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: aiam5364OpenMartin M. Sackoff, Ph.D. Executive Director of Laboratories International Testing Laboratories 578-582 Market Street Newark, NJ 07015-2913; Martin M. Sackoff Ph.D. Executive Director of Laboratories International Testing Laboratories 578-582 Market Street Newark NJ 07015-2913; "Dear Dr. Sackoff: This responds to your letter to this agency wit reference to Federal Motor Vehicle Safety Standard No. 109, New Pneumatic Tires. Your specific question addressed S4.2.2.4, Tire strength, which states: 'Each tire shall meet the requirements for minimum breaking energy specified in Table I when tested in accordance with S5.3.' You asked for an interpretation of the term 'breaking,' whether it means a blowout of the tire or the breaking of the tire caused by the plunger used in the test specified in the standard. The breaking energy test is a measure of the resistance of the tire to bruise or damage due to impact of the tire with road hazards. This agency tests such resistance in accordance with the procedures of S5.3, Tire strength, of the standard. In that test, a cylindrical steel plunger is forced perpendicularly into the tire rib at the rate of 2 inches per minute at five test points equally spaced around the circumference of the tire. The inch-pounds of force required to push the plunger into the tire is continuously monitored. As the plunger pushes into the tire, the resistance to the plunger force increases. That resistance requires ever-increasing force applied to the plunger to continue pushing it into the tire. Ultimately, one of two things will happen: 1. The plunger will push all the way to the rim, or 2. The tire cords, plies, innerliner, or other components of the tire will stretch, separate, crack or break so that the resistance pressure of the tire diminishes. The 'breaking' of the tire at that point does not require an actual blow-out although, obviously, a blow-out would constitute a 'breaking.' The plunger force is measured just prior to contact with the rim as in 1 above or just prior to the force reduction described in 2 above. The measured force is then combined with the penetration of the plunger into the tire as specified in S5.3.2.3 and S5.3.2.4 of the standard. The breaking energy value of the tire is then determined by computing the average of the values obtained at the five test locations on the tire. Table I, Appendix A of the standard specifies the minimum breaking energy of tires based on tire type, size, composition, and inflation pressure. I hope this information is helpful to you. Should you have any further questions or need any additional information, please feel free to contact Walter Myers of my staff at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam0536OpenJohann und Konen, 53 Bonn-Beuel 1, Rosenbach 32, Ortsteil Putzen, Germany; Johann und Konen 53 Bonn-Beuel 1 Rosenbach 32 Ortsteil Putzen Germany; Gentlemen: This is in reference to your letter of August 22, 1972, requestin information relative to Federal Motor Vehicle Safety Standard No. 125, 'Warning Devices.'; You state that the width of the reflex reflective material in th Warning Triangle you are concerned with is 1.6732 inches, and inquire whether it is permissible to utilize 'for manufacturing reasons' a non-reflective border around the reflective material which would increase the width of the red reflective section to 1.8504 inches.; Paragraph S5.2.2 of Standard 125 specifies that the width of each o the three sides of the triangular portion of the warning device shall be not less than 2 and not more than 3 inches wide, as depicted in Figure 1. If the required widths specified in S5.2.5 for the red reflex reflective and orange fluorescent materials are met, provision of non-reflective or non-fluorescent 'border' material is permitted, as long as the overall width requirements for the side of the triangle are also met.; I hope this answers your questions. Sincerely, E.T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
