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: aiam3101OpenMr. M. Ogata, Toyo Kogyo U.S.A. Office, Detroit Branch, 23777 Greenfield Road, Southfield, MI 48075; Mr. M. Ogata Toyo Kogyo U.S.A. Office Detroit Branch 23777 Greenfield Road Southfield MI 48075; Dear Mr. Ogata: This responds to your recent letter concerning the labelin requirements of Safety Standard No. 209, *Seat Belt Assemblies*. You ask whether the brand name of your vehicles, 'Mazda', may be dropped from the label on your seat belts.; The answer to your question is yes. Paragraph S4.1(k) of Safet Standard No. 209 requires the seat belt label to include year of manufacture of the assembly, model name or number of the assembly, and trade-mark of manufacturer or distributor. The name of the vehicle on which the assembly will be installed is not required to be on the seat belt assembly label.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3414OpenMr. Dietmar K. Haenchen, Executive Director, Vehicle Regulations, Volkswagen of America, Inc., 27621 Parkview Boulevard, Warren, MI 48092; Mr. Dietmar K. Haenchen Executive Director Vehicle Regulations Volkswagen of America Inc. 27621 Parkview Boulevard Warren MI 48092; Dear Mr. Haenchen: This is in reply to your letter of May 27, 1981, asking for a interpretation of Motor Vehicle Safety Standard No. 108. Your company is considering, for fuel economy purposes, use of an engine stop/start system by which the engine would be switched off within a few seconds after a vehicle has come to a complete stop, and, to save battery capacity, the headlamps would also be deactivated. The parking lamps, however, will remain on. You believe that Standard No. 108 would not preclude such a system.; Although your letter does not mention it, we assume that when th parking lights are activated, the taillamps, license plate lamps, and side marker lamps would also be on, as required by S4.5.7(a) of Standard No. 108. The question then arises whether the system described is prohibited by paragraph S4.1.3 which states that 'No...motor vehicle equipment shall be installed that impairs the effectiveness of lighting equipment required' by Standard No. 108. Although the primary function of headlamps is to illuminate the roadway in front of the driver at night or under conditions of reduced visibility, they also serve to indicate the presence of the vehicle to traffic approaching from the opposite direction. In a situation where, on a two-lane road, a car has pulled to the shoulder temporarily, a headlamp will be perceived at a greater distance than a parking lamp to oncoming traffic. Headlamps also serve an illuminating function when people have paused in unfamiliar neighborhoods in an effort to discern their whereabouts. We believe, therefore, that your device could be viewed as impairing the effectiveness of headlamps within the meaning of S4.1.3.; This, however, is not a view dispositive of the issue. Compliance wit Standard No. 102 would also appear to be affected as that standard requires that the engine starter be inoperable when the transmission shift lever is in the forward or reverse position. Last year the agency granted a rulemaking petition with respect to an engine stop/start system such as you have discussed. I enclose a copy for your information. Although no notice has yet been published on this question, we shall endeavor to include a reference to headlamp switching devices in any future rulemaking activity on this subject.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1429OpenMr. James P. Coughlin, Vice President-Marketing, Bell Helmets Inc., 2850 East 29th Street, Long Beach, CA 90806; Mr. James P. Coughlin Vice President-Marketing Bell Helmets Inc. 2850 East 29th Street Long Beach CA 90806; Dear Mr. Coughlin: This is in reply to your letter of February 12, 1974, requesting definition for 'motorcyclists and other motor vehicle users' used in paragraph S1. *Scope*, of Federal Motor Vehicle Safety Standard No. 218, *Motorcycle Helmets*. You ask specifically what this phrase means relative to public thoroughfares, motorcycle race tracks, off-road public and private lands, and any other vehicles.; >>>'Motorcycle' is defined in 49 CFR Part 571.3 as-- 'a motor vehicle with motive power having a seat or saddle for the us of the rider and designed to travel on not more than three wheels in contact with the ground.'<<<; A 'motorcyclist,' then, would be any rider of a motorcycle as define above. 'Other motor vehicle users' means any occupant of a motor vehicle not a motorcycle. 'Motor vehicle' is defined in the National Traffic and Motor Vehicle Safety Act of 1966 (15 U.S.C. 1391(3)) as--; >>>'any vehicle driven or drawn by mechanical power manufacture primarily for use on the public streets, roads, and highways, except any vehicle operated exclusively on a rail or rails.'