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: aiam1323OpenMr. James C. Martin, Attorney at Law, P. O. Box 1019, Carson City, NV 89701; Mr. James C. Martin Attorney at Law P. O. Box 1019 Carson City NV 89701; Dear Mr. Martin: This is in reply to your letter of November 9 to the U. S. Departmen of Transportation concerning the operation of 4-way flashers and brake lights on a 1972 Toyota.; Since there is no requirement that the hazard warning signal (4-wa flashers) be capable of operating independently of the stop signal, it is permissible for the stop signal to override the hazard warning signal. If fact, these signals on most passenger cars and multipurpose passenger vehicles manufactured in the United States operate similarly.; Sincerely, E. T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
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ID: aiam1056OpenMr. Gorou Utsunomiya, Branch Manager, Toyo Kogyo USA Rep. Office, 28777 Greenfield Road, Suite 462, Southfield, MI 48075; Mr. Gorou Utsunomiya Branch Manager Toyo Kogyo USA Rep. Office 28777 Greenfield Road Suite 462 Southfield MI 48075; Dear Mr. Utsunomiya:#This is in reply to your letter of March 15, 1973 asking our conformation of your understanding of the illumination requirements of Standard No. 101 as it applies to certain controls.#Your understanding is correct. Only the controls listed in Column 1 of Table 1 must be illuminated, and if any of those controls are located on the steering column, illumination need not be provided. If you provide illumination for other controls, the intensity need not be adjustable.#Yours truly, Richard B. Dyson, Assistant Chief Counsel; |
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ID: aiam0054OpenMr. H.G. Webster, Director and Chief Engineer, The Standard-Triumph Motor Company, Limited, Coventry, England; Mr. H.G. Webster Director and Chief Engineer The Standard-Triumph Motor Company Limited Coventry England; Dear Mr. Webster: #This letter is in response to your February 27 1968, request for approval of equivalent rims for use in the following tire and rim combinations: #>>>A. *Bias Ply Tires* #1. 5.20-13 on 4 1/2J rim. #2. 5.60-13 on 3 1/2J rim. #B. *Radial Ply Tires* #1. 145-13 on 3 1/2J rim. #2. 145-13 on 4 1/2J rim. #3. 185-15 on 4 1/2J rim.<<< #On the basis of the supporting information submitted, your request for approval of the equivalent rims and proposed tire combinations listed above is granted. #Sincerely, George C. Nield, Acting Director, Motor Vehicle Safety Performance Service; |
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ID: aiam1855OpenMr. Emanuel Laster, 8th Floor Mears Building, Scranton, PA; Mr. Emanuel Laster 8th Floor Mears Building Scranton PA; Dear Mr. Laster: This responds to your March 19, 1975, question whether Standard No 121, *Air brake systems*, applies to an air-braked trailer which has a primary cargo-carrying surface that is 23 inches above the ground in the unloaded condition and has a rack-type structure which may be added to the trailer to permit carrying several boats.; I have enclosed an amendment of Standard No. 121 which excludes certai trailers from its requirements until September 1, 1976. From your description of the sides as easily removable, and from the enclosed illustration, it appears that the trailer in question qualifies as a heavy hauler trailer and would not be required to conform to Standard No. 121 until September 1, 1976.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1820OpenMr. R.W. Hildebrandt, Bendix Heavy Vehicle Systems Gp., 901 Cleveland Street, Elyria, Ohio 44035; Mr. R.W. Hildebrandt Bendix Heavy Vehicle Systems Gp. 901 Cleveland Street Elyria Ohio 44035; Dear Mr. Hildebrandt:#This is in response to your letter of Februar 14, 1975, requesting an interpretation of the labelling requirements of Federal Motor Vehicle Safety Standard No. 106-74, *Brake Hoses*. #You have asked whether Bendix may use the same manufacturer identification designation on brake hose, brake hose end fittings, and brake hose assemblies manufactures at three plants which are geographically separated. While S5.2 of Standard no. 106-74 requires designations identifying the manufacturer of these components, nothing in the standard prohibits a single manufacturer from applying the same designation to components manufactured at different plant locations. #Yours truly, Richard B. Dyson, Assistant Chief Counsel; |
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ID: aiam1968OpenMr. Dennis M. Dykiel, Hendrickson Mfg. Company,8001 West Forty-Seventh Street, Lyons, Illinois 60534; Mr. Dennis M. Dykiel Hendrickson Mfg. Company 8001 West Forty-Seventh Street Lyons Illinois 60534; Dear Mr. Dykiel: #Please forgive the delay in responding to your lette of March 26, 1975, requesting an interpretation of the masking requirements of Federal Motors Vehicle Safety Standard No. 106-74, *Brake Hoses*. #The requirement that the label on a brake hose remain visible after painting was amended on March 17, 1975, (40 FR 12088, Docket No. 1-5, Notice 16) to permit the label to remain masked if (1) the masking material is affixed in such a way that no adhesive contacts any part of the label and (2) the masking is manually removable. Since the requirement that the label be masked or visible, rather than obscured, is a vehicle requirement, it is not effective until September 1, 1975. Vehicles manufactured before that date may contain hose which has been painted over. #Sincerely, James C. Schultz, Chief Counsel; |
