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: aiam4810OpenMr. Paul G. Scully Vice President Peterson Manufacturing Company 4200 East 135th Street Grandview, MO 64030; Mr. Paul G. Scully Vice President Peterson Manufacturing Company 4200 East 135th Street Grandview MO 64030; "Dear Mr. Scully: This is in reply to your letter of August l4, l99 (postmarked September l9), asking that we notify the police department of Tuscon, Arizona, that reflex reflectors are not required to have SAE markings 'in order to be perfectly legal reflectors.' You also state that another agency of the Department of Transportation, the Federal Highway Administration's Office of Motor Carrier Safety, 'still retain(s) these marking requirements in their publication' and appeal for 'a uniform set of regulations between the two government agencies involved.' Because this matter has not been brought to our attention by the police department of Tuscon, we are responding directly to you so that you may furnish copies to whomever you deem it most advisable. We confirm your understanding that 49 CFR 571.108, Federal Motor Vehicle Safety Standard No. 108, Lamps, Reflective Devices, and Associated Equipment, does not require that reflex reflectors bear SAE markings. Although they must meet the requirements of SAE Standard J594f, Reflex Reflectors, January 1977, there is no requirement that they bear SAE markings according to SAE Recommended Practice J759c, Lighting Identification Code, January l975. Although the Federal Highway Administration's Office of Motor Carrier Safety (OMCS) has amended most of its vehicle lighting regulations to conform to Standard No. 108, up until now that agency has required, under 49 CFR 393.26(c), that reflectors bear (among other markings), the letters 'SAE-A'. However, OMCS has informed us that it will amend its regulation to conform to Standard No. 108 as early as convenient, and in the meantime will notify its field office that the marking requirement is no longer to be enforced. Therefore, failure to mark reflectors with the letters 'SAE-A' may be inconsistent with current OMCS requirements, but it is not a failure to comply with Standard No. 108. Further, to the extent that Arizona law itself may require marking of reflectors with the letters 'SAE-A', that provision is inconsistent with Standard No. 108 and is subject to the preemption provisions of l5 U.S.C. 1392(d). Under the preemption provisions, no State or political subdivision thereof may enact or continue in effect a standard covering the same aspect of performance as a Federal motor vehicle safety standard, unless it is identical to the Federal standard. Thus, any State or local requirement for SAE markings on reflex reflectors is one that is not identical to Standard No. 108, and subject to the preemption provisions. Other than the reference to OMCS regulations, we do not know under what authority the Tuscon police are acting. Certainly, a local official cannot enforce a Federal standard per se. If Arizona law requires vehicles in interstate commerce to comply with regulations of the OMCS, and the Tuscon police are attempting to enforce State law, we conclude that the State law is subject to the preemption provisions discussed above, and that such enforcement action has been precluded under Federal law. I hope that this responds to your concerns. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam3334OpenMr. R. H. Snyder, Vice President, Tire Technology, Uniroyal Tire Company, 6600 East Jefferson Avenue, Detroit, MI 48232; Mr. R. H. Snyder Vice President Tire Technology Uniroyal Tire Company 6600 East Jefferson Avenue Detroit MI 48232; Dear Mr. Synder: This is in response to your letter of August 14, 1980, requestin interpretation of the Uniform Tire Quality Grading (UTQG) Standards (49 CFR S 575.104) with regard to the assignment of treadwear grades. You report that Uniroyal has encountered variations in treadwear test data derived from UTQG tests conducted by different testing organizations. You ask whether a tire manufacturer is obligated under the UTQG treadwear grading procedure to base its grades on those test results which produce the lowest treadwear grade, or may use any available test data as the basis for grade assignment.; Uniform Tire Quality Grading, as with other National Highway Traffi Safety Administration (NHTSA) regulations, involves a self-certification process in which manufacturers bear the primary responsibility for assuring that their products conform to required levels of performance, in this case the levels represented by their assigned grades. NHTSA's Office of Vehicle Safety Compliance (OVSC) conducts testing to verify that various tires actually provide levels of performance consistent with their grades. When OVSC testing produces results at variance with assigned grades, the manufacturer involved is given an opportunity to provide justification for its grade assignments.; In determining that a product achieves a particular level o performance under the UTQG procedures, a manufacturer may exercise a considerable degree of discretion as to the amount of testing necessary to assure that its conclusions regarding compliance will withstand NHTSA scrutiny. In evaluating the performance of a product, NHTSA does not