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: aiam0097OpenMr. Toyotaro Yamada, Manager, Toyota Motor Company, Limited, 231 Johnson Avenue, Newark, NJ 07108; Mr. Toyotaro Yamada Manager Toyota Motor Company Limited 231 Johnson Avenue Newark NJ 07108; Dear Mr. Yamada: Thank you for your letter of July 23, 1968, to Mr. George C. Nield Acting Director, Motor Vehicle Safety Performance Service, concerning the requirements for turn signal and hazard warning signal flashers as specified by Motor Vehicle Safety Standard No. 108.; With certain exceptions, paragraph S3.3 of Standard No. 108 permits th use of combination lamps, reflective devices and items of associated equipment, provided the requirements for each lamp, reflective device and item of associated equipment are met. Therefore, a combination turn signal and hazard warning signal flasher may be used, provided the requirements for each signal (turn and hazard warning) are met.; You are correct in your understanding that Standard No. 108 an basically referenced SAE Standards J590 and J945 do not require operation of the flasher unit with only one signal bulb in the test circuit. The standard test circuit shown in Figure I of SAE Standard J823 indicates a minimum of two signal lamps and one pilot indicator lamp as the lamp load.; Thank you for writing. Sincerely, David A. Fay, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service; |
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ID: aiam3306OpenMr. J. Bill Simpson, Simpson Sports, 22630 South Normandie Avenue, Torrance, CA 90502; Mr. J. Bill Simpson Simpson Sports 22630 South Normandie Avenue Torrance CA 90502; Dear Mr. Simpson: This responds to your May, 1980, letter asking whether the Departmen of Transportation preempts State approval programs designed to enforce State standards on equipment regulated by Federal safety standards. In a subsequent conversation with Roger Tilton of my staff, you indicated that several States require you to obtain advance approval from them prior to sale of your motorcycle helmets. You further stated that each of these advance approvals can be very costly.; The National Traffic and Motor Vehicle Safety Act of 1966 (the Act) (1 U.S.C. 138 *et* *seq*.) in section 1392(d) preempts States from having any safety standard applicable to the same aspect of performance as a Federal standard unless the State standard imposes a higher level of performance and applies only to vehicles or equipment purchased for the State's own use. The Act is silent with respect to the preemption of State enforcement procedures, such as approval schemes that require State permission prior to the sale of vehicles or equipment in their jurisdictions.; We note that the issue of advance approval schemes was litigated i *Truck Safety Equipment Inst. v. Kane*, 466 F.Supp. 1242 (D.C., Pa. 1979). In that case (copy enclosed) the court held that a State advance approval scheme was preempted by the Act. We suggest that you bring this case to the attention of the appropriate officials in the States in question. If either you or officials from those States have further questions, you can contact Mr. Tilton at 202-426-9511.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0514OpenMr. Armand F Macmanus, Esq., Phillips Petroleum Company, Bartlesville, Oklahoma 74004; Mr. Armand F Macmanus Esq. Phillips Petroleum Company Bartlesville Oklahoma 74004; Dear Mr. Macmanus: This is in reply to a request made on behalf of Phillips Petroleu Company by Veigh J. Nielson for an assigned identification mark for two of Phillips' plants which manufacture tires for research purposes.; As I informed you in my letter of September 20, 1971, if Phillip purchases a new tire, removed the tread material an then applies its own experimental tread containing various rubber compounds, Phillips is considered to be a new tire manufacturer. If Phillips applies its experimental tread to a used tire, it is considered a retreader of tires.; As a new tire manufacturer you are required to certify the tire a conforming to the new passenger car tire standard (No. 109) and comply with Part 574 - Tire Identification and Record Keeping (49 CFR 574). Accordingly, you are assigned the identification mark of 'J1' for tires made in your Bartlesville, Oklahoma plant and 'K1' for tires manufactured in you Stow, Ohio plant.; If you act as a retreader then Part 574 would not be applicable for th tires you retread because they are retreaded for your own use. (Enclosed is a copy of Docket No. 70-12, Notice No. 8 which makes the regulation inapplicable to retreaders who retread for their own use). As explained in my letter of September 20, you are, of course, required to certify that your new tires and your retreaded tires comply with the respective standards for new and retreaded tires if they are to be used on public highways, by placing the symbol DOT on the tires in the prescribed location.; Sincerely, Lawrence R. Schneider |