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ID: aiam4826OpenMr. Gene Schlanger President ROC Capital, Inc. 63 Greens Road Hollywood, FL 33021; Mr. Gene Schlanger President ROC Capital Inc. 63 Greens Road Hollywood FL 33021; "Dear Mr. Schlanger: This is in reply to your FAX of January 3, l991 to Taylor Vinson of this Office, asking about the permissibility under Federal and State regulations of a 'lighted sign' on which messages could be scrolled from left to right. Such a sign 'is designed to be mounted inside the car, either on a rear or side window.' However, 'if that is deemed legally inappropriate, the sign can be designed to be placed outside on the roof of the auto.' The sign would incorporate LEDs and would not project a beam or flash. You intend to sell it 'to the general public.' The National Highway Traffic Safety Administration has no specific Federal motor vehicle safety standard that addresses your device, nor any prohibition against your selling it. The question arises, however, as to whether and under what circumstances Federal law may allow its use. As a general rule, aftermarket equipment such as this is acceptable under Federal law provided that its installation by a manufacturer, distributor, dealer, or motor vehicle repair business, does not entail removal of, or otherwise rendering inoperative, in whole or in part, equipment installed in accordance with a Federal motor vehicle safety standard. This means that removal by any of the persons just mentioned of the high-mounted stop lamp that has been required on passenger cars manufactured on or after September 1, l985, in order to substitute your lighted sign, would be a violation of Federal law. The question arises of whether the lighted sign may be installed in the rear window of any other vehicle, or in a passenger car manufactured before September 1, l985, or on the top of any vehicle, situations where there is no direct removal of safety equipment. The agency regards any impairment of the effectiveness of rear lighting equipment as tantamount to rendering it partially inoperative. Thus, if aftermarket equipment is likely to create confusion or distraction in a following motorist, we regard it as likely to impair the messages that required lighting equipment is supposed to impart. A lighted sign with a changing message is likely to create a distraction, diverting attention from signals sent by stop lamps or turn signal lamps. Thus, we believe that this device has the potential of rendering those lamps partially inoperative within the meaning of the statutory prohibition. Even when installed in a side window, where it may not be visible directly to the rear, the device has the potential of distraction when the vehicle carrying it is approached in other lanes, i.e., at an angle from the rear. We are unable to tell you whether the device is illegal under the laws of each of the 50 States. If you are interested in pursuing this question, we recommend that you consult the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, Va. 22203. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam1777OpenMr. C. M. Xeros, Chief Engineer, Marmon Motor Co., P.O. Box 5175, Dallas, TX 75222; Mr. C. M. Xeros Chief Engineer Marmon Motor Co. P.O. Box 5175 Dallas TX 75222; Dear Mr. Xeros: This responds to your January 15, 1975, request for confirmation that vehicle is complete for purposes of establishing its 'date of manufacture' and the applicability of Federal motor vehicles safety standards, although minor finishing operations and the attachment of mirrors, grab rails, etc. have not been accomplished.; As you describe the type of minor finish work and readily attachabl components which remain uncompleted, your vehicles would be complete for purposes of establishing 'date of manufacture.' I enclose a discussion of this concept as it applies to truck, bus, and trailer manufacture under Standard No. 121, *Air brake systems*.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam0865OpenMr. Gerald D. Stapley, K-146 Northwood Apartments, Capital Hill Drive, RFD-2, Londonderry, NH 03053; Mr. Gerald D. Stapley K-146 Northwood Apartments Capital Hill Drive RFD-2 Londonderry NH 03053; Dear Mr. Stapley: This is in reply to your letter of September 9, 1972, proposing 'tha legal standards for the performance of windshield defrosting systems be established and applied to vehicles manufactured in or imported into USA.'; The National Highway Traffic Safety Administration has opened Docke No. 1-3 to receive comments on extension of coverage of the passenger car defrosting and defogging system standard, Federal Motor Vehicle Safety Standard No. 103, to multipurpose passenger vehicles, trucks, and buses. Ice or slush buildup on the windshield, as well as the overall performance of the defroster system, are among the problems and concerns currently being investigated by the NHTSA.; We plan to combine all the problems associated with vision an precipitation into an Adverse Weather Visibility standard such as you suggest in your letter. This would also include wiping and washing requirements. At the present time research has been initiated to obtain data so that we can propose definite performance requirements for all types of weather conditions. Under our Program Plan such a standard would become effective September 1, 1976.; Your suggestion and the mention of the specific problems ar appreciated and will be considered as we proceed in our rulemaking. Thank you for writing and if we can be of further service, please let us know.; Sincerely, E. T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
