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: aiam1297OpenThomas N. O'Leary, Esq., Messrs. Pain & Julian, 1940 East Camelback, Phoenix, AZ 85016; Thomas N. O'Leary Esq. Messrs. Pain & Julian 1940 East Camelback Phoenix AZ 85016; Dear Mr. O'Leary: In your letter of October 8, 1973, to the Department of Transportatio you ask whether it is true that DOT requires trailer braking systems to have stainless steel conduits rather than copper ones.; Neither the Federal motor vehicle safety standards nor the regulation of the Bureau of Motor Carrier Safety contain such a requirement, and we are unaware of any Federal regulation of this nature.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3300OpenHonorable John P. Murtha, Member, U.S. House of Representatives, Post Office Building, Room 15, 201 North Center Avenue, Somerset, PA 15501; Honorable John P. Murtha Member U.S. House of Representatives Post Office Building Room 15 201 North Center Avenue Somerset PA 15501; Dear Mr. Murtha: This responds to your recent request for information on behalf of you constituent, Mr. Steve Zufall. Mr. Zufall is interested in the specifications applicable to the manufacture of propane tanks to be used in the conversion of gasoline-powered vehicles. He asked how to obtain 'numbers' to be listed on the tanks and mentioned the designation '4VA-240', which someone had discussed with him.; The enclosed discussion sets forth the implications under Federal la of converting gasoline-powered vehicles to use propane, as well as a general discussion of auxiliary fuel tanks. The applicable statutory authority is the National Traffic and Motor Vehicle Safety Act, as amended 1974 915 U.S.C. 1381, *et seq*.). The discussion first looks at the Federal Motor Vehicle Safety Standard (FMVSS) applicable to fuel systems and then at the defect responsibilities that might be involved. Next, a brief mention is made of the possibility of product liability suits.; There are no requirements under the Federal motor vehicle safet regulations that specify 'numbers' which must be stamped on propane gas tanks. The designation mentioned by Mr. Zufall, 4VA- 240', is actually '4BA-240' and refers to specifications under the Bureau of Motor Carrier Safety regulations relating to fuel systems on commercial vehicles or to tanks used for shipment of propane gas in interstate commerce. These regulations would not apply, however, to tanks or fuel systems on private vehicles. For further information regarding these regulations, Mr. Zufall should contact Mr. W. R. Fiste of the Bureau of Motor Carrier Safety (202-426-0033).; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2263OpenMr. G.E. Adams, Technical Manager, Dunlop Limited, Engineering Group, Holbrook Lane Coventry CV6 4AA, England; Mr. G.E. Adams Technical Manager Dunlop Limited Engineering Group Holbrook Lane Coventry CV6 4AA England; Dear Mr. Adams: This is in response to your letter of March 17, 1976, requestin information concerning steps which you, as a manufacturer of wheel equipment which will be offered for importation into the United States, must take in order to comply with all applicable National Highway Traffic Safety Administration regulations.; You should be aware of 49 CFR Part 566, *Manufacturer Identification* and 49 CFR Part 573, *Defect Reports*. In addition, Federal Motor Vehicle Safety Standard No. 119, *New Pneumatic Tires for Vehicles Other Than Passenger Cars*, may be of interest to you. Copies of these rules and an information sheet entitled 'Where to Obtain Federal Motor Vehicle Safety Standards and Regulations' are enclosed for your convenience.; Section 110(e) of the National Traffic and Motor Vehicle Safety Act (1 U.S.C. S1399(e)) requires every manufacturer who offers a motor vehicle or item of motor vehicle equipment for importation into the United States to designate a permanent resident of the United States as his agent, upon whom service of all processes, orders, notices, decisions, and requirements may be made.; The procedural regulations (49 CFR 551.45) for designation of agen pursuant to the Act requires that it include:; >>>(1) A certification by its maker that the designation is binding o Dunlop Limited under the laws, corporate bylaws, or other requirements governing the making of the designation at the time and place where it is made,; (2) The full legal name, principle place of business and mailin address of Dunlop Limited,; (3) Trade names or other designations of origin of the products o Dunlop Limited that do not bear its legal name,; (4) A provision that the designation of agent remain in effect unti with drawn or replaced by Dunlop Limited,; (5) A declaration of acceptance duly signed by the agent appointed which may be an individual, a firm, or a U.S. Corporation, and (6) The full legal name and address of the designated agent.<<<; A copy of the procedural regulation for designation of agent i enclosed for your convenience.; Sincerely, John Womack, Assistant Chief Counsel |
