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: aiam5101OpenMr. Michael J. Motzkin Pioneer Plumbing Post Office Box 35833 Tucson, AZ 85740-5833; Mr. Michael J. Motzkin Pioneer Plumbing Post Office Box 35833 Tucson AZ 85740-5833; Dear Mr. Motzkin: This responds to your letter of October 14, 199 regarding Federal requirements pertaining to brake specifications. In particular you asked whether there are any regulations requiring automotive brake drums and rotors not to be milled beyond manufacturer specifications, and whether manufacturers are required to stamp their specifications on brake drums and rotors. I am pleased to have this opportunity to explain our law and regulations for you. The National Traffic and Motor Vehicle Safety Act of 1966 (Safety Act) authorizes the National Highway Traffic Safety Administration (NHTSA) to issue Federal motor vehicle safety standards for new motor vehicles and new motor vehicle equipment. All motor vehicles and items of motor vehicle equipment manufactured or imported for sale in the United States must comply with all applicable safety standards. This agency does not provide approvals of motor vehicles or motor vehicle equipment. Under the Safety Act, the manufacturer is responsible for certifying that its motor vehicles or equipment meet applicable standards. NHTSA has issued a number of safety standards which specify performance requirements for new motor vehicle brake systems and certain new brake equipment. The standards do not require manufacturers to stamp specifications on drums or rotors, although it is common practice for manufacturers to do so. The Federal motor vehicle safety standards do not apply to a motor vehicle after its first sale to a consumer. However, manufacturers, distributors, dealers, or motor vehicle repair businesses modifying a used vehicle are prohibited by section 108(a)(2)(A) of the Safety Act from knowingly rendering inoperative any safety device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with a safety standard. The milling or turning of brake drums and rotors is typically performed during the course of repairing a used vehicle with worn brakes. We do not believe that the 'render inoperative' provision would ordinarily be relevant to such a situation. The states may regulate the repair of motor vehicles. We suggest you investigate the laws of Arizona to see whether they affect your situation. I hope this information is been helpful. If you have any further questions about NHTSA's safety standards, please feel free to contact David Elias of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam4582OpenMr. Keith E. Madden Research Associate College of Engineering Department of Chemical and Materials Engineering 125B Chemistry Building The University of Iowa Iowa City, Iowa 52242; Mr. Keith E. Madden Research Associate College of Engineering Department of Chemical and Materials Engineering 125B Chemistry Building The University of Iowa Iowa City Iowa 52242; "Dear Mr. Madden: This is in reply to your letter of February 3, l989 with respect to importation of ethanol-fueled trucks from Brazil. You have requested assurance that 'there are no legal or administrative roadblocks to this importation.' I am happy to provide the assurance you seek. Your letter indicates that you are well versed in our importation procedures, and that you have discussed this matter with Messrs. VanOrden and Vinson of this agency. The University of Iowa is permitted to import trucks that do not comply with all applicable Federal motor vehicle safety standards for purposes of test and experimentation, pursuant to Title l9, Code of Federal Regulations, Section 12.80(b)(i)(vii). When the trucks reach the United States, the importer of record makes the appropriate declaration (in this instance, Box 7 of the HS-7 Form). If vehicles imported for testing and experimenting will be used on the public roads, the importer must attach a sheet to the Form stating the purpose for which the vehicles are imported, the estimated amount of time that the vehicles will be used on the public road, and whether after testing they will be exported, abandoned to the United States, or brought into compliance. Permission for the noncomplying vehicles to remain in the United States for the purposes of testing and experimenting is renewable annually for a maximum total of three years. Thus, for example, at the end of the first year, if the importer requires more time for on-road testing, it must write this Department of that need. Generally, permission is granted for an additional year. If a third year is needed for on-road testing, the importer must again request permission of this agency. We see no legal or administrative impediments to this importation. Further, under these circumstances, the Brazilian manufacturer of these trucks has no responsibilities to the Department of Transportation under any of its laws or regulations. Sincerely, Erika Z. Jones Chief Counsel"; |
