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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



Displaying 4261 - 4270 of 6047
Interpretations Date

ID: nht68-3.3

Open

DATE: 12/30/68

FROM: AUTHOR UNAVAILABLE; H. M. Jackson, Jr.; NHTSA

TO: General Motors Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This will acknowledge your letter of October 23, 1968, requesting the addition of the 5-inch alternative rim size for use with the 155-13/6.15-13 tire size designation.

In your request you cited a letter from the German Rubber Industry stating that "for passenger car tires in addition to the rims specified in the German Industrial Standards (DIN) also the use of the next large size rims is permissible." The subject of the foot note in the German standard was discussed by my staff in conversations with Mr. Von Polhemus. When the Federal Motor Vehicle Safety Standards were written, it was the intent to accept the German Industrial Standards (DIN) of 1967 for all tire and rim combinations listed based on established usage. We did not intend to apply foot notes from any 1967 reference materials to the present or future tire and rim combinations.

However, on the basis of the data submitted indicating compliance with the requirements of Federal Motor Vehicle Safety Standards No. 109 and No. 110 and other information submitted in accordance with the procedural guidelines set forth in the Federal Register, Volume 33, No. 195, page 14969, dated October 5, 1968, the 5J alternative rim size for the 155-13/6.15-13 tire size designation will be listed within Table I of Appendix A to Standard No. 110. This change will be published in the Federal Register in the near future.

The addition of this new alternative rim size to the table is accomplished through an abbreviated procedure consisting of the publication in the Federal Register of the petitioned alternative rim size. If no comments are received, the amendment became effective after 30 days from the date of publication. If comments objecting to amendments are received, additional rule making pursuant to Part 216 of the Procedural Rules for Motor Vehicle Safety Standards will be considered.

ID: nht68-3.33

Open

DATE: 05/06/68

FROM: AUTHOR UNAVAILABLE; David A. Fay; NHTSA

TO: Utility Body Company

TITLE: FMVSS INTERPRETATION

TEXT: Thank you for your letter of March 11, 1968, to Mr. George C. Nield requesting clarification of the positioning of lamps and reflectors as required by Motor Vehicle Safety Standard No. 108.

The lamps and reflectors that are shown on your Drawing No. X-78, dated January 17, 1968, appear to be in conformance with the requirements of Standard No. 109 with the following exceptions:

1. The front clearance lamps mounted on the chassis-cab of the top two vehicles on your drawing are not required by Standard No. 108, since those on the body and crew-carrying cab adequately define the extreme width and are as high as practicable.

2. The rear clearance lamps shown on the crew-carrying cab should be mounted on the rear of the bed similar to those on the bottom vehicle (P) to meet the requirement that they be mounted on the rear and indicate the extreme width.

3. The front clearance lamps on the third vehicle (S, SL, CO) should be mounted on the front of the tool panels at or near the same level as the rear clearance lamps to indicate the extreme width.

4. The front clearance lamps on the bottom vehicle (P) should be mounted on the front of the bed or platform if it projects beyond the sides of the chassis-cab.

Since no dimensions are specified on your drawing, we can only assure that the locations are as specified in the standard.

With respect to the requirements of Standard No. 108, I must point out that this Bureau does not issue approval on items of lighting equipment or on vehicle designs incorporating this equipment. Therefore, the above comments are for your information only and in no way relieve the vehicle manufacturer from his responsibility for certifying that the assembled vehicle meets the requirements of Standard No. 108.

ID: nht68-4.3

Open

DATE: 08/20/68

FROM: AUTHOR UNAVAILABLE; Charles A. Baker; NHTSA

TO: Calumet Corporation

TITLE: FMVSS INTERPRETATION

TEXT: Thank you for your letter of July 22, 1968, to Mr. George C. Nield, concerning the applicability and effective date of Motor Vehicle Safety Standard No. 108.

Standard No. 108 is applicable to new vehicles manufactured on or after the effective date of the standard. Initial Standard No. 108 was published on February 3, 1967, and became effective January 1, 1968. The initial standard is applicable only to vehicle that are 80 inches or more in overall width. Revised Standard No. 108 was published on December 16, 1967, and becomes effective January 1, 1969. The revised standard is applicable to passenger cars, multipurpose passenger vehicles, trucks, buses, trailers and motorcycles, regardless of overall width; however, the special requirements for vehicles that are 80 inches or more in overall width have been identified in the standard. Copies of the initial and revised standard are enclosed for your information.

