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: aiam0643OpenMr. Louise C. Lundstrom, Director, Automotive Safety Engineering, General Motors Technical Center, Warren, MI, 48090; Mr. Louise C. Lundstrom Director Automotive Safety Engineering General Motors Technical Center Warren MI 48090; Dear Mr. Lundstrom: This is in reply to your letter of December 21, 1971, requestin elaboration of several statements made in the denial of General Motors' petition for reconsideration of Motor Vehicle Safety Standard No. 302 of December 2, 1971. You cite four statements in our letter to you and request that we furnish supporting material regarding them. You further request that we specifically identify all material relied on by the NHTSA in reaching the quoted 'determinations' and 'findings.'; A large amount of material has been placed in this public docket a background for the rulemaking action. All of this material has been carefully studied by the NHTSA, and together with the expertise and judgment of NHTSA personnel, 'relied on' in reaching the decisions involved in issuing Standard 302. In informal rulemaking proceedings, the decisions are based on the total weight of the agency's knowledge, not on particular items of information. For these reasons, the NHTSA does not consider it appropriate, nor required by law, to sift through the background materials and identify particular items as the 'supporting material' for statements or decisions concerning the rulemaking.; I will, however, make the following comments in elaboration of th statements you have quoted:>>>1. 'The 4-inch-per-minute burn rate was incorporated into the standard as a result of the agency's determination that it provided a flammability rate sufficiently low to provide adequate escape time from a vehicle in the event fire should occur.'; The 4-inch-per-minute rate is intended to meet three safety problem created during vehicle fires. The first is that of burns to occupants resulting from contact with the flames themselves. The second is that of noxious effects resulting from the inhalation of fumes released during combustion of the vehicle interior materials. The third is the danger of crashes caused when the driver or passengers are alarmed or panic as a result of a rapidly spreading interior fire, especially from critical concentrations of combustion by- products.; The NHTSA realizes that the danger from flame and combustion by products in a burning vehicle, and the ability of occupants to leave a vehicle, will vary from situation to situation. Any flammability level set in a standard, short of inert and incombustible materials having a zero burn rate, must represent a compromise seeking reasonable cost and adequate protection. Data compiled by NHTSA and now summarized in Docket 3-3 (Docket No. N4-3-3-26) indicate that some typical interior materials burning at more than 4 inches per minute can release critical concentrations of noxious substances, particularly hydrogen chloride. This would necessitate a fast stop and exit before a panic occurs.; 2. '. . . the Administration believes there is sufficient data on th number or degree of non-fuel fires in motor vehicles to justify the 4-inch-per- minute rate.'; Data placed in the docket discuss various studies showing a larg number of these fires are of interior origin and are not fuel fires. A study made by the Illinois Institute of Technology Research Institute (IITRI) estimated that as many as 120,000 vehicle fires occur during the course of a year which originate in the vehicle compartment. The National Fire Protection Association estimated that the total number of vehicle fires for the year 1970 was 461,000. The University of Oklahoma Research Institute, using a different means for sampling, estimated the total number of motor vehicle fires to be 800,000 annually. Other figures obtained from many sources by the Oklahoma group attribute an estimated 25 percent of vehicle fires to smoking materials. Thus, the estimated number of yearly interior vehicle fires, not related to fuel, varies from 115,000 to 200,000. The NHTSA regards even the smaller figure as a significant number of potentially injurious situations.; 3. 'The evidence available to the NHTSA does not, however, indicat that it is necessary to use flame retardant treatments that display these undesirable characteristics (aging effects) in order to comply with the standard.'; Evidence that has been placed in the docket indicates that man materials exist that can meet the requirements of Standard No. 302 without undergoing flame-proofing treatments. Test results submitted by the motor vehicle industry indicate that materials that pass the flammability requirements are presently being used in the same applications as other materials that do not pass the flammability requirements. IITRI also describes various complying vinyl and cloth materials.; 4. 'Based on the Administration's findings, such a 12-per-minute rat will not provide the necessary escape time.'; The amount of noxious substances released by certain materials used i vehicle interiors that have a 12-inch-per-minute burn rate can quickly produce panic in vehicle occupants, and inhibit the safe evacuation of the vehicle. A 12-inch-per-minute burn rate for certain materials could produce in approximately 5 seconds from 50 to 100 parts per million of hydrogen chloride, a concentration generally considered subjectively intolerable. In shortly more than 20 seconds a critical concentration that is dangerous to life would be reached. This burn rate does not provide sufficient time, in our judgment, to allow for safe exit from a moving vehicle.<<<; Sincerely, Robert L. Carter, Acting Associate Administrator, Moto Vehicle Programs; |
