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: aiam3226OpenMr. Brian O'Meara, President & General Manager, O'Meara Ford Center, 400 West 104th Avenue, Denver, CO 80234; Mr. Brian O'Meara President & General Manager O'Meara Ford Center 400 West 104th Avenue Denver CO 80234; Dear Mr. O'Meara: This responds to your February 26, 1980, letter asking about the prope certification for a Ford Mustang that has been converted to a convertible. You ask what certification is required before you would be permitted to sell such a vehicle.; The National Highway Traffic Safety Administration requires al manufacturers of motor vehicles to certify that their vehicles comply with Federal safety standards prior to first sale. In the case of the vehicle that you mention, Ford Motor Company would have certified it when it was sold to the company that converted it to a convertible. Ford's certification label is located on the driver's door or pillar post.; The company that converted the vehicle, Tomaso of America, i responsible for putting its own label on the vehicle indicating that as altered the vehicle continues to comply with the applicable Federal safety standards. The requirements for alterers' labels are located in Title 49 of the Code of Federal Regulations, Section 567.7. Tomaso's label should also be located on the vehicle in the same area as Ford's.; If both of the labels are on the vehicle, it is legal for you to sel it. If either of the labels is missing from the vehicle, then the vehicle is not correctly certified and may be in noncompliance with the safety standards.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2821OpenMr. W. G. Milby, Manager, Engineering Services, Blue Bird Body Company, P.O. Box 937, Fort Valley, GA 31030; Mr. W. G. Milby Manager Engineering Services Blue Bird Body Company P.O. Box 937 Fort Valley GA 31030; Dear Mr. Milby: This responds to your April 24, 1978, letter asking two question concerning Standard No. 222, *School Bus Passenger Seating and Crash Protection*.; In your first question, you ask what the National Highway Traffi Safety Administration (NHTSA) means by the phrase 'seat components shall not separate at any attachment point.' This phrase is found in the forward and rearward loading performance tests. You suggest that the NHTSA interpret this to mean a complete separation of a seat component from another component. The NHTSA disagrees with this suggestion.; The standard as written clearly indicates that the agency has intende that seat components remain connected at all attachment points during testing. If the agency had intended a complete separation of seating components to be the test for separation, it would have used that language in the drafting of the regulation. Therefore, the agency declines to adopt the interpretation that you suggest and will require the seat to remain attached at all attachment points during testing.; Your second suggestion concerns a possible problem in the computatio of loads during rearward testing. You state that occasionally the loading bar will become buried in the upholstery material and, therefore, distort the actual seat loads. The NHTSA has not noted the phenomenon to which you refer. However, if it were to occur in compliance testing the agency would be certain to factor out any aberrations in the test results that occurred owing to this loading bar problem.; Sincerely, Joseph J. levin, Jr., Chief Counsel |
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ID: aiam3733OpenMr. H. Nakaya, Manager, Mazda (North America) Inc., 23777 Greenfield Road - Suite 462, Southfield, MI 48075; Mr. H. Nakaya Manager Mazda (North America) Inc. 23777 Greenfield Road - Suite 462 Southfield MI 48075; Dear Mr. Nakaya: This is in response to your letter of July 8, 1983 asking for a interpretation of Motor Vehicle Safety Standard No. 108.; Section S4.2 of SAE Standard J588e *Turn Signal Lamps* establishes minimum distance of 4 inches from the optical axis (filament center) of the front turn signal to the inside diameter of the retaining ring of the headlamp providing the lower beam. You believe that it is not necessary to have a retaining ring on a semi-sealed headlamp and you have asked whether you may substitute the edge of the reflector (as shown on your drawing) to measure the dimension covered by S4.2 of J588e.; The point depicted on your drawing appears to be the inner edge of th reflector, rather than the extreme edge, nevertheless, the 'reflector edge' you have indicated is the approximate location of a retaining ring on a fully sealed headlamp, and is therefore acceptable as a measuring point under Standard No. 108.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3363OpenMr. James A. Guenther, Guenther Auto Works, 3908 West Main - 8B, Belleville, Illinois 62223; Mr. James A. Guenther Guenther Auto Works 3908 West Main - 8B Belleville Illinois 62223; Dear Mr. Guenther: This is in reply to your letter of September 26, 1980 providing furthe information on your proposed manufacturing operation. I am pleased you found our earlier response 'most workable and least bureaucratic' and hope that you will find this letter equally so.; A vehicle consisting of a new body on a used chassis, and retaining th same title, is a 'used' vehicle, which does not have to meet the Federal safety standards that apply to new vehicles. If you were using the chassis of vehicles built on or after January 1, 1968, the resulting vehicle would have to meet the standards that applied when the