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: 1983-1.36OpenTYPE: INTERPRETATION-NHTSA DATE: 04/00/83 EST FROM: GREAT WEST CASUALTY CO. TITLE: GW SAFETY TALK ATTACHMT: DECEMBER 30, 1988 LETTER FROM JONES TO SPRUNK, OCTOBER 8, 1987 LETTER FROM SPRUNK TO JONES, BROCHURES ON TIRE SIPING, 1978 NSC WINTER TEST REPORT, AUGUST 19, 1986 LETTER FROM KEIL TO SPRUNK, ARTICLE FROM AUGUST 1986 ISSUE OF "SCHOOL BUSINESS AFFAIRS," ARTICLE ENTITLED "SLASHING TIRES FOR SAFETY AND SAVINGS" FROM DECEMBER 1984 "NATIONAL SCHOOL BUS REPORT," MARCH 20, 1985 LETTER FROM GIFFORD TO SPRUNK, AND OCTOBER 15, 1982 LETTER FROM PALMER TO MARCY MANUFACTURING TEXT: LOSS PREVENTION TOOL: In our mailing to fleets, we will include a brochure or pamphlet regarding Siping of Tires. We do not have any statistics or facts concerning the Siping of Tires. However, we insure several carriers who siping every tire in the fleet and they and their drivers are convinced it is a major safety factor that cannot be ignored on rain, snow, or ice slick highways. These carriers talk in terms of better control, better maneuverability, cooler running tires, better mileage, etc. SIPING OF TIRES. Some time ago, we wrote a short article about siping of tires which improved traction on wet and icy roads, ran cooler, etc. We were surprised at the calls from carriers who didn't know what siping was. I personally talked to 2 carriers and their drivers report substantial traction improvement on wet and slick roads. One carrier was having some difficulty with unusual wear patterns on the tire. They siped them and it corrected the problem. When the carrier and the driver gives validity to the process, then it is worthy of consideration. SAF-TEE SIPING CALL YOUR FELLOW TRUCKER AND *Improves Traction on Wet and CHECK FOR YOURSELF Icy Roads (22% National Safety Council) *Increases Tire Life 15% to 20% 1. Palmer Trucking - Jim Palmer, (406) 721-5151 2. Unthum Trucking - Keith Reilly, (515) 448-4707 *Decreases Uneven Wear Patterns 3. Holland Trucking - Dennis Holland, (701) 280-2634 50% - 70% (Tread Flexes More) 4. Apple Lines - Dale Coates, (605) 256-6661 |
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ID: nht94-2.25OpenTYPE: Interpretation-NHTSA DATE: April 8, 1994 FROM: John Womack -- Acting Chief Counsel, NHTSA TO: Daniel T. Mason -- Product Development Engineer, Avery Dennison - Automotive Division (Troy, MI) TITLE: None ATTACHMT: Attached to letter dated 2/14/94 from Daniel T. Mason to Barbara Gray (OCC 9807) TEXT: This responds to your request for an interpretation of labeling requirements under 49 CFR part 541 Federal motor vehicle theft prevention standard. Your letter has been referred to my office for a reply. You asked whether a label that leaves a fluoresc ent "footprint" of a vehicle identification number (VIN) on a vehicle part, complies with section 541.5(d)(1)(v)(B) of part 541. The answer is yes. Section 541.5(d)(1)(v)(B) requires that if a theft program label is removed from a vehicle part, "residual parts of the label" be left in the area of the part where the label was affixed. The residual parts, also known as "footprints," provide investiga tors evidence that a label was originally present. "Footprint" requirements for theft labels were discussed in the preamble to the final rule establishing 49 CFR part 541 (See 50 FR 43166, at 43174; October 24, 1985): ... this standard requires only that removal of the labels must leave residual parts of the label ... , on the part, and that these residual parts must be discernible by trained investigators. For purposes of this requirement, "disce rnible" does not mean that residual parts must be visible under natural light. (50 FR 43174). In your letter, you stated that Avery Dennison's VIN marked labels have a fluorescent agent that transfers onto vehicle parts when the label is applied. If the label is removed, and the formerly labelled area is viewed under an ultraviolet light, a repro duction of the VIN is visible. If the labels, when removed, leave "residual part(s) of the label ... on the part" that is "discernible" under ultraviolet light, the Avery Dennison label would fulfill section 541.5(d)(1)(v)(B). I hope this responds to your question. If you have any further questions, please contact Dorothy Nakama of my staff at (202) 366-2992. |