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ID: aiam5011OpenThe Honorable Phil Gramm United States Senator 2323 Bryan Street, #1500 Dallas, TX 75201; The Honorable Phil Gramm United States Senator 2323 Bryan Street #1500 Dallas TX 75201; Dear Senator Gramm: This responds to your Memorandum attachin correspondence from your constituent Stephen Newmark of Tarrant County. Mr. Newmark, Vice-President of Lonestar Classics, Inc., states that his company 'has requested an exemption' from this agency 'for the purposes of manufacturing kit cars,' and asks your help 'in determining whether our exemption will be granted or whether the National Highway Traffic Safety Administration (NHTSA) requires further information.' He also states that 'the timing of NHTSA's response is critical to our moving ahead.' Mr. Newmark FAXED the Administrator on May 5, 1992, about the possibility of obtaining an exemption, and followed up with a telephone call to the Office of Chief Counsel on May 15. As we understand it from that conversation, the business plan intended by Lonestar is to sell and deliver a certain number of unassembled components to purchasers who will complete the assembly of the vehicle by providing the engine, drive train, and suspension. We informed Mr. Newmark orally that, given these facts, Lonestar is not considered to be a 'manufacturer' of motor vehicles under the National Traffic and Motor Vehicle Safety Act. Because of this, Lonestar is not required to ensure the compliance of the completed vehicle with the Federal motor vehicle safety standards, and, hence, no exemption is required for it to implement its business plan. We informed Mr. Newmark of your interest in his behalf, and that our response to you would also serve as a reply to his FAX of the 5th to the Administrator. For this reason we are providing him a copy of this letter. Sincerely, Frederick H. Grubbe Enclosure: Constituent's Correspondence cc: Washington Office; |
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ID: aiam0213OpenMr. Walter D. Peck, Standards Director, Recreational Vehicle Institute, Inc., 2720 Des Plaines Avenue, Des Plaines, IL 60018; Mr. Walter D. Peck Standards Director Recreational Vehicle Institute Inc. 2720 Des Plaines Avenue Des Plaines IL 60018; Dear Mr. Peck: This is in response to your letter of February 13, 1970 to th Administrator, in which you requested an interpretation of Standard 206, *Door Locks and Door Retention Components*, as applied to motor homes and chassis-mount campers. Specifically, you asked whether door components must conform to the requirements of the standard when the door is located across the width of the vehicle from a seating position.; The relevant language is in paragraph S4. of the standard: >>>'Side door components referred to herein shall conform to thi standard if any portion of a 90-percentile two-dimensional manikin as described in SAE Practice J826, when positioned at any seating reference point, projects into the door opening area on the side elevation or profile view.'<<<; This language clearly covers, and was intended to cover, the situatio that you describe. The phrase 'projects into the door opening area on the side elevation or profile view' eliminates, in respect to the standard's application, any consideration of the lateral distance of the seating position from the door opening. The door components of vehicles you described in your letter must therefore conform to the standard.; We are pleased to be of assistance. Sincerely, Douglas W. Toms, Director |
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ID: aiam3829OpenMr. Joel S. Premack, Research and Development Laboratories, U.S. Postal Service, Rockville, MD 20852-8101; Mr. Joel S. Premack Research and Development Laboratories U.S. Postal Service Rockville MD 20852-8101; Dear Mr. Premack: This responds to your March 7, 1984 letter to Roger Fairchild of thi office regarding Federal Motor Vehicle Safety Standard (FMVSS) 111, *Rearview Mirrors*. In particular, you asked whether the covering of the rear and rear-side windows on Postal Service Vehicles would be consistent with the requirements of FMVSS 111.; FMVSS 111 (copy enclosed) establishes requirements regarding rearvie mirror systems on new motor vehicles. New Postal Service vehicles would be required to employ one of three optional mirror systems. The first system is a system permitted for use on passenger cars, and includes an inside rearview mirror with a specified field of view and a plane, driver's side exterior mirror also having a specified field of view. The