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
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ID: aiam4567OpenMr. Sadato Kadoya Mazda Research & Development of North America, Inc. 1203 Woodbridge Avenue Ann Arbor, MI 48105; Mr. Sadato Kadoya Mazda Research & Development of North America Inc. 1203 Woodbridge Avenue Ann Arbor MI 48105; Dear Mr. Kadoya: This is in reply to your letter of August 24, l989 with respect to an interpretation of paragraph S5.3.1.8 of Standard No. 108, as it applies to the location of center highmounted stop lamps. The paragraph requires that no portion of the lens shall be lower than 3 inches below the rear window, if the lamp is mounted below the rear window. Your letter depicts two areas in which a lamp lens may be mounted, denoted '(A)' and '(B)'. In both, the lower edge of the rear window is curved. In '(A)', the boundary of the allowable area is curved, and follows the curve of the lower edge of the rear window at a parallel distance of 3 inches. In '(B)', the boundary of the allowable area is a straight line which measures 3 inches from the end of the lower edge of the rear window, but which is greater than 3 inches at all other points because of the curve of the window. The initial requirement of paragraph S5.3.1.8 is that the highmounted lamp be 'mounted with its center on the vertical centerline of the passenger car as the car is viewed from the rear.' This means that the 3-inch distance is measured from the lower edge of the rear window that is at the vertical centerline. Thus, your '(A)' is the correct location because the boundary line is 3 inches directly below the center point of the vertical centerline, and your '(B)' is not acceptable because its boundary line is more than 3 inches below that point. I hope that this answers your question. Sincerely, Stephen P. Wood Acting Chief Counsel; |
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ID: aiam2519OpenMr. K. W. Schang, Director, Vehicle Safety Programs, American Motors Corp., 14250 Plymouth Road, Detroit, MI 48232; Mr. K. W. Schang Director Vehicle Safety Programs American Motors Corp. 14250 Plymouth Road Detroit MI 48232; Dear Mr. Schang: This is in response to your letter of November 24, 1976, requesting favorable response by the National Highway Traffic Safety Administration (NHTSA) to your petitions for reconsideration of the Part 581, *Bumper Standard*, requesting an effective date of September 1, 1979.; The NHTSA is continuing to examine the petitions submitted in respons to the publication of Part 581. On Tuesday, February 22, 1977, the NHTSA issued a Federal Register notice proposing to delay for 1 year, until September 1, 1980, implementation of the second phase of requirements under Part 581. This action was taken in response to petitions for reconsideration from Ford Motor Company and General Motors. I have enclosed a copy of the notice for your information. I want to assure you that every consideration is being given to the matters raised both in your petition and in your November 24, letter. The issues you have mentioned will, of course, be thoroughly addressed by notice in the Federal Register.; Sincerely, John W. Snow |
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ID: aiam0524OpenMr. Albert D. Ekegren, Vice President and General Manager, Cats-Eye Lamp Division, Holophane Company, Inc., Post Office Box 567, Columbus, OH, 43216; Mr. Albert D. Ekegren Vice President and General Manager Cats-Eye Lamp Division Holophane Company Inc. Post Office Box 567 Columbus OH 43216; Dear Mr. Ekegren: This is in response to your letter of December 13, 1971, in which yo made further comments on the requirements of Standard No. 108 with respect to school bus lighting. You expressed concern over the fact that a company holds a patent relating to the wiring for eight-lamp systems that are permitted (though not required) under Standard No. 108.; Although the existence of patents is one factor that may be taken int account in setting motor vehicle safety standards, it is not the primary one. This agency is charged by Congress with the responsibility of setting standards that represent the best possible resolution of the problems of safety, cost, and technological feasibility. If two alternative regulatory courses of action are found to be substantially equal in other respects, the agency might prefer the one in which the largest number of companies were free to compete at will. But the granting of patents is a long-established policy of our government, administered by the U.S. Patent Office under the direction of Federal statutes and the Constitution. We do not, therefore, agree with your suggestion that it is 'against public interest' to issue regulations that have the incidental effect of favoring or requiring the use of patented products.