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ID: nht71-3.50OpenDATE: 07/27/71 FROM: AUTHOR UNAVAILABLE; E. T. Driver; NHTSA TO: Ichikoh Industries, Ltd. TITLE: FMVSS INTERPRETATION TEXT: This is in response to your inquiry of July 16, 1971, concerning supplemental mirrors. Federal Motor Vehicle Safety Standard No. 111 does not prohibit the installation of a supplemental outside mirror on the passenger's side. The Standard does stipulate certain field of view requirements for both the inside and driver's outside mirror, but the manufacturer is certainly free to exceed these field of view requirements with additional mirrors. |
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ID: 9807Open Mr. Daniel T. Mason Dear Mr. Mason: This responds to your request for an interpretation of labeling requirements under 49 CFR part 541 Federal motor vehicle theft prevention standard. Your letter has been referred to my office for a reply. You asked whether a label that leaves a fluorescent "footprint" of a vehicle identification number (VIN) on a vehicle part, complies with section 541.5(d)(1)(v)(B) of part 541. The answer is yes. Section 541.5(d)(1)(v)(B) requires that if a theft program label is removed from a vehicle part, "residual parts of the label" be left in the area of the part where the label was affixed. The residual parts, also known as "footprints," provide investigators evidence that a label was originally present. "Footprint" requirements for theft labels were discussed in the preamble to the final rule establishing 49 CFR part 541 (See 50 FR 43166, at 43174; October 24, 1985): ... this standard requires only that removal of the labels must leave residual parts of the label ... , on the part, and that these residual parts must be discernible by trained investigators. For purposes of this requirement, "discernible" does not mean that residual parts must be visible under natural light. (50 FR 43174) In your letter, you stated that Avery Dennison's VIN marked labels have a fluorescent agent that transfers onto vehicle parts when the label is applied. If the label is removed, and the formerly labelled area is viewed under an ultraviolet light, a reproduction of the VIN is visible. If the labels, when removed, leave "residual part[s] of the label ... on the part" that is "discernible" under ultraviolet light, the Avery Dennison label would fulfill section 541.5(d)(1)(v)(B). I hope this responds to your question. If you have any further questions, please contact Dorothy Nakama of my staff at (202) 366-2992. Sincerely,
John Womack Acting Chief Counsel ref:541 d:4/8/94 |
1994 |
ID: nht94-6.43OpenDATE: April 8, 1994 FROM: John Womack -- Acting Chief Counsel, NHTSA TO: Daniel T. Mason -- Product Development Engineer, Avery Dennison - Automotive Division (Troy, MI) TITLE: None ATTACHMT: Attached to letter dated 2/14/94 from Daniel T. Mason to Barbara Gray (OCC 9807) TEXT: This responds to your request for an interpretation of labeling requirements under 49 CFR part 541 Federal motor vehicle theft prevention standard. Your letter has been referred to my office for a reply. You asked whether a label that leaves a fluorescent "footprint" of a vehicle identification number (VIN) on a vehicle part, complies with section 541.5(d)(1)(v)(B) of part 541. The answer is yes. Section 541.5(d)(1)(v)(B) requires that if a theft program label is removed from a vehicle part, "residual parts of the label" be left in the area of the part where the label was affixed. The residual parts, also known as "footprints," provide investigators evidence that a label was originally present. "Footprint" requirements for theft labels were discussed in the preamble to the final rule establishing 49 CFR part 541 (See 50 FR 43166, at 43174; October 24, 1985): ... this standard requires only that removal of the labels must leave residual parts of the label ... , on the part, and that these residual parts must be discernible by trained investigators. For purposes of this requirement, "discernible" does not mean that residual parts must be visible under natural light. (50 FR 43174). In your letter, you stated that Avery Dennison's VIN marked labels have a fluorescent agent that transfers onto vehicle parts when the label is applied. If the label is removed, and the formerly labelled area is viewed under an ultraviolet light, a reproduction of the VIN is visible. If the labels, when removed, leave "residual part(s) of the label ... on the part" that is "discernible" under ultraviolet light, the Avery Dennison label would fulfill section 541.5(d)(1)(v)(B). I hope this responds to your question. If you have any further questions, please contact Dorothy Nakama of my staff at (202) 366-2992. |
