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
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ID: aiam2052OpenMr. John B. White, Engineering Manager, Technical Information Department, Michelin Tire Corporation, P.O. Box 3467, New Hyde Park P.O., New York 11040; Mr. John B. White Engineering Manager Technical Information Department Michelin Tire Corporation P.O. Box 3467 New Hyde Park P.O. New York 11040; Dear Mr. White: This is in reply to your letter of July 9, 1975, inquiring as to th proper designation of plies on a truck tire constructed with two polyamide plies in the casing and two steel plies in the belt.; The designation that you suggested ('Tread: 2 Steel Plies, Sidewall: Polyamide Plies') is incorrect. The designation on such a tire should indicate the presence of four plies in the tread area and two in the sidewall area (with compositions in each case).; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0595OpenMr. Victor Wouk, Chairman, Technical Advisory Committee, Electric Vehicle Council, Edison Electric Institute, Petro- Electric Motors, Ltd., 342 Madison Avenue, New York, NY 10017; Mr. Victor Wouk Chairman Technical Advisory Committee Electric Vehicle Council Edison Electric Institute Petro- Electric Motors Ltd. 342 Madison Avenue New York NY 10017; Dear Mr. Wouk:#This is in further response to your letter of Decembe 16, 1971, requesting interpretations of several Federal motor vehicle safety standards as they apply to electric vehicles.#The engine retardation braking effect of Standard No. 102 applies only to vehicles equipped with automatic transmission, and not to an electric vehicle that has no transmission.#Standards Nos. 201 through 204 do not apply to trucks. You have stated that your electric vehicle is designed to that 'the rear . . . will normally be used for tools, service equipment, spare parts, etc., as would be required in a service vehicle as used by an electric utility company for going out and making repairs.' You have also stated that the back area could be converted to a seating area for two passengers, but that this would be 'unusual and occasional.' On the basis of this information we have concluded that you vehicle is a 'truck' and need not meet Standards Nos. 201-204.#Sincerely, Richard B. Dyson, Assistant Chief Counsel; |
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ID: aiam3213OpenMr. Glenn Brinks, 2110 Magnolia Avenue, Santa Ana, CA 92707; Mr. Glenn Brinks 2110 Magnolia Avenue Santa Ana CA 92707; Dear Mr. Brinks: This is in further reply to your earlier questions concerning Federa requirements for fuel systems on motorcycles. As stated in our previous letter, Federal Motor Vehicle Safety Standard No. 301-75, *Fuel System Integrity* (49 CFR 571.301-75), does not apply to motorcycles. You are correct in your assumption that there are no Federal regulations that would preclude the use of fiberglass fuel tanks for motorcycles. I might add that Safety Standard No. 301-75 does not specify design requirements for any vehicles (e.g., that the tank be made of metal or any particular material). Rather, the standard specifies performance levels that the entire fuel system must achieve during barrier crash tests.; Although no safety standards or other regulations preclude the use o fiberglass fuel tanks for motorcycles, you should still be responsible for assuring that such tanks are safe. Under the National Traffic and Motor Vehicle Safety Act, amended 1974, a manufacturer of motor vehicles or motor vehicle equipment is responsible for any defect relating to motor vehicle safety which may exist in the manufacturer's product (15 U.S.C. 1411, *et seq*.). The manufacturer would be required to notify all purchasers of the existence of the defect and to remedy the defect at the manufacturer's expense.; I might point out that the agency is concerned that fiberglass fue tanks will shatter upon impact in a collision, rather than crushing as do metal tanks. If you have any crash data regarding the performance of fiberglass motorcycle fuel tanks, we would appreciate receiving the information.; I hope this has answered all your questions. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2951OpenMr. Hisakazu Murakami, Staff, Safety, Nissan Motor Co., Ltd., P.O. Box 1606, 560 Sylvan Avenue, Englewood Cliffs, NJ 07632; Mr. Hisakazu Murakami Staff Safety Nissan Motor Co. Ltd. P.O. Box 1606 560 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Murakami: This responds to your January 9, 1979, letter concerning a mistake o the certification labels of approximately 2000 Datsun trucks. You stated that the vehicles, although manufactured in 1979, were incorrectly dated on their certification labels as being manufactured in 1978. You propose to remedy the affected vehicles by crossing out the incorrect date and inserting the correct information.; Your proposed correction is acceptable to the National Highway Traffi Safety Administration. As long as all other information on the certification label is correct, your modification of existing certification labels will comply with the agency's regulations.