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam4834OpenMr. Louis F. Wilson Instant Traffic Lights 2580 W. Venice Boulevard Los Angeles, CA 90019; Mr. Louis F. Wilson Instant Traffic Lights 2580 W. Venice Boulevard Los Angeles CA 90019; Dear Mr. Wilson: This is in reply to your letter of February 20, 1991 with respect to the acceptability under Federal law of your product, the 'Instant Traffic Light. I regret that we do not appear to have a record of your earlier letters to the agency on this subject. The 'Instant Traffic Light' is a four-section unit intended to perform three functions, each indicated by a different color. A green light appears when the accelerator is applied, an amber light when the accelerator is released, and a red light when the brakes are applied. The lamp's shipping carton shows the unit mounted on the rear parcel shelf behind the rear window. The text on the carton says that the lamp is easy to assemble. You have asked whether the product meets Standard No. 108, whether it would be 'legal' in the U.S. 'and her territories', and whether the product could replace, or be an option to, the requirements of Standard No. 108 for the center high-mounted stop lamp. Finally, of the l6 States that have responded to your inquiry, an equal number (six) have indicated that the lamp is and is not acceptable to them, while the remaining four 'said they will follow the Federal requirement.' Standard No. 108 does not permit the center high-mounted stop lamp to be combined with any other lamp. This means that your product could not be used as original equipment on a passenger car, whether as standard equipment or as an option, or marketed and sold as replacement equipment for a center lamp on a passenger car that was originally equipped with it. However, Standard No. 108 does not apply to the 'Instant Traffic Light' if it is marketed or sold exclusively for use on passenger cars that were not originally required to be manufactured with the center stop lamp, i.e., those cars that were manufactured before September 1, l985. Under this circumstance, the question of the legality of use of the device is to be determined by the laws of the individual States. The 'territories' are 'States' for purposes of this discussion. Since there is no legal prohibition under Federal law for installation of your lamp only on older passenger cars, we presume that the four States that reserved their decision would permit it on pre - l985 vehicles registered and/or operating within their borders. We are aware that, nevertheless, there may be some owner interest in replacing original equipment center stop lamps with your product. We would like to advise that such replacement would be a violation of the National Traffic and Motor Vehicle Safety Act, if performed by a manufacturer, distributor, dealer, or motor vehicle repair business. There is no such restriction upon a vehicle owner who performs the replacement of the lamp himself. I hope that this responds to your questions. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam2149OpenMr. W. G. Milby, Staff Engineer, Blue Bird Body Company, P.O. Box 937, Fort Valley, GA 31030; Mr. W. G. Milby Staff Engineer Blue Bird Body Company P.O. Box 937 Fort Valley GA 31030; Dear Mr. Milby: This responds to Blue Bird Body Company's November 11, 1975, reques for confirmation that a manufacturer's location of the seating reference point, as the term is defined in 49 CFR S 571.3, may take into account nominal deflection of the seat and seat back cushions.; Blue Bird Body is correct that subparagraph (c) of the NHTSA' definition of seating reference point contemplates some deflection of seat cushions to simulate compression of padding material under the weight of a human torso and thigh. As noted in the preamble of the second proposal for a school bus seating standard (39 FR 27585, July 30, 1974), 'It can be seen that the manufacturer's freedom to locate the point is sharply restricted by the definition which specifies that it actually simulate the position of the pivot center of the human torso and thigh, following SAE placement procedures.'; Blue Bird Body's nominal seat and seat back cushion deflections appea to be reasonable, based on our understanding of the drawing your enclosed.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0174OpenMr. David A. Zawolkow, Staff Engineer, Challenge-Cook Bros. Incorporated, 15421 East Gale Avenue, Industry, CA 91745; Mr. David A. Zawolkow Staff Engineer Challenge-Cook Bros. Incorporated 15421 East Gale Avenue Industry CA 91745; Dear Mr. Zawolkow: This is in response to your letter of August 12, 1969, concerning th responsibility of manufacturers who assemble work bodies such as concrete mixers to chassis-cabs produced by another company. You stated:; >>>'We understand that in the case of installing concrete mixers of ou manufacture on a chassis vehicle, our certification will cover only those Safety Standards relating to our own equipment and its installation, plus modifications, if made by us to the chassis vehicle in the area where Safety Standards apply.'<<<; As a final-stage assemblies you are responsible for any standard applicable to the completed vehicle to which conformity has not been certified by the chassis-cab manufacturer, and for any standards conformity to which is affected by the addition of the body. The chassis- cab manufacturer is required to affix an label listing the standards the chassis-cab conforms to. If the list includes all relevant standards, and you have no specific knowledge that the chassis-cab may not conform (as, for example, where it has been damaged in transit), then your statement above is essentially correct.; The relevant rulings are contained in the Federal Register notices o January 3, 1968, together with the certification regulations published July 9, 1969. Copies are enclosed.; Sincerely, David E. Wells, Chief Counsel |