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ID: aiam2858OpenMr. J. W. Yarbrough, Assistant Superintendent for Business, West Seneca Central School District, 45 Allendale, West Seneca, NY 14224; Mr. J. W. Yarbrough Assistant Superintendent for Business West Seneca Central School District 45 Allendale West Seneca NY 14224; Dear Mr. Yarbrough: This responds to your May 4, 1978, letter asking whether you can modif several buses that you have purchased by adding stanchion bars near the front door to facilitate the loading of smaller school children.; The National Highway Traffic Safety Administration does not prohibi the use of stanchion bars in school buses. Some manufacturers, however, have discontinued putting them in buses because it is difficult to pad them sufficiently such that they comply with the head impact zone requirements when the bars fall within the head impact zone.; The National Traffic and Motor Vehicle Safety Act of 1966 (the Act prohibits modification of vehicles by repair businesses, dealers, or manufacturers that would render inoperative compliance with safety standards (section 108(a)(2)(A)). Therefore, if a dealer, repair business, or manufacturer were to install stanchion bars in your school buses, it would be required to ensure that the installation does not render inoperative compliance with the head impact zone requirements. The Act does not prohibit, however, modifications by individuals of their vehicles even when such modification would not comply with Federal safety standards. Accordingly, a school district could itself install stanchion bars that do not comply with the head impact zone requirements.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam4575OpenMr. Robbie Folino-Nazda Attorney-in-Fact Fritz Companies, Inc. 7550 22nd Avenue South Minneapolis, MN 55450; Mr. Robbie Folino-Nazda Attorney-in-Fact Fritz Companies Inc. 7550 22nd Avenue South Minneapolis MN 55450; Dear Mr. Folino-Nazda: We have received a copy of your letter o December l9, l988, to Commissioner Young of the Food and Drug Administration, forwarded to us by the Consumer Product Safety Commission. You have asked whether the 'vehicle safety device' you described (with samples enclosed) are subject to any restrictions which would prevent importation of the device. The device provides an 'ultrasonic animal warning.' At a speed 'over 30 mph air flow produces a high pitch whistle which animals try to avoid.' It is designed for owner installation on 'bumpers, grills, fenders, mirrors and roofs' of motor vehicles. Because the device is intended solely as an accessory to motor vehicles, it is an item of motor vehicle equipment subject to the jurisdiction of this agency under the National Traffic and Motor Vehicle Safety Act. However, there are no Federal motor vehicle safety standards that apply to this type of equipment. You should also be aware that if the device's manufacturer ('manufacturer' includes both the maker as well as any importer for resale) or this agency were to determine that the device contains a safety-related defect, importers of this foreign-made device would be required by the Vehicle Safety Act to recall the device and remedy the defect or replace the device without charge. We are returning your samples to you. Sincerely, Erika Z. Jones Chief Counsel; |
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ID: aiam1327OpenMr. L. Clinton Rich, R.F. & W. Auto Wheel Service, 2807 Cresmont Avenue, Baltimore, Md. 21211; Mr. L. Clinton Rich R.F. & W. Auto Wheel Service 2807 Cresmont Avenue Baltimore Md. 21211; Dear Mr. Rich: Confirming our recent conversation: No Federal motor vehicle safet standard regulates the straightening and subsequent sale of motor vehicle wheels.; Our regulations are applicable to the manufacture and sale of new moto vehicle and motor vehicle equipment only up to the point of their first sale for purposes other than resale. I assume that straightened wheels are used equipment that has been reworked, and as such they would not be subject to any standard unless they were placed on new vehicles as original equipment. There is a standard, No. 110, that applies to passenger cars, requiring the wheel rims to meet the rim manufacturer's specified rim dimensions and to retain a tire which loses all pressure at 60 miles per hour.; A regulation applying directly to wheels is under consideration, but i would still apply only to new equipment and vehicles.