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3643OpenMr. Masakatsu Kano, Executive Vice President, MMC Services Inc., 3000 Town Center, Suite 1960, Southfield, MI 48075; Mr. Masakatsu Kano Executive Vice President MMC Services Inc. 3000 Town Center Suite 1960 Southfield MI 48075; Dear Mr. Kano: This responds to your letter of April 20, 1983, asking severa questions concerning the requirements for armrests in Safety Standard No. 201, *Occupant Protection in Interior Impact*. That standard requires, as one optional means of compliance (S3.5.1(c)), that each armrest have at least 2 inches of coverage within the pelvic impact area, when measured vertically in side elevation. You ask whether this 2-inch measurement may be made from the outermost points of the base of the armrest as it fits against the door inner trim, or whether the measurement must be made from the inboard portion of the armrest that would actually contact a vehicle occupant. You also ask if the standard permits an armrest surface that would contact an occupant to be tilted at a 15 degree angle from the vertical, and whether it permits that surface to have 'low moles' or 'shallow bezels' (i.e., minor protrusions or indentations).; With reference to the drawing included in your letter, Standard No. 20 would require the specified 2-inch measurement to be taken at the 'H1' parameters, rather than the 'HO'. The purpose of the requirement is to ensure that there is at least 2 inches of coverage within the pelvic impact area. For this requirement to be meaningful, the covered surface must be contactable by the vehicle occupant. The vehicle occupant would not contact the base of the armrest illustrated in your drawing, regardless of its vertical length.; Paragraph S3.5.1(c) does not preclude 'moles' or 'bezels' in th armrest, since there are no limitations on radius of curvature. A 'mole' which projected only moderately into the vehicle interior would be included in the calculation to determine compliance with the requirement for 2 inches of covered surface. If a mole projected so far into the vehicle interior that it would prevent pelvic contact with the rest of the armrest, however, only the mole would be included in the calculation.; By the same token, while a 'bezel' is not precluded, it is not include in the calculation if it is so deep that it cannot be contacted.; Paragraph S3.5.1(c) does not specify any particular angle at which a armrest must be set with relation to the door inner trim. Therefore, it is permissible for the inboard surface of the armrest illustrated in your drawing to make an angle of 15 degrees from the vertical.; Finally, I would point out that paragraph S3.5.1(c) is one of thre optional means of compliance for manufacturers who install armrests. A manufacturer may also satisfy the requirements of Standard No. 201 by complying with either S3.5.1(a) or S3.5.1(b), in which case it is not necessary to provide 2 inches of coverage within the pelvic impact area.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4186OpenThomas J. Flanagan, Esq., Wiggin & Dana, 195 Church Street, P.O. Box 1832, New Haven, CT 06508; Thomas J. Flanagan Esq. Wiggin & Dana 195 Church Street P.O. Box 1832 New Haven CT 06508; Dear Mr. Flanagan: This responds to your letter to Mr. Brian McLaughlin, of our Rulemakin division, seeking an interpretation of the requirements of 49 CFR 541, *Federal Motor Vehicle Theft Prevention Standard*. You described a situation in which a client, Saab-Scania of America, imports cars subject to the theft prevention standard and uses them directly as company cars or leases them to employees for their personal use. After such use, the company sells the cars to dealers as used cars. On occasion, these vehicles may have an original equipment major part covered by the theft prevention standard that is so badly damaged during such use that the part must be replaced before the vehicle is delivered to a dealer or distributor. When this occurs, you asked whether the repair would be required to be made with a part marked with the full VIN or whether the repair could be made with a properly marked replacement part. We conclude that when a manufacturer uses a car as a company car in the manner you describe, it may make any necessary repairs to damaged major parts by installing parts marked as replacement parts. This conclusion is explained in detail below.; Section 2(7) of the Cost Savings Act (15 U.S.C. 1901(7)) defines manufacturer as 'any person engaged in the manufacturing or assembling of passenger motor vehicles or passenger motor vehicle equipment *including any person importing motor vehicles or motor vehicle equipment for resale*.' (Emphasis