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ID: nht90-1.63OpenTYPE: Interpretation-NHTSA DATE: March 6, 1990 FROM: Bev Wilson -- Head Start Director, Western Community Action, Inc. TO: Dan Giles -- Christianson, Stoneberg, Giles & Myers, P.A. TITLE: Re Head Start Busettes - Are we under Federal Law or State Law? ATTACHMT: Attached to memo dated 2-22-90 from D. Baker to B. Wilson; Also attached to letter dated 3-18-88 from R.C. Rost to Chief Council, NHTSA; Also attached to letter dated 8-26-88 from E.L. Jones to R.C. Rost; Also attached to letter dated 9-7-90 fr om P.J. Rice to D.L. Giles (A36; Std. 108; VSA 103(d)); Also attached to letter from D.L. Giles to S.P. Wood; Also attached to letter dated 3-8-90 from D.L. Giles to D. Baker TEXT: We have two 23-passenger busettes, blue with six-light warning system. Captain Roger Hess received a call from his state office to contact me to have the flashing lights removed. He told me that David Baker, Law Compliance Representative from Mankato, w ould be contacting me. I was to follow his direction on the lights but to tape over them or be cited. They are taped over. (See Mr. Baker's correspondence.) I called Minnesota Body and Equipment out of Shakopee and asked them to pay to have the lights removed, as our purchase agreement said busettes were to meet or exceed all Federal and State requirements. They said they have to put on the lights and would send me the Federal regulations they are under (enclosed). They would not pay to have the lights removed but did say in Minnesota we shouldn't use the lights. In Jackson our driver was told by the police to also have a sign added "this vehicle stops at all railroad crossings" and use the lights. In Marshall the City Attorney contacted us to have the lights removed. If we are to use the Federal warning light system and stop at railroad crossings, are our busettes to be painted yellow? Your help is appreciated. |
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ID: nht88-4.23OpenTYPE: INTERPRETATION-NHTSA DATE: 12/01/88 EST FROM: ERIKA Z. JONES -- CHIEF COUNSEL NHTSA TO: GARRY GALLAGHER -- VICE PRESIDENT METZELER MOTORCYCLE TIRE TITLE: NONE ATTACHMT: LETTER DATED 07/22/88 FROM GARRY GALLAGHER TO LARRY COOK -- NHTSA, OCC 2372 TEXT: Dear Mr. Gallagher: This responds to your letter seeking an interpretation of Standard No. 119, New Pneumatic Tires for Motor Vehicles Other Than Passenger Cars (49 CFR @ 571.119). More specifically, you asked whether the letter "B" must appear as part of the size designati on of a motorcycle tire if that tire is of bias belted construction. The answer to your question is no. As you noted in your letter, section @ 6.5 of Standard No. 119 sets forth the marking requirements for tires used on motor vehicles other than passenger cars, including tires for use on motorcycles. Subsection S6.5(c) states that each such tire shall be marked with "The tire size designation as listed in the documents and publications designated in S5.1." Section S5.1, in turn, specifies tire and rim matching information that must be provided to the public. Generally speaking, the size designation of a tire shows only the physical dimensions of that tire, not necessarily its construction. Thus, the common meaning of the term "size designation" does not necessarily include an indication of the tire's construction type. Further, no provision of Standa rd No. 119 requires a tire's size designation to indicate the tire's construction type. The only reference in section S6.5 of Standard's No. 119 to a tire's construction type is in subsection