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: aiam5171OpenTrooper Bob Dittert Texas Department of Public Safety 10110 NW Freeway Houston, TX 77092; Trooper Bob Dittert Texas Department of Public Safety 10110 NW Freeway Houston TX 77092; "Dear Mr. Dittert: This responds to your inquiry about how the Federa Motor Vehicle Safety Standards affect State laws applicable to the same aspect of performance. You were particularly interested in our requirements for window tinting. I am pleased to have this opportunity to explain our regulations to you. After providing background information, I will answer the specific questions raised in your letter. The National Traffic and Motor Vehicle Safety Act authorizes the National Highway Traffic Safety Administration (NHTSA) to issue Federal motor vehicle safety standards that establish specific levels of safety performance for new motor vehicles and new items of motor vehicle equipment. Standard 205, 'Glazing Materials,' issued under the Safety Act, has requirements that limit the amount of tinting that can be placed on windows in new vehicles. The standard currently imposes a minimum level of light transmittance of 70% in all areas requisite for driving visibility (which includes all windows on passenger cars). The primary purpose of this requirement is to ensure adequate visibility through the windows, thereby reducing the risk of a motor vehicle crash. Under 108(a)(1)(A) of the Safety Act, no person shall manufacture or sell a new motor vehicle or new item of motor vehicle equipment that does not meet all applicable FMVSS's. NHTSA tests vehicles and equipment sold to consumers for compliance with the FMVSS's and investigates defects relating to motor vehicle safety. If a manufacturer or NHTSA determines that a noncompliance or safety- related defect exists, the manufacturer must notify purchasers of its product and remedy the problem free of charge. A manufacturer of a noncomplying product is also subject to a civil penalty of up to $1,000 for each noncomplying item it produces. The prohibition in 108(a)(1)(A) against selling complying vehicles and items of equipment does not apply to a vehicle or item of equipment after its first sale to a consumer. However, 108(a)(2)(A) of the Act applies to modifications made to new and used vehicles by motor vehicle manufacturers, distributors, dealers and repair businesses. That section provides that: No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative, in whole or in part, any device or element of design installed on or in a motor vehicle ... in compliance with an applicable Federal motor vehicle safety standard. Please note that the 'render inoperative' provision of section 108(a)(2)(A) does not apply to actions by individual vehicle owners. I would now like to apply this background to the particular questions raised in your letter. Question One: 'Are the CFRs law and enforceable only by federal agents?' NHTSA's regulations and safety standards are set forth in Title 49 of the Code of Federal Regulations (CFR). These regulations and standards apply without State ratification to the manufacture and sale of new motor vehicles and new items of motor vehicle equipment. NHTSA enforces these regulations and safety standards. Question Two: 'Are the Federal Motor Vehicle Safety Standards law and only enforceable on new manufactured vehicles?' The FMVSS's apply to new motor vehicles and new items of motor vehicle equipment, and not to used vehicles or equipment. NHTSA may bring enforcement actions against manufacturers of new vehicles and new items of equipment that do not comply with applicable FMVSS's. NHTSA also enforces the 'render inoperative' provision of the Safety Act against commercial entitites that modify new or used vehicles in a manner that violates the 'render inoperative' provision. We also note that NHTSA can investigate safety defects in new or used vehicles or items of equipment. Question Three: 'Are states allowed to enact legislation that allows less stringent standards than the CFRs?' We understand you to ask this in the context of window tinting requirements, since elsewhere in your letter you ask whether a Texas law that allows light transmittance of 35 percent violates Federal law. Your question relates to 103(d) of the Safety Act, which states: Whenever a Federal motor vehicle safety standard ... is in effect, no State or political subdivision of a State shall have any authority either to establish, or to continue in effect, with respect to any motor vehicle or item of motor vehicle equipment any safety standard applicable to the same aspect of performance of such vehicle or item of equipment which is not identical to the Federal standard. Whether State law is preempted under 103(d) depends in part on the conduct that is regulated by that law. Federal safety standards regulate the manufacture and sale of new motor vehicles and new items of motor vehicle equipment. State law would be preempted to the extent it established performance requirements applicable to the manufacture of vehicles or glazing that differ from those in Standard 205. State law would also be preempted if it purported to allow the manufacture or sale of glazing materials or new