added). It is clear under this statutory definition that your client is a 'manufacturer' for the purposes of the theft prevention standard, since it is importing motor vehicles for resale.; Section 606(c)(1) of the Motor Vehicle Information and Cost Savings Ac (15 U.S.C. 2026(c)(1)) requires vehicle manufactures to certify that each vehicle complies with the requirements of the theft prevention standard 'at the time of delivery of such vehicle'. The preamble to the final rule establishing the theft prevention standard discussed this agency's conclusion that the 'delivery' as used in this part of section 606(c)(1) means the delivery from the manufacturer to a dealer or distributor, and that the delivery occurs when the goods are delivered by the seller to a carrier. 50 FR 43166, at 43185-43187, October 24, 1985. In the next sentence, section 606(c)(1) specifies that the certification shall accompany the vehicle until delivery to the first purchaser. NHTSA believes that this statutory requirement means that each vehicle in the lines selected as high theft lines and listed in Appendix A of Part 541 must be delivered to the first purchaser with *all* covered major parts marked in accordance with the theft prevention standard. However, NHTSA does *not* interpret this statutory provision as requiring that ever first purchaser be delivered a vehicle with all covered major parts marked with the VIN. Instead, the agency believes this means that the first purchaser may receive a vehicle with the undamaged covered original equipment major parts marked with the VIN, and with those covered major parts installed by a dealer or distributor to replace damaged original equipment parts marked as replacement parts.; In accordance with this interpretation, NHTSA does not believe that manufacturer delivers a car to itself, when the car is sold to the public as a new car. However, you have noted a circumstance in which cars are *bona fide* used as company cars and are sold to the public as used cars, not new cars. Congress knew that used cars frequently have some replacement parts substituted for the original equipment parts. However, Title VI contains no requirement that used cars have all covered major parts marked with the VIN. In fact, Title VI presumes that when an original equipment major part is so badly damaged that it must be replaced, it will be replaced with a replacement part marked in conformity with Part 541. This reflects a legislative judgment that such replacement does not increase the opportunity for car thieves to steal the car without fear of being apprehended, or otherwise frustrate the purposes of Title VI, even though the car no longer has all major parts marked with the VIN.; On the other hand, a severe burden would be imposed on al manufacturers if they were required to deliver all *bona fide* company cars to distributors or dealers with all covered major parts marked with the VIN. If this were required and the company car were involved in an accident that required a covered major part to be replaced, the manufacturer would have a choice of either asking the factory to produce a replacement part with the VIN marked on the part and waiting to repair the vehicle until the part marked with the VIN arrived, or ending the vehicle's use as a company car and shipping the unrepaired vehicle to a dealer or distributor with the damaged major part marked with the VIN still on the vehicle. Nothing in the legislative history of Title VI explicitly or implicitly suggests that Congress intended such harsh treatment of company cars under the theft prevention standard.; Balancing the absence of negative policy consequences under Title VI i manufacturers are allowed to repair company cars with properly marked parts against the significant burdens that would be imposed on manufacturers if damaged major parts on company cars had to be replaced with parts marked with the full VIN, NHTSA concludes that Title VI of the Cost Savings Act permits cars damaged while in *bona fide* use as company cars and sold to the public as used cars, to be repaired by the manufacturer using properly marked replacement parts. This conclusion is based on NHTSA's interpretation that *bona fide* use of the car as a company car by the manufacturer is, for all practical and policy purposes, tantamount to a delivery of the vehicle under section 606(c)(1). The conclusion is reinforced by the fact that when a company car is later sold to the public as a used car, the consumer purchasing the company car will get a car with the same theft markings as any other used car.; NHTSA would like to note that this interpretation applies only to Titl VI of the Cost Savings Act, and not to any other statutes administered by this agency. Those statutes may have different underlying policy considerations, which might mandate a different conclusion for cars used as company cars. Further, the agency wishes to emphasize that this interpretation applies only to *bona fide* company cars that are sold to the public as used cars, and not to most of the cars manufactured by the manufacturer.; Please feel free to contact me if you have any further questions abou our theft prevention standard.