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: aiam0146OpenMr. Sam W. Folsom, Jr., Gold Cross Ambulance Service, Inc., 304 Northwest Tenth, Oklahoma City, OK 73103; Mr. Sam W. Folsom Jr. Gold Cross Ambulance Service Inc. 304 Northwest Tenth Oklahoma City OK 73103; Dear Mr. Folsom: This is in reply to your letter of January 18, 1969, to Dr. Willia Haddon, Jr., requesting information on Federal Motor Vehicle Safety Standards (FMVSS) applicable to ambulances.; If the ambulance is built on a passenger car chassis, all of the FMVS applicable to passenger cars would apply. However, if the ambulance is built on a truck chassis, the FMVSS applicable to multi-purpose passenger vehicles would apply. There have been no special exceptions granted for ambulances.; Enclosed for your information and guidance are copies of the Nationa Traffic and Motor Vehicle Safety Act of 1966 and the FMVSS established thereunder.; Sincerely, Francis Armstrong, Director, Office of Performance Analysis Motor Vehicle Safety Performance Service; |
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ID: aiam2481OpenMr. J. W. Lawrence, Manager, Safety & Environmental Engineering, White Motor Corporation, 35129 Curtis Boulevard, Eastlake, OH 44094; Mr. J. W. Lawrence Manager Safety & Environmental Engineering White Motor Corporation 35129 Curtis Boulevard Eastlake OH 44094; Dear Mr. Lawrence: This is in reply to your letter of February 18, 1977, asking whether 4 CFR Part 577 conflicts with Section 153(c)(4) of the National Traffic and Motor Vehicle Safety Act.; Pursuant to Section 153(c)(4) notification by a manufacturer to dealer must be 'by certified mail or other more expeditious means.' On the other hand, Part 577 requires notification to be given by first class mail to the first or most recent purchaser known to the manufacturer, in your view, which could mean a dealer. You stated that the 'apparently conflicting' requirements affect the mailing of notices to dealers when they are the last known purchasers.; There is no conflict. Part 577 is a regulation for the notification o owners of vehicles, not dealers. The regulation sets forth-- 'requirements for notification to owners of motor vehicles' (577.1) and its purpose 'is to insure that notifications of defects or noncompliances adequately inform and effectively motivate owners...to have such vehicles...inspected and, when necessary, remedied as quickly as possible' (577.2). A dealer is not an 'owner' within the intent of Part 577 and a manufacturer's notification obligation to its dealers is that set out in Section 153(c)(4).; Therefore, we cannot confirm that first class mailings from manufacturer to a dealer conform to Part 577, and your letter offers no facts upon which to base a finding that first class mail is a 'more expeditious means' of dealer notification than certified mail.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam5344OpenMr. Frank Williams President Safety Brake Set 3508 Cascade Highway Silverton, OR 97381; Mr. Frank Williams President Safety Brake Set 3508 Cascade Highway Silverton OR 97381; "Dear Mr. Williams: This responds to your letter requesting informatio about Federal requirements related to a product that 'sets the brakes on an air brake vehicle when the driver exits the cab.' I apologize for the delay in our response. You stated that your 'device does not hook into the brake system but pops the parking button out if the driver is off the seat and the door is open. The brake then must be manually disengaged.' You requested confirmation that the agency will neither support nor oppose the aftermarket installation of such a device. I am pleased to have this opportunity to explain our regulations to you. I am also enclosing a copy of a fact sheet entitled 'Information for New Manufacturers of Motor Vehicles and Motor Vehicle Equipment.' By way of background information, the National Highway Traffic Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its vehicles or equipment comply with all applicable standards. The following represents our opinion based on the facts provided in your letter. NHTSA does not have any specific regulations about a product such as your device. However, since this device is related to a vehicle's air brake system, it could affect a vehicle's compliance with Standard No. 121, Air Brake Systems. That standard applies to almost all new trucks, buses, and trailers equipped with air brake systems. If your system is installed as original equipment on a new vehicle, the vehicle manufacturer is required to certify that, with the device installed, the vehicle satisfies the requirements of all applicable safety standards, including Standard No. 121. (See 15 U.S.C. 1397(a)(1) and 49 CFR Part 567). If the device is added to a previously certified new motor vehicle prior to its first consumer purchase, then the person who modifies the vehicle would be an alterer of a previously certified motor vehicle and would be required to certify that, as altered, the vehicle continues to comply with all of the safety standards affected by the alteration. 