vehicles containing glazing material that did not meet the specifications of Standard 205. As stated above, Federal law also regulates modifications made to new and used vehicles by motor vehicle manufacturers, distributors, dealers and repair businesses (108(a)(2)(A) of the Safety Act). The effect of 108(a)(2)(A) is to impose limits on the tinting practices of businesses listed in 108(a)(2)(A). These businesses may not install tinting on new or used vehicles that reduces the light transmittance of windows covered by Standard 205 to a level below the Federal requirement of 70 percent. A state law would be preempted if it purported to allow modifications violating Standard 205 by these named businesses. Section 108(a)(2)(A) does not apply to actions by individual vehicle owners. Because Federal safety standards regulate the manufacture and sale of new motor vehicles, state requirements applicable to the registration and inspection of motor vehicles after the first sale to a consumer are not preempted merely because they are not identical to the Federal safety standards, as long as they do not interfere with the achievement of the purposes of Federal law. Therefore, a state could permit the registration of a vehicle which had been altered by its owner by the addition of window tinting, even when the tinting reduces the light transmittance below the Federal standard. However, the state cannot legitimize conduct - the rendering inoperative of glazing by commercial businesses installing window tinting - that is illegal under Federal law. Question 4: 'Concerning the installation of non-complying automotive equipment, i.e., sun screening, taillamp `black out' lenses, neon license plate lamps, etc., is this allowed by the owner but prohibited installation by a commercial entity?' You are correct that 108(a)(2)(A) of the Safety Act regulates the modifications of only the commercial entities listed in that section of the Act, and that the Safety Act does not prohibit an individual from modifying his or her vehicle such that it no longer complies with the FMVSS's. The States may have requirements governing the modification of a vehicle by individual owners. I hope you find this information helpful. If you have any other questions, please contact Mr. Marvin Shaw of my staff at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam5447OpenOctober 4, 1994; October 4 1994; "Mr. Ashpy Lowrimore Senior Vice President Southern National Bank P.O Box 6676 Florence, SC 29502 Dear Mr. Lowrimore: This responds to your August 11, 1994 letter regarding our requirements for school vehicles. You explain that your church owns a 'commercial bus' and a 15-passenger van and would like to use these vehicles to transport children attending a kindergarten and after school care program that the church operates. You ask to be advised of any requirements applicable to those two vehicles, and have three questions, which I will answer below. I would like to begin with background information about our requirements. Our agency has two sets of regulations, issued under different Acts of Congress, that affect school vehicles. The first of these, the Federal motor vehicle safety standards (FMVSS's) issued under 49 U.S.C. 30101, et seq., apply to the manufacture and sale of new motor vehicles. Our agency was directed by Congress in 1974 to issue standards on specific aspects of school bus safety, including floor strength, seating systems, and crashworthiness. The standards we issued apply to all new vehicles designed to carry 11 or more persons and sold for pupil transportation purposes. Under our requirements, such a vehicle is a 'school bus,' and any person selling such a vehicle must ensure that the new vehicle is certified as meeting the FMVSS's for school buses. The second set of regulations issued by this agency was promulgated under the Highway Safety Act of 1966. These 'regulations' are actually recommendations from NHTSA to the States for use in developing their highway safety programs. Highway Safety Program Guideline No. 17, Pupil Transportation Safety, 23 CFR 1204 (copy enclosed), applies to school vehicles, and contains recommendations for the design, identification and operation of school vehicles. Individual States have chosen to adopt some or all of Guideline No. 17 as their own policies governing their highway safety programs. With that background in mind, I turn now to your specific questions: 1. Can we transport children who are related with our various schools by utilizing the van? ANSWER: The answer depends on State law, because the States regulate the use of motor vehicles, not NHTSA. NHTSA regulates the manufacture and sale of new vehicles. Any person selling a new bus or a new 15-passenger van to your church for purposes that include transporting kindergarten students to and from school or related events must sell buses that meet our FMVSS's for school buses, or face substantial civil fines and injunctive sanctions. NHTSA does not have the authority to regulate vehicle users, and thus does not mandate what vehicle can be used to transport school children. Thus, our regulations impose no requirement on schools that require them to transport students in complying school buses. While