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ID: aiam2799OpenMr. Joe Purko, Director, Bureau of Transportation, Room 4201, City Hall, Los Angeles, CA 90012; Mr. Joe Purko Director Bureau of Transportation Room 4201 City Hall Los Angeles CA 90012; Dear Mr. Purko: This responds to your March 10, 1978, question whether Standard No 121, *Air Brake Systems*, applies to a device that automatically applies to (sic) vehicle's service brakes when a sensing bumper mounted at the rear of the vehicle is tripped by contact with an object during backing maneuver. For purposes of your question, I assume that the vehicle, whether new or used, has been certified to comply with Standard No. 121 prior to installation of the device.; The answer to your question is no. Paragraph S3 (Applicability) o Standard No. 121 states that the standard applies to trucks, buses, and trailers equipped with air brake systems (with some specified exceptions). The standard therefore applies only to vehicles, and does not apply to motor vehicle equipment such as the braking actuator you describe. The vehicle must, of course, conform to Standard No. 121 following installation of the device, if the installation occurs prior to the first purchase in good faith for purposes other than resale.; After the first retail sale, S108(a)(2)(A) of the National Traffic an Motor Vehicle Safety Act (the Act) (15 U.S.C. S1397(a)(2)(A)) prohibits, with one exception, manufacturers, distributors, dealers, and repair businesses from knowingly rendering inoperative devices or elements of design installed in satisfaction on a safety standard such as Standard No. 121.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam2633OpenMr. John A. McLaine, Chief, Automotive Engineering Standards, State of New Jersey, Division of Motor Vehicles, 25 South Montgomery Street, Trenton, NJ 08666; Mr. John A. McLaine Chief Automotive Engineering Standards State of New Jersey Division of Motor Vehicles 25 South Montgomery Street Trenton NJ 08666; Dear Mr. McLaine: This is in reply to your letter of June 28, 1977, to Mr. Vinson of thi office, asking for our comments on the flashing of ambulance headlamps for signaling purposes. You enclosed a copy of a Bulletin dated June 27, 1977, that New Jersey recently sent to its Inspection Stations advising rejection of ambulances equipped with headlamp flashing devices.; Paragraph S4.6(b) of Federal Motor Vehicle Safety Standard No. 10 *Lamps, Reflective Devices, and Associated Equipment,* requires that lamps other than turn signals, hazard warning signals, and school bus warning signals be steady-burning in use, 'except that means may be provided to [automatically] flash headlamps . . . for signaling purposes.' The purpose of the exception was to allow continued use of automatic flashing devices in jurisdictions where it was permitted when the standard was adopted, for without the exception manufacture and sale of vehicles so equipped would have violated the National Traffic and Motor Vehicle Safety Act. The exception provided by S4.6(b) has a preemptive effect only in that a State cannot forbid the sale and registration of a vehicle equipped with a flashing device, but there is no restriction on a State's authority to forbid the use of such mechanisms when it deems it in the interests of traffic safety to do so.; Thus, we have no objection to New Jersey's Bulletin of June 27, 1977. Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam4521OpenMrs. Alice Collins 703 Cohassett Ave. Lake Wales, FL 33853; Mrs. Alice Collins 703 Cohassett Ave. Lake Wales FL 33853; "Dear Mrs. Collins: This is a response to your letter of January 15 1988. I apologize for the delay in responding to your letter. In your letter, you described yourself as a parent of school-age children, and as a volunteer who drives children to school-related activities in your 1986 Plymouth Voyager mini-van. You stated that in the 1986-1987 school year, the U.S. Department of Transportation decided that Voyager Mini-Vans were 'unsafe.' You go on to say that 'the classification of M.P.V. was used on all mini-vans,' and suggest that it is a mistake to characterize your Voyager as a multipurpose passenger vehicle (MPV) because it is more like a passenger car than a truck. You concluded by asking us to change the decision that the Plymouth Voyager mini-van is unsafe. You raised other concerns in telephone conversations with Joan Tilghman, a member of my staff. First, I will address the request in your letter that the Department change what you believe is a decision concerning the safety of your vehicle. Then, I will address the matters you raised in conversations with Ms. Tilghman. Let me begin by assuring you that the agency has never stated that the Plymouth Voyager is 'unsafe.' Except in the context of a specific enforcement proceeding, NHTSA does not make blanket determinations that vehicles are 'safe' or 'unsafe.' Instead, we establish safety standards, and manufacturers must certify that each of their vehicles complies with all applicable standards. If we determine that a group of vehicles fails to comply with an applicable standard, or that a group of vehicles contains a defect related to motor vehicle safety, we order the manufacturer to recall the vehicles. Again, we make these determinations only in the context of an enforcement proceeding. There has been no such proceeding with respect to the 1986 Plymouth Voyager. With respect to your suggestion that it was a mistake to classify the Voyager as an MPV, it is the manufacturer's responsibility to determine, in the first instance, what a vehicle's classification should be. Chyrsler has classified the Voyager as an MPV, and so must certify that the Voyager meets all Federal safety standards applicable to that vehicle class. We have no information which suggests