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1384OpenMr. Gordon Needleman, Patent Attorney, Dow Corning Corp., Midland, Michigan 48640; Mr. Gordon Needleman Patent Attorney Dow Corning Corp. Midland Michigan 48640; Dear Mr. Needleman: This is in reply to your letter of January 10, 1974, to Mr. Schneider. It is uncertain whether 'sometime in July of 1974 Federal standard will become effective relating to silicone brake fluids' The proposed effective date for DOT 5 fluids if July 1, 1974, but the comments on this rulemaking action are still under consideration and the actual effective date, if the proposal is adopted, will probably be somewhat later.; It is true the S5.4.3 of Standard No. 105a does not require that al reservoir labelling be 'DOT 3.' The letters '*e.g.*' mean 'for example'. If DOT 4 is the recommended fluid the 'DOT 4' would be the appropriate insertion in the required statement; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0983OpenMr. F. S. Murley, Administrative Engineer, Oshkosh Truck Corporation, P.O. Box 560, Oshkosh, WI 54901; Mr. F. S. Murley Administrative Engineer Oshkosh Truck Corporation P.O. Box 560 Oshkosh WI 54901; Dear Mr. Murley: This is in response to your letter of January 31, 1973, in which yo asked us to confirm your 'understanding that FMVSS No. 121 will not apply to fire-fighting vehicles until 1 September 1976, two years from the effective date.' In general, you suggest that 'we would expect to comply with FMVSS for firefighting vehicles within two years after the effective date or two years from the date of publication of the FMVSS, whichever date occurs later'.; You have misread the relevant language of 49 CFR S 571.8. That sectio provides that the effective date of a standard as applied to firefighting vehicles is 'either 2 years after the date on which such standard or amendment is published in the Rules and Regulations section of the *Federal Register*, or the effective date specified in the notice, whichever is later', except as otherwise specified in the standard with reference to those vehicles. The alternatives are thus (a) 2 years after the publication date, or (b) the effective date, whichever is later -- *not* 2 years after the effective date, as you have read it.; Your reading would not be reasonable, since the effective date canno be before the publication date, there would be no point to the alternative phrasing.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4169OpenRobert G. Russell, Acting Director, Division of School Traffic Safety and Emergency Planning, Indiana Department of Education, Room 229, Indianapolis, IN 46204-2798; Robert G. Russell Acting Director Division of School Traffic Safety and Emergency Planning Indiana Department of Education Room 229 Indianapolis IN 46204-2798; Dear Mr. Russell: This responds to your letter asking about NHTSA's regulations fo school buses and the relationship between State and Federal school bus definitions and regulations. I regret the delay in responding to your letter.; According to your letter, Indiana distinguishes 'special purpose buses' from 'school buses.' Under your State's law, 'school buses' are defined as motor vehicles, other than special purposes buses, designed for more than 10 passengers and used to transport school children. 'Special purpose buses' are motor vehicles accommodating more than six passengers used by schools to transport handicapped students to special programs, or school children and supervisors to extracurricular school activities. Special purpose buses are prohibited from being used on a regular basis to carry students between their residences and schools and are not required to meet any State identification, construction or equipment standards for school buses.; You asked whether Indiana's definitions of 'school buses' and 'specia purpose buses' conflict with our school bus definition, and how Federal law might preempt State law in this matter.; To begin, it is important to keep in mind how State and Federal schoo bus definitions and regulations differ in their application. The standards we have issued under the National Traffic and Motor Vehicle Safety Act apply to vehicles according to our motor vehicle type classifications regardless of the classifications used by the various states. Our safety standards apply to the manufacture and sale of new motor vehicles, including school buses. Our regulatory definitions, set forth in 49 CFR Part 571.3, define a 'school bus' as a motor vehicle designed to carry 10 or more passengers plus a driver, sold for purposes that include carrying students to or from