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ID: aiam4585OpenSamson Helfgott, Esq. Helfgott & Karas, P.C. 60th Floor Empire State Building New York, NY l0ll8-0ll0; Samson Helfgott Esq. Helfgott & Karas P.C. 60th Floor Empire State Building New York NY l0ll8-0ll0; Dear Mr. Helfgott: This is in reply to your letter of January 12, l989 asking whether Federal regulations permit the use of an amber lamp either as original or aftermarket equipment. The lamp would be placed adjacent to the center highmounted stop lamp, but in a separate housing and wholly independent of it. It would be activated when the ignition is turned on, and deactivated whenever the stop lamps are illuminated. The purpose of the amber lamp is to improve conspicuity of the vehicle in order to lessen the braking response time of drivers in vehicles following. Paragraph S4.1.3 of 49 CFR 571.108 Federal Motor Vehicle Safety Standard No. 108 Lamps, Reflective Devices and Associated Equipment allows a supplementary lighting device such as the amber lamp if it does not impair the effectiveness of lighting equipment required by Standard No. 108. The decision regarding impairment is initially that of the manufacturer of the vehicle on which the supplementary device is installed, and which the manufacturer certifies as complying with all applicable Federal safety standards. In this instance you have indicated that the wiring of the amber lamp is independent of the center lamp, and that the amber lamp is inoperative when the stop lamps are on. While your lamp does not appear to impair the effectiveness of the center lamp, you should consider whether your lamp, since it would be a steady-burning amber lamp, might confuse following drivers unused to seeing a steady burning amber lamp on the rear of a vehicle, or because of its brightness. Should the amber lamp create confusion, it may impair the effectiveness of the other rear lamps required by Standard No. 108, each of which (other than the stop lamps) would when in use operate contemporaneously with it, such as an amber turn signal lamp, or a back up lamp. As part of the vehicle manufacturer's certification to Standard No. 108, it must certify that this situation would not occur, if the lamp is to be permissible as an item of original equipment. As an aftermarket device, the amber lamp is not regulated by Standard No. 108, but is subject to the general prohibition of l5 U.S.C. 1397(a)(2)(A) against rendering inoperative, in whole or in part, equipment installed in accordance with a safety standard. The same considerations as discussed above should be taken into consideration when making this determination. In addition, the use of this lamp is subject to local laws. We are not able to advise you as to these laws, and suggest that you consult for an opinion the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, VA 22203. Sincerely, Erika Z. Jones Chief Counsel; |
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ID: aiam2024OpenHonorable Bob Packwood, United States Senate, Washington, DC 20510; Honorable Bob Packwood United States Senate Washington DC 20510; Dear Senator Packwood: Thank you for your letter of August 8, 1975, forwarding a copy of letter to me from Mr. William G. White, President of Consolidated Freightways Corporation, and asking for early consideration of Mr. White's request. In that letter, Mr. White asks that the National Highway Traffic Safety Administration require reports from all truck operators and antilock system manufacturers on any malfunction they experience with antilock systems.; I have given full consideration to the important matter of collectin sufficient data on the reliability of antilock systems used on production vehicles, and I have responded to Mr. White with my conclusions. A copy of that response is enclosed to provide you with a complete explanation of my decision.; Sincerely, William T. Coleman, Jr. |
