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: aiam3151OpenMr. W.G. Milby, Manager, Engineering Services, Blue Bird Body Company, P.O. Box 937, Fort Valley, Georgia 31030; Mr. W.G. Milby Manager Engineering Services Blue Bird Body Company P.O. Box 937 Fort Valley Georgia 31030; Dear Mr. Milby: This is in response to your letter of March 29, 1979, requesting a interpretation of Federal Motor Vehicle Safety Standard No. 115 (49 CFR 571.115). We are sorry for the delay in responding.; You wish to know whether the 'body number' that Blue Bird Body Compan assigns to its school buses will satisfy the requirement of S4.5.3.3 that the last six characters of the Vehicle Identification Number (VIN) represent the production sequence of the vehicle. Your concern arises from the fact that the 'body number' does not indicate the true numerical sequence of manufacture. As explained in Notice 5 (43 Fr 36448) and Notice 6 (43 FR 52246) the production sequence represents the 'number sequentially assigned by the manufacturer in the production process' (S4.5.3.3), rather than the numerical sequence of actual manufacture. Consequently, the Blue Bird body number may be used as the production sequence number since the 'body numbers' are sequentially assigned when purchase orders for the buses are received.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1496OpenMr. J. Alec Reinhardt, 100 Erieview Plaza, Cleveland, OH 44114; Mr. J. Alec Reinhardt 100 Erieview Plaza Cleveland OH 44114; Dear Mr. Reinhardt: This is in reply to your letter of May 17, 1974, asking us to approv language to be substituted for the first two sentences of the second paragraph of White's version of the defect notification letter in campaign No. 73-0140, as well as substitute language suggested by the Court.; We would consider the language of either submission to conform to 4 CFR Part 577 if the word 'may' is stricken. The sentence would then read, 'We have found that a defect exists in that . . .' We have interpreted the regulations to require the finding that the defect exists, not that it may exist. However, the notification letter may indicate that the defect may not be present in every vehicle if that is the case.; Sincerely, Frank Berndt, Assistant Chief Counsel |
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ID: aiam3501OpenMr. Robert A. McDevitt, Avis Car Leasing, P.O. Box 117, Carle Place, NY 11514; Mr. Robert A. McDevitt Avis Car Leasing P.O. Box 117 Carle Place NY 11514; Dear Mr. McDevitt: This is in response to your letter of November 17, 1981, asking whethe the federal odometer disclosure forms may be put onto microfilm and the original hard copy destroyed. You indicated that if hard copy was later needed, it could be reproduced from the microfilm.; Section 580.7 of Title 49 of the Code of Federal Regulations has th following provision:; >>>The statement may be reproduced (e.g., photocopies or put o microfilm) as long as no information or identifying marks such as signatures are lost in the reproduction.<<<; The purpose of this provision is to allow dealers and distributors t conserve storage space by condensing the retained documents. The original documents could then be destroyed, provided the copies contained the same information as the originals.; If you have any further questions, please do not hesitate to write. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3014OpenMr. F.A. McGuirk, Jr, Wagner Electric Corp., 100 Misty Land, Parsippany, New Jersey 07054; Mr. F.A. McGuirk Jr Wagner Electric Corp. 100 Misty Land Parsippany New Jersey 07054; Dear Mr. McGuirk: I regret the delay in responding to your letter regarding Federal Moto Vehicle Safety Standard 127, *Speedometers and Odometers*. You asked which of the following digital speedometer designs was permissible under the standard: (1) A dual display, with one display expressing speeds in mph and the other in km/h, (2) a single display that alternately expresses the speed in mph and km/h, and (3) a single display that, by means of a switch, may be made to express speed in either mph or km/h.; Section 4.1.2 of the standard requires that speedometers be graduate in miles per hour and kilometers per hour. The agency interprets this requirement to mean that both systems of measurement must be simultaneously viewable by the driver. As stated in the March 16, 1978 final rule, the purpose of the dual graduation is to aid motorists in becoming acquainted with the metric system.; Only the firs design meets the requirement. the second design does no show both systems simultaneously. Further, its distracting and potentially confusing nature may draw a driver's attention away from the road for undersirably(sic) long periods of time. The third design might never serve the educational purpose underlying the dual graduations. If left switched to the mph system, as it most likely would be, the speedometer would not contribute at all to the driver; |