S6.5(i), which requires the word "radial" to appear on the ti re's sidewall if the tire is of radial construction. Therefore, in response to your question, Standard No. 119 does not require the letter "B" to be included in the size designation of bias belted motorcycle tires. You noted that your company sometimes adds the letter "B" to the size designation of these tires as an internal code. NHTSA has long said that manufacturers are free to include additional information on the sidewall of their tires, provided that the add itional information does not obscure or confuse the meaning of the required information, or otherwise defeat the purpose of the required information. In this case, the addition of the letter "B" to the size designation would not appear to confuse or obs cure the meaning of the size designation. Hence, there would be no apparent violation of Standard No. 119 by including the letter "B" in the size designation of bias belted motorcycle tires. If you have any further questions or need additional information on this subject, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, |
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ID: nht87-2.64OpenTYPE: INTERPRETATION-NHTSA DATE: 08/10/87 FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA TO: Mr. Thomas Baloga TITLE: FMVSS INTERPRETATION TEXT: Mr. Thomas Baloga Safety Engineering Mercedes-Benz of North America, Inc. P.O. Box 350 Montvale, NJ 07645 Dear Mr. Baloga: Thank you for your letter of May 12, 1987, to Stephen Oesch of my staff concerning the requirements of Standard No. 208, Occupant Crash Protection. You asked the agency to confirm that the 36 millisecond time interval to be used in the calculation of the head injury criterion (HIC) applies both to the Part 572, Subpart B test dummy and to the Subpart E test dummy. This is to confirm that the 36 millisecond time interval should be used in the calculation of a HIC for both types of test dummies. On October 17, 1986 (51 F2 37028), NHTSA published a final rule in the Federal Register amending Safety Standard No. 208, Occupant Crash Protection. One of the amendments modified the manner in which a HIC is calculated in the crash testing required by t he standard. That amendment referred to @6.2 as the provision of the standard containing the HIC requirement. Instead, the notice should have amended @6.1.2, which sets out the HIC calculation for the Part 572, Subpart B test dummy, and @6.2.2, which set s out the HIC calculation to be used with the new Part 572. Subpart E test dummy.. The agency will publish an amendment to adopt the necessary changes to @6.1.2 and @6.2.2 to make clear that the change to the calculation of the HIC criterion affects thos e two provisions. If you need further information, please let me know. Sincerely, Erika Z. Jones Chief Counsel Mr. Steve Oesch Legal Counsel Department of Transportation NHTSA 400 Seventh St., S.W. Washington, DC 20590 Subject: Docket 74-14, Notice 47 Concerning FMVSS 208 Published in the Federal Register October 17, 1986 Dear Mr. Oesch: Confirming our telephone request of May 4, 1987, we would be most appreciative if NHTSA could acknowledge in writing that in the subject FR it was erroneously printed, on page 37033 paragraph @6.2, that for calculating HIC values, the 36 millisecond time interval applies only to the Part 572, Subpart E, Hybrid III test dummy. A corrected Part 571.208 will, in the future, indicate that the 36 millisecond time interval for HIC calculation applies to using either a Hybrid III or a Part 572 Subpart B test dummy. Since a correction notice in the FR may be further delayed due to hi gher priorities, we are eager to obtain this confirmation as soon as practicable. Thank you very much for your assistance. Sincerely, Thomas Baloga Safety Engineering (201) 573-2622 |
