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: aiam3778OpenCapt. Bill Perzinsky, President, TWI Inc., 14525 Bessemer Street, Van Nuys, CA 91411; Capt. Bill Perzinsky President TWI Inc. 14525 Bessemer Street Van Nuys CA 91411; Dear Capt. Perzinsky: This is in reply to your letter of October 14, 1983, to Mr. Vinson o my staff regarding your F-S- 700 A flasher. The device is essentially a slender bar of lights mounted on the rear panel shelf of a passenger car. The left and right sides blink to indicate turns in the appropriate direction. The entire bar lights up when the brake pedal is applied. You ask for our 'approval' of this device.; The Federal motor vehicle safety standard on lighting forbids th installation of motor vehicle equipment that impairs the effectiveness of lighting equipment required by the standard. Stop lamps are required by the standard. They must be red. They must go on when the brake pedal is applied. The stop signal put out by the F-S-700 flasher is amber, not red. Therefore, an amber signal coming on at the same time as a red one would impair the effectiveness of the red stop lamp by creating confusion.; The Federal lighting standard allows either amber or red turn signa lamps. There is obviously a potential for confusion if your amber light device is on a vehicle whose turn signals are red. But an even greater problem with interior-mounted lamps, whatever their color, is the reflection that they cause in the rear glass, particularly when it's raining or snowing, interfering with the rear vision of the vehicle's driver.; For the reasons given above the F-S-700 A flasher causes us som concern. Further, you should investigate whether the laws of the jurisdiction where you wish to sell this device will permit its installation and use.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1745OpenMr. Gerhard P. Reichel, Attorney, Volkswagen of America, Inc., Englewood Cliffs, New Jersey 07632; Mr. Gerhard P. Reichel Attorney Volkswagen of America Inc. Englewood Cliffs New Jersey 07632; Dear Mr. Reichel: This is in reply to your letter of December 4, 1974, to Michael Pesko of this office asking whether it is permissible under Standard No. 110 to refer to air conditioning and automatic transmission option in stating the 'vehicle capacity weight' on the placard required under S4.3 of the standard. The format you suggest would state a vehicle capacity weight, followed on a separate line by the statement: 'If air conditioning is installed, subtract 82 pounds.' you also ask whether basic vehicle body style may be similarly treated. Your request is based on your desire to standardize the placard required by Standard No. 110, to make the placarding requirements less expensive to meet.; We interpret Standard No. 110 to permit the use of a standardize placard that contains various vehicle capacity weights based on body style or the presence of various options. However, in such a case we believe that label should at least initially contain the lowest vehicle capacity weight for the vehicle, that is, a weight which presumes that the vehicle is equipped with those options having an effect on vehicle capacity weight. If the absence of these options increases the vehicle capacity weight, we believe this should be stated beneath the basic vehicle capacity weight, and by specifying the actual weight with the option omitted rather than asking the reader to perform a computation.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam0857OpenMr. Bob Rauscher, Product Engineer, The Gates Rubber Company, Galesburg, IL, 61401; Mr. Bob Rauscher Product Engineer The Gates Rubber Company Galesburg IL 61401; Dear Mr. Rauscher: This is in reply to your letter of August 1, 1972, requesting a interpretation in regard to the application of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials', to hoses used in engine compartments and to hoses used in engine compartments that would also 'lead through the firewall into the passenger compartment'.; Hoses are not included in the list of motor vehicle interior component (Section S4.1) to which the Standard applies, and therefore they are not covered by the Standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3282OpenMr. Thomas E. Cole, Tire Division, Rubber Manufacturers Association, 1901 Pennsylvania Avenue, N.W., Washington, DC 20006; Mr. Thomas E. Cole Tire Division Rubber Manufacturers Association 1901 Pennsylvania Avenue N.W. Washington DC 20006; Dear Mr. Cole: This is in response to your letter of April 14, 1980, regarding tw apparent discrepancies in the revised