second permissible system is also a passenger car system and is identical to the first system, except that the inside mirror need not provide the specified field of view and an additional passenger side plane or convex rearview mirror must be provided to compensate for the more restricted field of view of the inside mirror. The third system has two plane mirrors of 19.5 square inches reflective surface area each, one mounted on each side of the vehicle.; Based on the materials you provided with your letter, it appears tha Postal Service DJ-5G Models employ the second system described above. In that case, further reduction of the field of view of the inside rearview mirror would not affect compliance with our standard, since an additional passenger side mirror is provided.; If the proposed covering of the rear windows is to be accomplished as modification to vehicles already delivered to the Postal Service, these modifications may not be subject to FMVSS 111 at all. Modifications to vehicles must be consistent with safety standards only to the extent those modification are performed by a vehicle manufacturer, distributor, dealer, or private motor vehicle repair business which knowingly renders inoperative safety equipment installed on the vehicle. See 15 U.S.C. 1397(a)(2)(A). Thus, if the window covering is done by the Postal Service itself, FMVSS requirements are not applicable.; If you have any further questions on this matter, please feel free t contact us.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1814OpenMr. Kevin P. Tighe, National Automobile Dealers Assoc., 2000 K Street N.W., Washington, DC 20006; Mr. Kevin P. Tighe National Automobile Dealers Assoc. 2000 K Street N.W. Washington DC 20006; Dear Mr. Tighe: This is in response to your letter of December 27, 1975, (sic concerning the use of Form AADA-65 for purposes of disclosing odometer mileage when a vehicle is sold.; The NHTSA disagrees with your apparent contention that the portion o the preamble you cited, authorizing use of disclosure forms other than the one prescribed in Part 580, covers the use of Form AADA-65. That language limits the use of odometer forms which do not simulate the form contained in the regulation to situations where a State requires execution of an odometer statement which 'contains equivalent information' to the Federal one. It is our understanding that the AADA form was adopted by the Arizona Automobile Dealers Association upon recommendation of the National Automobile Dealers Association. We are unaware of any Arizona State law that mandates use of the AADA form as a basis for compliance.; While the NHTSA appreciates the efforts of the NADA to develop a usefu and effective odometer disclosure document, we cannot approve a format that is not substantially the same as the Federal form without following standard rulemaking procedures of notice and comment. We welcome your suggestions as to how you feel the odometer form can be improved, and suggest that you submit them in the form of petitions for rulemaking under the procedures specified in 49 CFR 553.31.; As pointed out in your letter, the NHTSA has determined that th AADa-65 form does not fulfill the requirements of Part 580. We appreciate your cooperation in notifying your membership of this decision. A changeover to use of the Federal odometer form by April 1, 1975, is considered reasonable by the agency. We thank you for your comments and look forward to receiving your ideas on the matters mentioned in your letter.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0706OpenJoseph C. Good, Esquire, South Carolina Attorney General's Office, P. O. Box 11549, Wade Hampton Office Building, Columbia, SC 29201; Joseph C. Good Esquire South Carolina Attorney General's Office P. O. Box 11549 Wade Hampton Office Building Columbia SC 29201; Dear Mr. Good: This is in response to your telephone inquiry of May 17, 1972 concerning the preemptive effect of section 103(d) of the National Traffic and Motor Vehicle Safety Act of 1966 (15 U.S.C 1392) on the authority of States to adopt laws regarding bumpers on passenger cars and other vehicle types.; You stated that you interpreted this section as preventing the adoptio by a State of a passenger car bumper law that was not identical to the Federal motor vehicle safety standard (FMVSS 215) on that subject. You stated further that this result (sic) obtained regardless of whether the State law were cast in terms of safety or property damage reduction.; We agree with both statements. This result is required by both sectio 103(d) and the Federal 'common law' of premption (sic), based on the Supremacy Clause of the Constitution. Were the result otherwise, States could adopt laws which frustrated not only the clear Congressional intent of establishing a uniform set of national regulations, but also the specific objectives of many of our safety standards.; You also asked whether, in view of FMVSS 215's application to passenge cars only, section 103(d) prevented the adoption of State laws regarding bumpers on multipurpose passenger vehicles. You indicated that you thought the answer to be 'no'.; Again, we agree. Section 