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ID: nht76-2.12OpenDATE: 04/14/76 FROM: AUTHOR UNAVAILABLE; S. P. Wood; NHTSA TO: Blue Bird Body Company TITLE: FMVSS INTERPRETATION TEXT: This responds to Blue Bird Body Company's March 15, 1976, request for confirmation that calculation of the material tensile strength of body panels under S6.2(a) of Standard No. 221, School Bus Body Joint Strength, is based on the minimum thickness permitted by American Society for Testing and Materials (ASTM) Standard 525 for the thickness specified in ordering the material. This response also reflects the April 1, 1976, meeting held between Blue Bird representatives and National Highway Traffic Safety Administration (NHTSA) personnel at Department of Transportation headquarters. Under ASTM standards, the thickness of listed materials is permitted to vary from the specified or "nominal" thickness by a small amount. If the thickness tolerance of a material is specified by the ASTM, the NHTSA bases its determination of thickness on the "minimum thickness" specified for that material in the 1973 edition of the Annual Book of ASTM Standards. If the thickness tolerance of a material is not specified by the ASTM, the NHTSA uses the minimum thickness permitted by the school bus manufacturer's material specification. YOURS TRULY, BLUE BIRD BODY COMPANY March 15, 1976 Mr. Richard B. Dyson Assistant Chief Counsel National Highway Traffic Safety Administration SUBJECT: FMVSS 221 - SCHOOL BUS BODY JOINT STRENGTH In S6.2(a) the subject standard makes provision for the manufacturer to determine the material tensile strength as published by the ASTM. This information is required before a manufacturer can design body joints and tooling to manufacture those joints in compliance with the subject standard. Material tensile strength as published by the ASTM has a tolerance and we need to know to which end of the tolerance we must design. The standard adequately addresses this problem in S6.2(a) by stating ". . . .the relative tensile strength for such material is the minimum tensile strength specified for that material in the 1973 Edition of the Annual Book of ASTM Standards." This only addresses half of the tolerance problem. The ASTM standards show tolerances for metal thickness ranges. In the absence of specific guidelines of this problem and because we must commit for tooling immediately, we are using the minimum thickness based on our specified thickness and tolerance in ASTM A525-73. This approach seems to be justified in light of the tensile strength guidelines given in S6.2(a). If this approach is not satisfactory, please contact us by telephone immediately. We will also appreciate a written reply to this letter at your earliest convenience. W. G. Milby Staff Engineer cc: Bob Williams; Jim Moorman; Jim Swift |
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ID: nht90-3.8OpenTYPE: Interpretation-NHTSA DATE: July 9, 1990 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA TO: Pat Crahan -- Director, Government Relations, U-Haul International TITLE: None ATTACHMT: Letter dated 1-26-90 to A. L. Burgett from Pat Crahan attached; OCC 4404 TEXT: Thank you for your letter to Dr. August Burgett of this agency, seeking an interpretation of Standard No. 115, Vehicle Identification Number - Basic Requirements (49 CFR S571.115). I apologize for the delay in this response. Specifically, you stated th at U-Haul manufactures its trailers itself and never sells those trailers to any other party. You asked if Standard No. 115 requires trailers that are used exclusively by the party that manufactures them to be identified with a vehicle identification nu mber (VIN). The answer to your question is yes. S2 of Standard No. 115 specifies that the standard applies to trailers, and makes no exception for trailers that are used exclusively by the manufacturer. S4.1 of Standard No. 115 provides that: "Each vehicle manufactured in one stage shall have a VIN t hat is assigned by the manufacturer." Again, no exceptions are set forth for vehicles that will be used exclusively by the manufacturer. Because those regulatory provisions do not include any special exceptions, every new trailer must have a VIN, irres pective of whether the trailer will only be used by the same party that manufactured it. I hope this information is useful. If you have any further questions or need any additional information about this topic, please feel free to contact Dorothy Nakama of my staff at this address or by telephone at (202) 366-2992.
LPDS 1989 |
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.