require that a manufacturer base its judgment on any particular piece of test data or on all available data. In fact, a manufacturer may disregard data from a particular source entirely, if the manufacturer can establish that other data provides a reasonable basis for grading.; However, a manufacturer cannot establish compliance by arbitraril picking and choosing among available data to select results of that test which happened to produce the most favorable result. Data used to establish compliance must be reliable and consistently reproducible, and cannot have been derived through manipulative devices, e.g., abusive driving, or unexacting test procedures. It is the responsibility of the manufacturer to base its conclusions on data demonstrably developed in full conformance with the requirements of the regulation.; NHTSA will provide confidential treatment for your letter of August 14 1980, and the accompanying data.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3335OpenMr. R. H. Snyder, Vice President, Tire Technology, Uniroyal Tire Company, 6600 East Jefferson Avenue, Detroit, MI 48232; Mr. R. H. Snyder Vice President Tire Technology Uniroyal Tire Company 6600 East Jefferson Avenue Detroit MI 48232; Dear Mr. Synder: This is in response to your letter of August 14, 1980, requestin interpretation of the Uniform Tire Quality Grading (UTQG) Standards (49 CFR S 575.104) with regard to the assignment of treadwear grades. You report that Uniroyal has encountered variations in treadwear test data derived from UTQG tests conducted by different testing organizations. You ask whether a tire manufacturer is obligated under the UTQG treadwear grading procedure to base its grades on those test results which produce the lowest treadwear grade, or may use any available test data as the basis for grade assignment.; Uniform Tire Quality Grading, as with other National Highway Traffi Safety Administration (NHTSA) regulations, involves a self-certification process in which manufacturers bear the primary responsibility for assuring that their products conform to required levels of performance, in this case the levels represented by their assigned grades. NHTSA's Office of Vehicle Safety Compliance (OVSC) conducts testing to verify that various tires actually provide levels of performance consistent with their grades. When OVSC testing produces results at variance with assigned grades, the manufacturer involved is given an opportunity to provide justification for its grade assignments.; In determining that a product achieves a particular level o performance under the UTQG procedures, a manufacturer may exercise a considerable degree of discretion as to the amount of testing necessary to assure that its conclusions regarding compliance will withstand NHTSA scrutiny. In evaluating the performance of a product, NHTSA does not require that a manufacturer base its judgment on any particular piece of test data or on all available data. In fact, a manufacturer may disregard data from a particular source entirely, if the manufacturer can establish that other data provides a reasonable basis for grading.; However, a manufacturer cannot establish compliance by arbitraril picking and choosing among available data to select results of that test which happened to produce the most favorable result. Data used to establish compliance must be reliable and consistently reproducible, and cannot have been derived through manipulative devices, e.g., abusive driving, or unexacting test procedures. It is the responsibility of the manufacturer to base its conclusions on data demonstrably developed in full conformance with the requirements of the regulation.; NHTSA will provide confidential treatment for your letter of August 14 1980, and the accompanying data.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam5518OpenMr. Tom Hindson 7810 N.W. 40 Street Coral Springs, FL 33065; Mr. Tom Hindson 7810 N.W. 40 Street Coral Springs FL 33065; "Dear Mr. Hindson: This responds to your letter asking about how thi agency's regulations might apply to your product. I apologize for the delay in responding. In your letter, you described your product as a car cover that stows beneath the rear bumper of an automobile. When used, the cover is propelled from its casing by an electric motor as the driver guides the cover over the car with a handle, which then attaches to the front bumper. In a February 14, 1995 telephone conversation with Paul Atelsek of my staff, you described the product in more detail and said that vehicle owners will not be installing your product. Instead, you plan to market this either as a dealer-installed option on new cars or by having a business approved by you retrofitting used cars. The short answer to your question is that there are no regulations that apply specifically to your car cover. However, there are some safety concerns and Federal requirements that you should know about. The National Highway Traffic Safety Administration (NHTSA) has not issued any standards for car covers. However, the cover is an item of motor vehicle equipment. As a manufacturer of motor vehicle equipment, you are subject to the requirements in sections 30118-30122 of Title 49 of the U.S. Code concerning the recall and remedy of products with defects related