NHTSA does not require the use of any particular type of vehicle to transport students, we believe that school buses are the safest motor vehicle transportation currently available. We have included in Guideline No. 17 a recommendation that States require any bus (or van carrying 11 or more persons) used to carry school children to comply with all FMVSS's applicable to school buses at the time of their manufacture (see, recommendation number IV.B.1.h). However, since Guideline No. 17 will affect your church's school vehicles only if South Carolina has adopted it, you should check to see what State requirements are set for the operation of the school vehicles in question. Mr. Perry Brown, Deputy Director of South Carolina's Office of Highway Safety Programs, would be able to provide information about your State's requirements. He can be contacted at the following address: Mr. Perry Brown Edgar A. Brown State Office Building 1205 Pendleton St., Rm. 453 Columbia, SC 29201 2. Are there restrictions associated with the use of the bus in the transportation of children, young adults or senior adults? As explained above, NHTSA has no restriction on the use of motor vehicles. Restrictions on the use of a vehicle are matters of State law. Among other things, the State could require a special driver's license for persons operating buses as you described. A South Carolina official would be able to provide the information you need. 3. If there are special restrictions, can you elaborate on the type of equipment that we must obtain in order to meet any regulations or requirements that are in place? ANSWER: Again, NHTSA has no restrictions on the use of the vehicles by the church. Further, NHTSA does not require schools operating their vehicles to ensure that the vehicles are specially identified or equipped as school vehicles. However, Guideline No. 17 contains recommendations for identifying school buses and equipping them with safety equipment, including school bus lamps and mirrors and emergency equipment. South Carolina may have adopted some of these recommendations in its highway safety program for school vehicles. In summary, NHTSA does not have the authority to regulate the use of school vehicles owned and operated by your church. You should check with South Carolina officials to find out which, if any, State requirements apply to your church's activities. We hope this information is helpful to you. Should you have any further questions regarding this matter, please feel free to contact Walter Myers of my staff at this address or at (202) 366-2992. Sincerely, Philip R. Recht Chief Counsel Enclosure "; |
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ID: aiam3252OpenMr. Mark Wood, MPI, Inc., P.O. Box EE, Coldwater, MS, 38618; Mr. Mark Wood MPI Inc. P.O. Box EE Coldwater MS 38618; Dear Mr. Wood: This confirms your April 9, 1980, telephone conversation with Roge Tilton of my staff in which you asked whether a styrofoam board that lies beneath a layer of polyurethane foam would be required to comply with the flammability requirements of Standard No. 302, *Flammability of Interior Materials*.; As Mr. Tilton explained to you, the standard applies to seatin components such as yours only to the extent that they fall within 1/2 inch of the occupant compartment air space. This requirement is specified in paragraph S4.2 of the standard. You indicate that your styrofoam board would not fall within 1/2 inch of the compartment because the polyurethane cover will always be thicker than 1/2 inch. Assuming this is true, your styrofoam board would not be required to comply with the standard.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0864OpenMr. W. G. Milby, Project Engineer, Blue Bird Body Company, Fort Valley, GA, 31030; Mr. W. G. Milby Project Engineer Blue Bird Body Company Fort Valley GA 31030; Dear Mr. Milby: This is in reply to your letter of August 10, 1972, concerning th application of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials', to shower curtains in the motor homes you manufacture. You ask whether the NHTSA would consider it 'acceptable' for you not to supply a shower curtain with the motor homes you equip with showers.; You have the right, under the Vehicle Safety Act, to sell a motor hom with equipment omitted, as long as the equipment is not required by a safety standard or necessary for the safe functioning of the vehicle. Naturally, we would prefer that you fully equip the vehicle with a conforming curtain, but we cannot force you to do so.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0590OpenMrs. I. Goliath, Technical Relations, BASF Syandotte Corporation, 100 Cheery Hill Road, P.O. Box 181, Parsippany, NJ, 07054; Mrs. I. Goliath Technical Relations BASF Syandotte Corporation 100 Cheery Hill Road P.O. Box 181 Parsippany NJ 07054; Dear Mrs. Goliath: This is in reply to your letter of February 9, 1972, inquiring as t the length of time, after the manufacture of an automobile, that it must still comply with the requirements of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials.' You indicate that due to the influence of cleaning or preservative agents, the flammability properties could change over a period of time.; The safety standards do not apply to a domestic vehicle after it ha been sold to a purchaser for purposes other than resale. Until this point of first sale, however, regardless of the time interval after manufacture, the vehicle must comply with the standards.