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ID: aiam5376OpenMr. Allan Garman M.F. Bank & Co., Inc. 2505 W. 2nd Avenue Suite 14 Denver, CO 80219-1655; Mr. Allan Garman M.F. Bank & Co. Inc. 2505 W. 2nd Avenue Suite 14 Denver CO 80219-1655; "Dear Mr. Garman: This responds to your letter and telephone cal asking several questions about the responsibilities of various parties after child restraint systems have been involved in a collision and fire during transit from the manufacturer (Gerry Products) to a retail outlet (Toys R Us). I apologize for the delay in responding. You indicate in your letter that the child restraint manufacturer, Gerry Baby Products, has determined that the DOT certification on the child restraints is no longer valid because the restraints were subjected to potential stress by the impact of the truck accident. We understand from your letter that M.F. Bank is storing the child restraint systems damaged in transit, and is prepared to liquidate the stock if directed to do so by the insurer of the transit company. However, the insurer has asked that M.F. Bank ask this agency whether the child restraint systems involved in the loss can be sold as salvage to the public. You state your belief that the systems are salvagable because they did not experience structural damage in the incident. By way of background information, the National Traffic and Motor Vehicle Safety Act (15 U.S.C. sections 1381 et seq.) authorizes the National Highway Traffic Safety Administration (NHTSA) to issue Federal motor vehicle safety standards (FMVSSs) for new motor vehicles and new items of motor vehicle equipment. Under that authority, NHTSA issued FMVSS No. 213, 'Child Restraint Systems' (49 CFR 571.213) to reduce the number of children killed or injured in motor vehicle crashes and in aircraft. Section 108(a)(1)(A) of the Safety Act prohibits any person from manufacturing for sale or selling any new item of equipment that does not conform to all applicable FMVSSs or is not covered by a certification of compliance with the applicable FMVSSs. Thus, each new child restraint system must comply with FMVSS No. 213 and must be certified as complying with that standard when it is sold. You first ask whether Federal law would prohibit the sale of the child restraint systems as salvage. The answer is yes, since according to your letter and telephone call, Gerry has indicated that its certification is no longer valid, and has thereby withdrawn the certification. If the child seats are not certified, selling them would violate 108(a)(1)(A). Section 109 of the Act provides any violation of Section 108 is punishable by civil penalties of up to $1,000 per violation, up to a maximum of $800,000 for a series of related violations. You ask in your telephone call whether Federal law prohibits Gerry from concluding that the certification remains valid. If your question is whether the Safety Act or our regulations require Gerry to withdraw the certification simply because the seats were involved in an incident, the answer is no. However, 108(a)(1)(C) of the Safety Act prohibits any person from certifying that a child restraint system complies with Standard 213 if that person, in the exercise of due care, has reason to know that the certificate is false or misleading in a material respect. Gerry is therefore required by the Safety Act to withdraw the certification of the unsold seats if it believes the certification is invalid. If a manufacturer determines, for any reason, that the unsold seats do not comply, NHTSA will not second guess the decision to withdraw the certification. Finally, you ask if it would be possible for NHTSA to send someone to your warehouse to inspect the child restraint systems to determine whether the systems comply with FMVSS No. 213. The answer is no, NHTSA does not inspect products for compliance outside the context of its enforcement activities. The Safety Act establishes a self-certification system under which child restraint manufacturers are responsible for ensuring that their products comply with FMVSS No. 213. NHTSA does not approve, endorse, or give assurances of compliance of any product. I hope this information answers your questions. If you need further information, please feel free to contact Ms. Deirdre Fujita of my staff at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam4971OpenDr. Larry J. French President and CEO Magnascreen 265 Kappa Drive Pittsburgh, PA 15238; Dr. Larry J. French President and CEO Magnascreen 265 Kappa Drive Pittsburgh PA 15238; "Dear Dr. French: This responds to your letter inquiring about