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 |
|---|---|
| search results table | |
ID: aiam2451OpenMr. Donald I. Reed, Director of Engineering, Trailer Manufacturers Association, 401 North Michigan Avenue, Chicago, IL, 60611; Mr. Donald I. Reed Director of Engineering Trailer Manufacturers Association 401 North Michigan Avenue Chicago IL 60611; Dear Mr. Reed: This is in reply to your letter of October 29, 1976, asking whether th '47 Series Tite-Lite,' in our opinion, has an ''optically combined' clearance lamp function.' The lamp in question is represented as having 'two lights [that] provide 15 functions' and you have advised us that 'there are no partitions inside the multi-function lens of this lamp.'; Paragraph S4.4.1 of Motor Vehicle Safety Standard No. 108 prohibits th optical combination of clearance lamps with tail lamps and identification lamps. This means that a single bulb in the 47 Series Tite-Lite may not provide both tail lamp and clearance lamp functions. It also means that the light emitted by one bulb must not be perceived as performing the function of the other in addition to its design function. You have neither identified the function performed by both bulbs nor provided us with their candle-power output and we are unable to determine whether the lamp complies with Standard No. 108.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
|
ID: aiam0196OpenMr. H. Kirstein, Volkswagen of America, Incorporated, Englewood Cliffs, New Jersey 07632; Mr. H. Kirstein Volkswagen of America Incorporated Englewood Cliffs New Jersey 07632; Dear Mr. Kirstein: This will acknowledge your letter of November 25, 1969, to the Nationa Highway Safety Bureau requesting the addition of the 4-J and 4 1/2-J rims for use with the 5.60x15 tire size designation and the 4 1/2-J rim use with the 6.00x15 tire size designation to Table I, Appendix A of Federal Motor Vehicle Safety Standard No. 110.; The addition of these rims to Standard No. 110 is not necessary, a these combinations are listed within the references cited in S.3 of Standard No. 109. The fact that you have changed the hump configuration on these rims requires no action on our part as we do not list variations from the basic Tire and Rim Association's contours. We consider only the rim width and flange contour designation at this time when listing rims in the standard.; Manufacturers who modify rims are, of course, responsible to see tha their product will perform satisfactorily to the requirements of Standard No. 109 and No. 110.; Sincerely, Charles A. Baker, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service; |
|
ID: aiam0482OpenMr. F. R. Hoffman, Assistant Traffic Manager, Barber-Greene Company, Aurora, IL, 60507; Mr. F. R. Hoffman Assistant Traffic Manager Barber-Greene Company Aurora IL 60507; Dear Mr. Hoffman: Please forgive our delay in responding to your letter of August 27 1971, asking if Department of Transportation safety equipment applicable to trailers is required for portable asphalt mixing machinery.; It is our current position that portable asphalt mixing machinery is 'trailer' and must be equipped with the lamps and reflectors required by Motor Vehicle Safety Standard No. 108. I am enclosing a copy for your information. A temporary lighting harness is an acceptable means of conformance. Mud flaps, incidentally, are not required under the Federal motor vehicle safety standards.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
|
ID: aiam0178OpenMr. Warren M. Heath, Commander, Engineering Section, Department of California Highway Patrol, P. O. Box 898, Sacramento, CA 95804; Mr. Warren M. Heath Commander Engineering Section Department of California Highway Patrol P. O. Box 898 Sacramento CA 95804; Dear Mr. Heath: Thank you for your letter of August 29, 1969, to Dr. Robert Brenner Acting Director, National Highway Safety Bureau, concerning the flashing of sidemarker lamps when the turn signal switch is activated.; Paragraph S3.5 of Federal Motor Vehicle Safety Standard No. 108 permit the flashing of sidemarker lamps simultaneously with the turn signal lamps on the side to which a turn is contemplated.; Sincerely, Charles A. Baker, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service; |
|
ID: aiam2145OpenMr. Byron A. Crampton, Manager of Engineering Services, 5530 Wisconsin Avenue, Suite 1220, Washington, D.C. 20015; Mr. Byron A. Crampton Manager of Engineering Services 5530 Wisconsin Avenue Suite 1220 Washington D.C. 20015; Dear Mr. Crampton: In response to your November 24, letter concerning the relationshi between Federal Motor Vehicle Safety Standards No. 109 and 119, I am enclosing a copy of a prior interpretation letter on the same subject, which was sent to Mr. C.D. McCarty of the B.F. Goodrich Company on October 15, 1975.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
|
