mr. Dick Umphrey Director of Marketing American Bumper Sales Company 1150 E. Slauson Avenue Los Angeles CA 90011; Dear Mr. Umphrey: This is in reply to your letter of January 29, 1974, concerning th effect of the rules issued under the Motor Vehicle Information and Cost Savings Act upon the manufacture of after-market pickup truck bumpers.; If your sales are confined to the after-market, it is unlikely that an rules issued under the Act will affect you directly. At present, the bumper standard proposed under Title I of the Act would apply only to passenger cars. If other types of vehicles are subsequently included, the rules would affect you only insofar as they may affect the design of the vehicles on which your bumpers would be mounted.; The rule to be issued by February 1, 1975, relates only to insuranc costs and would have little or no effect on your business.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5400OpenSpectrum Engineering Group 1111 South Main Street Cheshire, CT 06410; Spectrum Engineering Group 1111 South Main Street Cheshire CT 06410; "Dear Sir/Madam: This responds to your letter to this office regardin your reconstruction of an accident involving a 16-passenger school bus. I apologize for the delay in responding. You stated in your letter that the original latch/hinge mechanism of the right front entrance door of the bus in question was disabled by removal of the striker plate and equipped instead with a remote door opening/closing apparatus and latching mechanism. The bus was involved in an accident in which the driver was ejected through that door. You then asked a series of questions concerning the classification of the vehicle and the Federal safety standards pertaining to the door in question. By way of background, the National Traffic and Motor Vehicle Safety Act, 15 U.S.C. 1381, et seq. (Safety Act), authorizes the National Highway Traffic Safety Administration (NHTSA) to issue Federal motor vehicle safety standards (FMVSS) applicable to new motor vehicles and new items of motor vehicle equipment. The Safety Act establishes a self-certification system in which manufacturers are responsible for certifying that the vehicle or equipment complies with all applicable FMVSSs in effect on the date of manufacture. Once the vehicle or equipment has been sold to the first customer for purposes other than resale, Federal jurisdiction over the manufacture and sale of the vehicle or equipment generally terminates and use of the vehicle or equipment becomes a matter of state jurisdiction. You first asked, 'Would this vehicle be classified as a multi-purpose passenger vehicle, a bus, or a school bus?' The answer to your question is that each manufacturer classifies its vehicles in accordance with the definitions set forth in the Safety Act and in NHTSA's regulations. The Safety Act defines a 'school bus' as A passenger motor vehicle which is designed to carry more than 10 passengers in addition to the driver, and which the Secretary determines 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. 15 U.S.C. 1391(14). Our regulations define a 'bus' as a motor vehicle designed to carry more than 10 persons, and further define a 'school bus' as a bus that is sold for purposes that include carrying students to and from school and related activities, but does not include a bus sold for operation as a common carrier in urban transportation. 49 CFR 571.3. Thus, whether a vehicle is a school bus under our regulations depends on the purpose for which it was originally sold. Although you did not indicate who purchased the bus originally and for what purpose, you referred to the vehicle in your letter as a 'mini school bus,' you stated that the body was manufactured by Mid Bus, a school bus manufacturer, and the descriptive literature you enclosed with your letter depicts different models of small school buses manufactured by Mid Bus. Accordingly, it appears the vehicle in question would have been classified as a school bus under 49 CFR 571.3. Our regulations require the vehicle manufacturer to state the vehicle type classification on the vehicle's certification label. The certification label of the vehicle in question should have that information. Your second question asks, 'Does FMVSS 206 and/or FMVSS 217 apply to the right front entrance door of this vehicle?' With respect to FMVSS 206, Door locks and door retention components, the answer is no. Standard 206 applies only to passenger cars, multipurpose passenger vehicles, and trucks. The standard does not apply to buses. With respect to FMVSS 217, Bus emergency exits and window retention and release, the standard specifies requirements for window retention other than windshields in buses, except buses designed to transport persons under restraint, and establishes operating forces, opening dimensions, and markings for emergency exits. The glazing requirements of S5.1 of FMVSS 217 would apply to the right front entrance door, and if the door was also used as an emergency exit, it must also have complied when new with the emergency exit requirements of S5.2.3, S5.3, S5.4.2, and S5.5.3 of the standard. Your third question asked, 'Which FMVSS would apply to the right front entrance door (particularly its loading requirements)?' The answer is that apart from the provisions of FMVSS 217 discussed in our answer to your second question, there was no FMVSS in 1988 that specified performance standards for the right front entrance doors of buses. Effective September 1, 1993, however, the side door strength requirements of FMVSS 214, Side Impact Protection, will apply to 90 percent of the buses with a gross vehicle weight rating (GVWR) of 10,000 pounds or less produced after that date, and all buses with a GVWR of 10,000 pounds or less produced on and after September 1, 1994, must comply with those requirements. I would like to make the following observation about the modification of the door in question. Modifications of new and used vehicles by commercial parties are subject to 108(a)(2)(A) of