Uniform Tire Quality Grading tread label format, published on November 29, 1979, in Docket 25, Notice 35 (44 FR 58475). As you note, the word 'Vehicle' was omitted from the term 'Federal Motor Vehicle Safety Standard No. 109' under the heading 'Temperature' in Figure 2, Part II, of the regulation as published. This was an inadvertent omission which the National Highway Traffic Safety Administration (NHTSA) plans to correct in a future notice.; You also point out that paragraph (d)(1)(i)(B)(1) of the regulation (4 CFR 575.104(d)(1)(i)(B)(1)), applicable to tires manufactured prior to October 1, 1980, provides for use of the heading 'DOT QUALITY GRADES' in capital letters, while Part I of Figure 2 of the regulation contains the heading 'DOT Quality Grades' using lower case letters. The label format specified in paragraph (d)(1)(i)(B)(1) parallels the label format originally announced in Docket 25, Notice 24 (43 FR 30542, July 17, 1978), the heading of which used all capital letters. Since Part I of Figure 2 is not required on labels printed in accordance with paragraph (d)(1)(i)(B)(1), the use of lower case letters in the heading of Part I does not affect the requirements of paragraph (d)(1)(i)(B)(1). NHTSA will permit, at the manufacturer's option, the use of all capital letters in the heading of Figure 2, Part I, in printing labels to comply with the new two-part label format.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4547OpenMr. George Ziolo DOT Paperwork Processor 234l7 Everett Place Ramona, CA 92065; Mr. George Ziolo DOT Paperwork Processor 234l7 Everett Place Ramona CA 92065; Dear Mr. Ziolo: This is in reply to your letter of April 20, 1988 asking about the acceptability under Safety Standard No. 108 of modifying imported vehicles so that they are equipped with two Type 2D1 and two Type 1C1 headlamps. You have been informed by the agency's Office of Vehicle Safety Compliance that this is impermissible 'because they are 'nonconforming' 'headlight systems'.' You disagree because you believe that the minimum requirements of the Standard are satisfied by the Type 2D1 lamps, and that 'S4.4 appears to permit such a combination.' Paragraph S4.4 is not applicable to the situation you present as it refers to combinations of lamps serving different functions, in your discussion, the lamps serve the identical function of headlighting. Given the fact that the Type 2D1 sealed beam 7' diameter headlamps fulfill the headlighting requirements of the Standard, your question must be viewed as whether a supplement to the headlighting system is permissible under Standard No. 108. Paragraph S4.l.3 of Standard No. 108 permits the addition of nonrequired lighting equipment provided it does not impair the effectiveness of the equipment that the standard requires. The two Type 1C1 5 3/4' diameter sealed beam lamps in a four lamp headlighting system form the major portion of an upper beam headlighting system. The two Type 2D1 lamps in a two lamp headlighting system form the whole of an upper beam headlighting system. Thus, a vehicle furnished with the systems you posit would be equipped with more than one upper beam headlighting system. The Type 2D1 system must be designed to conform to the photometric requirements of SAE Standard J579c DEC79 'Sealed Beam Headlamp Units for Motor Vehicles.' The SAE Standard establishes at two test points, H-V and 4 D-V, maximum allowable candela of 75,000 and 5,000 respectively for each Type 2D1 headlamp. This means that the maximum allowable candela for headlighting systems at these test points is 150,000 and l0,000 candela. The Type 1C1 headlamps will also be designed to conform to SAE J579c. Corresponding maxima at test points H-V and 4 D-V for Type 1C1 systems are 60,000 and 5,000. Thus, a vehicle equipped with the lamps you have described could emit a total of 270,000 candela at test point H-V (when only 150,000 is permitted), and 20,000 at 4D-V (when only l0,000 is allowable). Agency research has shown that candela readings in excess of 150,000 greatly increase the potential for glare with little increase in seeing ability. This glare would be visible both to the driver of an oncoming car, and the driver of the modified vehicle itself through creation of a 'veiling' glare. The addition of the Type 1C1 headlamps would therefore impair the effectiveness of the Type 2D1 headlighting system, and is forbidden by S4.1.3. We appreciate your interest in safety. Sincerely, Erika Z. Jones Chief Counsel; |