a recen amendment to Safety Standard No. 111, Rearview Mirrors. (49 CFR 571.111) You explained that your company is developing electronically controlled dimmable (day/night) rearview mirrors for motor vehicles and requested that the agency assess your reading of section S11 of the standard. We are pleased to have this opportunity to interpret our standard for you. By way of background information, the National Highway Traffic Safety Administration (NHTSA) does not provide approval of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, the manufacturer is responsible for certifying that its vehicles or equipment comply with applicable standards. The following letter represents our opinion based on the facts presented in your letter. Safety Standard No. 111 specifies requirements for the performance and location of rearview mirrors. Section S11, which was recently amended to better address new mirror designs, specifies requirements for mirror construction. (See 56 FR 58513, November 20, 1991.) The section states in relevant part that: All single reflectance mirrors shall have an average reflectance of at least 35 percent. If a mirror is capable of multiple reflectance levels, the minimum reflectance level in the day mode shall be at least 35 percent and the minimum reflectance level in the night mode shall be at least 4 percent. A multiple reflectance mirror shall either be equipped with a means for the driver to adjust the mirror to a reflectance level of at least 35 percent in the event of electrical failure, or achieve such reflectance level automatically in the event of electrical failure. You asked whether an alternate power source can be used to achieve the specified fail-safe operation (i.e., adjusting the mirror to a reflectance level of at least 35 percent in the event of electrical failure). While your letter did not specify what you meant by 'alternate power source,' we assume that it means an electrical power source other than the one intended to normally operate the mirror. Examples of an alternate electrical power source include solar energy or a self-contained battery system. We interpret the term 'electrical failure,' as used in section S11 of Standard No. 111, to include any type of electrical failure. This would include electrical failure related to an alternate power source as well as electrical failure related to the primary power source. Therefore, unless adjustment of the mirror to a reflectance level of at least 35 percent occurred even in situations where there was electrical failure related to the alternate power source, the alternate electrical source could not be used to provide the fail-safe operation required by section S11. The preamble to the final rule amending Standard No. 111 explained that the agency wanted to assure that multiple reflectance mirrors are capable of providing adequate images at all times during the vehicle's operation, including electrical failure situations where the mirror is unpowered. The agency noted that situations can occur where the mirror would be unpowered even though the vehicle could be operational, citing connector faults and circuit board faults. See 56 FR 58515. To comply with section S11 in situations where a mirror is unpowered as a result of electrical failure, a mirror would either have to default automatically to the high reflectance mode (as in the case of an opposite polarity fail-safe liquid crystal mirror described in the preamble) or be capable of being manually adjusted to the high reflectance mode. We do not have enough information about your proposed mirror to determine whether it would comply with the amendments in the case of electrical failure related to the alternate power source. I hope this information is helpful. If you have any further questions about NHTSA's safety standards, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosure"; |
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ID: aiam5399OpenMr. Saburo Inui Vice President Toyota Motor Corporate Services of North America, Inc. 1850 M Street, N.W. Washington, D.C. 20036; Mr. Saburo Inui Vice President Toyota Motor Corporate Services of North America Inc. 1850 M Street N.W. Washington D.C. 20036; "Dear Mr. Inui: This responds to your letter asking about the tes conditions for the dynamic side impact test of Standard No. 214, 'Side Impact Protection.' I apologize for the delay in responding. The test conditions are set forth in S6 of the standard. S6.1 explains how to achieve 'test weight:' Test weight. Each passenger car is loaded to its unloaded vehicle weight, plus its rated cargo and luggage capacity, secured in the luggage area, plus the weight of the necessary anthropomorphic test dummies. Any added test equipment is located away from the impact areas in secured places in the vehicle. * * * You first ask whether the weight of the added test equipment inside the vehicle is added to the test weight, or whether parts of the vehicle (weighing the same as the 'added test equipment') are removed to keep the vehicle weight at the 'test weight.' The answer is that parts of the vehicle may be