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ID: aiam1029OpenMr. J. Henry Cooley, President, Nashville Glass Company, 1520 Demonbreun Street, Nashville, TN 37203; Mr. J. Henry Cooley President Nashville Glass Company 1520 Demonbreun Street Nashville TN 37203; Dear Mr. Cooley: This is in response to your letter of February 14, 1973, requestin information concerning Federal Motor Vehicle Safety Standard No. 212 and replacement of motor vehicle windshields.; Federal Motor Vehicle Safety Standard No. 212 applies only up to th point where a vehicle is first sold to a user. The National Highway Traffic Safety Administration currently has no standards that apply to vehicles in use. A program for the development of standards that would apply to vehicles other than new vehicles is being considered by the Administration for implementation in the future.; Thank you for your inquiry. Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam1183OpenMr. Rene Politis, Director, Product Reliability and Assurance Department, Signal-Stat Corporation, 1200 Commerce Avenue, Union, NJ 07083; Mr. Rene Politis Director Product Reliability and Assurance Department Signal-Stat Corporation 1200 Commerce Avenue Union NJ 07083; Dear Mr. Politis: This is in reply to your letter of July 10, 1973, to Mr. Schneide asking which SAE Standard incorporated into Standard No. 108 applies to turn signal operating units, SAE J589 or J589a.; The correct standard is SAE J589. You noted that the tables in th standard refer to J589, while paragraph S5.1 states that subreferenced standards shall be those published in the 1970 edition of the SAE Handbook. The key word in S5.1 is '*sub*referenced', *i.e.*, referred to only in an SAE standard itself referenced in the Federal standard. J589 is directly referenced, not subreferenced and the number identified is correct. An example of a subreferenced standard would be J575, which is mentioned in J589.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3444OpenMr. Antonio Cano, Sales Representative, P. O. Box 904, Buckingham, PA 18912; Mr. Antonio Cano Sales Representative P. O. Box 904 Buckingham PA 18912; Dear Mr. Cano: This responds to your question, raised during a meeting with Car Clark, Vernon Bloom, Harry Thompson and Edward Glancy, whether any Federal motor vehicle safety standard precludes the importation or sale of your anti-theft device called 'Hyperblock.' The device works by preventing release of the brakes. Installation of the device requires cutting into a vehicle's braking system.; By way of background information, the agency does not give approvals o vehicles or equipment. The National Traffic and Motor Vehicle Safety Act places the responsibility on the manufacturer to ensure that its vehicles or equipment comply with applicable requirements. A manufacturer then certifies that its vehicles or equipment comply with all applicable standards. We note that the term 'manufacturer' is defined by section 102(5) of the Act to mean 'any person engaged in the manufacturing or assembling of motor vehicles or motor vehicle equipment, *including any person importing motor vehicles or motor vehicle equipment for resale*.' [emphasis added]; The agency does not have any regulations covering anti- theft device that work by preventing release of the brakes. However, since installation of Hyperblock requires cutting into a vehicle's braking system, it may affect a vehicle's compliance with other safety standards.; If your device is added to a new motor vehicle prior to its first sale 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. In the case of Hyperblock, this would include Safety Standard No. 105, *Hydraulic Brake Systems* (49 CFR 571.105). You will find the specific certification requirements for alterers at 49 CFR Part 567.7, *Certification*. On the other hand, you as the manufacturer of Hyperblock would have no certification requirements, because we have no safety standards applicable to your equipment. However, an alterer would probably require information from you in order to make the necessary certification.; If your device is installed on a used vehicle by a business such as garage, 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 the compliance of the vehicle with any safety standard. This is required by section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act, which states in relevant part:; >>>No manufacturer, distributor, dealer, or motor vehicle repai business shall knowingly render inoperative, in whole or 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...<<<; You indicated at the aforementioned meeting that installation o Hyperblock does not affect a vehicle's braking performance. You also indicated that Hyperblock maintains the integrity of a vehicle's split system. In addition to requirements in those areas, Standard No. 105 establishes brake system integrity requirements, requiring that a braking system be able to withstand a series of spike stops. You may wish to consider testing Hyperblock as to whether it affects a vehicle's compliance with the spike stop test requirements, if you have not done so already. We suggest that you carefully examine all of Standard No. 105's requirements to determine the degree to which installation of your device affects compliance with the standard.; While we do not have any opinion as to the safety of your particula device, we do have a general concern about the safety of anti-theft devices which work by preventing release of the brakes. We note that some manufacturers state in their service manuals that hydraulic brake locking devices should not be used on their vehicles.; Should a safety-related defect be discovered in your device, whether b agency or yourself, you as the manufacturer would be required under sections 151 *et seq*. of the Act to notify vehicle owners, purchasers, and dealers and provide a remedy for the defect.; Finally, in addition to the provisions of Federal law discussed above there is a possibility of liability in tort should your device prove to be unsafe in operation. You may wish to consult a local lawyer concerning liability in tort.