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1266OpenMr. John H. Mueller, Manager, Engineering Standards, The Weatherhead Company, 300 East 131st Street, Cleveland, OH, 44108; Mr. John H. Mueller Manager Engineering Standards The Weatherhead Company 300 East 131st Street Cleveland OH 44108; Dear Mr. Mueller: This is in reply to your letter of August 16, 1973, concerning th application of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials,' to nylon tubing used in the interior of a motor vehicle.; The components that must meet the requirements of the standard ar listed in Paragraph S4.1. Nylon tubing is not listed in Paragraph S4.1 and normally will not be subject to the standard's requirements. However, materials may nevertheless be covered to the extent that they are 'designed to absorb energy on contact by occupants in the event of a crash,' or to the extent that they form part of a component listed under Paragraph S4.1.; Yours truly, Richard B. Dyson, Assistant Chief Counsel. |
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ID: aiam0718OpenMr. John E. Wade, Purchasing Manager, Rok-A-Chair Manufacturing Co., Inc., P. O. Box 254, North Central Street, Coffeyville, KS, 67337; Mr. John E. Wade Purchasing Manager Rok-A-Chair Manufacturing Co. Inc. P. O. Box 254 North Central Street Coffeyville KS 67337; Dear Mr. Wade: In reply to your letter of May 9, 1972, I have enclosed a copy of Moto Vehicle Safety Standard No. 302, 'Flammability of Interior Materials,' which specifies flammability requirements for materials used in motor vehicles.; The standard applies to passenger cars, multipurpose passenge vehicles, trucks, and buses. Among the recreational vehicles you list, motor homes and chassis-mount campers mounted on new chassis would be included. Mobile homes and travel trailers are not subject to the standard. Slide-in campers and chassis-mount campers that are not mounted on new chassis are not presently subject to the standard, but NHTSA is considering amendments that would bring these camper types within the standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0870OpenMr. Keith Morton, Para-Chem Southern, Inc., P.O. Box 127, Simpsonville, SC, 29681; Mr. Keith Morton Para-Chem Southern Inc. P.O. Box 127 Simpsonville SC 29681; Dear Mr. Morton: This is in reply to your letter of September 28, 1972, concerning th application of Paragraph S5.2.2 of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials.' You ask whether, in testing automotive interior fabrics, test specimens 'must be burned in warp and filling directions only, or does it also include testing in the face-down (inverted) positions?' As you point out, under the standard test specimens for each component are to be tested 'so as to provide the most adverse results.' This means that the relevant test result is the most adverse one achieved in any horizontal orientation, either upward- or downward-facing. How you determine which positioning of the test specimen produces the most adverse results is within your own discretion.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5363OpenMr. David Fabrycky 1633 W. Willeta St. Phoenix, AZ 85007; Mr. David Fabrycky 1633 W. Willeta St. Phoenix AZ 85007; "Dear Mr. Fabrycky: This responds to your letter about an aftermarke product you wish to manufacture. The product is a child safety seat buckle shield, which is intended to prevent a child from opening the buckle on a child restraint system. You state that your device would cover the buckle and prevent the child from gaining access to the pushbutton of a child seat buckle. To depress the pushbutton, the device requires that a latch be actuated and the cover pivoted away from the buckle. You indicated that the device requires 'manual dexterity to exert the forces in many directions simultaneously.' Although we understand your concern that young children not be able to easily unbuckle a child safety seat, we have reservations about devices that interfere with the unbuckling of the seats. I hope the following discussion explains those reservations and answers the questions in your letter about the effect of our regulations on your product. Our agency has the authority to issue safety standards applicable to new motor vehicles and new items of motor vehicle equipment. We have exercised this authority to establish Safety Standard No. 213, 'Child Restraint Systems,' which applies to all new child restraint systems sold in this country. However, Standard 213 does not apply to aftermarket items for child restraint systems, such as your buckle shield. Hence, you are not required to certify that this product complies with Standard 213 before selling the product. Additionally, you are not required to get 'approval' from this agency before selling the buckle shield. NHTSA has no authority to 'approve' motor vehicles or motor vehicle equipment, nor do we endorse any commercial product. Instead, the National Traffic and Motor Vehicle Safety Act establishes