49 CFR 567.7. If the device is installed on a used vehicle by a manufacturer, distributor, dealer, or motor vehicle repair business, then the installer would not be required to attach a certification label. However, it would have to make sure that it did not knowingly render inoperative, in whole or in part, any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard. 15 U.S.C. 1397(a)(2)(A). In particular, these entities should ensure that the installation of your device does not render inoperative the vehicle's compliance with the parking brake requirements set forth in S5.6. I hope this information is helpful. If you have any questions about NHTSA's safety standards, please feel free to contact Marvin Shaw at this address or by telephone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosure"; |
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ID: aiam0516OpenMr. Armand F. Macmanus, Esq., Phillips Petroleum Company, Bartlesville, OK 74004; Mr. Armand F. Macmanus Esq. Phillips Petroleum Company Bartlesville OK 74004; Dear Mr. Macmanus: This is in reply to a request made on behalf of Phillips Petroleu Company by Veigh J. Nielson for an assigned identification mark for two of Phillips' plants which manufacture tires for research purposes.; As I informed you in my letter of September 20, 1971, if Phillip purchases a new tire, removes the tread material and then applies its own experimental tread containing various rubber compounds, Phillips is considered to be a new tire manufacturer. If Phillips applies its experimental tread to a used tire, it is considered a retreader of tires.; As a new tire manufacturer you are required to certify the tire a conforming to the new passenger car tire standard (No. 109) and comply with Part 574 - Tire Identification and Record Keeping (49 CFR 574). Accordingly, you are assigned the identification mark of 'J1' for tires made in your Bartlesville, Oklahoma plant and 'K1' for tires manufactured in your Stow, Ohio plant.; If you act as a retreader then Part 574 would not be applicable for th tires you retread because they are retreaded for your own use. (Enclosed is a copy of Docket No. 70-12, Notice No. 8 which makes the regulation inapplicable to retreaders who retread for their own use). As explained in my letter of September 20, you are, of course, required to certify that your new tires and your retreaded tires comply with the respective standards for new and retreaded tires if they are to be used on the public highways, by placing the symbol DOT on the tires in the prescribed location.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam4806OpenMr. Mitch L. Williams President, Hella Inc. P.O. Box 1064 Cranford, NJ 07016; Mr. Mitch L. Williams President Hella Inc. P.O. Box 1064 Cranford NJ 07016; "Dear Mr. Williams: This is in reply to your letters of November 1 an 8 to Richard Van Iderstine of this agency. In your letter of November 1 you ask 'How would NHTSA view the addition of a rear spoiler with integrated third rear brake light to a vehicle already originally equipped with a third rear brake light?' There are two relevant provisions of Standard No. 108 that deal with your question. The first is relevant if installation of the spoiler prevents the original lamp from meeting the photometric or visibility requirements of Standard No. 108. If this occurs, compliance may be maintained by installing another center high-mounted lamp that meets all requirements of Standard No. 108. See S5.3.1.1. Presumably, the lamp in the spoiler is designed, or could be designed, to comply to all applicable requirements. A further question is whether two center high-mounted stop lamps are permissible. An auxiliary lamp is prohibited by S5.1.3 if it impairs the effectiveness of the lighting equipment required by Standard No. 108. One example of impairment is when the auxiliary lamp creates confusion as to the function of the original lamp. The motoring public is used to seeing only one center lamp in operation. Although we cannot reach a definitive conclusion that an auxiliary center stop lamp would impair the effectiveness of the original center stop lamp, it would probably be prudent to ensure that there is only one center stop lamp in operation. Thus, if the spoiler lamp complies with Standard No. 108, the original lamp may be disconnected. If the spoiler lamp does not comply with Standard No. 108 and the original lamp remains in compliance with Standard No. 108, the question of impairment arises. On balance, it would appear unlikely that impairment would result from this configuration. In your letter of November 8 you ask several questions with respect to the installation of center high-mounted stop lamps on pickup trucks. On May 31, l990, NHTSA proposed that the lamp be installed on pickup trucks and some other types of vehicles as well. We anticipate publishing a final rule on this issue in the Federal Register in the near future. The preamble to the rule will address your questions on location of the lamp. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam1757OpenMr. Norman E. Salzman, General Manager, The Fairmount Press, P.O. Box 3, Bronx, NY 10453; Mr. Norman E. Salzman General Manager The Fairmount Press P.O. Box 3 Bronx NY 10453; Dear Mr. Salzman: This is in response to your letter of December 31, 1974, inquiring a to the compliance of your MVF odometer disclosure form with the Federal odometer requirements.; The MVF form enclosed in your letter appears to comply with th requirements of Part 580, *Odometer Disclosure Requirements*.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam2878OpenMr. J. Kawano, Director/General Manager, Factory Representative Office, Toyota Motor Sales, U.S.A., Inc., One Harmon Plaza, Secaucus, NJ 97094; Mr. J. Kawano Director/General Manager Factory Representative Office Toyota Motor Sales U.S.A. Inc. One Harmon Plaza Secaucus NJ 97094; Dear Mr. Kawano: This is in reply to your letter of September 6, 1978, requesting a interpretation of Federal Motor Vehicle Safety Standard No. 108, *Lamps, Reflective Devices and Associated Equipment*. You referred to the Society of Automotive Engineers (SAE) Standard J571d, referenced in Standard No. 108, which specifies dimensions for rectangular headlamp retaining rings in its Figure 8(B). The table of dimensions in Figure 8 specifies a maximum of 1.52 mm for the 'K' dimension on the drawing, the distance of the forward portion of the retaining ring from the lens surface. You stated that Toyota plans to increase that dimension by an unspecified amount for ornamental purposes.; You further advised that the proposed design would not interfere wit the ability of the headlamps to meet the performance requirements of SAE J580a and b and of the mechanical aiming requirements of SAE J602c.; Since Figure 8(B) of SAE J571d shows that the 'K' dimension shall no exceed 1.52 mm, any greater dimension would not meet the specifications of the standard. However, you may petition for rulemaking to appropriately amend Standard No. 108. We cannot, however, offer any assurance that the standard would be changed in response to your petition.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam0845OpenMr. S.G. Jonas, Attorney and Counselor, American Motors Corporation, 14250 Plymouth Road, Detroit, MI 48232; Mr. S.G. Jonas Attorney and Counselor American Motors Corporation 14250 Plymouth Road Detroit MI 48232; Dear Mr. Jonas: This is in reply to your letter of May 24, 1972, concerning the tes procedures applicable to a passenger car headlamp after the impacts required by Motor Vehicle Safety Standard No. 215.; Your question is whether the requirements of SAE Standard J580a, whic are incorporated in the lighting systems standard, Standard No. 108, are meant to be incorporated into Standard No. 215, and, if so, whether the 'Aiming Adjustment Tests' of SAE J580a are to be performed in a laboratory fixture or on the vehicle.; Our answer is that Standard No. 215, in adopting the headlam adjustment requirements of Standard No. 108, incorporates the requirements of SAE J580. Contrary to your impression, SAE J580 can be conducted either as a bench test or as an on-vehicle test, and as incorporated into Standard No. 215 its aiming adjustment test will be applied as an on-vehicle test. The use of the bench test procedure by our Office of Standards Enforcement in its laboratory procedures manual for Standard No. 108 should not be understood to mean that we consider the bench test to be the only test method under SAE J580a.; Sincerely, Richard B.DDyson (sic), Assistant Chief Counsel |
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ID: aiam4555OpenGeorge F. Ball, Esq. Office of the General Counsel General Motors Corporation New Center One Building 3031 West Grand Boulevard P.O. Box 33122 Detroit, MI 48232; George F. Ball Esq. Office of the General Counsel General Motors Corporation New Center One Building 3031 West Grand Boulevard P.O. Box 33122 Detroit MI 48232; "Dear Mr. Ball: This responds to your letter seeking our opinion as t whether a new minivan GM plans to introduce (referred to as the GM 200 minivans in your letter) could be classified as a 'multipurpose passenger vehicle' for the purposes of the Federal Motor Vehicle Safety Standards. In your letter, you indicated GM's belief that this new minivan should be classified as a multipurpose passenger vehicle, because it will be constructed on a truck chassis. Your