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: aiam0067OpenMr. John F. Dando, Chief Engineer, FWD Corporation, Clintonville, WS 54929; Mr. John F. Dando Chief Engineer FWD Corporation Clintonville WS 54929; Dear Mr. Dando: Thank you for your letter of January 11, 1968, to Dr. William Haddon Jr., concerning the location of headlamps on vehicles which are used for snow plow service. I regret that a clerical error resulted in this late reply to your inquiry.; Snow plows are motor vehicles and subject to regulatory actions a established by the National Traffic and Motor Vehicle Safety Act of 1966.; Motor Vehicle Safety Standard No. 108 requires that vehicles to whic the standard is applicable be equipped with headlamps that are located not less than 24 inches nor more than 54 inches above the road surface (see Table II of the standard). This requirement does not prohibit the use of additional headlamps located at greater heights as illustrated by the photographs enclosed with your referenced letter.; Thank you for writing. Sincerely, David A. Fay, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service; |
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ID: aiam2026OpenMr. Russ Jura, Legislative Analyst, Engineering Division, Yamaha International Corporation, P. O. Box 6600, Buena Park, CA 90622; Mr. Russ Jura Legislative Analyst Engineering Division Yamaha International Corporation P. O. Box 6600 Buena Park CA 90622; Dear Mr. Jura: This is in reply to your letter of August 5, 1975, asking whether prototype 'stiff rubber supported turn signal' would comply with S4.3.1 of Motor Vehicle Safety Standard No. 108.; S4.3.1 requires lighting equipment to 'be securely mounted on a rigi part of the vehicle.' Your proposed turn signal lamp is mounted at the end of a stiff rubber bracket which is attached to the vehicle. The bracket must be considered part of the vehicle. Obviously, even with a metal mounting there will be some vibration transmitted from the motorcycle to the lamp when the engine is running. We would consider the prototype mounting to be sufficiently 'rigid' to conform to the standard if the rubber mount is stiff enough so that there is little or no amplification of vibration when the engine is running.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0093OpenMr. B.A. Luff, General Manager, Lotus Vehicle Engineering, Division of Lotus Cars Limited, Wymondham 3411, Norwich 92W, England; Mr. B.A. Luff General Manager Lotus Vehicle Engineering Division of Lotus Cars Limited Wymondham 3411 Norwich 92W England; Dear Mr. Luff: Mr. Bridwell has asked that I reply to your letters dated November 1 and July 3 which ask if Motor Vehicle Safety Standard No. 201 requires your company's 'Elan Convertible' to have sun visors.; The National Highway Safety Bureau recognizes that the requirements fo every passenger car to have two sun visors of energy-absorbing material with mountings that have no rigid material edge radius of less than 0.125 if statically contactable by a 6.5 inch diameter head form, aay(sic) create a problem for manufacturers of certain types of vehicles. However, the requirement will, on balance, contribute to the safety of the general public.; Compliance with the requirement can and should be made in a manner s as to increase occupant protection.; Sincerely, Robert M. O'Mahoney, Assistant Chief Counsel for Regulations |
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ID: aiam3555OpenMr. Gary M. Ceazan, Vice President, Riken America, Inc., P.O. Box 3698 Terminal Annex, Los Angeles, Californian 90051; Mr. Gary M. Ceazan Vice President Riken America Inc. P.O. Box 3698 Terminal Annex Los Angeles Californian 90051; Dear Mr. Ceazan:This responds to your recent letter inquiring whethe it would be permissible for your company to label your tires in both the European metric size and the domestic P-metric size. Dual markings of sizes in the manner you have described are specifically prohibited by Federal Motor Vehicle Safety Standard No. 109 (49 CFR S 571.109).; Paragraph S4.3(a) of Standard No. 109 specifies that each tire shall b labeled with '*one* size designation, except that equivalent inch and metric size designations may be used.' A European metric size and its comparable domestic P-metric size are assigned different maximum load carrying capacities and different recommended maximum inflation pressures, because different formulae are used to calculate the load carrying capacities of the tires at the different inflation pressures. Because of the different load carrying capacities and recommended inflation pressures, substituting a European metric tire for a P-metric tire might cause the European metric tire to be unsafely overloaded. Dual markings could lead to such substitutions.; The dual-size markings you have requested were explicitly prohibite when this agency amended the labeling requirements of Standard No. 109 at 36 FR 1195, January 26, 1971. The prohibition has been expressly repeated in subsequent amendments addressing the question of tire labeling under the standard, *see* FR 10162, March 18, 1974, and 42 FR 12869, March 7, 1977. The agency s reasoning is that these dual size markings are a representation by the manufacturer that a particular tire meets all requirements of Standard No. 109 for both listed sizes, which is not true. In fact, dual-size markings represent a marketing effort by tire manufacturers to persuade consumers to change the size and/or type of tires mounted on their cars, i.e., by representing that the manufacturer's tire is an appropriate replacement for either European metric or P-metric tires. It is inappropriate to extend this marketing effort to the Federally required label on the tire. The only purpose of that label is to provide the consumer, in a straightforward manner, with technical information necessary for the safe operation of the consumer's automobile.