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: aiam1154OpenMs. Cam Brame, Quality Assurance Analyst, Bendix Automotive Aftermarket, 1217 South Walnut Street, South Bend, Indiana 46620; Ms. Cam Brame Quality Assurance Analyst Bendix Automotive Aftermarket 1217 South Walnut Street South Bend Indiana 46620; Dear Ms. Brame: This is in reply to your letter of May 30, 1973 and confirms th telephone conversation with Mr. Vinson of my staff on June 14, 1973.; The amendments to Motor Vehicle Safety Standard No. 116 published o May 17, 1973 modified container labelling requirements only for silicone-based brake fluid and hydraulic system mineral oil (paragraph S5.2.2.3) and did not affect the requirements for conventional DOT 3 and DOT 4 fluids (paragraph S5.2.2.2) as you assumed. Therefore you appear to have no problem, and it is not necessary to consider your letter as a petition for reconsideration.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam2914OpenJames P. Bally, Esq., Messrs. Brownfield, Kosydar, Bowen, Bally & Sturtz, 140 East Town Street, Columbus, OH 43215; James P. Bally Esq. Messrs. Brownfield Kosydar Bowen Bally & Sturtz 140 East Town Street Columbus OH 43215; Dear Mr. Bally: We understand that you are interested in an interpretation of th relationsip (sic) of a rear lighting system, developed by your client Mr. Leno Bevilacqua, to Federal motor vehicle lighting requirements. As you described this device in your letter of September 29, 1978, to the Nevada Department of Highways:; >>>'The device will project a green light for the vehicle which woul be in a constant or accelerated speed, a yellow light for the vehicle in a decelerated moving state and a red light for the vehicle which would be stopping.'<<<; Federal Motor Vehicle Safety Standard No. 108, *Lamps, Reflectiv Devices, and Associated Equipment*, (49 CFR 571.108) neither requires nor expressly prohibits a lighting device of this nature as original equipment on motor vehicles. One section of the standard, however, S4.1.3, prohibits the installation of all original lighting equipment not mandated by the standard 'that impairs the effectiveness of lighting equipment required by this standard.' While we make no judgment with respect to Mr. Bevilacqua's 18-inch long 1 1/2 inch high rectangular device, I think it important to note that the agency's research into rear green signal lights indicate that there may be disadvantages rather than advantages to such a lighting system. One major disadvantage is the problem of confusing the unfamiliar colored rear lamps in urban environments having multicolored lights.; Standard No. 108 does not cover this device as an aftermarket item, an it would therefore be subject to regulation by the individual States.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3745OpenMr. Otto Major, 219 West Bel Air Avenue, Aberdeen, MD 21001; Mr. Otto Major 219 West Bel Air Avenue Aberdeen MD 21001; Dear Mr. Major: This is in response to your letter of August 18, 1983, in which yo assert that the Maryland Certificate of Title does not comply with the Federal Odometer disclosure statement requirements.; Your assertion is incorrect. States are permitted to use their titl documents in lieu of a separate Federal form, provided that the State form contains the odometer disclosure information specified in 49 CFR Part 580. Maryland's Certificate of Title contains this information and, therefore, satisfies the Federal odometer disclosure statement requirements. For your information, I have enclosed a copy of Part 580.; You also requested an interpretation regarding whether the installatio of a replacement engine of unknown mileage will require the transferor to report the mileage on the certificate as being unknown. The answer is no.; Section 408 of the Motor Vehicle Information and Cost Savings Act, 1 U.S.C. S 1968, and its implementing regulations, require the transferor of a motor vehicle to disclose to the transferee the cumulative mileage registered on the odometer or, that the actual mileage is unknown, if the odometer reading is known to be different from the number of miles the *vehicle* has actually traveled.; The Act does not require the separate disclosure of the number of mile traveled by the motor vehicle components, nor is there a mechanism in motor vehicles to measure the distance traveled by each component. Therefore, the installation of a replacement engine will not change the disclosure requirements of the transferor.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4361OpenMr. Thomas Baloga, Safety Engineering, Mercedes-Benz of North America, Inc., P. O. Box 350, Montvale, NJ 07645; 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 staf concerning the requirements of Standard No. 208, *Occupant Crash Protection.* You asked the agency to confirm that the 36 millisecond time interval 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 FR 37028), NHTSA published a final rule in th 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 the standard. That amendment referred to S6.2 as the provision of the standard containing the HIC requirement. Instead, the notice should have amended S6.1.2, which sets out the HIC calculation for the Part 572, Subpart B test dummy, and S6.2.2, which sets 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 S6.1.2 and S6.2.2 to make clear that the change to the calculation of the HIC criterion affects those two provisions.; If you need further information, please let me know. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam2486OpenMr. Jack D. Gross, Jr., National Sales Manager, Marchal America, 14622 Southlawn Lane, Rockville, MD 20850; Mr. Jack D. Gross Jr. National Sales Manager Marchal America 14622 Southlawn Lane Rockville MD 20850; Dear Mr. Gross: This is in reply to your letter of December 17, 1976, asking whether 1 U.S.C. 1392(d) permits the installation of quartz halogen headlamps on State-owned vehicles. It is understood that these headlamps are manufactured in France, and are not of sealed beam construction. Thus they do not conform to Motor Vehicle Safety Standard No. 108. Your letter also commented that certain 'state highway and law enforcement agencies . . . have indicated . . . that they prefer the quartz halogen units but are reluctant to install these units in their state vehicles because they are not of an approved type.'; Importation and sale of nonconforming motor vehicle equipment i expressly forbidden by Section 108 (a) (1) (A) of the National Traffic and Motor Vehicle Safety Act. A civil penalty of up to $1,000 may be imposed for each violation. Therefore, quartz halogen headlamps that do not conform to Standard No. 108 may not be imported into the United States and sold to State agencies.; Your inquiry appears premised that such may be allowable pursuant t Section 1392(d) which reads in pertinent part:>>>Nothing in the section shall be construed to prevent. . . the government of any State or political subdivision thereof from establishing a safety requirement applicable to motor vehicle or motor vehicle equipment procured for its own use if such requirement establishes a higher standard of performance than that required to comply with the otherwise applicable federal standard.; << |
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ID: aiam0157OpenMr. LaVern Goetz, State Chemist, Corporation Commission of Oklahoma, Jim Thorpe Building, Oklahoma City, Oklahoma 73105; Mr. LaVern Goetz State Chemist Corporation Commission of Oklahoma Jim Thorpe Building Oklahoma City Oklahoma 73105; Dear Mr. Goetz: This is in reply to your letter of April 15, 1969, in which you inquir about Federal regulation of brake fluid.; Brake fluid performance is regulated under the National Traffic an Motor Vehicle Safety Act by Federal Motor Vehicle Safety Standard No. 116. Copies of the Act and the current standards are enclosed.; Under the Vehicle Safety Act, manufacturers of motor vehicles an equipment (including brake fluid) that are covered by standards are fully responsible for ensuring that all of their products conform to the standards. The National Highway Safety Bureau conducts conformity tests of vehicles and equipment, either through its own personnel and facilities or under contract with other public or private testing organizations, but these are for enforcement purposes only.; The Bureau is conducting a continuing series of tests on brake fluid that has included samples from a majority of the major manufacturers, and will include the remainder in the near future. If you need more detailed information concerning this testing program, I suggest that you contact Mr. Francis Armstrong, Director, Office of Performance Analysis, National Highway Safety Bureau, Federal Highway Administration, Washington, D.C. 20591.; In answer to your final question, Standard No. 116 applies to all brak fluid manufactured or sold in the United States, and is not limited to that sold by automobile manufacturers or distributors.; Sincerely, Robert M. O'Mahoney, Assistant Chief Counsel for Regulations |
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ID: aiam0772OpenMr. O. Yamauchi, Manager, Export Sales Department, Mitsubishi Motors Corporation, 33-8, 5-Chome, Shiba, Minato-Ku, Tokyo, Japan; Mr. O. Yamauchi Manager Export Sales Department Mitsubishi Motors Corporation 33-8 5-Chome Shiba Minato-Ku Tokyo Japan; Dear Mr. Yamauchi: This is in replay to your letter of June 7, 1972, concerning whethe thin transparent polyethylene covers used to protect the inside of vehicles until delivery are subject to the requirements of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials.' You indicate that the material does not conform to the requirements of the standard, and ask whether you may nonetheless utilize it if you place a label in the vehicle directing that the cover be removed before the car is delivered to the customer.; Whether the material must meet the requirements of the standard depend upon the likelihood that it will be retained as a protective cover by the purchaser. If it is installed in a manner that promotes its use by purchasers, we would consider it to be part of any component which it covers, and subject to the standard when used to cover those components enumerated in S4.1 of the standard. Manufacturers must therefore take appropriate steps to see that it is not so used. The use of a label that states that the material must be removed before delivery to a purchaser is one step a manufacturer might take. We believe the manufacturer should also install the material in such a way that purchasers will not wish to use it as a protective covering. If these steps are taken the NHTSA would not consider the material to be required to comply with the standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5657OpenTerence