In reply to your specific questions, information is provided as follows:

1. With respect to your first question, Standard No. 108 is applicable to trailers manufactured for personal use by an individual and for commercial use.

2. With respect to your second question, Revised Standard No. 108, effective January 1, 1969, specifies the lighting requirements for trailers that are less than 80 inches in overall width.

3. With respect to your third question, the regulations of individual States and of the Bureau of Motor Carrier Safety (for vehicles engaged in interstate commerce) presently govern the lighting required on trailers that are less than 80 inches in overall width. Effective January 1, 1969, these trailers will be subject to the requirements of Revised Standard No. 108. Installation and location requirements for the individual lamps are contained in the referenced SAE standards (see Table III of Standard No. 108) and in Table IV of Standard No. 108.

Also enclosed is a copy of the notice on "Certification Requirement," which provides information on the manufacturer's certification of vehicles that are subject to the Federal motor vehicle safety standards.

ID: nht69-1.18

Open

DATE: 02/11/69

FROM: AUTHOR UNAVAILABLE; Clue D. Ferguson; NHTSA

TO: Payne, Barlow and Green, Attorneys at Law

TITLE: FMVSS INTERPRETATION

TEXT: Thank you for your letter of January 23, 1969, to William Haddon, Jr., M.D., requesting information on Federal standards for child restraint devices.

I am enclosing a copy of Federal Motor Vehicle Safety Standard No. 209, "Scat Belt Assemblies - Passenger Cars, Multipurpose Passenger Vehicles, Trucks and Buses" which includes requirements for a Type 3 seat belt assembly for persons weighing not more than 50 pounds and capable of sitting upright by themselves.

The technical requirements of the present standard No. 209 were previously included in "Standard for Seat Belts for Use in Motor Vehicles (15 CFR Part 9; 31 F.R. 11528)" which was incorporated by reference in the initial Standard No. 209. I am also enclosing copies of these previous documents.

We are in the process of developing a standard for child car seats and I am enclosing a copy of a recently issued Notice of Proposed Rule Making on this subject. It is important to note that this is only a proposed regulation and the requirements may be modified somewhat when the final rule is published. However, this proposed rule indicates those safety features which are considered to be important for a child car seat.

There are no other existing Federal standards on child restraint systems for use in motor vehicles.

Sincerely,

January 23, 1969

William Haddon, Director National Highway Safety Bureau Department of Transportation

Dear Dr. Haddon:

I am seeking information regarding Federal Standards for Child Restraint Devices and will appreciate your furnishing same to me as soon as it is convenient for you.

I am attempting to measure the adequacy of a particular device that apparently contributed to a child's injury that occurred on May 15, 1968. I do not know the date of manufacture of this device but it is important that I obtain an itemization of minimum standards that have applied for several years.

Sincerely,@@53:426

ID: nht70-2.9

Open

DATE: 05/13/70

FROM: AUTHOR UNAVAILABLE; Rodolfo A. Diaz; NHTSA

TO: Department of California Highway Patrol

TITLE: FMVSS INTERPRETATION

TEXT: Thank you for your letter of March 2, 1970, petitioning for amendments to Federal motor vehicle safety standard No. 205-Glazing Materials. I apologize for the delay in this response to your petition.

The first amendment you propose would require each manufacturer to mark each piece of glazing material with his name, the model number and "AS" classification. A manufacturer electing the certification alternative now in S3.4 must provide the same information you request, except that a code number is substituted for the manufacturer's name. In this connection, the Director of the National Highway Safety Bureau is considering the issuance of a notice of proposed rule making which would require all manufacturers of glazing materials to adopt the certification method in S3.4. Consequently, while we are not granting your petition on identification requirements, we are actively considering your suggestions for future rule making.

The second amendment you propose would add to the standard a definition of "area requisite for driving visibility." Subsequent to the writing of your letter, the Director issued an advance notice of proposed rule making concerning a new standard, Direct Fields of View. In this notice, a copy of which is enclosed for your convenience, the Director announced that he was

considering the establishment of performance requirements for (1) direct fields of view outside the vehicle in all directions to provide adequate visibility for the driver from specified eye reference loci; (2) light transmission characteristics (including maximum

levels of tinting) of vehicle glazing materials; and (3) shade band boundaries of vehicle glazing materials. (Emphasis added)

Requirements developed with regard to items (3) and (3) would supercede provisions regarding shade band boundaries and tinting in standard No. 205. If this new standard is issued, it will deal with the problem which you mention.