original vehicle was built. However, there were no vehicle safety standards that applied before January 1, 1968 so your contemplated use of a 1964 chassis(of 1965-67 for that matter) frees you totally of responsibility for vehicle safety standards compliance, no matter whether you are a kit supplier or an end assembler, or are using new or reconditioned components.; A few of our safety standards, however, apply to equipment items specifically brake hoses, brake fluid, lighting equipment, tires, glazing, seat belt assemblies, and wheelcovers/hub caps. If you by any of these items from an outside supplier, and the item is manufactured in the U.S.A., it is virtually certain that it will be certified by its manufacturers as meeting federal equipment standards. From your letter, it would appear that only the glazing standard (Standard No. 205) might be of concern to your operations since you write that you 'will have constructed ... glass panes ...' Glazing bearing the designation 'AS-1' must be installed in the windshield of the new body. I am enclosing a copy of Standard No. 205 for your information.; Under the National Traffic and Motor Vehicle Safety Act you are 'manufacturer' with respect to any vehicle equipment you fabricate or vehicle you assemble. This means that in the event a 'safety related defect' developed in your product, you would be obligated to notify the owners and remedy the defect. I enclose our 'Part 573' which tells you haw to file a defect report with us an 'Part 577' which details how you notify purchasers and the optional remedies you may provide (See 577.5 (g)(i)(g)(v) and (g)(vi)). Finally, if you intend to assemble the vehicles yourself, or if you are fabricating glazing (or other item covered by a Federal standard, you should submit the information required by our 'Part 566' which I also enclose.; If you have any further questions we will, of course, be happy t answer them and we appreciate your wish to be informed of your obligations under Federal law.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3699OpenMr. Stephen E. Parmeter, Route 4, Potsdam, NY 13676; Mr. Stephen E. Parmeter Route 4 Potsdam NY 13676; Dear Mr. Parmeter: This responds to your recent letter concerning the process of repairin breaks in automobile windshields. You ask whether such repairs would conflict with any present Federal motor vehicle safety standards.; The National Highway Traffic Safety Administration has issued Federa Motor Vehicle Safety Standard No. 205 which specifies performance and location requirements for glazing materials used on motor vehicles (copy enclosed). This standard would not apply to a repair process such as you describe, however. There is no Federal regulation which would prohibit the use of a product or process in the repair of windshields which have previously been installed in vehicles and damaged in use.; Please note, however, that using such a material or process in a ne windshield which may require repair (as a result of damage sustained, for example, in shipment) could cause the windshield to fail to meet the performance requirements of Safety Standard No. 205, or could fail to bring a noncomplying windshield back into compliance. Either case of noncompliance would be the responsibility of the person selling the windshield (49 CFR 567.7, copy enclosed). Therefore, we do not recommend use of windshield repair processes prior to the first purchase of a new windshield by a consumer.; You will have to contact a private attorney to determine your liabilit under civil law with regards to such a business.; Please contact Hugh Oates of my staff if you have any furthe questions.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2122OpenHonorable John P. Murtha, House of Representatives, Washington, DC 20515; Honorable John P. Murtha House of Representatives Washington DC 20515; Dear Mr. Murtha: This responds to your November 5, 1975, request for the criteri necessary for construction of testing equipment used to demonstrate compliance with Standard No. 121, *Air Brake Systems*.; The motor vehicle safety standards, including Standard No. 121, ar established as requirements that vehicles must be capable of meeting if tested by the National Highway Traffic Safety Administration (NHTSA). However, the standards are not developed as demonstration procedures that detail methods a manufacturer would use to establish that its products comply. The development of actual test protocols to determine that products conform to the requirements is the responsibility of the regulated industry and the associated industries that service them.; Thus the Thiele Corporation, as a manufacturer of air-braked vehicles may choose whatever test method gives it an adequate basis for certification that its products comply (15 U.S.C. S 1397(a)). Test equipment has been developed by several commercial sources, and Thiele can choose proper systems by consulting with the manufacturers of the brake components it uses. As for specifications for a test track, actual road tests are not necessary to establish compliance with Standard No. 121 where other reasonable means, such as engineering calculations coupled with laboratory tests, can be used to the same effect. Supplier warranties and instructions are one of the primary means by which small assemblers ascertain that their products conform.