<<<; Standard No. 218 applies to the manufacturers, distributors, an dealers of helmets to be used at least in part by motorcyclists or other motor vehicle users. The circumstances under which such helmets must be worn, however, is under the jurisdictional control of the respective States and their political subdivisions.; You also ask whether it is lawful to manufacture and sell helmets fo racing purposes that are designed to meet the Snell standard, irrespective of Standard No. 218. The answer is yes, if due care is taken by such manufacturers, distributors, and dealers to prevent non-conforming helmets from being introduced into interstate commerce for eventual use by motorcyclists and other motor vehicle users on the public streets, roads, and highways.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1583OpenMr. Paul D. Carfagna, Technical Representative, Plastics Department, E. I. DuPont de Nemours & Company, Incorporated, Wilmington, DE 19898; Mr. Paul D. Carfagna Technical Representative Plastics Department E. I. DuPont de Nemours & Company Incorporated Wilmington DE 19898; Dear Mr. Carfagna: This is in reply to your letter of August 2, 1974, asking for th appropriate method for bending plastic material over the mandrel as specified in Test No. 22 of ANS Z26.1-1966, which is incorporated into Federal Motor Vehicle Safety Standard No. 205 (49 CFR 571.205). You indicate that the test procedure does not specify either the bending force, or whether mechanical means for bending are allowed.; Paragraph 5.22.2 of Test 22 states, in part, as follows: >>>After conditioning, the test specimens shall be immediately ben over a mandrel so that either the entire length of the specimen shall conform to the surface of the mandrel or that it be bent 180 degrees over the mandrel, with the longitudinal axis of the specimen normal to the axis of the mandrel. (emphasis added)<<<; As the procedure does not specify the bending force, or the method i which it is to be applied, the NHTSA would consider as appropriate any force or method of application that would permit the plastic to be bent immediately after conditioning. There is nothing to prohibit the use of hand or mechanical pressure, but it must be applied in such a way that an immediate bending takes place.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam3044OpenMr. R. G. Clifton, Manager, Tyre Legislation, Dunlop Limited, Tyre Technical Division, Fort Dunlop, Birmingham, England B24 9QT; Mr. R. G. Clifton Manager Tyre Legislation Dunlop Limited Tyre Technical Division Fort Dunlop Birmingham England B24 9QT; Dear Mr. Clifton: This is in response to your letter of May 8, 1979, requesting a exemption from the Uniform Tire Quality Grading (UTQG) Standards (49 CFR 575.104), Federal motor vehicle safety standard 109 (49 CFR 571.109), and the tire identification and recordkeeping requirements of Part 574 (49 CFR Part 574) for several lines of 'antique' tires.; Dunlop's petition for exemption does not qualify as a petition fo temporary exemption from motor vehicle safety standards under Part 555 (49 CFR Part 555), since that part applies only to manufacturers of motor vehicles. However, the regulations you refer to apply only to tires for use on vehicles manufactured after 1948 (49 CFR 575.104(c)), (sic)49 CFR 571.109, S2, 49 CFR 574.4), and therefore, many of the tires listed in your letter are not within the scope of these regulations. Also, the National Highway Traffic Safety Administration plans to issue in the near future a notice of proposed rulemaking to exclude limited production tires from the application of the UTQG Standards, regardless of the tire's intended use.; You also asked that some form of labeling system be adopted for tire which are not required to be graded under the UTQG regulation, to facilitate processing of such tires by United States customs authorities. Regulations governing importation of motor vehicle equipment (19 CFR 12.80) only require compliance with applicable Federal motor vehicle safety standards, as set forth in 49 CFR Part 571. Any tire marked with the DOT symbol as required by Standard No. 109 (49 CFR 571.109, S4.3.1) or Standard No. 119 (49 CFR 571.119, S6.5(a)), as applicable, or which is not required to comply with such standards, will be processed expeditiously by customs authorities, and the question of compliance with the UTQG regulation should not arise. While NHTSA does not consider it necessary to impose a labeling system for tires excluded from the UTQG Standard, the agency has no objection to voluntary labeling by manufacturers or importers.