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ID: aiam0504OpenMr. Charles A. Eisenhardt, Chairman, Hess and Eisenhardt Company, Blue Ash Avenue, Cincinnati, OH 45242; Mr. Charles A. Eisenhardt Chairman Hess and Eisenhardt Company Blue Ash Avenue Cincinnati OH 45242; Dear Mr. Eisenhardt: This is in response to your letter of November 12, 1971. As correctly stated in that letter there is no current requirement that multi-purpose passenger vehicles must comply with standards 105, 109, 110, 201, 202, 203, 204, 212, 214, 215, and 301. Additionally, the information depicted in the chart you provided is correct as of October 11, 1971. However, your dates for proposed future requirements (columns 3 and 5) may change.; The small vans and similar type vehicles being converted for use a emergency medical vehicles are required to conform to the Federal Motor Vehicle Safety Standard definition for a 'multi-purpose passenger vehicle,' since they utilize a truck chassis. Contrary to your opinion concerning the safety hazard of the converted emergency vehicles, we have not received any factual data indicating that these converted emergency medical vehicles constitute a safety hazard to the general public, to the sick or injured occupants, or to the attendants who must operate such vehicles.; As stated in our previous correspondence to you and Senator Rober Taft, Jr., at this point in time the Department is not in the position of proposing an expenditure for the construction of a prototype ambulance. Our limited resources are being devoted to those traffic safety programs which result in the greatest savings in lives and in the reduction of injuries.; We are retaining your correspondence for reference. If, in the future our priorities include the development of standards relating to the design of an emergency medical vehicle, please be assured that your interests will be fully considered.; Your continued interest in our traffic safety programs is appreciated. Sincerely, Dana L. Scott, Associate Administrator for Administration |
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ID: aiam2539OpenMr. Jeffrey L. Link, Supervisor, Product Safety, Safety and Legislation Department, U.S. Suzuki Motor Corporation, 13767 Freeway Drive, Santa Fe Springs, California 90670; Mr. Jeffrey L. Link Supervisor Product Safety Safety and Legislation Department U.S. Suzuki Motor Corporation 13767 Freeway Drive Santa Fe Springs California 90670; Dear Mr. Link: This responds to your February 23, 1977, letter asking whether thre proposed labeled satisfy the requirements for label identification found on Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*.; The National Highway Traffic Safety Administration (NHTSA) does no issue advance approval of compliance by manufacturers with motor vehicle safety standards or regulations. The agency, however, will give an informal opinion as to whether your sample labels appear to comply with the requirements of Standard No. 120. A review of the labels you supplied indicates that you have used a different format than illustrated in our notice of February 7, 1977 (42 Federal Register 7140). For example, the amended Standard No. 120 does not require the words 'with the tires listed below' or even the word 'with' before the tire size. The deletion of such superfluous words from the label requirements of Standard No. 120 resulted from comments by manufacturers, particularly motorcycle manufacturers, that unnecessary word needlessly increase the size of the label.; The example of label information shown in S5.3 of the standard i intended only as a guide to manufacturers. A manufacturer can vary the illustrated format somewhat as long as the requirements of S5.3 are satisfied. Since the additional words on your label do not obfuscate the certification statement, the labels appear to comply with the requirements of Standard No. 120 and Part 567.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam4814OpenMr. Chino O'Hara Minority Co-ordinator Del Mar Manufacturing Company 2713-B North Towne Avenue Pomona, California 91767; Mr. Chino O'Hara Minority Co-ordinator Del Mar Manufacturing Company 2713-B North Towne Avenue Pomona California 91767; "Dear Mr. O'Hara: This responds to your letter of December 11, 1990 i which you ask whether your product 'Husky Brake Anti-Squeek' needs approval of the Department of Transportation (DOT). An enclosure to your letter indicates that the product is intended for application on the pad surface of motor vehicle disc brakes to 'stop brake squeeking' and to 'produce a surface that gives better braking' by acting as a 'lubricant to the friction material.' I am pleased to have this