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ID: aiam2658OpenMr. Bernhard Schwartz, Sales Manager, Sate-Lite Mfg. Co., 4600 North Olcott Avenue, Harwood Heights, Illinois 60656; Mr. Bernhard Schwartz Sales Manager Sate-Lite Mfg. Co. 4600 North Olcott Avenue Harwood Heights Illinois 60656; Dear Mr. Schwartz: This responds to your August 2, 1977, letter asking whether you ca submit to the National Highway Traffic Safety Administration (NHTSA) a piece of your equipment for confirmation that it complies with Standard No. 125, *Warning Devices*.; The NHTSA does not issue advance approvals of equipment or moto vehicles manufactured in accordance with the safety standards. It is the responsibility of each manufacturer of motor vehicles or equipment to ensure that his motor vehicle or equipment complies with the requirements. Therefore, it is not necessary for you to submit your design to the NHTSA prior to its production.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam2196OpenW. Thomas James, III, Miller Spreader Company, Youngstown, Ohio 44512; W. Thomas James III Miller Spreader Company Youngstown Ohio 44512; Dear Mr. James: This is in response to your letter of January 1, 1976, to Regiona Office V of the National Highway Traffic Safety Administration (NHTSA), concerning whether your company's spreader product must comply with the requirements of Federal motor vehicle Safety standards and regulations, particularly Standard No. 119, *New Pneumatic Tires*.; The NHTSA issues safety standards and regulations for 'motor vehicles. Section 102(3) of the National Traffic and Motor Vehicle Safety Act defines a motor vehicle as a vehicle 'manufactured primarily for use on the public streets, roads, and highways.' Thus, a motor vehicle is a vehicle which the manufacturer expects will use public highways as part of its intended function. The primary function of some vehicles is of a mobile, work-performing nature, and, as such, their manufacturer contemplates a primary use of the highway. Mobil cranes, rigs, and towed equipment such as chippers and pull-type street sweepers that travel at a normal highway speed are examples in this area. These motor vehicles qualify as trucks or trailers. As such they are subject to the Federal motor vehicle safety standards and regulations. On the basis of the information you have sent us your company's towed paver appears to be in this category of vehicles, and would therefore be considered a 'motor vehicle.'; There are some vehicles which are excepted from the motor vehicl classification despite their use on the highway. Highway maintenance and construction equipment, lane stripers, *self-propelled* asphalt pavers, and other vehicles whose maximum speed does not exceed 20 mph and whose abnormal configuration distinguishes them from the traffic flow are not considered motor vehicles. Your company's paver would not appear to qualify in this category of vehicles since, as a towed paver, it would travel at a speed greater than 20 mph, at least when moving between job sites. Consequently, your product must comply with the requirements of the Federal standards and regulations. Standard No. 119 does not directly impose any duty on you, because it applies to tires rather than vehicles. However, the NHTSA has recently issued Federal Motor Vehicle Safety Standard No. 120, *Tire Selection and Rims for Vehicles Other Than Passenger Cars* (copy enclosed). This standard does require, effective September 1, 1976, that your vehicles be equipped with tires that conform to Standard No. 119 and are of sufficient load rating.; Please contact us if we can be of any further assistance. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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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: aiam4757OpenMr. Peter Brown President, KC HiLites, Inc. Avenida de Luces Williams, AZ 86046; Mr. Peter Brown President KC HiLites Inc. Avenida de Luces Williams AZ 86046; Dear Mr. Brown: This is in reply to your letter of April 25, l990 asking for our 'comments and approval' regarding an automotive lighting product that your company intends to market. The product is intended for use in a four headlamp systems with lens designations of 'L', 'LF' or 'HB4' on the outboard lamps, and 'U', 'UF' or 'HB3' on the inboard lamps. In normal operation, the lower beam is extinguished when the upper beam is activated, your device would ensure that the lower beam would remain activated when the upper beam is used. You view this as permissible under S5.5.8 of Motor Vehicle Safety Standard No. 108. Initially, let me note that we have no authority to 'approve' any device or invention for use on motor vehicles. We advise whether such products are permissible under the Federal motor vehicle safety standards, but this advice must not be represented in advertising as Federal approval of the device or invention. Section S5.5.8 of Standard No. 108 states in pertinent part that 'On a motor vehicle equipped with a headlighting