J. Kann, P.A. 115 N.E. Seventh Avenue Gainesville, FL 32601; Terence J. Kann P.A. 115 N.E. Seventh Avenue Gainesville FL 32601; Dear Mr. Kann: This responds to your letter of November 14, 1995, t Ricardo Martinez, M.D. Administrator of the National Highway Traffic Safety Administration. You have asked whether 'pole trailers such as those used in the logging industry, are required to have retro-reflective sheeting, reflex reflectors, or a combination?' If not, you asked whether NHTSA issued 'any explanation for failing to extend the requirements to pole trailers.' As you noted, Section S3(a) of Motor Vehicle Safety Standard No. 108 applies to 'trailers (except pole trailers) . . . .' This means that pole trailers, as defined in 49 CFR 571.3(b) are exempted from all the requirements of Standard No. 108 including those of Section S5.7 which specifies conspicuity requirements for 'each trailer of 80 or more inches overall width and with a GVWR over 10,000 pounds'. Pole trailers have always been excluded from Standard No. 108 (see 23 CFR 255.51, Motor Vehicle Safety Standard No. 108, Section S2, effective January 1, 1968). Thus, the agency never proposed in the first instance that conspicuity requirements apply to pole trailers, and there was no discussion of pole trailers in the preambles to the proposal and final rule. Apparently, pole trailers were defined and excluded on the basis of comments to Standard No. 108 as originally proposed late in 1966 that a standardized lighting scheme might be impracticable for this category of vehicle. If you have any questions, you may refer them to Taylor Vinson of this Office (202-366-5263). Sincerely, Samuel J. Dubbin Chief Counsel; |
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ID: aiam1935OpenMr. Ernest D. Mathews, Chief, Field Services, Department of Motor Vehicles, Sate of Vermont, Montpelier, VT 05602; Mr. Ernest D. Mathews Chief Field Services Department of Motor Vehicles Sate of Vermont Montpelier VT 05602; Dear Mr. Mathews: This is in reply to your letter of April 17, 1975, to this agenc asking questions about paragraph S4.6(b) of Motor Vehicle Safety Standard No. 108, relating to headlamp flashers. Your reference to S4.5.8(b) is out-dated by approximately three years and I am enclosing a copy of Standard No. 108 as it now exists.; You asked the reason for the section in question, which provides tha 'All other lamps shall be steady- burning, except that means may be provided to flash headlamps and side marker lamps for signaling purposes.' You also asked whether all motor vehicles, including motorcycles, are 'authorized' by this section to use flashing headlamps, and finally whether the standard prohibits States from promulgating regulations to control flashing headlamps.; S4.6(b) was not intended as a regulation of this aspect of moto vehicle performance, in the sense that it would preempt all State regulation of the sale or use of headlamp flashers. It is basically merely an exception to the requirement of Standard 108 that all lamps (other than turn signals, hazard warning signals, and school bus warning signals) be steady-burning. The section, in other words, was included to make it clear that automatic headlamp flashers are not prohibited by the Federal standard. With reference to your questions, this is the only way in which they are 'authorized' by Standard 108.; We have concluded, therefore, that State regulation of headlam flashers is not preempted by the Federal standard.; Sincerely, James C. Schultz, Chief Counsel |
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ID: aiam4742OpenJoseph R. Wheeler, Esq. P.O. Box 2808 424 Church St., Suite 2900 Third National Financial Center Nashville, TN 37219; Joseph R. Wheeler Esq. P.O. Box 2808 424 Church St. Suite 2900 Third National Financial Center Nashville TN 37219; "Dear Mr. Wheeler: This is in response to your letter to Kennet Weinstein of my staff requesting information about actions by the Secretary of Transportation pursuant to Federal Motor Vehicle Safety Standard No. 208, Occupant Crash Protection (49 CFR 571.208). More specifically, you noted that S4.1.4.1 of Standard No. 208 states that, 'Except as provided in S4.1.5 and another section not relevant to your inquiry , each passenger car manufactured on or after September 1, 1989 shall comply with the automatic restraint requirements .' S4.1.5 of Standard No. 208 provides that: 'If the Secretary of Transportation determines, by not later than April 1, 1989, that state mandatory safety belt usage laws have been enacted that meet the criteria specified in S4.1.5.2 and that are applicable to not less than two-thirds of the total population . . ., the automatic restraint requirements will not go into effect .' You asked whether the Secretary ever made a determination under S4.1.5 regarding State safety belt use laws. The answer is no. Under S4.1.5, the Secretary was not required to make any determination about any State safety belt laws. In fact, the Secretary never did so. Because no determination was made under S4.1.5, the automatic restraint requirements are now in effect for all passenger cars. This letter expresses no opinion about the implications under Tennessee law of the absence of a determination by the Secretary of Transportation regarding any State's safety belt law. Sincerely, Paul Jackson Rice 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.