company has concluded that this minivan will be constructed on a truck chassis for several reasons. First, you state that this chassis has 'truck attributes' that make it more suitable for commercial use than a passenger car chassis would be. The examples of such truck attributes set forth in your letter were an integrated ladder-type frame with full-length longitudinal rails and supporting cross-members, an extended width rear axle, a powertrain certified as complying with the light-duty truck emissions standards, and a flat load floor. Second, you state the chassis is a truck chassis because a cargo van version of this vehicle will be marketed and sold for commercial use. Third, you provided an analysis showing that this minivan will have certain chassis and body characteristics similar to those characteristics of minivans that are now produced and classified as multipurpose passenger vehicles. At the outset, I would like to make clear that the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq.) places the responsibility for classifying a particular vehicle in the first instance on its manufacturer. For this reason, NHTSA does not approve or endorse any vehicle classifications before the manufacturer itself has classified a particular vehicle. NHTSA may reexamine the manufacturer's classification in the course of any enforcement actions. We will, however, tentatively state how we believe we would classify this vehicle for the purposes of the safety standards. It is important for GM to be aware that these tentative statements of classification are based entirely on the information presented to the agency by GM, and the tentative classifications may change after NHTSA has had an opportunity to examine the vehicle itself or otherwise acquire additional information about the vehicle. With those caveats, we believe that the GM 200 minivan family could be classified as a multipurpose passenger vehicle for the purposes of the safety standards, because it will be constructed on a truck chassis. The fact that a cargo van version of the GM 200 will be marketed and sold for commercial use is evidence that the common chassis is a truck chassis. Additionally, the front to rear longitudinal side rails and supporting cross-members that are not present on the A-car chassis shows the GM 200 minivan chassis design is more suitable for heavy duty, commercial operations than the A-car chassis. Finally, the characteristics of the GM 200 chassis appear to be similar to the characteristics of other chassis that have been identified as 'truck chassis' by their manufacturers. Accordingly, assuming that your description of the GM 200 chassis is accurate, it appears to us that this minivan is constructed on a truck chassis. The version of your letter to me that has been placed in the public docket has all the information for which you requested confidential treatment deleted from it. Sincerely, Erika Z. Jones Chief Counsel"; |
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ID: aiam3290OpenMr. Donald E. Boyd, Donald Boyd & Associates, Inc., 5617 W. 6th Street, Stillwater, OK 74074; Mr. Donald E. Boyd Donald Boyd & Associates Inc. 5617 W. 6th Street Stillwater OK 74074; Dear Mr. Boyd: This responds to your recent letter requesting confirmation that larg commercial truck tractors do not have to comply with Federal Motor Vehicle Safety Standard No. 216, *Roof Crush Resistance*. You also asked whether large trucks should be designed to comply with the 'belt system' option under Safety Standard No. 208, *Occupant Crash Protection*.; You are correct in your assumption that large commercial trucks woul not have to comply with Safety Standard No. 216 since that standard only applies to passenger cars. You are also correct in stating that trucks with a GVWR greater than 10,000 pounds may meet the seat belt option of Safety Standard No. 208 found in paragraph S4.3.2 Under S4.3.1, manufacturers do have the option of meeting the crash protection requirements of S5 by means that require no action by vehicle occupants (with current technology this means air cushion restraints or automatic seat belts). Further, vehicles manufactured prior to August 15, 1977, were permitted to comply with Safety Standard No. 216 in lieu of the 'rollover' requirements of Standard No. 208, and for large trucks this would have been a simple test to meet. However, since the vehicle would also have been required to meet the 'frontal' and 'lateral' requirements by automatic means if option S4.3.1 were taken, no truck manufacturer chose to comply with the 'rollover' requirements of Standard No. 208 via the Standard No. 216 option. Rather, seat belts were installed on all large trucks.; Sincerely, Frank Berndt, Chief Counsel |
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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.