the Safety Act (15 U.S.C. 1397(a)(2)(A)). That section prohibits any manufacturer, distributor, dealer, or vehicle repair business from knowingly rendering inoperative any device or element of design installed on or in a vehicle in compliance with a Federal motor vehicle safety standard. In this case, your letter did not indicate who disabled the original latch mechanism on the vehicle or who installed the remote door latch mechanism. If the work was done by a party listed in 108(a)(2)(A), the person modifying the vehicle was responsible for not degrading the performance of the door with regard to FMVSS 217. Section 108(a)(2)(A) does not apply to individual vehicle owners. Thus, vehicle owners can modify the vehicle in any manner he/she chooses without violating any Federal requirements. I hope this information answers your questions. We have enclosed copies of FMVSS 206 and 217 that were effective in 1988, photocopied from the October 1, 1987 edition of the Code of Federal Regulations, as you requested. Should you have other questions, please feel free to contact Walter Myers of my staff at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosures"; |
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ID: aiam0602OpenMr. Y. Ishii, Manager, Technical Administration Section, Mitsubishi Motors Corporation, 33-8, 5-Chome, Shiba, Minato-Ku, P. O. Box 17, Takanawa, Tokyo, Japan; Mr. Y. Ishii Manager Technical Administration Section Mitsubishi Motors Corporation 33-8 5-Chome Shiba Minato-Ku P. O. Box 17 Takanawa Tokyo Japan; Dear Mr. Ishii: This is in reply to your letter of January 14, 1972, in which you as whether the vibrating paper cone of a cone-type radio speaker is required to meet the performance requirements of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials.' You also ask whether the answer to this question depends upon whether the radio, although factory installed, is optional or standard equipment.; The relevant language of the standard as it is presently worded, i whether the cone is 'an interior material . . . designed to absorb energy on contact by occupants in the event of a crash' (S4.1). Whether or not the cone is within this language depends upon whether in fact it has been designed by the manufacturer for the stated purpose. It is of no consequence, further, whether the radio is standard or optional, if it is installed at the factory or before sale to the consumer. I would add that NHTSA presently has the above quoted language of S4.1 under review, and may modify it in future rulemaking which we expect to issue shortly.; In a conversation of February 4, 1972, it was indicated to Michae Peskoe of my staff that you had additional questions regarding the standard which you would submit to us in writing. You mentioned particularly whether a steering wheel would be subject to the standard. The answer, as in the case of the cone, is whether the manufacturer has designed it to be an energy-absorbing component.; We regret the delay in answering your letter, however, it was ou understanding that you would submit the aforementioned additional questions to us, and we would respond at that time to your letter of January 14. We have not received this additional correspondence from you.; We are pleased to be of assistance. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1910OpenMr. Warren M. Heath, Department of California Highway Patrol, P.O. Box 898, Sacramento, CA 95804; Mr. Warren M. Heath Department of California Highway Patrol P.O. Box 898 Sacramento CA 95804; Dear Commander Heath: This is in reply to your letter of February 25, 1975, requestin several interpretations of 49 CFR Part 569, 'Regrooved Tires.' The present Regrooved Tire regulation results from a U.S. Court of Appeals decision (NAMBO v. *Volpe* 484 F.2d 1294 (D.C. Cir. 1973), cert. denied ______ U.S. _______ (1974)) which invalidated certain aspects of the previous requirements. The confusion apparent in the existing requirements results from Section 204 of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1424) which, when read literally, only authorizes the NHTSA to permit the sale of regrooved tires. That statutory section has since been revised (Sec. 110, Pub. L. 93-492, 88 Stat. 1470, October 27, 1974) and the NHTSA will revise Part 569 to provide a more realistic regulatory scheme than that contained in the present requirements. While we have answered as best we can the questions you raise, we believe any extensive enforcement program you plan for the requirements should be deferred until new regulations are issued.; Section 569.1 *Purpose and scope*, provides that the regulatio specifies requirements under which regrooved tires may be sold. This should not be interpreted as precluding the enforcement of the regulation against other commercial transfers, such as offering for sale, the introduction or delivery for introduction into interstate commerce, etc. Section 569.7(a) specifically prohibits those activities. Section 569.7(a) also prohibits an operator, including a public transit system, from regrooving his own tires under any circumstance, he may not, as you suggest, regroove them and sell them to others. Section 569.7(a)(1) specifically states that a person regrooving his own tires for use on motor vehicles is to be considered as delivering those tires for introduction into interstate commerce, which is a prohibited activity.; Section 569.7(b) prohibits any of the proscribed commercial activitie with respect to tires siped in the manner set forth in that section. You are apparently again misinterpreting the Scope section.; With respect to your question regarding the labeling of retreade regroovable tires, such tires must be labeled in accordance with section 569.9. There are numerous procedures by which labeling can be molded onto retreaded tires. Two with which we are familiar involve either a cutting or engraving of the matrix or the insertion of metal strips into the matrix during curing.; 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.