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: aiam2792OpenMr. R. G. Wilkins, Product Safety and Reliability, Grove Manufacturing Co., Shady Grove, PA 17256; Mr. R. G. Wilkins Product Safety and Reliability Grove Manufacturing Co. Shady Grove PA 17256; Dear Mr. Wilkins: This responds to your recent letter asking whether plastic glazin materials may be used on the superstructure operator cabs of mobile construction cranes. Apparently, the upper superstructure cab is used only for craning operations and is distinct from the cab used to drive the crane over public highways.; Under Federal Motor Vehicle Safety Standard No. 205, *Glazin Materials* (49 CFR Part 571.205), plastic glazing may be used only in locations to the rear of the driver in trucks or truck tractor cabs and only at levels not requisite for driving visibility. Therefore, plastic glazing could not be used in the windshield or windows to the right or left of the driver in the main driving cab of the mobile crane. It is our interpretation, however, that the superstructure operator cab is, effectively, to the rear of the driver when the vehicle is being used on the highway and could be equipped with plastic glazing materials meeting the requirements of Standard No. 205. This interpretation assumes that the operator cab cannot be used to drive the mobile crane on the highway. If the operator cab could be used as the driving cab, plastic glazing could only be used in locations to the rear of the driver at levels not requisite for driving visibility.; Please contact this office if you have any questions concerning thi interpretation.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam0266OpenMr. B. Borisoff, Consulting Engineer, 5403 Blanco Avenue, Woodland Hills, CA 91364; Mr. B. Borisoff Consulting Engineer 5403 Blanco Avenue Woodland Hills CA 91364; Dear Mr. Borisoff: Reference is made to your letter of October 14, 1970 to Secretary Volp regarding our Consumer Information publication.; Concerning your comments on stopping distance, the wording used on pag 4 is the exact wording of this regulation. The category 'Stopping distance in feet with emergency brakes (partial service brake system)' is a generalization of the regulatory wording meant to convey the sense of this requirement to a consumer who may have no engineering background. The paragraph on page 193 paraphrases the regulatory wording. The title 'Partial Failure on One System' is, again, meant to convey the meaning to an otherwise uninformed consumer. I trust this clarifies the situation for you.; The reason many motorcycles are not listed is the fact that the dat was not received in time to be included in the book. I am enclosing copies of the data available for U.S. made motorcycles as you requested.; Volume 2, covering the 1971 makes and models will be availabl approximately November 15, 1970 and can be obtained from the Government Printing Office at a cost of $2.00. In addition two (2) new Consumer Aid publications entitled 'BRAKES - A Comparison of Braking Performance for 1971 Passenger Cars' and 'TIRES - A Comparison of Tire Reserve Load for 1971 Passenger Cars' will also be available at a cost of $.40 each.; Many thanks for your kind words and your interest in our motor vehicl safety program.; Sincerely, Rodolfo A. Diaz, Acting Associate Director, Motor Vehicl Programs; |
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ID: aiam0398OpenMr. M. G. Uttley, Technical Dept. Manager, Norton Villiers Limited, Engine Division, Marston Road, Wolverhampton WV2 4NW, England; Mr. M. G. Uttley Technical Dept. Manager Norton Villiers Limited Engine Division Marston Road Wolverhampton WV2 4NW England; Dear Mr. Uttley: This is in reply to your letter of June 17, 1971, concerning complianc of the Morton Villiers Commando Production Racer with the front side marker requirements of the Federal lighting standard, No. 108.; It is our understanding that the racer fairing is detachable only wit considerable time and effort. For all intents and purposes the fairing can be regarded as a permanent part of the vehicle and thus an appropriate place to mount the side markers.; Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam0774OpenMr. Barry G. Taylor, Executive Vice President, Argo Plastic Company, 6830 E. Washington Boulevard, Los Angeles, CA 90040; Mr. Barry G. Taylor Executive Vice President Argo Plastic Company 6830 E. Washington Boulevard Los Angeles CA 90040; Dear Mr. Taylor: This is in reply to your letter of June 27, 1972, requesting Federa 'approval' for plastic glazing material you manufacture. You enclose copies of certificates showing approval by the State of California.; The NHTSA does not provide approvals for glazing materials subject t its requirements. These requirements are found in Federal Motor Vehicle Safety Standard No. 205, 'Glazing Materials,' and apply to glazing materials for use in motor vehicles manufactured for sale in the United States. (This includes the 50 States, the District of Columbia, Puerto Rico, Guam, the Virgin Islands, the Canal Zone, and American Samoa, and not 37 States as you mention.); Under the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 138 *et seq.*) manufacturers must use due care to ensure that products they manufacture conform to applicable standards (15 U.S.C. 1397 (b)(2)). The manufacturer must certify conformity as specified in section 114 of the Act (15 U.S.C. 1403), and in the case of Standard No. 205, as specified in the standard. The NHTSA does not approve manufacturers' products or their certification, but monitors compliance with the standards by purchasing materials on the open market, and testing them to the requirements of the standard. The failure of materials to conform can result in the imposition of civil penalties against the manufacturer, and other sanctions (15 U.S.C. 1398, 1399).; A copy of Standard No. 205 and the National Traffic and Motor Vehicl Safety Act are enclosed for your information.