ID: aiam4992OpenL. Louis Raring, Esquire Raring & Lipoff 4400 MacArthur Boulevard Newport Beach, CA 92660; L. Louis Raring Esquire Raring & Lipoff 4400 MacArthur Boulevard Newport Beach CA 92660; "Dear Mr. Raring: This responds to your request for information o Federal Motor Vehicle Safety Standard No. 218, Motorcycle Helmets (49 CFR 571.218). Specifically, you were interested in whether this agency 'approves' motorcycle helmets pursuant to Standard No. 218. I am pleased to have this chance to explain our laws and regulations for you. The National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq., Safety Act) authorizes this agency to issue safety standards applicable to new motor vehicles and items of motor vehicle equipment. We have exercised this authority to establish Standard No. 218, which applies to all new helmets designed for use by motorcyclists and other motor vehicle users. Standard No. 218 sets forth a series of performance tests to ensure that motorcycle helmets will reduce deaths and injuries to motorcyclists resulting from head injuries. When a safety standard like Standard No. 218 is in effect, section 108(a)(1)(A) of the Safety Act (15 U.S.C. 1397(a)(1)(A)) provides that no person shall 'manufacture for sale, sell, offer for sale, or introduce or deliver for introduction in interstate commerce, or import into the United States' any motorcycle helmet unless that helmet is in conformity with Standard No. 218 and is covered by a certification issued under section 114 of the Safety Act (15 U.S.C. 1403). This statutory requirement that every motorcycle helmet be covered by a certification pursuant to section 114 of the Safety Act means that the United States follows a different approach to ensuring conformity with its motor vehicle safety standards than do some other countries. In the European countries, for example, a helmet manufacturer would deliver a sample of its helmets to a governmental entity for approval before any of those helmets can be offered for sale. The governmental entity would then conduct testing and, assuming the helmet passed the tests, assign an approval code to these helmets. The manufacturer could offer this type of helmet for sale after it receives this government approval code. The United States follows a substantially different approach. Instead of putting the burden on the government to initially decide if a motorcycle helmet or other item of motor vehicle equipment complies with all applicable safety standards, the Safety Act puts the burden on the manufacturer of the motorcycle helmet. It is the motorcycle helmet manufacturer that must, in the first instance, determine whether its helmets conform to Standard No. 218. Once the manufacturer is satisfied that its helmets conform to the requirements of the standard, it certifies that conformity by labeling the symbol DOT on the helmet, pursuant to S5.6.1(e) of Standard No. 218. The manufacturer may offer its helmet for sale as soon as it has certified the helmet as conforming with Standard No. 218. For enforcement purposes, NHTSA periodically purchases certified motorcycle helmets and tests them to the specific requirements of Standard No. 218. If, as is the case in the vast majority of instances, the helmets conform to all the requirements of the standard, no further action is taken. If the helmets are determined not to conform to all the requirements of the standard, the manufacturer is liable to notify owners of the noncompliance and to remedy the noncompliance without charge to the consumer, pursuant to sections 151-159 of the Safety Act (15 U.S.C. 1411-1419). In addition, the helmet manufacturer would be liable for a civil penalty of up to $1,000 for each noncomplying helmet it manufactured, pursuant to section 109 of the Safety Act (15 U.S.C. 1398). I hope this information is helpful. Please feel free to contact Dorothy Nakama of my staff at this address or by telephone at (202) 366-2992 if you have any further questions or need additional information. Sincerely, Paul Jackson Rice Chief Counsel"; |
|
ID: aiam4838OpenMr. Hiroshi Ozeki Executive Vice President Mazda Research & Development of North America, Inc. 1203 Woodbridge Avenue Ann Arbor, Michigan 48105; Mr. Hiroshi Ozeki Executive Vice President Mazda Research & Development of North America Inc. 1203 Woodbridge Avenue Ann Arbor Michigan 48105; Dear Mr. Ozeki: This responds to your letter of August 8, 199 requesting an interpretation of Standard No. 214. You state that one of Mazda's future models has a door design in which the door moulding extends below the door itself by approximately 15 millimeters. You asked whether, for purposes of positioning the loading device used in the quasi-static test of side door strength, the 'lowest point of the door' referred to in S4(c)(2) of the standard would be the bottom of the door moulding or the bottom of the door itself when the moulding extends lower than the door itself. For the quasi-static test of side door strength under Standard No. 214, S4(c)(2) currently provides that the loading device must be positioned so that '. . . (2) Its longitudinal axis is laterally opposite the midpoint of a horizontal line drawn across the outer surface of the door 5 inches above the lowest point of the door.' Under the current standard, we believe that door moulding should be considered part of the door. Therefore, the 'lowest part of the door' would be the lowest part of an attached door moulding. Under the current standard, that would be the reference point to be used in making the five-inch measurement. For your further information, the agency is considering proposing for public comment a possible amendment to the standard concerning the positioning of the test device. I hope that this information is helpful. If you have any questions, please contact John Rigby at 202-366-2992. Sincerely, Paul Jackson Rice Chief Counsel; |