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1479OpenMr. Charles R. Richards, Superior Trailer Works, 1430 East Washington Boulevard, Los Angeles, CA 90021; Mr. Charles R. Richards Superior Trailer Works 1430 East Washington Boulevard Los Angeles CA 90021; Dear Mr. Richards: This responds to your April 22, 1974, question concerning th certification responsibility of a small manufacturer of trailers that must conform to Standard No. 121, *Air brake systems*. You ask if road testing of any or all vehicles produced would be necessary to satisfy the requirements.; A manufacturer must 'exercise due care' in certifying that the vehicle manufactured by him comply with the applicable standards (National Traffic and Motor Vehicle Safety Act of 1966, S 108(b)(2), 15 U.S.C. S 1392(b)(2)). What constitutes due care in a particular case depends on all relevant facts, including such things as the time to elapse before a new effective date, the availability of test equipment to small manufacturers, the limitations of current technology, and above all the diligence evidenced by the manufacturer.; A small manufacturer of standard and custom trailers might fulfill hi due care responsibility to assure that each of his trailers is capable of meeting the standard in several ways. For example, he could establish categories of models which share a common brake and axle system and certify them all on the basis of tests on the most adverse configuration in the category. Calculations should be written down in such a case to establish that reasonable care was taken in these decisions.; Alternatively, joint testing might be undertaken with a trad association or with a major supplier of brake and axle components. In the case of standard models, you might be able to rely on the supplier's warranty of his products' capacities.; Neither of these methods would require road testing of each vehicl manufactured, nor would every model have to be road tested. A manufacturer must simply satisfy himself that the trailer is capable of meeting the stopping performance requirements if it were tested by the NHTSA.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4381OpenThe Honorable Bill Nelson, U.S. House of Representatives, 2404 Rayburn House Office Building, Washington, DC 20515-0912; The Honorable Bill Nelson U.S. House of Representatives 2404 Rayburn House Office Building Washington DC 20515-0912; Dear Mr. Nelson: Thank you for your letter on behalf of your constituent, Mr. Glen Gourley, who questions the effectiveness of safety belts and opposes the safety belt use law enacted by the State of Florida.; During the past decade, 470,000 persons have died on American highways Each year, an estimated 300,000 are injured seriously enough to require hospital treatment. These traffic deaths and injuries have resulted in an annual cost to society of approximately 57 billion dollars resulting from such costs as emergency medical services, long-term medical care and rehabilitation, worker's compensation, welfare payments, and lost tax revenue.; Numerous analyses have shown that safety belts reduce fatalities b 40-50 percent and reduce serious injuries by 45-55 percent. I have enclosed copies of a safety belt fact sheet and several pamphlets we have published explaining how and why safety belts are so effective. Because of the extensive body of evidence about the effectiveness of safety belts, the United States Supreme Court has said, 'We start with the accepted ground that, if used, seatbelts unquestionably would save many thousands of lives and would prevent tens of thousands of crippling injuries.'; In an effort to protect their citizens by substantially reducin vehicle-related deaths and injuries, and to reduce the financial burden on their taxpayers, 29 States and the District of Columbia have enacted safety belt use laws. I have also enclosed an occupant protection fact sheet. This sheet reports that among front seat occupants, safety belts saved about 2,200 lives in 1986, and 1750 of those lives were saved in States that have safety belt use laws.; I hope this information is helpful. If you have any further questions on this subject, please let me know. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3917OpenMr. Gordon Bonvallet, Manager, Photometric Division, ETL Testing Laboratories, Inc., P.O. Box 2040, Cortland, NY 13045- 2040; Mr. Gordon Bonvallet Manager Photometric Division ETL Testing Laboratories Inc. P.O. Box 2040 Cortland NY 13045- 2040; Dear Mr. Bonvallet: This is in reply to your letter of February 13, 1985, to this Offic asking whether the agency intended to eliminate the maximum allowable value for parking lamp candlepower in the amendments of November 26, 1984 which established Figure 1b.; Thank you for calling this matter to our attention. The amendmen appears to have the effect you ascribe to it, though it was not the agency's intention that it do so. The maximum values of SAE J222 December 1970 are those that should apply, and we shall reinstate them in the near future.; Sincerely, Jeffrey R. Miller, 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.