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ID: aiam3192OpenMr. Sylvester P. Gagnon, 3919 Third Avenue, Sioux city, Iowa 51106; Mr. Sylvester P. Gagnon 3919 Third Avenue Sioux city Iowa 51106; Dear Mr. Gagnon: This responds to your October 22, 1979, letter which was referred to u by the American Association of Motor Vehicle Administrators. In that letter, you ask about your proposed emergency notification system that would use numbers to inform other drivers of a disabled car's mechanical problem.; The National Highway Traffic Safety Administration does not endors specified products. The agency has a safety standard that requires emergency warning devices to be of a uniform construction. That standard is located in Volume 49 of the Code of Federal Regulations, Part 571.125. Emergency warning devices are devices that alert drivers to the presence of a disabled vehicle. Your device, however, is not used to warn drivers of the presence to a disabled vehicle. It would alert drivers to the nature if a vehicle's disability. the agency concludes, therefore, that you would not be prohibited from offering this device for sale as motor vehicle equipment.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3649OpenMr. H. Miyazawa, Director, Automotive Lighting, Engineering Department, Stanley Electric Co., Ltd., 2-19-13, Nakameguro, Meguro-ku, Tokyo 153, Japan; Mr. H. Miyazawa Director Automotive Lighting Engineering Department Stanley Electric Co. Ltd. 2-19-13 Nakameguro Meguro-ku Tokyo 153 Japan; Dear Mr. Miyazawa: This is in reply to your letter of November 23, 1982, to Mr. Elliott o this agency asking whether you may distinguish between U.S. and Japanese-manufactured lighting equipment subject to Federal Standard No. 108 by marking the lenses 'U.S.A. DOT' and 'JAPAN DOT', rspectively (sic).; As you know, the National Highway Traffic Safety Administration has no adopted the SAE standard on equipment marking, J759c. This means that the only marking subject to Standard No. 108 is that which certifies compliance to all applicable Federal motor vehicle safety standards, the DOT symbol. We believe that the intended proximity of the words 'Japan DOT' in your Japanese- manufactured equipment might create the impression that Stanley was certifying compliance to the requirements of the Japanese Ministry of Transport, rather than to those of the U.S. Department of Transportation. Therefore, we suggest that you place the word 'Japan' at the end of the line rather than adjacent to the 'DOT' symbol.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam5359OpenMr. John Bloomfield Manager, Engine Management Legislation and Certification Lotus Cars, Ltd. Hethel, Norwich, Norfolk NR14 8EZ England; Mr. John Bloomfield Manager Engine Management Legislation and Certification Lotus Cars Ltd. Hethel Norwich Norfolk NR14 8EZ England; Dear Mr. Bloomfield: This responds to the letter from Ms. Rachel Jelly formerly of your company, concerning low volume CAFE exemptions. I apologize for the delay in our response. Ms. Jelly asked whether Bugatti Automobili S.p.A. (Bugatti) and Lotus Cars, Ltd. (Lotus), both of which are controlled by the same holding company, may submit separate low volume CAFE exemption petitions requesting two alternative standards. The answer to this question is no. Since any alternative CAFE standard would apply to Bugatti and Lotus together, a single combined petition must be submitted for a single alternative standard. The reasons for the above response are discussed in the attached letter from NHTSA to Mr. Lance Tunick, of Bugatti. Mr. Tunick's letter to NHTSA raised issues that are of concern to both Bugatti and Lotus. Thus, NHTSA's response to Mr. Tunick should address Lotus' concerns about filing for alternative CAFE standards. I hope this information is helpful. If there are any questions, please contact Dorothy Nakama of my staff at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam1928OpenMr. Harold D. Jones, Bock & Jones, 435 Main Street, New Madrid, MO 63869; Mr. Harold D. Jones Bock & Jones 435 Main Street New Madrid MO 63869; Dear Mr. Jones: This is in response to your letter of May 2, 1975, inquiring about th existence of regulations governing the manufacture, design, and on-the-road operation of trailers used to transport fertilizer while hitched to a pickup truck.; The National Highway Traffic Safety Administration has th responsibility of promulgating safety standards that set minimum performance requirements for vehicles manufactured and/or sold in the United States. There are five motor vehicle safety standards that apply to trailers. These standards relate to trailer lighting, tires, and braking systems (Standard No. 106-74, *Brake Hoses* (49 CFR Part 571.106), Standard No. 108, *Lamps, Reflective Devices and Associated Equipment* (49 CFR Part 571.108), Standard No. 116, *Motor Vehicle Brake Fluids* (49 CFR Part 571.116), Standard No. 119, *New Pneumatic Tires for Vehicles Other Than Passenger Cars* (49 CFR Part 571.119), Standard No. 121, *Air Brake Systems* (49 CFR Part 571.121)).; There is no safety standard that applies to the towing of a trailer The use of a safety chain to guard against release of the trailer may, however, be mandated by state law.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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.