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4323OpenMr. Albert Schwarz, Senior Engineer, Product Development, Imperial Clevite Inc., Imperial Eastman Division, 6300 W. Howard Street, Chicago, IL 60648-3492; Mr. Albert Schwarz Senior Engineer Product Development Imperial Clevite Inc. Imperial Eastman Division 6300 W. Howard Street Chicago IL 60648-3492; Dear Mr. Schwarz: This responds to your January 12, 1987 letter to the National Highwa Traffic Safety Administration (NHTSA) concerning Standard No. 106, *Brake Hoses.* You ask whether the standard applies to flexible conduits (i.e., hoses and plastic tubing) used to transmit air pressure to accessories such as horns and Windshield wipers. The answer to your question is yes, if a failure of such a conduit results in a loss of air pressure in the brake system.; On August 3, 1984, NHTSA issued an interpretation of Standard No. 10 to Mr. Terry Teeter of the Eaton Corporation, who asked the same question you did about the applicability of the standard to conduits used for accessories. Our letter explains that flexible hoses (and tubing) connected to accessories are 'brake hoses' and subject to the standard if they transmit or contain the air pressure used to apply force to the vehicle s brakes--i.e., a failure of such a hose would result in a loss of air pressure in the brake system. I have enclosed a copy of our letter to Mr. Teeter for your information.; I understand that Ms. Hom of my staff sent you a copy of a Federa Register notice issued by NHTSA on April 17, 1986, which terminated rulemaking on whether the air brake hose tensile requirement of Standard No. 106 should be reduced for hoses typically used for accessories. NHTSA decided to terminate rulemaking because the agency believed that it would be in the interest of safety for the smaller-diameter hoses to comply with current requirements of the standard. Since you might want to review this notice in light of the information provided you in this letter, I have enclosed a duplicate for your convenience.; You also ask whether there are requirements other than those include in Standard No. 106 that must be met by accessory lines. The answer to your question is no. The air brake hoses you intend to use in accessory lines need comply only with Standard No. 106 to be manufactured and sold in this country.; I hope this information is helpful. Please contact my office if yo have further questions.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3833OpenB. R. Belsches, Captain, Safety Office, Department of State Police, Commonwealth of Virginia, P.O. Box 27472, Richmond, VA 23261-7472; B. R. Belsches Captain Safety Office Department of State Police Commonwealth of Virginia P.O. Box 27472 Richmond VA 23261-7472; Dear Captain Belsches: This is in response to your letter of April 20, 1984, asking for a interpretation of paragraph S4.6(b) of Motor Vehicle Safety Standard No. 108 and 'a history relative to the inclusion of such function of headlamps and marker lamps.'; Paragraph S4.6(b) allows means to be provided for the automati flashing of headlamps and side marker lamps for signaling purposes, as an exception to the general rule that vehicle lamps (other than turn and hazard warning signals, and school bus warning lamps) be steady-burning in use. This confirms your understanding of the wording of the standard and its effect. It does not allow, however, modulating headlamps which do not flash on and off, but deviate between a higher intensity and a lower one.; Originally, paragraph S3.5 of the standard (see *e.g.* 49 CFR 371.21 Standard No. 108 rev. as of January 1, 1970) stated that 'normally steady-burning lamps may be capable of being flashed for signaling purposes.' On January 3, 1970, the agency proposed paragraph S4.6 (35 F.R. 106) as it exists today. It was adopted on October 31, 1970 (35 F.R. 16840). The agency observed that some commenters requested that additional lamps be permitted to flash and some requested that flashing headlamps be prohibited. It also noted that, with the exceptions set forth in S4.6(a), flashing lamps should be reserved for emergency and road maintenance-type vehicles, and that flashing lamps are otherwise prohibited in the Uniform Vehicle Code. The agency further noted that lamps could be flashed by the driver merely by turning the switch on and off, and that it could not prohibit that type of operation, but that the definition of 'Flash,' also adopted in the amendments, made clear that automatic flashers for use with steady-burning lamps other than headlamps and side marker lamps were prohibited.; This is the rulemaking history of paragraph S4.6. I hope that this wil answer your questions.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2499OpenHonorable Mark O. Hatfield, United States Senate, Washington, D.C. 20510; Honorable Mark O. Hatfield United States Senate Washington D.C. 20510; Dear Senator Hatfield: With regard to my letter to you of July 1, 1976, concerning th application of Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other than Passenger Cars*, to the paver manufactured by Layton Manufacturing Company of Salem, Oregon, I would like to advise you of a clarification of the requirements of the standard that may be relevant to Layton's product.; Essentially, it has been clarified that the requirement of S5.1.1 o the standard accommodates a manufacturer's decision to equip its motor vehicle with tires other than 'tires for highway service.' This means that Layton can choose to use tires that do not conform to the requirements set forth in S5.1.1 of the standard. I have enclosed a copy of the notice that contains a detailed discussion of this clarification.