that Chrysler's classification of the Voyager is incorrect under our classification criteria. In your conversations with Ms. Tilghman, you explained that the Tallahassee, Florida school district will not permit parents to transport school children to school-sponsored or school-related events in MPVs, such as the Voyager. However, you stated that the district will permit parents to transport children to school-sponsored or school-related events in passenger cars. You said that the school district is following a recommendation by this agency that Florida school districts not condone transporting children to school-related events in buses other than certified school buses. Your understanding is that NHTSA made this recommendation to the State of Florida in an April 25, 1986 letter to Mr. Arnold Spencer, and repeated the recommendation in an August 7, 1986 letter to Mr. Larry McEntire. I have enclosed copies of both letters for your information. As you see, NHTSA made no such recommendation in either letter. Instead, we explained that we do not regulate the use of vehicles by owners, nor do we require the use of particular vehicles for particular purposes. There is no Federal prohibition against vehicle owners using their own vehicles to transport school children to school-related events. We also noted that the individual States have authority to establish any such regulations, in accordance with the principles of federalism set out in our Constitution. The State of Florida had already made its own decision to adopt and implement this policy before we were contacted by either Mr. Spencer or Mr. McEntire on this subject. Any changes to that policy would also reflect a decision by the State of Florida, not the Federal government. In the letter to Mr. Spencer, we made the observation that Florida's policy that school boards not condone transporting school children in vehicles that are not certified as complying with our school bus safety standards, 'is consistent with our belief that school buses certified to our school bus safety standards are the safest means of transportation for school children.' This was not a recommendation to the State of Florida, but a statement of our belief about the superior safety afforded to school children by buses that are certified as complying with our school bus standards. That belief continues to be supported by data showing that school buses continue to have one of the lowest fatality rates for any class of motor vehicle. Large school buses are the safest form of ground transportation in the United States because the passenger seats are 'compartmentalized' (special seat padding and spacing, and high seat backs), and because of the vehicle's size and weight (which generally reduce an occupant's exposure to injury-threatening crash forces), the drivers' training and experience, and the extra care other motorists usually take when they are near a school bus. I am sending you information on the agency's New Car Assessment Program (NCAP). NCAP is an experimental program in which we test light-duty vehicles, MPVs among them, to see how well they perform in a high-speed crash. You will find test results for vehicles that NHTSA has tested over the past few years, including results for the 1984 and 1987 Plymouth Voyager. Also, you will find the agency's April, 1988 report to Congress titled, 'Safety Programs for Light Trucks and Multipurpose Passenger Vehicles.' I hope you find this information helpful. If you have further questions, please contact Joan F. Tilghman, of my staff, at (202) 366-2992. Sincerely, Erika Z. Jones Chief Counsel Enclosures"; |
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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: aiam1723OpenMr. Henry Radintz, Service Manager, Schwartz Manufacturing Company, Route No. 2, Cokato, MN 55321; Mr. Henry Radintz Service Manager Schwartz Manufacturing Company Route No. 2 Cokato MN 55321; Dear Mr. Radintz: This is in acknowledgment of your Defect Information Report, i accordance with the defect reporting regulations, Part 573.; The Defect Information Report involves approximately 110 trailers whic may be equipped with Standard Forge axles with brake shoes which may fail in the area where the cam roller contacts the shoe.; Standard Forge and Axle Company informed us some time after Mr Tillotson's telephone conversation with Mr. Reinhart of my staff that they will assume some of the obligations relating to this specific safety problem. A National Highway Traffic Safety Administration identification number has therefore not been assigned to your campaign, since it will be filed as part of the Standard Forge and Axle Company campaign. Quarterly status reports, as normally required by Part 573, need also not be submitted by your company. It is, however, requested that you supply the Standard Forge and Axle Company with any relevant information sought by them for the purpose of completing this campaign in the proper manner.; The letter which you have sent to the owners of the subject trailer does not meet the requirements of Part 577 (49 CFR), the Defect Notification regulation. Specifically, the second sentence of your letter does not contain the precise language required by Part 577.4(b) due to use of the word 'may,' use the axle manufacturer's name instead of the vehicle manufacturer's name, and a description of the defect as existing in an