We would welcome any additional comments you may have on these matters.

ENCLOSURES

ID: nht71-2.2

Open

DATE: 02/05/71

FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA

TO: Century Products, Inc.

COPYEE: C. DIETRICH -- BOLT BERANEK AND NEWMAN; D. SCHRUM -- ELECTRICAL TESTING LABS.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of January 28, 1971, requesting an interpretation of Motor Vehicle Safety Standard No. 213. Although your letter-refers to S4.11(d) as the paragraph with which you are concerned, it appears from the test of your letter that you are requesting an interpretation of paragraph S5.1(d).

S5.1 of the standard specifies the test procedure that will be used by NHTSA to determine whether the child(Illegible Word) system meets the force resistance requirements specified in S4.1 of the standard. S5.1(d), the passage in question, rends as follows:

"Apply an increasing load to the torso block in a forward direction, not more than 15 degrees and not less than 5 degrees above the horizontal., until a loud of 1,000 pounds is achieved. The intersection of the lead application line and the back surface of the torso block, at the time that the force removes the slack from the lead application system, shall not be more than 8 inched or less than 6 inches above the bottom surface of the torso block. Maintain the 1,000-pound load for 10 seconds."

Your question is whether the angle at which the force is applied, even though initially between 5 degrees and 15 degrees above the horizontal, may above outside that range during application of the specified force.

The answer to your question is no. The relevant wording of the standard, that the force is to be applied in a forward direction "not more than 15 degrees and not less than 5 degrees above the horizontal, until a load of 1.000 pounds is achieved," clearfly requires that the direction of the test force remain within the specified angular limits throughout the period of force application.

Please write if you have further questions.

ID: nht72-1.27

Open

DATE: 11/21/72

FROM: AUTHOR UNAVAILABLE; L. R. Schneider; NHTSA

TO: Klein Tire Sales

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of November 1, 1972, asking whether you may sell tires from which the manufacturer has removed his name and DOT marking, if you tell the purchaser that the tires cannot be sold except for farm use, and if the buyer signs a sales invoice to that effect.

The information I gave you over the phone is incorrect. The answer to your question is that you may not sell such tires. Passenger car tires manufactured before October 1, 1972, can not be made eligible by their manufacturer for sales as farm use tires unless the manufacture has reclassified them in the manner specified in paragraph S6 of Motor Vehicle Safety Standard No. 109. This provision required the manufacturer to permanently label a tire with the words "UNSAFE FOR HIGHWAY USE", and to affix labels to the tread which state that the tire should not be used on a passenger car and that the sale of the tire for such use may subject the seller to civil penalties. A dealer who sells a nonconforming tire which the manufacturer has not reclassified in this manner will be in violation of section 108(a)(1) of the National Traffic and Motor Vehicle Safety Act, and likewise subject to civil penalties.

A recent amendment to Standard No. 109 prohibits manufacturers from reclassifying any tire after October 1, 1972, and requires them to destroy tires manufactured after that date which they will not certify.

With respect to reports on tires which you mention were obtained for testing purposes by Mr. Loewenstern of NHTSA, these tires, which were not purchased by Mr. Loewenstern but by a New Jersey State Policeman on behalf of NHTSA, were not purchased for testing purposes. Rather, they were purchased for the purpose of obtaining evidence against you that you were selling tires in violation of the National Traffic and Motor Vehicle Safety Act. The NHTSA does not return tires which have been purchased for evidentiary purposes.

ID: nht72-2.40

Open

DATE: 07/19/72

FROM: AUTHOR UNAVAILABLE; C. A. Baker for E. T. Driver; NHTSA

TO: Raybestos-Manhattan

TITLE: FMVSS INTERPRETATION

TEXT: In your letter of June 30, 1972, you raised two questions that touch on the responsibility of manufacturers who produce components, such as brake blocks, that affect the ability of a vehicle to meet a motor vehicle safety standard.