|
ID: aiam0528OpenMr. Satoshi Nishibori, Engineering Representative, Liaison Office In U.S.A., Nissan Motor Company, Ltd., 400 County Avenue, Secaucus, NJ 07094; Mr. Satoshi Nishibori Engineering Representative Liaison Office In U.S.A. Nissan Motor Company Ltd. 400 County Avenue Secaucus NJ 07094; Dear Mr. Nishibori: By letter of December 6, 1971, you have asked our opinion as to ho S6.1 of Standard 208 applies to two hypothetical situations. S6.1 requires that 'all portions of the test device shall be contained within the outer surfaces of the passenger compartment throughout the test.'; Your first situation involves a vehicle in which the impact of th dummy's head causes the windshield to bulge beyond its original location but does not penetrate the windshield. It is our opinion that in this case the vehicle has contained the occupant and would conform to S6.1.; In your second situation, the dummy's head pushes the windshield loos at its base and opens a gap between the windshield and the vehicle. It is our opinion that this drawing also shows the dummy to be satisfactorily contained.; In either situation, however, a manufacturer would have to assur himself that the windshield behavior shown in the drawings would be consistent and would not lead to failure in tests in which the test dummy strikes it in a different manner.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
|
ID: aiam2515OpenMr. B. R. Weber, Executive Vice President, Wesbar Corporation, Box 577, West Bend, WI 53095; Mr. B. R. Weber Executive Vice President Wesbar Corporation Box 577 West Bend WI 53095; Dear Mr. Weber: Thank you for your frank letter of January 13, 1977, commenting upo the lack of clarity you feel exists in my letter to you of December 6, 1976, interpreting Motor Vehicle Safety Standard No. 108.; As a lawyer it is obvious to me that the best regulatory practice is t be as specific as possible in establishing requirements and prohibitions. When a regulation itself is unclear, however, its interpretation may necessarily be imprecise. Because the term 'optical combination' in S4.4.1 is not defined, my answers were necessarily worded in general terms though with the thought of establishing a general framework of guidance for you. They were not intended to be 'a masterpiece of bureaucratic weasel words.' My letter meant, in plain English, that where tail lamps and clearance lamps are in a single compartment we don't want one lamp to perform, or to be perceived as performing, the function of the other. It is evident from your letter and others that our previous interpretations of the term 'optical combination' have been found to be ambiguous and lacking in the objective criteria that a Federal motor vehicle safety standard must provide. We have reviewed the matter, and now wish to modify our previous interpretation. In our view a lamp is 'optically combined' when the same light source (i.e. bulb) and the same lens area fulfill two or more functions (*e.g.* taillamp and stop lamp, clearance lamp and turn signal lamp). A dual filament bulb would be regarded as the 'same light source'. In determining conformance, the photometric requirements for clearance and taillamp functions, where two bulbs are located in a single compartment, must be met with only the bulb energized that is designed to perform the specific function. But the 15 candlepower maximum under Standard No. 108, however, would be determined with both the taillamp and clearance lamp bulb energized. Further, the lamp must be located to meet requirements for both clearance and taillamps. Our re- interpretation means that the issue of light spill-over from one area of the lamp to another is irrelevant to conformance.; Sincerely, Frank Berndt, Acting Chief Counsel |
|
ID: aiam1293OpenL.E. Haight, Esq., Attorney at Law, 805 Idaho Street, P.O. Box 2777, Boise, ID 83701; L.E. Haight Esq. Attorney at Law 805 Idaho Street P.O. Box 2777 Boise ID 83701; Dear Mr. Haight: This is in reply to your letter of September 21, 1973, concerning you desire to disconnect the interlock system on your new car.; The dealer who sold you the car was required to have the interloc working at the time of sale, pursuant to section 108(a)(1) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1397(a)(1)). However, section 108(b)(1) of the Act (15 U.S.C. 1397(b)(1)), provides that the requirements of 108(a)(1) do not apply after the first purchase of the vehicle for purposes other than resale. As a purchaser who intends to use the vehicle, you are therefore not subject to the requirements of the Act and may disconnect the interlock.; Despite the absence of legal sanctions for disconnecting the interlock we would hope that you could find a way to adjust the belt so that it could be worn without aggravating your bursitis. The physical sanctions for an unbelted person in a crash can be serious indeed.; Sincerely, Richard B. Dyson |
|
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.