opportunity to explain our law and regulations for you. The National Highway Traffic Safety Administration (NHTSA) (part of DOT) does not certify or approve motor vehicles or motor vehicle equipment for compliance with the Federal Motor Vehicle Safety Standards. Instead, the National Traffic and Motor Vehicle Safety Act (the Safety Act, 15 U.S.C. 1381 et seq.) establishes a 'self-certification' process under which each manufacturer is responsible for certifying that every one of its products complies with all applicable safety standards. This agency periodically tests vehicles and items of motor vehicle equipment for compliance with the safety standards and also investigates other alleged defects related to motor vehicle safety. There is currently no Federal motor vehicle safety standard that is directly applicable to the product you wish to manufacture and sell. However, there are other requirements that may affect this product. First, manufacturers of motor vehicle equipment are subject to the requirements in sections 151-159 of the Safety Act (15 U.S.C. 1411-1419) concerning the recall and remedy of products with defects related to motor vehicle safety. Section 102(4) of the Safety Act (15 U.S.C. 1391(4) defines, in relevant part, the term 'motor vehicle equipment' as: any system, part, or component of a motor vehicle as originally manufactured or any similar part or component manufactured or sold for replacement or improvement of such system, part, or component or as any accessory, or addition to the motor vehicle . . . If the 'Husky Brake Anti-Squeek' is manufactured and sold for the improvement of motor vehicle brake systems, it would be considered 'motor vehicle equipment' within the meaning of the Safety Act. If either the equipment manufacturer or this agency were to determine that your product contained such a defect, the manufacturer would have to notify purchasers of the defect and remedy the problem free of charge to the purchasers. Second, use of this product could be affected by section 108(a)(2)(A) of the Safety Act (15 U.S.C. 1397(a)(2)(A)). That section prohibits manufacturers, distributors, dealers, or repair shops from knowingly 'rendering inoperative' devices or elements of design that were installed in a motor vehicle to comply with the Federal Motor Vehicle Safety Standards. To avoid a 'rendering inoperative' violation, the above-named parties should review the application instructions for your product and determine if installing the product following those instructions would result in the vehicle no longer complying with the requirements of the safety standards. The most relevant safety standard appears to be Standard No. 105, Hydraulic Brake Systems. That standard applies to new motor vehicles. I hope that this information has been helpful. For your information, I am enclosing an information sheet for new manufacturers of motor vehicles and motor vehicle equipment and information on how to obtain copies of motor vehicle safety standards. Please feel free to contact us if you have any further questions. Sincerely, Paul Jackson Rice Chief Counsel Enclosure"; |
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ID: aiam0154OpenMr. John I. Tolson, IFFISA, Mariposa No. 1050, Mexico 13, D.F.; Mr. John I. Tolson IFFISA Mariposa No. 1050 Mexico 13 D.F.; Dear Mr. Tolson: We regret the delay in replying to your letter of January 15, 1969, t Dr. William Haddon, Jr., concerning regulations applicable to replicas of antique automobiles which you manufacture.; As a general rule, motor vehicles manufactured on or after January 1 1968, must comply with all applicable Federal Motor Vehicle Safety Standards in order to be imported into the United States. Section 114 of the National Traffic and Motor Vehicle Safety Act of 1966 (the Act) requires that manufacturers permanently affix a tag or label to the motor vehicle certifying that the motor vehicle conforms to all applicable Federal Motor Vehicle Safety Standards (FMVSS) established under authority of Section 103 of the Act. Your vehicles would properly be classified as passenger cars. Thus the FMVSS applicable to this classification would apply. The above standards are currently applicable only to motor vehicles over 1,000 pounds curb weight. Curb weight includes a full load of engine fuel, oil, and coolant as defined in 49 CFR 371.3. In accordance with a proposed rule making published in 32 FR, page 14282, October 14, 1967, the Administrator is considering adding new standards applicable to motor vehicles of 1,000 pounds or less curb weight, and revising