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: aiam2039OpenMr. Edward L. J. Young, Director, Engineering, Lear Siegler, Inc., Neway Division, P.O. Box 425, Muskegon, MI 49443; Mr. Edward L. J. Young Director Engineering Lear Siegler Inc. Neway Division P.O. Box 425 Muskegon MI 49443; Dear Mr. Young: I appreciate your letter of August 13, 1975, forwarding a copy o Neway's publication on Standard No. 121, *Air Brake Systems*. The efforts of companies like Neway to assist final-stage manufacturers in their certification responsibility has been an important part of the implementation of the air brake systems standard.; You asked for review of the booklet, which consists mainly o instructions to manufacturers concerning systems that must be tested and how to establish a basis for certification. This is an area which our statutory scheme leaves to the manufacturer, and in which, aside from discussions of general principles, this agency declined to issue statements of approval. While we appreciate the usefulness of the advice contained in your booklet, we regret that we can not judge the adequacy of a certification program in the abstract.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1623OpenMr. J. W. Boyd, Manager, Government & Industry, Tech. Relations, Dunlop Tire & Rubber Corporation, P. O. Box 1109, Buffalo, NY 14240; Mr. J. W. Boyd Manager Government & Industry Tech. Relations Dunlop Tire & Rubber Corporation P. O. Box 1109 Buffalo NY 14240; Dear Mr. Boyd: This is in response to your letter of September 11, 1974, askin several questions relating to our tire identification regulation as it applies to Dunlop Tire and Rubber Corporation (England).; When tires are manufactured for a brand name owner, as they will be i your case, you are correct in saying the first grouping in the identification number must contain the manufacturer's identification (DD, in your case) and the third grouping must contain up to four letters designating the brand name owner. Pursuant to section 574.5(c) you must maintain a detailed record of the brand name owner code used.; Pursuant to section 574.7(c), the brand name owner must maintain th information required by section 574.7 of the regulation. Therefore, no agreement between Dunlop and Armstrong is necessary.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam1731OpenMr. George McDonald, Engineering Manager, Tridon Limited, Box 5029, Burlington, Ontario, Canada; Mr. George McDonald Engineering Manager Tridon Limited Box 5029 Burlington Ontario Canada; Dear Mr. McDonald: This is in reply to your letter of December 6, 1974 to this offic requesting clarification of Motor Vehicle Safety Standard No. 108.; You are correct in your interpretations numbered 1, 2, and 3. Th applicable SAE Standard or Recommended Practice for a turn signal flasher is J590b, October 1965, and for a vehicular hazard warning signal flasher is J945, February 1966. The footnote 'See S4.4.2' is in error and should be deleted.; You are incorrect in your interpretation No. 4. Paragraph S4.4.1 allow use of a combination turn signal flasher-hazard warning signal flasher if the requirements of both J590b and J945 are met. The correct testing sequence is as follows: (1) for performance as a turn signal flasher, (2) for performance as a hazard warning signal flasher, (3) for durability as a turn signal flasher, and (4) for durability as a hazard warning signal flasher.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam1306OpenMr. Jerome Cooper, Green Bus Lines, Inc., 145-25 147th Avenue, Jamaica, NY 11434; Mr. Jerome Cooper Green Bus Lines Inc. 145-25 147th Avenue Jamaica NY 11434; Dear Mr. Cooper: This is in response to your letters of July 30 and August 21, 1973 concerning the requirements of Federal Motor Vehicle Safety Standard No. 205, Glazing Materials, for materials used in windshields.; We understand and share your concern over the damage and the hazard caused by vandalism toward buses. Standard No. 205 currently prohibits the use of plastics in windshields simply because today's commercial plastics, including the one for which you enclosed a brochure, cannot meet the abrasion resistance test specified in the standard. As long as windshield wipers are used, we are of the opinion that this requirement is essential. We hope that glazing manufacturers will develop materials that will protect against the problems you have described, while at the same time meeting the necessary performance requirements. When such materials are developed, we, or course, would amend the standard as necessary to permit their use.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam3629OpenMr. Gene Wright, Vice-President, Manufacturing, CAPACITY OF TEXAS, INC., P.O. Box 7848, Longview, TX 75607; Mr. Gene Wright Vice-President Manufacturing CAPACITY OF TEXAS INC. P.O. Box 7848 Longview TX 75607; Dear Mr. Wright: This responds to your letter of October 11, 1982, concernin regulations specifying the type of steering system required in vehicles. In particular, you asked if a mechanical link is required in the steering system or whether a hydraulic system is acceptable. As explained below, a manufacturer can use either a mechanical or hydraulic system to meet the requirements of the applicable Federal Motor Vehicle Safety Standards.; There are two Federal Motor Vehicle Safety Standards that apply t vehicle steering systems: Standard No. 203, *Impact Protection for the Driver Steering Control System*, and Standard No. 204, *Steering Column Rearward Displacement*. Both standards, copies of which are enclosed, establish performance requirements to protect the driver from steering column-related injuries in a crash. Any type of steering system, either mechanical or hydraulic, can be used as long as it meets the applicable requirements of those standards.; If you have any further questions please let me know. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3630OpenMr. Gene Wright, Vice-President, Manufacturing, CAPACITY OF TEXAS, INC., P.O. Box 7848, Longview, TX 75607; Mr. Gene Wright Vice-President Manufacturing CAPACITY OF TEXAS INC. P.O. Box 7848 Longview TX 75607; Dear Mr. Wright: This responds to your letter of October 11, 1982, concernin regulations specifying the type of steering system required in vehicles. In particular, you asked if a mechanical link is required in the steering system or whether a hydraulic system is acceptable. As explained below, a manufacturer can use either a mechanical or hydraulic system to meet the requirements of the applicable Federal Motor Vehicle Safety Standards.; There are two Federal Motor Vehicle Safety Standards that apply t vehicle steering systems: Standard No. 203, *Impact Protection for the Driver Steering Control System*, and Standard No. 204, *Steering Column Rearward Displacement*. Both standards, copies of which are enclosed, establish performance requirements to protect the driver from steering column-related injuries in a crash. Any type of steering system, either mechanical or hydraulic, can be used as long as it meets the applicable requirements of those standards.; If you have any further questions please let me know. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3732OpenMr. David E. Martin, Director, Automotive Safety Engineering, Environmental Activities Staff, General Motors Corporation, General Motors Technical Center, Warren, MI 48090; Mr. David E. Martin Director Automotive Safety Engineering Environmental Activities Staff General Motors Corporation General Motors Technical Center Warren MI 48090; Dear Mr. Martin: The Deputy Administrator has asked me to respond to your letter of Jul 18, 1983, concerning an expansion of your current field testing of anti-lacerative windshield glazing supplied by Saint-Gobain Vitrage. The expanded field test would involve the installation of anti-lacerative windshields produced by Libbey-Owens-Ford (LOF) in 550 1984 Buick Century and/or Oldsmobile Cutlass Ciera automobiles. You stated that the vision and abrasion resistance characteristics of the LOF material are similar to the Saint-Gobain material you are using in your current field tests. You also stated that you will closely monitor the test fleet and rectify any problems that may develop.; Under the limited and special circumstances of the field test describe in your letter, the agency would not enforce the abrasion requirement of Safety Standard No. 205, as it now stands, for the LOF anti-lacerative windshields to be used in your proposed field tests. We expect General Motors to keep the agency informed of all the results it obtains from this field test.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0377OpenMr. M. Grossman, U.S. Factory Representative, Automobiles Peugeot, 300 Kuller Road, Clifton, NJ 07015; Mr. M. Grossman U.S. Factory Representative Automobiles Peugeot 300 Kuller Road Clifton NJ 07015; Dear Mr. Grossman:#This is in reply to your letter of June 2 requesting an interpretation of Paragraph S4.2 of Motor Vehicle Safety Standard No. 101.#You may mark your windshield wiper control, and lighting - windshield washing control in the manner indicated in your letter. We do not consider the washing control a wiping control requiring identification as such merely because the wiper is momentarily activated when the washer system is in operation.#Sincerely, Lawrence R. Schneider, Acting Chief Counsel; |
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ID: aiam1008OpenMr. Edward L. Hawes, 1651 E. Nine Mile Road, Hazel Park, Michigan 48030; Mr. Edward L. Hawes 1651 E. Nine Mile Road Hazel Park Michigan 48030; Dear Mr. Hawes: This is in response to your petition for amendment of Standard 125 (4 CFR S571.125), *Warning Devices*, dated January 31, 1973. You requested that the standard be amended to make it mandatory for all warning devices to have the capability of being mounted on a vehicle roof as well as on the ground. At present the standard allows such a capability, but does not require it.; The NHTSA has not found it advisable to amend the standard as you hav requested. The requirements that have been issued are intended to provide for simple, inexpensive devices that have a uniform method of use, namely setting on the roadway in the direction of oncoming traffic. Any requirements that call for multiple uses and capabilities will tend to make the device for more complex and expensive. If persons are willing to pay extra for capabilities such as roof mounting, that is, if there is a market, then you will perform in these ways. There are many vehicles, however, for which roof mounting would not be feasible in any circumstances. The information that we have received to date on this subject does not justify imposing on all manufactures the additional requirements that you suggest.; For these reasons your petition for rulemaking to amend Standard 125 i denied.; Sincerely, Douglas W. Toms, Administrator |
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ID: aiam0237OpenMr. Thomas J. McKnight, President, Fleet Cap'n Trailers, Inc., P. O. Box 508, New Bern, NC 28560; Mr. Thomas J. McKnight President Fleet Cap'n Trailers Inc. P. O. Box 508 New Bern NC 28560; Dear Mr. McKnight: This is in reply to your letter of April 29, 1970, to Mr. Rodolfo A Diaz, Acting Associate Director, Motor Vehicle Programs, concerning the location of rear lamps on various models of your trailers.; From a review of the sketch attached to your letter, it appears tha the tail, stop and turn signal lamps mounted on the trailer frame rearward of the fenders will meet the location requirements specified in Table IV of Federal Motor Vehicle Safety Standard No. 108. However, Standard No. 108, by reference to SAE Standard J588d, also requires that '---visibility of the front turn signal to the front and the rear signal to the rear shall not be obstructed by any part of the vehicle throughout the photometric test angles for the lamps.' The photometric test angles for turn signal lamps are specified in Table 2 of SAE Standard J575c. From your sketch it appears that the required visibility of the turn signal lamps, when mounted in the proposed location, would be partially blocked by the framework of the trailer. Mounting the lamps on the rear crossmember may therefore be necessary to provide the required unobstructed visibility.; For your information I am enclosing copies of Standard No. 108, SA Standard J588d and SAE Standard J575c.; Sincerely, Roger H. Compton, Director, Office of Operating Systems Motor Vehicle Programs; |
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.