school or related events. Our definitions do not include one for 'special purpose buses.' A vehicle that is designed to carry 10 or more passengers and meets the Indiana definition of 'special purpose buses' is considered a 'school bus' under Federal law since it is intended for pupil transportation, notwithstanding its exclusion from Indiana's school bus definition.; Therefore, each person selling 10-passenger or larger 'special purpos buses' is required under the Vehicle Safety Act to ensure that those vehicles are certified as school buses. Violation of this Federal requirement by sellers of new school buses is punishable by civil penalties of up to $1,000. The requirement applies to new school bus sellers regardless of whether a vehicle is considered a 'school bus' under the laws of a particular State.; Further, the preemption provisions in section 103(d) of the Vehicl Safety Act are not limited in their effect by the fact that this agency's classification of a vehicle differs from that of one or more of the States. Regardless of how Indiana classifies a vehicle, Indiana may not apply to that vehicle standards which cover the same aspects of performance as Federal standards but are not identical to the Federal standards. The only exception is a State may set higher standards of performance for vehicles procured for the State's own use.; A State's definition of a 'school bus' is, of course, determinative o the application of State requirements to the operation of school buses, such as inspection, maintenance and identification requirements. It appears that the provision in Indiana's definitions that special purpose buses are not 'school buses' excludes those vehicles from the application of Indiana's definitions that special purpose buses are not 'school buses' excludes those vehicles from the application of Indiana's school bus operational requirements. While Indiana is responsible for determining requirements for vehicles operating in that State, NHTSA recommends that each State consider carefully setting operational requirements for all vehicles used to carry school children. Recommendations for specific aspects of States' pupil transportation programs have been issued in Highway Safety Program Standard No. 17, *Pupil Transportation Safety* (copy enclosed), which was promulgated by NHTSA under the Highway Safety Act in connection with the Federal funding of State highway safety programs. While not required to do so, individual States have chosen to adopt some or all of Program Standard No. 17's recommendations and Indiana might want to consider them for their special purpose buses.; You asked whether schools are permitted at any time under Federal la to transport school children to or from school related activities in a vehicle other than a school bus. Strictly speaking, the answer is yes, for two reasons. This is because, first, the requirements of the Vehicle Safety Act apply to new school bus manufacturers and sellers, and not to school bus users. Therefore, we cannot prohibit schools from using noncomplying buses to transport children although we do prohibit the manufacture and sale of new noncomplying school buses. Second, manufacturers and dealers are required to sell complying school buses only if they sell new *buses* for pupil transportation purposes. Other types of vehicles, for example 'multipurpose passenger vehicles' (vehicles constructed on truck chassis which carry nine or fewer passengers), may be sold to carry school children to school or school-related events.; I hope this information is helpful. Please contact my office if yo have further questions.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam0502OpenMr. G. E. Fouche', Jr., Project Leader, Kendall Company, P. O. Box 1828, 6300 Carmel Road, Charlotte, NC, 28201; Mr. G. E. Fouche' Jr. Project Leader Kendall Company P. O. Box 1828 6300 Carmel Road Charlotte NC 28201; Dear Mr. Fouche': This is in reply to your letter of November 2, 1971, concerning th application of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials,' to synthetic fabrics. You state that certain of these fabrics do not ignite when tested with a stationary flame as they melt and shrink away from the flame, but burn faster than the 4-inch-per-minute rate if the flame is moved to keep it in contact with the fabric. You ask whether materials that behave in this manner comply with the standard.; The standard requires that the vehicle components specified in S4.1 o the standard meet the burn rate requirements when tested as provided in S5.3 of the standard. This procedure specifies a stationary flame. Consequently, we would consider materials which melt and shrink away from the flame, but do not ignite, as long as the other aspects of the test procedure were followed, to comply with the standard.; Sincerely, Richard B. Dyson, Assistant 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.