assembly instead of the vehicle. In campaigns conducted by a vehicle manufacturer, it is the vehicle manufacturer who determines the existence of a defect in his vehicles, even if the defect is caused by a defective component. If the defect does not exist in every vehicle, the letter may state this in a subsequent sentence.; Your letter also fails to adequately evaluate the risk to traffi safety as required by Part 577.4(d), since it makes no mention of possible vehicle crash. Although the statement that reduced braking power or lockup may result may suggest the possibility of a crash to many owners, it is not entirely equivalent. Your letter also fails to meet the requirements of Part 577.4(e)(2), since it does not give an estimate of the day by which parts will be available, provide a detailed description of each step required to correct the defect, give an estimate of the required labor time, and make recommendations as to whom the purchaser should have perform the necessary work.; It is therefore necessary that those owners whose vehicles have not ye been corrected or who have not yet ordered replacement parts receive a notification letter which complies with Part 577 of the regulation. This can be done either by means of a revised letter sent by your company or by sending the names and addresses of the affected owners to the Standard Forge and Axle Company so that they can notify these owners. If your company intends to mail revised notification letters, please send a copy of the revised letter to this office.; A copy of Part 577 is enclosed. If you desire further information please contact Messrs. W. Reinhart or James Murray of this office at (202) 426- 2840.; Sincerely, Andrew G. Detrick, Acting Director, Office of Defect Investigation, Motor Vehicle Programs; |
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ID: aiam1236OpenMr. J.W. Kennebeck, Manager,Safety and Development,Volkswagen of America, Inc.,Englewood Cliffs, New Jersey 07632; Mr. J.W. Kennebeck Manager Safety and Development Volkswagen of America Inc. Englewood Cliffs New Jersey 07632; Dear Mr. Kennebeck:#This is in reply to your letter of August 8, 1973 to Mr. Schneider asking for confirmation of your interpretation of two sections of Standard No. 105a.#You ask first whether S5.3.1 requires that the activation of an indicator lamp upon application of 50 pounds of force be instantaneous, or whether a minimal time lag is permissible. You indicated that in a 'panic stop' there is a time lag of approximately 100 milliseconds between application of 50 pounds of force and lamp activities in the VW system. Since, as you state, it is 'humanly impossible' to discern such a minimal time lag, we consider that the VW system complies with S5.3.1, and that the lamp is activated upon application of 50 pounds of force.#You are also correct in your interpretation if S5.2.1 that the 5-minute requirement applies only to vehicles that do not exceed the limit of traction on a 30 percent grade.#Sincerely,Lawrence R. Schneider,Chief Counsel; |
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ID: aiam4034OpenMs. Scottie Brown Jones, Comfit Designs, 1721 S. La Rosa Drive, Tempe, AZ 85281; Ms. Scottie Brown Jones Comfit Designs 1721 S. La Rosa Drive Tempe AZ 85281; Dear Ms. Jones: Thank you for your letter dated July 29, 1985 inquiring about Federa requirements applicable to children's car seat covers which you manufacture for sale as accessories to child restraint systems.; This agency administers the National Traffic and Motor Vehicle Safet Act of 1966, as amended, 15 U.S.C. 1391 *et seq*. (the Act). Under the Act, the agency has issued Standard No. 213, *Child Restraint Systems*. Paragraph S5.7 of that standard requires each material used in a child restraint system to conform to the requirements of S4 of Standard No. 302, *Flammability of Interior Materials* (49 CFR Section 571.302). These flammability resistance requirements apply to *new* child restraint systems used in motor vehicles or aircraft. The flammability resistance requirements in Standard No. 302 must be met by aftermarket seat covers for child restraint systems only if such seat covers are installed by manufacturers, dealers, distributors, or repair shops. A manufacturer, distributor, dealer, or motor vehicle repair business must not install a seat cover for a child restraint system which does not comply with the flammability resistance requirements of Standard No. 302.; However, aftermarket seat covers which are sold to and installed b child restraint owners need not satisfy the flammability resistance requirements of Standard No. 302. Nevertheless, the agency urges all manufacturers of such seat covers to comply voluntarily with our safety standards.; A copy of Standard No. 302 is enclosed. I hope this information i helpful to you.; Sincerely, Erika Z. Jones, Chief Counsel |
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Request an Interpretation
You may email your request to Interpretations.NHTSA@dot.gov or send your request in hard copy to:
The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590
If you want to talk to someone at NHTSA about what a request for interpretation should include, call the Office of the Chief Counsel at 202-366-2992.
Please note that NHTSA’s response will be made available in this online database, and that the incoming interpretation request may also be made publicly available.