to motor vehicle safety. If you or NHTSA determines that your product contains a safety related defect, you would be responsible for notifying purchasers of the defective equipment and remedying the problem free of charge. Since your product would be installed by a motor vehicle manufacturer, distributor, dealer or repair business, you should know that section 30122(b) of title 49 prohibits those commercial businesses from 'knowingly mak ing inoperative any part of a device or element of design installed on or in a motor vehicle . . . in compliance with an applicable Federal motor vehicle safety standard . . .' Any violation of this 'make inoperative' prohibition would subject the violator (i.e., the installer) to a potential civil penalty of up to $1,000 for each violation. Because your product is not 'readily attachable,' if the car cover is installed on a new vehicle prior to sale, the installer would be considered an 'alterer' under section 567.7 of Title 49 of the Code of Federal Regulations. Therefore, the installer would have to certify that the vehicle, as altered, continues to comply with all the standards affected by the modification. There do not appear to be any definite problems with your system, as it was described to us. However, allow me to reiterate our concern in a few areas that Mr. Atelsek described to you over the phone. These are safety related areas that you want to be careful of. Our regulations are in title 49 of the Code of Federal Regulations. Part 581 describes the bumper standard, which basically requires that there be no damage in collision at 2.5 mph. The housing of the car cover unit bolts both to the bumper and to the trunk pan, thus bridging the area between the bumper and the vehicle chassis. Although you said the polyurethane housing 'gives' and did not degrade performance even in a 5 mph collision you conducted, this is a standard you should consider for all vehicles on which your device is installed. Standard 301 is the fuel system integrity standard. It restricts fuel system spillage in collisions from many angles. Although you told Mr. Atelsek there were no pieces that could pierce the gas tank in a rear end collision, the illustrations you sent him seem to show some kind of rod-like support structure running longitudinally on either side of the cover housing. These structures run the entire length of the housing and even extend slightly beyond it. You told him that the housing was approximately 40 to 44 inches in the longitudinal direction. In a rear end collision (the test we use is described in S6.2 of Standard 301) these structures must not be driven into the gas tank to cause an unsafe fuel leakage problem. A related area of concern is the electrical conduit that runs from the battery lead to the electrical motor on the rear bumper which deploys the car cover. We suggest that you consider constructing and routing the conduit so that it will not be damaged in an accident, possibly causing a short and increasing the likelihood of ignition if there is fuel spillage. Finally, you should be cautious when mounting your unit near hot exhaust system components. You stated that you may mount the housing within 3/4 of an inch underneath the muffler, in which case you would use heat resistant aluminum sheet materials. You appeared to be very conscious of this potential danger, and we agree the flammability of components attached to a vehicle is an important safety concern. I hope this information is helpful. I am also enclosing a copy of a general fact sheet titled 'Information for New Manufacturers of Motor Vehicles and Motor Vehicle Equipment.' If you have any further questions about NHTSA's safety standards, please feel free to contact Mr. Atelsek at this address or by telephone at (202) 366-2992. Sincerely, Philip R. Recht Acting Chief Counsel Enclosure"; |
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ID: aiam2046OpenMr. Frank Hardy, Owner, The Hardy Heater Company, 9609 Dixie Highway, Louisville, KY 40272; Mr. Frank Hardy Owner The Hardy Heater Company 9609 Dixie Highway Louisville KY 40272; Dear Mr. Hardy: This is in response to your letter of July 30, 1975, in which yo inquire as to any rules and regulations to which you may be subject with respect to your pre-heater defroster. Your letter was referred to this office by the Environmental Protection Agency.; We assume, from the material submitted with your letter, that you pre-heater is sold for installation in used cars and supplements the vehicle's existing defrosting system. If our assumption is incorrect, please advise us. If your pre-heater is installed in a motor vehicle prior to its first purchase or if it replaces an existing defrosting system, you will be subject to regulations in addition to those mentioned in this letter.; The National Traffic and Motor Vehicle Safety Act provides that manufacturer, dealer, distributor, or repair shop may not render inoperative any safety device or design in a motor vehicle after its first purchase by the owner. this means that the installation of the pre-heater must not take the vehicle out of compliance with an applicable Federal Motor Vehicle Safety Standard. The standard with which you will likely be most concerned is Standard No. 103, *Windshield Defrosting and Defogging Systems* (copy enclosed).; In addition, if the fuel used in your pre-heater has a boiling poin greater than 32 degrees Fahrenheit, you must ensure that the pre-heater fuel system complies with Standard No. 301, *Fuel System Integrity* (copy enclosed).; Thank you for your interest in motor vehicle safety. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3758OpenMr. H. Nakaya, Office Manager, Mazda (North America), Inc., 23777 Greenfield Road, Suite 462, Southfield, MI 48075; Mr. H. Nakaya Office Manager Mazda (North America) Inc. 23777 Greenfield Road Suite 462 Southfield MI 48075; Dear Mr. Nakaya: This responds to your letter of August 25, 1983, requesting a interpretation of the requirements of Standard No. 201, *Occupant Protection in Interior Impact*. Your specific questions concern the application of the requirements of S3.5.1(b) of the standard to an armrest.; The answers to your four questions are as follows: A) The requirements of S3.5.1(b), as with the requirements o S3.5.1(a), apply to the whole area of an armrest. In contrast, the requirements of S3.5.1(c) only apply to a part of an armrest (i.e., the portion of the armrest within the pelvic impact area).; B) See answer to A. C) The agency does not give prior approval to specific designs. I appears, however, that your design would not comply, since apparently the armrest will not deflect or collapse to within 1.25 inches of a rigid test panel surface without permitting contact with any rigid material, in this case the power window switch. In addition, the power window switch apparently does not have a minimum vertical height of not less than one inch. It is difficult to provide you with a definitive answer since section A-A of your drawing appears to be drawn to a different scale than the scale shown in the lower left corner of your drawing.; D) It appears from your drawing that even if the requirements o S3.5.1(b) were amended, as you suggested, to limit their application to the pelvic impact area of the armrest, the design would not comply since the power window switch area of the armrest is within the pelvic impact area. Rather than seeking an amendment to the standard, you may want to consider modifying your design so that it will comply with either 3.5.1(a) or (c) of the standard.; If you have any further questions, please let me know. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3343OpenMr. H. Miyazawa, Director, Automotive Lighting, engineering Department, Stanley Electric Co., Ltd., 2-9-13, Nakameguro, Meguro-ku, Tokyo 153, Japan; Mr. H. Miyazawa Director Automotive Lighting engineering Department Stanley Electric Co. Ltd. 2-9-13 Nakameguro Meguro-ku Tokyo 153 Japan; Dear Miyazawa: This responds to your August 4, 1980, letter asking whether severa vehicle components would be required to comply with Standard No. 302, *Flammability of Interior Materials.* In particular you ask whether a headlining lamp, a courtesy lamp installed on a door panel, or various pilot indicator lamps and meters installed in the front panel must comply with the requirements.; As you stated in your letter, Section S4.1 of the standard lists th components required to comply with the standard. Further, that section states that materials designed to absorb energy on contact by occupants must comply with the standard. Since the components that you mention are not listed in S4.1 and since they do not appear to be designed to absorb energy on contact by an occupant, we conclude that they are not required to comply with the standard.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3341OpenMr. H. Miyazawa, Director, Automotive Lighting, Engineering Department, Stanley Electric Co., Ltd., 2-9-13, Nakameguro, Meguro-ku, Tokyo 153, Japan; Mr. H. Miyazawa Director Automotive Lighting Engineering Department Stanley Electric Co. Ltd. 2-9-13 Nakameguro Meguro-ku Tokyo 153 Japan; Dear Mr. Miyazawa: This responds to your August 4, 1980, letter asking whether severa vehicle components would be required to comply with Standard No. 302, *Flammability of Interior Materials*. In particular you ask whether a headlining lamp, a courtesy lamp installed on a door panel, or various pilot indicator lamps and meters installed in the front panel must comply with the requirements.; As you stated in your letter, Section S4.1 of the Standard lists th components required to comply with the standard. Further, that section states that materials designed to absorb energy on contact by occupants must comply with the standard. Since the components that you mention are not listed in S4.1 and since they do not appear to be designed to absorb energy on contact by an occupant, we conclude that they are not required to comply with the standard.