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4125OpenMr. Bob Carlson, 8305 29th Avenue, N.W., Seattle, WA 98117; Mr. Bob Carlson 8305 29th Avenue N.W. Seattle WA 98117; Dear Mr. Carlson: This responds to your January 23, 1986 letter inquiring about Federa motor vehicle safety standards applicable to your projected sale of aftermarket windshield wiper systems for trucks.; Under the National Traffic and Motor Vehicle Safety Act, this agenc has issued Federal Motor Vehicle Safety Standard No. 104, *Windshield Wiping and Washing Systems*, applicable to new motor vehicles. As you note, this standard applies to trucks, as well as other types of vehicles. In your letter, you ask which performance requirements apply to wiping systems for trucks.; Under S4. *Requirements*, new trucks are required to have power-driven windshield wiping system that meets the requirements of S4.1.1. The frequency requirements in S4.1.1 apply to trucks, but the wiped area requirements of S4.1.2 apply only to passenger cars. Trucks must also have a windshield washing system that meets the requirements of SAE Recommended Practice J942, November 1965, except that the 'effective wipe pattern' is considered to be 'the pattern designed by the manufacturer for the windshield wiping system on the exterior surface of the windshield glazing.' Therefore, the vehicle manufacturer establishes the wipe pattern of the system.; If a new truck equipped with your wiper system did not comply wit Standard No. 104 due to some aspect of that system, the sale of that truck to the public would be a violation of the prohibition in section 108(a)(1)(A) of the Act against the sale of noncomplying vehicles.; I hope this information is helpful to you. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3930OpenMs. Beatrice Ho, Honest International Corp., P.O. Box 851391, Richardson, TX 75081; Ms. Beatrice Ho Honest International Corp. P.O. Box 851391 Richardson TX 75081; Dear Ms. Ho: This responds to your letter to Mr. Radovich of this agency' Rulemaking Division, seeking an interpretation of Standard No. 213, *Child Restraint Systems* (49 CFR S571.213). Specifically, you asked if a child restraint which has been certified as meeting the Japanese safety standard could automatically be considered as complying with Standard No. 213, and, if not, asked for the names and addresses of the U.S. testing laboratories.; There is no requirement that the measures, such as testing, taken by manufacturer to demonstrate it exercised due care to produce an item of equipment in accordance with Standard No. 213, be performed in this country. If a foreign standard is essentially identical to Standard No. 213, then it may be that the efforts made by a manufacturer in a foreign country to show compliance with that country's standard could form the basis for the manufacturer's certification that its product complied with Standard No. 213. The adequacy of those efforts would depend on a variety of factors, including the degree of similarity between the standards and the resources available to the manufacturer to determine its compliance. For additional information relating to your question, please see the enclosed letter written last year to an Austrian child restraint manufacturer. That letter explains in detail the procedures for certifying compliance with Standard No. 213.; For purposes of enforcing Standard No. 213, this agency conducts spo checks of child restraints after they have been certified by the manufacturer as complying with the standard, by purchasing child restraints and testing them in accordance with the procedures specified in the standard. If the child restraints pass those tests, no further steps are taken.; If a child restraint fails the tests and is determined not to compl with Standard No. 213 or if it is determined that the child restraint contains a safety- related defect, the manufacturer of the child restraint is required to remedy the problem. Section 154(a)(2)(B) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1414(a)(2)(B)) specifies that, in the case of a child restraint which fails to comply with Standard No. 213 or contains a safety- related defect, the manufacturer may elect to either:; (1) repair the child restraint so that the defect or noncompliance i removed, or; (2) replace the child restraint with an identical or reasonabl equivalent restraint which does not have the defect or noncompliance.; Whichever of these options is chosen, the child restraint manufacture must bear the expense and cannot charge the child restraint owner for the remedy.; Should you have any further questions or need more information on thi subject, please contact Mr. Stephen Kratzke of my staff at this address.; 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.