Motor Vehicle Safety Standard No. 121, Air Brake Systems, the standard of concern to you, regulates vehicles equipped with air brakes, but it does not regulate the brakes or their components as separate items of equipment. As a component manufacturer, your company is therefore not required by our regulations to certify its products as conforming to Standard 121. This is not to say that your customers will not be concerned about the performance of your products, but only that you have no direct responsibility under the standard.

A vehicle manufacturer who intends to use your brake blocks on a new vehicle will probably try to get as much test data from you as he can. His vehicle will have to conform to the standard. If our tests disclose a shortcoming in the brakes, he will have to show that he exercised due care in the manufacture of the vehicle and the data he obtains from you may be an important part of his case. Whether you supply him with dynamometer data or complete road test data is a matter to be arranged privately, however, and the subject is not regulated by our rules.

A brake block or other brake component sold as a replacement part is not at this time subject to regulation under Standard 121. A truck owner will presumably want to obtain components that are compatible with the rest of the brake system.

You have also asked for information about agencies equipped to run tests in accordance with Standard 121. At this time we have not compiled a list of test facilities, but we expect that such information will become widely available in the next few months.

ID: nht72-3.11

Open

DATE: 04/03/72

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: Pike Paint & Glass Company, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of March 15, 1972, requesting information on requirements for replacing broken glass in campers and trailers.

Federal regulations (Motor Vehicle Safety Standard No. 205, "Glazing Materials" (49 CFR 571.205, formerly 571.21)) require glazing materials for use in motor vehicles and motor vehicle equipment such as campers to meet the requirements of the American National Standards Institute Test Z26.1-1966 (July 15, 1966), and other requirements enumerated in the standard. In addition, manufacturers of such materials are required to certify, pursuant to section 114 of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1403) that the materials comply with the standard. This requirement applies to both prime manufacturers (those who either fabricate, temper, or laminate the material) and those who cut material from larger sheets.

The standard does not apply to trailers. With reference to campers, the standard requires that forward facing windows be constructed of glazing materials meeting tests for AS1, AS2, AS3, AS4, or AS5 glazing materials, which are described in ANS Test Z26.1-1966. Other camper windows may be of any glazing material that meets the requirements of the standard (AS1 through AS11). All of the materials which can be used under the standard are readily available. A notice of proposed rulemaking issued January 9, 1971, would allow additional materials to be used in campers, and the preparation of a final regulation regarding this matter is currently in process. The final regulation will, when issued, be published in the Federal Register.

A copy of Standard No. 205 is enclosed. The American National Standards Test Z26.1-1966, which is incorporated into the standard must, however, be obtained directly from the American National Standards Institute. Their address is 1430 Broadway, New York, New York 10018.

If you have further questions, please write.

ID: nht72-3.18

Open

DATE: 05/31/72

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: GO Industries

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of April 26, 1972, requesting an opinion as to whether "Abcite," a product of the Dupont Company, may be used in campers and "mini-mobile homes."

Whether a particular glazing material may be used in motor vehicles or campers depends upon whether the material meets the requirements of Motor Vehicle Safety Standard No. 205, "Glazing Materials" (49 CFR 571.205), which incorporates, as you indicate, the American National Standards Institute Standard Z26.1-1966. That standard also specifies the locations in motor vehicles where specific materials may be used.

Standard No. 205 does not apply to trailers. While we are not familiar with the phrase "mini-mobile home," we consider mobile homes to be trailers, and the standard does not apply to them. With respect to campers, Standard No. 205 allows the use of any material meeting the requirements of Z26 in any location except for forward-facing windows. Forward-facing camper windows may not be manufactured of item 6 and item 7 material (AS6, AS7), but may be manufactured of any of the other materials (AS1-AS5, AS8-AS11) that meets the requirements of Z26.

Whether Abcite conforms to the requirements for glazing allowed to be used in campers is a determination that should be made in the first instance by its manufacturer, Dupont. If the manufacturer determines that such use is within the requirements of Standard No. 205, he is required by section 114 of the National Traffic and Motor Vehicle Safety Act to certify that the material conforms to the requirements of the standard. He is also required by the marking requirements in Section 6 of Z26.1-1966 to indicate on the material its AS designation. Any material that is so certified can be used in the camper locations listed on the standard as appropriate for that designated type.

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.

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