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam2572OpenMr. Robert B. Kurre, Director of Engineering, Wayne Corporation, Post Office Box 1447, Industries Road, Richmond, IN 47374; Mr. Robert B. Kurre Director of Engineering Wayne Corporation Post Office Box 1447 Industries Road Richmond IN 47374; Dear Mr. Kurre: This responds to your April 1, 1977, letter asking whether the hea protection zone requirements of Standard No. 222, *School Bus Passenger Seating and Crash Protection*, extend to contactable surfaces 30 inches forward of the seating reference point of the front passenger seat behind the driver.; The head protection zone requirements are outlined in S5.3.1.1 of th standard. This section requires that the zone extend 30 inches forward of the seating reference point. The fact that the requirement may extend the head protection zone into the driver occupant space and thus involve contactable surfaces does not diminish the applicability of the requirements to contactable surfaces within that space. Contactable surfaces within that 30-inch zone, as shown on your sketch, must meet the requirements of the standard.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam2088OpenMr. Heinz W. Gerth, Assistant Vice President, Mercedes-Benz of North America, Inc., P.O. Box 350, Montvale, NJ 07645; Mr. Heinz W. Gerth Assistant Vice President Mercedes-Benz of North America Inc. P.O. Box 350 Montvale NJ 07645; Dear Mr. Gerth: This is in response to your letter dated May 7, 1975, regarding a apparent conflict between the inertia load requirement of Standard 206, *Door Locks and Door Retention Components*, (49 CFR 571.206, S4.1.1.3) and the test procedure incorporated by S5.1.1.2, Paragraph 5 of SAE Recommended Practice J839b. I regret the delay in responding, your letter was mistakenly routed to our Docket Section and only recently came to our attention.; The answer to your question is that the requirement of S4.1.1. controls. It is sufficient that the door latch system withstand a 30g load only in the transverse and longitudinal directions. The system is not required to withstand this load in 'any direction.'; You asked further about the acceptability of centrifuge testing t demonstrate compliance with the inertia load requirement of Standard 206. Although S5.1.1.2 mentions 'approved tests,' NHTSA has consistently refused to approve or supervise the methods manufacturers use to test to the standard. Any government inertia load compliance testing will be done in accordance with paragraph 5 of SAE Recommended Practice J839b. Mercedes-Benz, of course, may employ any method it chooses to ensure compliance with this and other safety standards, as long as the product complies. We recognize that centrifuge testing may be highly useful in a variety of applications, and I do not by any means want to discourage innovations in developmental or compliance testing.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5063OpenMr. Paul D. Barron Professional Technologies International Inc. 400 South Vermont #116 Oklahoma City, OK 73108; Mr. Paul D. Barron Professional Technologies International Inc. 400 South Vermont #116 Oklahoma City OK 73108; "Dear Mr. Barron: This responds to your inquiry about this agency' requirements that are applicable to your product, a 'UV Heat Shield.' Your sales literature explains that this product is a UV protective window film that permits between 88 to 92 percent light transmission through the front windshield. You state that the UV Heat Shield blocks ultra-violet radiation from entering the vehicle's occupant compartment. I am pleased to have this opportunity to explain our regulations to you. By way of background information, section 103 of the National Traffic and Motor Vehicle Safety Act ('Safety Act,' 15 U.S.C. 1392) authorizes NHTSA to issue safety standards for new motor vehicles and new items of motor vehicle equipment. NHTSA does not however approve or certify any vehicles or items of equipment. Instead, the Safety Act establishes a 'self-certification' process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. The agency periodically tests vehicles and items of equipment for compliance with the standards. In addition, the Safety Act requires manufacturers to recall and remedy any motor vehicle or item of motor vehicle equipment that contains a safety-related defect. Under the authority of the Safety Act, NHTSA has issued Standard No. 205, Glazing Materials, which specifies performance and location requirements for glazing used in vehicles. These requirements include specifications for minimum levels of light transmittance (e.g., 70 percent in areas requisite for driving visibility, which includes all windows in passenger cars). The purpose of this requirement is to ensure driver visibility through the windows, thereby reducing the risk of a motor vehicle crash. Manufacturers must certify that their new vehicles comply with the requirements of all applicable safety standards. If, before the vehicle were first purchased by a consumer, a subsequent manufacturer or dealer were to install your window film over the glazing, that subsequent manufacturer would be required to certify that the vehicle continues to comply with the requirements of Standard No. 205 with the window film installed. I note that while you state that your window film permits between 88 to 92 percent light transmission through the front windshield, it is the windshield with your product installed that would be required to meet the 70 percent light transmittance requirement. After a vehicle is first sold to a consumer, modifications to the vehicle are affected by 108(a)(2)(A) of the Safety Act (15 U.S.C. 