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ID: aiam0516OpenMr. Armand F. Macmanus, Esq., Phillips Petroleum Company, Bartlesville, OK 74004; Mr. Armand F. Macmanus Esq. Phillips Petroleum Company Bartlesville OK 74004; Dear Mr. Macmanus: This is in reply to a request made on behalf of Phillips Petroleu Company by Veigh J. Nielson for an assigned identification mark for two of Phillips' plants which manufacture tires for research purposes.; As I informed you in my letter of September 20, 1971, if Phillip purchases a new tire, removes the tread material and then applies its own experimental tread containing various rubber compounds, Phillips is considered to be a new tire manufacturer. If Phillips applies its experimental tread to a used tire, it is considered a retreader of tires.; As a new tire manufacturer you are required to certify the tire a conforming to the new passenger car tire standard (No. 109) and comply with Part 574 - Tire Identification and Record Keeping (49 CFR 574). Accordingly, you are assigned the identification mark of 'J1' for tires made in your Bartlesville, Oklahoma plant and 'K1' for tires manufactured in your Stow, Ohio plant.; If you act as a retreader then Part 574 would not be applicable for th tires you retread because they are retreaded for your own use. (Enclosed is a copy of Docket No. 70-12, Notice No. 8 which makes the regulation inapplicable to retreaders who retread for their own use). As explained in my letter of September 20, you are, of course, required to certify that your new tires and your retreaded tires comply with the respective standards for new and retreaded tires if they are to be used on the public highways, by placing the symbol DOT on the tires in the prescribed location.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam3305OpenMr. J. Bill Simpson, Simpson Sports, 22630 South Normandie Avenue, Torrance, CA 90502; Mr. J. Bill Simpson Simpson Sports 22630 South Normandie Avenue Torrance CA 90502; Dear Mr. Simpson: This responds to your May, 1980, letter asking whether the Departmen of Transportation preempts State approval programs designed to enforce State standards on equipment regulated by Federal safety standards. In a subsequent conversation with Roger Tilton of my staff, you indicated that several States require you to obtain advance approval from them prior to sale of your motorcycle helmets. You further stated that each of these advance approvals can be very costly.; The National Traffic and Motor Vehicle Safety Act of 1966 (the Act) (1 U.S.C. 138 *et* *seq*.) in section 1392(d) preempts States from having any safety standard applicable to the same aspect of performance as a Federal standard unless the State standard imposes a higher level of performance and applies only to vehicles or equipment purchased for the State's own use. The Act is silent with respect to the preemption of State enforcement procedures, such as approval schemes that require State permission prior to the sale of vehicles or equipment in their jurisdictions.; We note that the issue of advance approval schemes was litigated i *Truck Safety Equipment Inst. v. Kane*, 466 F.Supp. 1242 (D.C., Pa. 1979). In that case (copy enclosed) the court held that a State advance approval scheme was preempted by the Act. We suggest that you bring this case to the attention of the appropriate officials in the States in question. If either you or officials from those States have further questions, you can contact Mr. Tilton at 202-426-9511.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0831OpenZundapp-Werke GMBH Munchen, 8 Munchen 8, Anzinger Str. 1-3, Germany; Zundapp-Werke GMBH Munchen 8 Munchen 8 Anzinger Str. 1-3 Germany; Gentlemen: Your letter of August 8 and your follow-up letter of August 22 to Mr Francis Armstrong, Director, Office of Standards Enforcement, concerning the lighting requirements for motor-driven cycles, were forwarded to this Office for consideration and reply.; The lighting requirements specified in Federal Motor Vehicle Safet Standard No. 108 are identical for a motorcycle and a motor-driven cycle (except for headlamps, see SAE J584 April 1964), because the latter is defined in Part 571 of the standards as 'a motorcycle with a motor that produces 5- brake horsepower or less.'; In addition, the answers to your specific questions follow -- >>>1. Must the stop-light of a motor-driven cycle be operated by han and foot brake?; *Answer* - Yes. Paragraph S4.5.4 of FMVSS No. 108 requires the stop lamps on eac vehicle to be activated upon application of the service brakes, and since both the hand and foot brakes are service brakes, the application of either must activate the stop lamps.; 2. Does there exist any regulations concerning the light intensity o the brake-light?; *Answer* - Yes. Currently stop lamps must conform to the photometric requirement specified in SAE Standard J575d. Paragraph S4.1.1.6 of FMVSS No. 108 also requires that vehicles manufactured on or after January 1, 1973, be equipped with stop lamps meeting the candlepower requirements for Class A turn signal lamps in SAE J575d.; 3. Are turn signals prescribed? *Answer* - Yes. Class B turn signal lamps (see SAE J575d) are required o motorcycles manufactured on or after January 1, 1973, and should be mounted as specified in Table IV of FMVSS No. 108 (copy enclosed for your information).; Sincerely, E. T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