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1079OpenMr. Barry Kulik, 114 West 30 Street, New York, NY 1001 (sic); Mr. Barry Kulik 114 West 30 Street New York NY 1001 (sic); Dear Mr. Kulik: This is in response to your letter of March 9, 1973, requesting ou confirmation of an opinion given you by phone concerning the method of testing the sensitivity of seat belt warning systems under Motor Vehicle Safety Standard No. 208.; We hereby confirm our previous statement that the weight sensin provisions of sections S7.3 and S7.4 do not require the use of a specified test dummy. The sections refer to 'persons' of specified weights, thereby implying some distribution of the weight, but they do not reference the test dummy used in other sections of the standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4781OpenMr. A. Roger Hirstein Industry Development Center 3M Commercial Graphics Div. 3M Center, BUilding 220-6W-06 St. Paul, MN 55144-1000; Mr. A. Roger Hirstein Industry Development Center 3M Commercial Graphics Div. 3M Center BUilding 220-6W-06 St. Paul MN 55144-1000; Dear Mr. Hirstein: This is in reply to your letter of June 1, l990, t Taylor Vinson of this Office. One of your customers has asked whether 3M's Diamond Grade Reflective Sheeting can be used in a red and white block pattern on the side of a trailer for conspicuity without violating Standard No. 108. Your interpretation is that the Sheeting can be used in addition to devices meeting the requirements of Standard No. 108 but not in place of them. You are essentially correct. However, because we do not know both the pattern and location of the design, whether 'side' includes the front and rear of a trailer, the reflective qualities of your sheeting, who will apply the sheeting, and whether the application will occur before or after delivery of the trailer to its purchaser, we can only provide general guidelines. Under S5.1.3 of Standard No. 108, supplementary reflective devices, i.e., devices other than those required by the standard, may be installed and present on vehicles at the time of their first sale as long as they do not impair the effectiveness of lamps and reflectors required by the standard. The initial determination of whether there is impairment is to be made by the manufacturer who certifies that the vehicle complies with all applicable Federal motor vehicle safety standards. If that decision appears incorrect to the agency, NHTSA will advise accordingly. After the initial sale, the supplementary reflective devices may be installed by a manufacturer, dealer, distributor, or motor vehicle repair business subject to the limitation in section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act that such installation not 'render inoperative in whole or in part' any of the lighting equipment required by Standard No. 108. There is no statutory prohibition under the Act against owner modifications, even if they involve impairing or removing devices required by Standard No. 108. However, the trailer would still remain subject to the laws of the individual States in which the trailer is registered and operated, and (if applicable), to the regulations of the Office of Motor Carrier Standards of the Federal Highway Administration. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam0238OpenMr. A.J. Calhoun, Calhoun & Phelan, Suite 1235, 100 North Main Street, Memphis, Tennessee 38103; Mr. A.J. Calhoun Calhoun & Phelan Suite 1235 100 North Main Street Memphis Tennessee 38103; Dear Mr. Calhoun: This is in further reply to your letter of April 29, 1970, to th National Commission on Products Safety, that has been referred to this office.; In your letter you ask for our advice as to whether or not there ar any accepted standards for passenger car automobile tires such as weight and size limits. We do have standards for passenger car tires such as weight limit versus ply rating and there are accepted tests to determine the reliability of tires. Federal Motor Vehicle Safety Standard No. 109 has been established for that purpose. the Standard's requirements are for labeling, which includes maximum inflation pressure and maximum load rating, strength, continuous load-carrying endurance and high speed performance under load.; Federal Motor Vehicle Safety Standard No. 110, Tire Selection and Rim - Passenger Cars, requires, among other things, a placard, permanently affixed to the glove compartment door or an equally accessible location. The placard must contain all of the information spelled out in part S.4.3 of that Standard, a copy of which is contained in the enclosed booklet on page 19. Tire labeling requirements along with test procedures are listed under Federal Motor Vehicle Safety Standard No. 109, on pages 12 through 19.; The tire to which you refer is a 2-ply 4-ply rated tire. The loa ratings for a 855-14 tire can be found on page 15 of the enclosed booklet. The maximum load rating is 1,770 lbs, at the maximum inflation pressure of 32 p.s.i.; It is important for you to note that the test procedures have to d with new tires. We have no procedures for testing tires that have failed.; Although we do not become involved in private litigations, There is publication for sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402, under the title, 'Automobile Accident Litigation - A report to the Federal Judicial Center to the Department of Transportation,' that might be of interest to you. The price for publishing is $s.75.; We are also enclosing the following publications: >>>The National Traffic and Motor Vehicle Safety Act of 1966 Summary of 1968 Compliance Tests Arranged by Standard, that includes General 855-14 tire and, a form letter explaining the Bureau's position relative to test results and where they might be obtained.<<<; We trust this information will be useful to you. Sincerely, Rodolfo A. Diaz, Acting Associate Director, Motor Vehicl Programs; |