103(d) provides that whenever there is Federal safety standard applicable to an aspect of performance of any motor vehicle, a State may not 'establish . . . any safety standard applicable to the *same aspect of performance* of *such vehicle* . . . which is not identical to the Federal standard. (Emphasis added.) The application of this section turns upon both of the underlined factors. Consequently, the existence of a Federal safety standard applicable to an aspect of performance of a particular vehicle type does not preclude the establishment of a State law regarding the same aspect of performance of another vehicle type unregulated by the Federal standard. Since FMVSS 215 does not apply to multipurpose passenger vehicles, a State may regulate the bumpers of such vehicles without regard to the Federal standard. Of course, if FMVSS 215 is subsequently extended to multipurpose passenger vehicles, State laws regulating the bumpers on those vehicles would have to be made to conform with the Federal standard or they would be preempted.; Thank you for your interest in motor vehicle safety. As requested, have enclosed a copy of the notice issuing FMVSS 215 (36 F.R. 7218) and related notices. Among the other notices is the notice of proposed rulemaking (35 F.R. 17999) which preceded issuance of the standard. The preamble of that notice contains a passage regarding the preemptive effect of the standard.; Please let me know if I can be of any further assistance. Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam5504OpenMr. Malcolm Bricklin President The Electric Bicycle Company 27426 Pacific Coast Highway Malibu, CA 90265; Mr. Malcolm Bricklin President The Electric Bicycle Company 27426 Pacific Coast Highway Malibu CA 90265; Re: Petition for Exemption Dear Mr. Bricklin: We have received you letter of March 20, 1995, asking for an exemption from two provisions of Motor Vehicle Safety Standard No. 123 on the basis that 'compliance with the standards, in this instance, will constitute a greater hazard to the general public and will result in more accidents caused by operator error than the alternatives that we propose.' I am sorry to inform you that we cannot consider your request in its current form. For your guidance, I enclose a copy of our temporary exemption regulation, 49 CFR Part 555. I suggest that the appropriate basis for your petition under that regulation is section 555.6(d): that you are otherwise unable to sell a vehicle whose overall level of safety is the equivalent of, or exceeds, the overall level of safety of a nonexempted vehicle. When you have filed a petition that provides the information required by Part 555, we shall be pleased to consider this matter further. Because of the need to afford the public an opportunity to comment, a decision is rarely reached until three to four months after a petition is received. If you have any questions on the regulation, Taylor Vinson of this Office will be glad to answer them (202-366-5263, FAX: 202-366-3820). Sincerely, Philip R. Recht Chief Counsel Enclosure; |
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ID: aiam0356OpenMr. Charles J. Calvin, Managing Director, Truck Trailer Manufacturers Association, 141 K Street, N.W., Washington, DC 20006; Mr. Charles J. Calvin Managing Director Truck Trailer Manufacturers Association 141 K Street N.W. Washington DC 20006; Dear Mr. Calvin: This is in reply to your letter of May 28, 1971, requestin clarification of whether a vehicle manufacturer, under 574.10 of the Tire Identification and Record Keeping regulation, may designate someone to maintain the records for him.; This letter is to confirm that motor vehicle manufacturers may assign designee for the record keeping requirements of Part 574.; Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam3983OpenCorporal Frank Browne, Supervisor - Property Services, Santa Ana Police Department, 24 Civic Center Plaza, Santa Ana, CA 92702; Corporal Frank Browne Supervisor - Property Services Santa Ana Police Department 24 Civic Center Plaza Santa Ana CA 92702; Dear Corporal Browne: Thank you for your letter of July 5, 1985, concerning Federa regulations on safety belts in your patrol vehicles. You specifically asked about regulations affecting either the removal of the shoulder belt portion of a lap-shoulder belt system of the replacement of lap-shoulder belt systems with lap belt only systems. I hope that the following discussion answers your questions.; The National Traffic and Motor Vehicle Safety Act authorizes our agenc to establish Federal Motor Vehicle Safety Standards applicable to all new motor vehicles sold in the United States. We have issued Standard No. 208, *Occupant Crash Protection*, which requires the installation of crash protection systems, such as safety belts, in the front and rear seats of motor vehicles. We have also issued Standard No. 209, *Seat Belt Assemblies*, which sets performance requirements for safety belts used in motor vehicles. A copy of each standard is enclosed for your reference. As you know, each new motor vehicle sold to your Department must be certified by its manufacturer as complying with all applicable Federal Motor Vehicle Safety Standards, including Standards Nos. 208 and 209.; The alteration of a safety belt system in a used vehicle is affected b section 108(a)(2)(A) of the Vehicle Safety Act. A copy of that section of the Act is enclosed. That section provides, in part, that:; >>>No manufacturer, distributor, dealer, or motor vehicle repai business shall knowingly render inoperative, in whole or part, any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard....<<<<; Thus, none of those commercial businesses could alter or replace th safety belts in your vehicles, if by doing so they would 'render inoperative' the compliance of the vehicle or the safety belt system with Standard Nos. 208 and 209. Removal of a portion of a belt system or the substitution of a lap belt for a lap-shoulder belt would have that effect. Note that Section 108(a)(2)(A) does not apply to individual vehicle owners. Therefore, your Department can remove or alter your safety belts in any manner without violating Federal law. Such removals or alterations could be affected by State law.; I urge you to carefully consider the effects of altering or removin safety belts, even though Federal law would not prohibit you from making such modifications yourself. Our accident and test data show that lap-shoulder belts are very effective in reducing deaths and injuries in vehicle crashes. Particularly since your officers face the possibility of pursuit situations, we believe that it is important that they have safety belt systems that will effectively protect them in a crash.; I hope this information is of assistance. Please let me know if yo have any further questions.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam5154OpenMr. Steve Thomas General Manager Texas Bragg Enterprises Route 6, Box 875 Mt. Pleasant, TX 75455; Mr. Steve Thomas General Manager Texas Bragg Enterprises Route 6 Box 875 Mt. Pleasant TX 75455; "Dear Mr. Thomas: This responds to your letter of March 16, 1993 addressed to Walter Myers of this office. You stated in your letter that several of your dealers want to buy trailers from you without tires and wheels. You expressed doubt that those dealers have that many customers desiring to mount their own tires and wheels, and asked whether you can legally sell trailers to your dealers without tires and wheels and if so, whether you need them to sign a waiver or form to that effect. Federal Motor Vehicle Safety Standard No. 120. Tire selection and rims for motor vehicles other than passenger cars (copy enclosed), provides that each vehicle equipped with pneumatic tires for highway use must be equipped with tires that, in the case of trailers, meet the requirements of Standard No. 119, New pneumatic tires for vehicles other than passenger cars (copy enclosed). Rims mounted on new trailers must meet the requirements of S5.2 of Standard 120. There is, however, no specific requirement in Standard 120 that vehicles be equipped with tires and wheels. In fact, this agency's definition of a 'completed vehicle' envisions the situation where a vehicle is sold without tires and wheels. That definition is set forth at 49 CFR Part 568.3, which defines a 'completed vehicle' as 'a vehicle that requires no further manufacturing operations to perform its intended function, other than the addition of readily attachable components, such as mirrors or tire and rim assemblies, or minor finishing operations such as painting' (emphasis added). The trailer dealers to whom you ship your trailers are required by the National Traffic and Motor Vehicle Safety Act, 15 U.S. Code 1381 - 1431 (Safety Act) to sell vehicles that comply with all applicable Federal motor vehicle safety standards, including Standard 120. Therefore, if they sell the trailers with tires and wheels installed, those tires and wheels must meet the requirements for tires and wheels set forth in Standard 120. In the event a new trailer sold by one of your dealers has tires and wheels that do not meet the applicable requirements of Standard 120, from a compliance standpoint it would be important to determine who equipped that vehicle with the noncomplying tires and wheels. Therefore, although not required by this agency, you might consider obtaining written statements or acknowledgements from the dealers concerned that you provided the trailers without tires and wheels, and retain those documents for your records. You might also consider consulting your attorney regarding any potential liability on your part for the actions of your dealers. Finally, we recommend that you inform any dealer whom you know to be considering installing noncomplying tires and wheels on your trailers to contact this agency for information about their responsibility under the Safety Act to sell trailers that meet the requirements of Standard 120. I hope this information will clarify this matter for you. If you have any further questions or need further clarification, please feel free to contact Mr. Myers at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosures"; |
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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.