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2587OpenMr. Jackson Decker, Chief Product Engineer, E.D. Etnyre & Co., 200 Jefferson Street, Oregon, IL 61061; Mr. Jackson Decker Chief Product Engineer E.D. Etnyre & Co. 200 Jefferson Street Oregon IL 61061; Dear Mr. Decker: This responds to your March 30, 1977, letter asking whether th rebuilding of a motor vehicle with all new running gear and an old body constitutes the manufacture of a new motor vehicle requiring compliance with Federal regulations.; In the rebuilding operation you describe, you retain the old body tan structure while replacing the entire running gear assembly. The National Highway Traffic Safety Administration (NHTSA) has determined by regulation in 49 CFR 571.7(f) that the rebuilding of a motor vehicle using old running gear with a new body does not constitute the manufacture of a new motor vehicle. The vehicle will be considered newly manufactured unless, at a minimum, the trailer running gear assembly is not new and was taken from an existing trailer whose identity is continued with respect to the Vehicle Identification Number. In addition, the trailer must be owned or leased by the same party both before and after the remanufacture. Since the running gear with which you plan to equip your vehicle is new, your operation constitutes the new manufacture of a vehicle.; You ask secondly what portion of the running gear can be replaced a normal repairs without such replacement being considered the manufacture of a new vehicle. You may replace any part of the running gear assembly that breaks or malfunctions during operation of the motor vehicle. The NHTSA would consider this to be normal maintenance of the vehicle, not subject to the requirements applicable to vehicle manufacture.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam5401OpenMr. R. H. Goble President, Goble Enterprises P.O. Box 423 Lake Mary, FL 32795; Mr. R. H. Goble President Goble Enterprises P.O. Box 423 Lake Mary FL 32795; "Dear Mr. Goble: This is in reply to your letter of May 16, 1994, wit respect to two motor vehicle lighting systems that you have developed, and your question about the regulations that may apply to each. As we understand the first system, when the brake pedal is applied, the front turn signal lamps and front side marker lamps are simultaneously activated to indicate to observers from the front and side that the vehicle is braking. It appears that this activation is in a steady burning state which continues unless and until the turn signal lamps are activated in either the flashing turn signal or hazard warning signal more. You have also developed a 'Wheel Well lighting system', which 'will provide light indicators all around (brake, clearance, turn signal, emergency flashers)' through amber lamps mounted in the well at the top of each front and rear wheel opening. As we understand this system, these supplementary lamps will be activated simultaneously when the four named lamp systems are activated. The regulation governing the lighting on new motor vehicles (i.e., requirements that must be met when a new vehicle is delivered to its first purchaser) is Federal Motor Vehicle Safety Standard No. 108. With respect to optional equipment such as your systems, Standard No. 108 allows each, provided that each does not impair the effectiveness of the lighting equipment required by the standard. The law governing the lighting on motor vehicles after their first sale is the National Traffic and Motor Vehicle Safety Act. In essence, it allows installation of each of your systems by a manufacturer, dealer, distributor, or motor vehicle repair business as long as the system does not 'knowingly render inoperative, in whole or part, any device or element of design installed in accordance with' Standard No. 108. We regard any supplemental lighting system with the potential of creating confusion in the eye of the beholder as one that impairs the effectiveness of other lamps on the vehicle, and one that renders inoperative, in part at least, other lamps by compromising their effectiveness. This is especially true when existing vehicle lamps are used to convey messages that are different from the purpose of those lamps. We believe it especially important to motor vehicle safety that signal lamps convey their message unmistakably and without ambiguity. We see no real problem that might be occasioned by the activation of the front turn signal lamps in a steady burning mode, although this might cause initial puzzlement in the eye of an oncoming driver unfamiliar with the system. While confusion is more likely when the turn signal is operating on one side while the other side remains steady burning, we believe that the flashing of the turn signal will continue to be interpreted as an intention to turn. Of course, when the hazard warning system is activated and completely overrides the steady burning front stop lamp, there would be no confusion as to signal message. Therefore, in our opinion, Federal law permits use of your front stop lamp system. Your second system does not operate through existing vehicle lamps but consists of additional lamps mounted in the wheel wells. These lamps would appear not to have the potential of confusion since they supplement existing lamps and operate in conjunction with them to convey the same message. Thus, Federal law, in our view, does not preclude use of your second system either. However, even if a supplementary lighting system is permissible under Federal law, it is subject to regulation by any State in which it is operated. We are not able to advise you with respect to State law, and suggest that you write for an opinion to the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, Va. 22203. Sincerely, John Womack Acting 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.