removed, but only as a last resort. A brief explanation of how NHTSA calculates test weight follows. Under S6.1, 'test weight' is comprised of the combined weight of the vehicle with all fluids, the cargo and luggage weight, the test dummies, and nothing more. The cargo and luggage weight is derived by subtracting from the gross vehicle weight rating specified by the manufacturer the combined weight of the vehicle, fluids, and 150 pounds for each seating position. There are subtractions and additions to the vehicle weight in preparation for the test. The fuel is replaced with Stoddard solvent, but only to approximately 93 percent of capacity, and all other fluids (oil, washer fluid, etc.) are drained. Thus, the vehicle is lightened by the weight of 7 percent of the fuel and all of the other fluids. However, the added weight of cameras and any other necessary (non-dummy) test equipment usually more than compensates for the fluid weight loss, and the vehicle generally is slightly heavier than the test weight. Therefore, other weight must be removed until the test weight is reestablished. Please note that NHTSA will remove parts of the vehicle to compensate for the weight of the test equipment only as a last resort. The agency will first remove cargo or luggage ballast. If still more weight must be removed (i.e., in the unlikely event that the weight of the test equipment exceeds the weight of the removable cargo and luggage) the agency will remove parts of the vehicle. This is only likely to occur in vehicles with very small cargo capacities, such as sports cars. In this event, NHTSA would remove only parts of the car that play no part in the side impact test (e.g. bumpers). You next ask about the 'vehicle test attitude' specifications of S6.2. By way of background, NHTSA determines the attitude of the vehicle in its 'as delivered' condition (i.e., the vehicle as received at the test site, filled to 100 percent of all fluid capacities and with all tires inflated to the manufacturer's specifications) and in its 'fully loaded condition,' under the vehicle test attitude specification of S6.2. Under S6.2, the vehicle's pretest attitude is equal to either the as delivered or the 'fully loaded attitude' or between the as delivered and the fully loaded attitude. You ask whether the term 'fully loaded attitude' means the attitude of the vehicle in the 'fully loaded condition.' The answer is yes. Moreover, S6.2 specifies that ' t he `fully loaded condition' is the test vehicle loaded in accordance with S6.1.' As mentioned in our response to your first question, S6.1 explains how to load the vehicle to achieve the test weight. You also ask whether the 'as delivered' left-to-right attitude must be maintained when adding test equipment. The answer is also found in S6.2's specification that ' t he pretest vehicle attitude is equal to either the as delivered or fully loaded attitude, or between the as delivered attitude and the fully loaded attitude.' This language describes a range of attitudes, including the left-to-right attitude, which the vehicle may be in at the time of the test. The vehicle must be capable of passing the test anywhere within the prescribed range. Therefore, when NHTSA tests a vehicle, the agency has leeway in maintaining the as delivered left-to-right attitude when adding test equipment. As long as the left-to-right attitude after adding equipment is somewhere between the attitude in the as delivered condition and the fully loaded condition, an acceptable pretest vehicle attitude will be achieved. Finally, I would like to note that NHTSA's Enforcement Office prepares updates to its laboratory test procedures on an as-required basis. The updates include rule changes and maintenance revisions. We project a maintenance update to the side impact test procedures (TP-214D-03) will be published within the next six months. During this update, issues addressed in this letter will be considered. I hope you find this information helpful. If you have any other questions, please contact Ms. Deirdre Fujita of my staff at (202) 366-2992. Sincerely, John G. Womack Acting Chief Counsel"; |
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ID: aiam0461OpenMr. Paul F. Bennett, Utility Trailer Manufacturing Company, P. O. Box 1299, City of Industry, CA, 91747; Mr. Paul F. Bennett Utility Trailer Manufacturing Company P. O. Box 1299 City of Industry CA 91747; Dear Mr. Bennett: Thank you for your letter of September 22 asking for clarification o the requirement for spacing of rear identification lamps on trailers, as applicable to your 'change number 21-23.'; Until January 1, 1972, Table II of Federal Motor Vehicle Safet Standard No. 108 requires that the three-lamp cluster be mounted 'as close as practicable to the vertical center line.' However, beginning January 1, 1972, the center lamp of the three-lamp cluster must be mounted on the vertical center line, and the offset arrangement in change number 21-23 will no longer meet the requirements of Standard No. 108.; Sincerely, Lawrence R. Schneider, 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.