certain of the initial standards to extend their applicability to these motor vehicles. Comments have been received from industry and a discussion paper on the subject prepared. This discussion paper will be mailed to industry in the near future, together with a notice of a meeting to be held on the subject. Your name is being added to the mailing list for this information.; 19 CFR 12.80, Importation of Motor Vehicles and Items of Motor Vehicl Equipment, was jointly issued and published by the Secretary of Transportation and the Secretary of Treasury in implementation of Section 108(b)(3) of the Act. This regulation makes provision for importation of certain motor vehicles not conforming to the Federal Motor Vehicle Safety Standards, subject to specific conditions.; An amendment to the Act has granted authority to the Secretary o Transportation, based upon certain specified findings, to exempt temporarily, a limited production motor vehicle from any Federal Motor Vehicle Safety Standard. A limited production motor vehicle is a defined as a motor vehicle produced by a manufacturer whose total motor vehicle production, as determined by the Secretary, does not exceed 500 annually. It is to be noted, however, that exemptions are granted to the person actually producing the motor vehicle, not to the importer or distributor of such motor vehicle. Regulations for petitioning for an exemption are contained in 49 CFR 355.5.; In the United States, motor vehicles are licensed for operation by eac of the states and the District of Columbia. A letter addressed to the State Department of Motor Vehicles in the capitol city of the states in which you intend marketing your product, should reach an individual who can provide you with information regarding state licensing requirements.; While you did not inquire about Federal regulations concerning contro of anti-pollution emission devices, this is another area of possible effect in your situation. These regulations are not the responsibility of the Department of Transportation, but of the Department of Health, Education and Welfare. By copy of this letter, Mr. William H. Megonnell, Associate Commissioner for Standards and Compliance, Department of Health, Education and Welfare, National Air Pollution Control Administration, BCT, 801 North Randolph Street, Arlington, Virginia, 22203, is being requested to forward such information as he deems appropriate.; Publications of the Socity (sic) of Automotive Engineers (SAE) including copies of SAE Standards, may be obtained by writing to: Society of Automotive Engineers, Inc., 2 Pennsylvania Plaza, New York, New York, 1001 (sic).; For your information and guidance, enclosed are copies of the Act, a amended, the Federal Motor Vehicle Safety Standards, (49 CFR 351, 353, 355 and 371), 19 CFR 122.80, Importation of Motor Vehicles and Items of Motor Vehicle Equipment, Declaration Form HS-7, Importation of Motor Vehicles and Motor Vehicle Equipment Subject to Federal Motor Vehicle Safety Standards and the proposed rule making, Docket 5-1.; Sincerely, Robert Brenner, Acting Director |
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ID: aiam2169OpenMr. W. A. May, Corporate Secretary, American Safety Equipment Corporation, 16055 Ventura Blvd., Encino, CA 91436; Mr. W. A. May Corporate Secretary American Safety Equipment Corporation 16055 Ventura Blvd. Encino CA 91436; Dear Mr. May: This responds to American Safety's December 5, 1975, question whether state or local government agency such as a municipal policy department may modify Type II seat belt assemblies to permit detachment of the upper torso restraint, and whether a seat belt manufacturer may 'participate in the modifications of the vehicle and seat belt assemblies.'; Section 108(a) of the National Traffic and Motor Vehicle Safety Ac (the Act) (15 U.S.C. S 1397(a)(2) prohibits a manufacturer, distributor, dealer, or repair business from 'knowingly render[ing] inoperative, in whole or part, any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard [except during a repair].' This prohibition applies to changing a non-detachable upper torso restraint to a detachable upper torso restraint.; Under this language of the Act, the police department would not b prohibited from modification of the seat belts. A manufacturer could not actively participate in the modification of the vehicles. Sale of a seat belt assembly to the police department would not of itself, however, constitute a violation of the Act.; Yours truly, Richard B. Dyson, Assistant 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.