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam4201OpenMr. David M. Wise, Gary Precision Products, 530 Old Post Road No. 3, Greenwich, CT 06830; Mr. David M. Wise Gary Precision Products 530 Old Post Road No. 3 Greenwich CT 06830; Dear Mr. Wise: This is in reply to your letter of August 7, 1986, asking if Federa Motor Vehicle Safety Standard No. 108, or any other Federal regulation applies to a plastic ice scraper with a reflector on it that you may manufacture.; Although the title of Standard No. 108 is *Lamps, Reflective Devices and Associated Equipment*, the reflective devices covered by the standard are those that are mounted on the rear and side of a motor vehicle, which are necessary for signalling and the safe operation of vehicles during darkness and other times of reduced visibility. It does not apply to ice scrapers. Nor does the other Federal motor vehicle safety standard dealing with reflectivity, Standard No. 125 'Warning Devices,' or any other regulation of this Department.; I hope this answers your question. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3673OpenMr. J. N. Uranga, Cummins Engine Company, Inc., Box 3005, Columbus, IN 47201; Mr. J. N. Uranga Cummins Engine Company Inc. Box 3005 Columbus IN 47201; Dear Mr. Uranga: This responds to your January 28, 1983, letter asking about th responsibilities of an original equipment manufacturer for compliance with Part 573, *Defect and Noncompliance Reports*, and other agency recall-related regulations. In particular, you ask questions concerning a hypothetically defective original equipment fan that is a component of an original equipment engine that you manufacture. You ask whether your company would be responsible for compliance with agency regulations if you notified the fan manufacturer of a defect in its product and if that manufacturer refused to report to the National Highway Traffic Safety Administration.; Part 579, *Defect and Noncompliance Responsibility*, states clearl that original equipment is the responsibility of the vehicle manufacturer. As such, the manufacturer(s) of the vehicles in which the equipment is installed would be responsible for recalling and remedying the defective fan. However, Part 573 states that in the case of original equipment, defect reports shall be submitted by either the equipment or the vehicle manufacturer when the defective equipment has been supplied to only one vehicle manufacturer. On the other hand, where such equipment is supplied to more than one manufacturer, both the vehicle manufacturers and the original equipment manufacturer must submit the required reports.; Your hypothetical situation further complicates the reports questio because the original equipment is a component of the original equipment that you manufacture. The agency concludes that in the situation that you posit, the manufacturer of the fan and the manufacturer of all of the vehicles in which the fan is installed would be required to supply the necessary defect reports. Failure to do so would subject all manufacturers to the penalties provided by law. If the fan manufacturer refuses to submit the required reports, it would be the responsibility of your company to issue the report to the agency, since you would also be considered an original equipment manufacturer and the defective component would be part of your equipment. The agency would not require both your company and the fan manufacturer to report. A report submitted by either company would be considered compliance by both companies. However, failure of both companies to report could result in the imposition of penalties on both.; I trust this fully answers your question. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3674OpenMr. J. N. Uranga, Cummins Engine Company, Inc., Box 3005, Columbus, IN 47201; Mr. J. N. Uranga Cummins Engine Company Inc. Box 3005 Columbus IN 47201; Dear Mr. Uranga: This responds to your January 28, 1983, letter asking about th responsibilities of an original equipment manufacturer for compliance with Part 573, *Defect and Noncompliance Reports*, and other agency recall-related regulations. In particular, you ask questions concerning a hypothetically defective original equipment fan that is a component of an original equipment engine that you manufacture. You ask whether your company would be responsible for compliance with agency regulations if you notified the fan manufacturer of a defect in its product and if that manufacturer refused to report to the National Highway Traffic Safety Administration.; Part 579, *Defect and Noncompliance Responsibility*, states clearl that original equipment is the responsibility of the vehicle manufacturer. As such, the manufacturer(s) of the vehicles in which the equipment is installed would be responsible for recalling and remedying the defective fan. However, Part 573 states that in the case of original equipment, defect reports shall be submitted by either the equipment or the vehicle manufacturer when the defective equipment has been supplied to only one vehicle manufacturer. On the other hand, where such equipment is supplied to more than one manufacturer, both the vehicle manufacturers and the original equipment manufacturer must submit the required reports.; Your hypothetical situation further complicates the reports questio because the original equipment is a component of the original equipment that you manufacture. The agency concludes that in the situation that you posit, the manufacturer of the fan and the manufacturer of all of the vehicles in which the fan is installed would be required to supply the necessary defect reports. Failure to do so would subject all manufacturers to the penalties provided by law. If the fan manufacturer refuses to submit the required reports, it would be the responsibility of your company to issue the report to the agency, since you would also be considered an original equipment manufacturer and the defective component would be part of your equipment. The agency would not require both your company and the fan manufacturer to report. A report submitted by either company would be considered compliance by both companies. However, failure of both companies to report could result in the imposition of penalties on both.; I trust this fully answers your question. 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.