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2672OpenMr. J. Shillinger, Project Engineer, AM General Corporation, 32500 Van Born Road, Wayne, MI 48184; Mr. J. Shillinger Project Engineer AM General Corporation 32500 Van Born Road Wayne MI 48184; Dear Mr. Shillinger: This responds to AM General Corporation's July 18, 1977, request fo confirmation that certain aspects of the M.A.N. articulated transit bus conform to the requirements of Standard No. 121, *Air Brake Systems*, and Standard No. 124, *Accelerator Control Systems*. In an October 3, 1977, telephone call with Mr. Herlihy of this office, it was determined that the request for interpretation is now limited to confirmation that the four-way pressure protection valve described in M.A.N.'s June 22, 1977, letter would meet the location and functional requirements of S5.1.2.3 of Standard No. 121. Section S5.1.2.3 specifies--; >>>S5.1.2.3 Each service reservoir shall be protected against loss o air pressure due to failure or leakage in the system between the service reservoir and its source of air pressure by check valves or equivalent devices.<<<; I am enclosing prior interpretations of the location requirement o S5.1.2.3. While the agency cannot 'approve' systems based on schematic drawings, it appears that the location of the four-way protection valve in the M.A.N. drawings does not violate the provisions contained in S5.1.2.3.; As we understand the description and capabilities of the four-wa valve, it appears to be a pressure protection device that is 'equivalent' to the check valve otherwise required by S5.1.2.3.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam4019OpenDouglas I. Greenhaus, Esq. National Automobile Dealers Association, 8400 Westpark Drive, McLean, VA 22102; Douglas I. Greenhaus Esq. National Automobile Dealers Association 8400 Westpark Drive McLean VA 22102; Dear Mr. Greenhaus: This is in response to your request of October 7, 1985, concernin Federal odometer disclosure regulations, 49 CFR Part 580.; The form you enclosed, as is, does not meet the requirements of sectio 580.4(a)(3) and/or (4). However, if the purchasing/selling dealer includes his/her name and address at the upper left hand corner of the form, the requisite information will be set forth and the form will conform to agency procedural requirements. There is no prohibition against combining odometer disclosure information with other information concerning the sales transaction.; Sincerely, Kathleen DeMeter, Assistant Chief Counsel for General Law |
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ID: aiam2674OpenMr. Joseph A. Labert, President, Sharon Recreation World, Inc., 3960 Union Road, Cheektowaga, NY 14225; Mr. Joseph A. Labert President Sharon Recreation World Inc. 3960 Union Road Cheektowaga NY 14225; Dear Mr. Labert: This is in response to your letter of September 1, 1977, concerning th permissibility of installing hitches which inhibit the shock absorbing capability of vehicle bumpers.; The attachment of hitches to motor vehicle bumpers will not constitut a violation of any Federal motor vehicle safety standard. The testing requirements of the Federal safety standard that applies to bumpers (Standard No. 215, *Exterior Protection*) specify that trailer hitches are to be removed prior to testing for compliance. Thus, it is only necessary that the vehicle comply with the standard when the trailer hitch is not attached.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3658OpenMr. M. Iwase, Manager, Technical Administration Department, Koito Mfg. Co., Shizuoka Works, 500, Kitawaki, Shimizu-Shi, Shizuoka-Ken, Japan; Mr. M. Iwase Manager Technical Administration Department Koito Mfg. Co. Shizuoka Works 500 Kitawaki Shimizu-Shi Shizuoka-Ken Japan; Dear Mr. Iwase: This is in reply to your letter of January 27, 1983, to Mr. Elliott o this agency asking whether your 'lighting device with 1 bulb and 2 functions' is permissible under Federal Motor Vehicle Safety Standard No. 108.; The front combination lamp design (parking lamp and side marker lam functions) is permissible provided that, as you note, all color and photometric requirements for the respective functions are met.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0363OpenMr. Bob Stallius, Hopkinsville Tire Service, Route 1, Fort Campbell Boulevard, Hopkinsville, KY 42240; Mr. Bob Stallius Hopkinsville Tire Service Route 1 Fort Campbell Boulevard Hopkinsville KY 42240; Dear Mr. Stallius: This is in reply to your letter of May 14, 1971, concerning the Tir Identification and Record Keeping Regulation. Please accept my apology for not responding earlier.; The National Highway Traffic Safety Administration considers eac enforcement case on an individual basis. If a retreader could demonstrate that good faith attempts had been made to obtain the tin plate by May 22, 1971, and due to circumstances beyond his control he was unable to mark tires manufactured after May 22, 1971, with the required information, we would certainly take this into consideration before beginning any enforcement action.; Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam2979OpenMr. C. J. Newman, Vice President, Engineering, The Grote Manufacturing Company, State Route 7, P.O. Box 766, Madison, IN 47250; Mr. C. J. Newman Vice President Engineering The Grote Manufacturing Company State Route 7 P.O. Box 766 Madison IN 47250; Dear Mr. Newman: This is in reply to your letter of February 15, 1979, asking for a interpretation of S4.3.1.1.1 of Motor Vehicle Safety Standard No. 108.; You have informed us that dimensional changes in refrigeration units o the front of commercial trailers mean that clearance lamps are no longer visible at 45 degrees inboard if they are mounted as they have been in the past. You have proposed three alternate solutions to the problem.; S4.3.1.1.1 provides in pertinent part that 'clearance lamps may b mounted at a location other than on the front and rear if necessary to indicate the overall width of the vehicle...and at such a location they need not be visible at 45 degrees inboard.' Your first proposed solution is that 'The lamps could be mounted on the front of the vehicle as normal and the 45 degree inboard visibility requirements waived in accordance with S4.3.1.1.1.'; We believe that this is preferable to your other suggested solution that utilize angle-mounted combination lamps. Standard No. 108 appears to prescribe alternate requirements for location and visibility of clearance lamps--preferable on the front and visible throughout 45 degree angles, but if not, elsewhere than the front and where they need not be visible through the 45 degree angles. Your first proposed solution comprises elements of each of Standard No. 108's alternatives, and while it is not expressly permitted by Standard No. 108, it does not appear to violate it.; Sincerely, Frank Berndt, Acting 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.