1397(a)(2)(A)). That section prohibits any manufacturer, distributor, dealer, or motor vehicle repair from knowingly 'rendering inoperative' any device or element of design installed in a vehicle in compliance with any applicable safety standard. This provision means that no manufacturer, dealer, distributor, or repair business could install window tinting film if the addition of the tinting film to the glazing would result in a light transmittance of less than 70 percent, or otherwise cause the vehicle to no longer comply with the applicable requirements of Standard No. 205. Violations of this 'render inoperative' prohibition can result in Federal civil penalties to the manufacturer, dealer, distributor, or repair business of up to $1,000 for each noncomplying installation. Section 108(a)(2)(A) of the Safety Act does not affect vehicle owners. Hence, vehicle owners themselves may install tinting film or any other product on the glazing of their vehicle, regardless of whether the installation causes the vehicle to no longer comply with Standard No. 205. Individual States have the authority to regulate the operational use of vehicles by their owners, and, therefore, have the authority to regulate or preclude individual owner modifications to the glazing of their vehicles. If you are interested in further information on the provisions on the provisions of State laws, you may wish to contact the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, VA 22203. In addition, under the Safety Act, the UV Heat Shield would be considered an item of motor vehicle equipment. Your company, as a manufacturer of motor vehicle equipment, would be subject to the requirements in 151-159 of the Safety Act concerning the recall and remedy of products with safety related defects. In the event that NHTSA or the product's manufacturer determines that a product that is an item of motor vehicle equipment contains a safety- related defect, the manufacturer is responsible for notifying purchasers of the defective equipment and remedying the problem free of charge. I have also enclosed a general information sheet for new manufacturers which summarizes NHTSA's regulations and explains where to obtain copies of Federal motor vehicle safety standards and other regulations. I hope that you find this information helpful. If you have any other questions, please contact Marvin Shaw of my staff at this address or by phone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosures"; |
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ID: aiam1889OpenMr. David M. Holden, Frigiking, Inc., 10858 Harry Hines Boulevard, Dallas, TX 75220; Mr. David M. Holden Frigiking Inc. 10858 Harry Hines Boulevard Dallas TX 75220; Dear Mr. Holden: Your letter of March 7, 1975 to Mr. Alex Calaluca, Motor Vehicl Programs Director of the National Highway Traffic Safety Administration's Region 6, has been referred to this office. You wish to be informed of Frigiking's responsibilities under the NHTSA's rules and regulations as a manufacturer of automotive air conditioners for sale to domestic and foreign auto manufacturers, automobile dealers and automobile supply retail outlets.; Mr. Calaluca correctly indicated that there is currently no Federa Motor Vehicle Safety Standard which regulates automobile air conditioners. He also correctly informed you that your firm is not deemed a manufacturer by the NHTSA when your product is installed as original equipment. Where the Frigiking air conditioner is installed in a vehicle prior the first sale of the vehicle the manufacturer of the vehicle is also deemed to be manufacturer of your product. However, you should understand that in all other cases your company is considered a manufacturer under the NHTSA's rules and regulations. For example, where units are sold under private label to mass merchandising firms for sale and installation to individual automobile owners, or where units are sold through Frigiking's distributor/dealer organization for individual unit retail sales where the sale is other than to a franchised auto dealer for installation prior to the sale of the new car, Frigiking has certain responsibilities under the National Traffic and Motor Vehicle Safety Act of 1966, as amended, notwithstanding the absence of any Safety Standard regulating air conditioners.; In the event that the NHTSA determined through its own investigatio that an air conditioner produced by your firm contained a defect related to motor vehicle safety, you would be required to give notice of the defect to every person who had purchased the produce manufactured during the period when a defect was known to exist. This manufacturing period could extend up to 8 years preceding the notification. In addition you would be required to repair or replace without charge every such defective air conditioner presented to you, and repurchase defective air conditioners from distributors and dealers.; Finally, it would be wise for Frigiking to remind manufacturers an dealers who install its air conditioners in motor vehicles prior to first sale that they must account for the addition of an air conditioning unit in certifying that the vehicle conforms to Federal standards and in certifying the Gross Vehicle Weight Rating and Gross Axle Weight Rating as required by the NHTSA regulations contained in 49 CFR Part 567.; Please do not hesitate to contact us if we can be of furthe assistance.; Yours truly, Richard B. Dyson, Assistant 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.