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ID: aiam2205OpenMr. Charles A. Smith, Director, Alaska Traffic Safety Bureau, Pouch N, Juneau 99811; Mr. Charles A. Smith Director Alaska Traffic Safety Bureau Pouch N Juneau 99811; Dear Mr. Smith:#This in (sic) in response to a request by Mr. Willia Hall, National Highway Traffic Safety Administration (NHTSA) Regional Administrator for Region X, for a review of Federal Motor Vehicle Safety Standard No. 104, *Windshield Wiping and Washing Systems* with special consideration of the comments of Mr. Robertson in his memorandum of November 24, 1975.#It is the opinion of this agency that Standard No. 104 is appropriate for the State of Alaska. The essential feature of a wiping system, as far as safety is concerned, is its ability to clear a specific portion of the windshield. The number of wipers necessary to provide the driver with a sufficient field of view is immaterial so long as the minimum percentages of critical areas are washed and wiped. These areas are established in the standard and are determined by the angles from the driver's eye position over which the windshield must be kept clear to provide a proper field of view. While targets of driver attention and environmental conditions may differ from state to state, if the critical areas are clear, the field of view provided to the driver is sufficient. The 1976 Scirocco (sic) appears to provide the required field of view.#The question therefore becomes whether the Federal standard on windshield wipers is intended to cover all aspects of wiping systems. If so, the situation is analogous to that presented to the court in *Motorcycle Industry Council v. Younger*, No. CIV S74-126(E.D.Cal. 1974) which resulted in a holding that Standard No. 108 did preempt an inconsistent state regulation in the field of lighting requirements. The NHTSA has determined that the standard on windshield wiping systems, No. 104, is intended to leave the number of wipers to the discretion of the manufacturers. Under *Thorpe v. Housing Authority of Durham*, 393 U.S. 268 (1969), and *Chrysler v. Tofany*, 419 F2d 499, 511-12 (2d Cir, 1969), the interpretation of this question by the administering agency is 'of controlling weight unless it is plainly erroneous or inconsistent with the regulation.' Thus, a state regulation differing from the standard would impair the Federal superintendence of the field within the meaning of the doctrine set forth in *Florida Lime & Avocado Growers v. Paul*, 373 U.S. 132, 141-142(1963) and be preempted under section 103(d) of the National Traffic and Motor Vehicle Safety Act of 1966, U.S.C. 1392(d).#Yours truly, Frank Berndt, Acting Chief Counsel; |
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ID: aiam0392OpenMr. Frank S. Elliott, Assistant to the Vice-President- Treasurer, Grove Manufacturing Company, Shady Grove, PA 17256; Mr. Frank S. Elliott Assistant to the Vice-President- Treasurer Grove Manufacturing Company Shady Grove PA 17256; Dear Mr. Elliott: This is in reply to your letter of June 22, 1971, regarding the Tir Identification and Record Keeping Regulation (49 CFR 574).; You have asked if Grove Manufacturing Company is a 'Motor Vehicl Manufacturer' within the meaning of section 574.10 of the regulation. As you indicated in your letter, you are the final-stage manufacturer of a truck mounted hydraulic crane, and as such, you are considered the vehicle manufacturer under section 568.3 of Vehicles Manufactured in Two or More Stages (49 CFR 568). As the vehicle manufacturer, you are required to maintain records of the name and address of the first purchaser of your vehicles, for purposes other than resale, along with a record of the tires on the vehicle at the time it is shipped.; Enclosed for convenience are copies of both regulations. For your information, I would direct you to section 568.7 which allow an incomplete vehicle manufacturer to assume all the responsibilities of a manufacturer, this would include the record keeping responsibilities of Part 574.; If we can be of further assistance, please feel free to write. Sincerely, Lawrence R. Schneider, Acting 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.