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ID: aiam4298OpenMr. Paul J. Ryan, Staff Engineer, SEMA, 11001 E. valley Mall, Suite 200, El Monte, California 91734; Mr. Paul J. Ryan Staff Engineer SEMA 11001 E. valley Mall Suite 200 El Monte California 91734; Dear Mr. Ryan: This responds to your March 24, 1977, letter asking about th applicability of Standard No. 120, *Tire Selection and Rims for Motor vehicles Other Than passenger Cars*, to aftermarket rims.; Your first assumption that vans and light trucks models are classifie as vehicles other than passenger cars is correct. Accordingly, rims manufactured for use in these vehicles must comply with the requirements of the standard. Where the rims may be used in the aftermarket either on passenger cars or vehicles other than passenger cars, they must comply with the requirements of Standard No. 120.; On a related matter concerning the aftermarket, you question whethe Standard No. 120 has applicability to rims sold for use on used vehicles. Section S3 of the standard states that the requirements apply to motor vehicles other than passenger cars and to rims for use on those vehicles. This indicates that the standard is both a motor vehicle and an equipment standard. Since it is an equipment standard, the requirements apply to all rims manufactured for use on the specified vehicles regardless of whether the rim will be original equipment or sold in the aftermarket.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam1808OpenMr. Leon C. Huneke, Chemical Engineer, Power Controls Division, Midland -Ross Corporation, 490 S. Chestnut Street, Owosso, Michigan 48867; Mr. Leon C. Huneke Chemical Engineer Power Controls Division Midland -Ross Corporation 490 S. Chestnut Street Owosso Michigan 48867; Dear Mr. Huneke:#This responds to your letter of January 16, 1975 concerning the relationship between the requirements of Federal Motor Vehicle Safety Standard No. 106-74, *Brake Hoses*, and Military Specification MIL-H-3992C.#Part 571.7(c) of the Federal Motor Vehicle Safety Standards, 49 CFR 571.7(c), provides that:#>>>No standard applies to a vehicle or item of equipment manufactured for, and sold directly to, the Armed Forces of the United States in conformity with contractual specifications.<<<#Therefore, brake hose and brake hose assemblies sold to the military in conformity with MIL-H-3992c are subject to neither the labeling nor the performance requirements of Standard No. 106-74. Hose and assemblies sold for commercial applications, however, are subject to all the requirements of Standard No. 106-74.#Yours truly,Richard B. Dyson,Assistant Chief Counsel; |
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ID: aiam2248OpenMr. John R. Pratte, Manager Materials Engineering, Pullman Trailmobile, 200 East Randolph Drive, Chicago, IL 60601; Mr. John R. Pratte Manager Materials Engineering Pullman Trailmobile 200 East Randolph Drive Chicago IL 60601; Dear Mr. Pratte: This responds to Trailmobile's March 4, 1976, letter asking if trailer equipped with one or more axles that have a gross axle weight rating (GAWR) of 24,000 pounds or more is excluded from the requirements of Standard No. 121, *Air Brake Systems*.; Section S3. of Standard No. 121 provides in part that any vehicl manufactured before September 1, 1977, that has a GAWR for any axle of 24,000 pounds or more is excluded from the standard. The determination of GAWR is made by the vehicle manufacturer (49 CFR 571.3) and must be based on the capabilities of the axle system at 60 mph. Because the determination is made by the vehicle manufacturer, the NHTSA is unable to say that the components you mention in your letter would necessarily constitute an axle system with a GAWR of 24,000 pounds.; Yours truly, Frank Berndt, Acting Chief Counsel |
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ID: aiam0072OpenMr. E. C. Dix, Sales Manager, Bert's Truck Equipment, Inc., Highway 2, East Grand Forks, MN 56721; Mr. E. C. Dix Sales Manager Bert's Truck Equipment Inc. Highway 2 East Grand Forks MN 56721; Dear Mr. Dix: Thank you for your letter of April 18, 1968, in which you provide certification information, and presented extra axle modification problems.; Enclosed is a copy of the Federal Motor Vehicle Safety Standards wit chassis-cab information from the Federal Register.; Your certification of compliance concerns compliance of the vehicle a the time of your installation or modification. It does not extend to subsequent additions or modifications by others.; With respect to an old truck body mounted on a chassis-cab which i manufactured on or after January 1, 1968, you are required to bring the lighting into compliance. (See Federal Standard 108 applicable for January 1, 1968.(sic); With regard to lighting requirements for trucks, the corner lights, o side marker and clearance lamp requirements are also provided in the foregoing, enclosed standard.; Your letter is being referred to the engineers responsible fo standards preparation, and the information is appreciated.; Sincerely, Joseph R. O'Gorman, Acting Director, Office of Performanc Analysis, Motor Vehicle Safety Performance Service; |
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.