a 'self- certification' process under which each manufacturer is responsible for certifying that its products meet our safety standards. The agency periodically tests vehicles and equipment items for compliance with the standards, and also investigates alleged safety-related defects. Although we do not have any standards that directly apply to your product, there are several statutory provisions that could affect it. Manufacturers of motor vehicle equipment such as your buckle shield are subject to the requirements in sections 151-159 of the Safety Act concerning the recall of products with defects related to motor vehicle safety. The agency does not determine the existence of safety defects except in the context of a defect proceeding, and thus is unable to say whether your product might or might not contain such a defect. However, the agency is concerned that people be able to easily and quickly operate a child safety seat buckle in an emergency. As the agency said in a rule on the force level necessary to operate child restraint buckles: The agency's safety concerns over child restraint buckle force release and size stem from the need for convenient buckling and unbuckling of a child and, in emergencies, to quickly remove the child from the restraint. This latter situation can occur in instances of post-crash fires, immersions, etc. A restraint that is difficult to disengage, due to the need for excessive buckle pressure or difficulty in operating the release mechanism because of a very small release button, can unnecessarily endanger the child in the restraint and the adult attempting to release the child. (50 FR 33722, August 21, 1985) It appears that your product could significantly increase the difficulty of using the buckle release and thus hinder a person attempting to release the belt in an emergency. In addition, use of your product could be affected by section 108(a)(2)(A) of the Safety Act. That section prohibits commercial businesses from knowingly tampering with devices or elements of design installed in an item of motor vehicle equipment, such as a child safety seat, in compliance with the Federal motor vehicle safety standards. In determining the effect of a buckle shield on a child seat's compliance with Standard 213, NHTSA would evaluate the performance of the seat with the buckle shield installed. Standard 213 specifies several elements of design with which a child restraint system is unlikely to comply if your buckle shield were installed. Section S5.4.3.5 of Standard 213 requires the pushbutton release for any buckle on a child restraint to have a minimum area for applying the release force. Since your device will completely cover the buckle when installed, the buckle shield would cause the child restraint to no longer comply with this requirement. That section also requires the buckle to release when a specified maximum force is applied. Your device will not allow the buckle to release when the force is applied because it will cover the buckle and require force to be applied 'in many directions simultaneously.' Your device would thus cause the child restraint to no longer comply with that requirement. Therefore, commercial establishments cannot legally install your device on customers' child safety seats. In addition, section S5.7 of Standard 213 requires each material used in a child restraint system to comply with the flammability resistance requirements of Standard 302, 'Flammability of Interior Materials.' If your buckle shield does not comply with the requirements of Standard 302, commercial establishments cannot legally install your device. The prohibition of section 108(a)(2)(A) does not apply to individual vehicle owners who may install or remove any items on child restraint systems regardless of the effect on compliance with Standard 213. However, our policy is to encourage child restraint owners not to tamper with or otherwise degrade the safety of their child restraints. I hope this information is helpful. If you have any further questions, please contact Ms. Deirdre Fujita of my staff at this address or by telephone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam0582OpenMr. E. G. Nagle, Vice President - Automotive Sales, Allen Industries, Inc., Executive Offices: Honeywell Bldg., 17515 West Nine Mile Road, Southfield, MI, 48075; Mr. E. G. Nagle Vice President - Automotive Sales Allen Industries Inc. Executive Offices: Honeywell Bldg. 17515 West Nine Mile Road Southfield MI 48075; Dear Mr. Nagle: This is in reply to your letter of January 24, 1972, requestin information on possible changes to Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials.'; At present, NHTSA is preparing an amendment to the standard based o the notice of proposed rulemaking published May 25, 1971 (36 F.R. 9565), and clarifying other questions pertaining to the standard that have been raised since its issuance. We hope to have this amendment prepared in the near future, but at present we cannot provide information on exact dates. At the same time, if the NHTSA determines that any changes in the standard made by the amendment require additional leadtime, appropriate action will be taken.; 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.