system designed to conform to the photometric requirements of Figure 15, the lamps marked 'L' or 'LF' may be wired to remain permanently activated when the lamps marked 'U' or 'UF' are activated. Standard No. 108 further specifies that headlamps designed to conform to Figure l5 are the four-lamp sealed beam system Type F (S7.3.7(b)), and a four-headlamp integral beam system (S7.4(a)(1)). In addition, certain types of replaceable bulb headlamp systems may also be designed to conform to Figure l5 photometrics, as shown in recently-adopted Figure 26 (copy enclosed). Replaceable bulb headlamps are also required to have the HB Type number on the lens, as well as the 'U' and 'L' markings. Therefore, installation of your device on the headlighting systems mentioned above would be permitted by Standard No. 108, and you need not be limited to systems that use HB3 and HB4 light sources. With respect to the copy on the material you submitted for review, it would be more accurate to reword the marking references to state ''LF','L', or 'L' and 'HB4' on the upper. . . and the corresponding designation 'UF', 'U', or 'U' and 'HB3' on the lower. . . .' We also note your remark 'Quad-Beam gives you this extra margin of lighting safety that the factory left out.' There is no basis in fact for this statement. Some drivers prefer more foreground light, but there is no indication that the addition of the lower beam when the upper beam is in use has a positive effect upon lighting safety. As you requested, we are returning your samples. Sincerely, Paul Jackson Rice Chief Counsel Enclosures; |
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ID: aiam0819OpenMr. Gerard Alexander, President, B. F. Goodrich Tire Company, 500 South Main Street, Akron, OH 44318; Mr. Gerard Alexander President B. F. Goodrich Tire Company 500 South Main Street Akron OH 44318; Dear Mr. Alexander: This is in response to your petition for rulemaking, submitted *Jul 39, 1971*, to amend Motor Vehicle Safety Standard No. 109 (49 CFR S 571.109) and the Tire Identification and Recordkeeping Regulations (49 CFR Part 574). Your petition requests that Standard No. 109 be amended to provide for a special tire category for folding sidewall-reduced tread tires, of which the 'Space Saver Spare' tire you manufacture is an example. You request specifically that requirements for these tires differ from conventional tires as follows: lower minimum breaking-energy values in the strength test (S4.2.2.4, Table II), modified minimum size factors for certain tire size designations which you list, elimination of the condition that the tire be mounted without lubricant for the bead unseating test (S4.2.2.3), and allowing the tire identification number to be placed on the lower sidewall (49 CFR 574.5). *For the reasons stated below, your petition is hereby denied insofar as it requests modifications to the strength and bead unseating requirements of Standard No. 109, and the requirements of Part 574. We make certain recommendations herein regarding your request for modification of the minimum size factors of Standard No. 109*.; The basis for your request for lower breaking-energy values in th strength test is that the values you request represent a level of performance equal to that of a conventional tire having the same amount of tread remaining as a new folding sidewall-reduced tread tire. *The NHTSA cannot accept this argument as a valid basis for specifying lower breaking-energy value requirements for folding sidewall-reduced tread tires. The requirements specified for the strength test are considered to be necessary minimum requirements for all new passenger car tires. Consequently, persons who purchase new tires, regardless of their construction, are entitled to at least this level of performance, and not the level of performance represented by a used tire*.; *The NHTSA does not believe, similarly, that you have presented sufficient basis for elimination of the condition,* in the *bead unseating test procedure, that the tire be mounted for the test without the use of lubricant*. While the NHTSA concurs in the benefits of run-flat performance, which the 'Space Saver Spare' appears to provide, *we do not believe that this advantage outweighs the necessity that the tire conform to the bead unseating requirements when mounted without lubrication. The NHTSA believes the possibility that tires will be mounted without lubrication in the field is sufficiently great to warrant the retention of this condition in the standard's test procedure*.; *We also do not consider sufficient the justification you provide fo your request that the identification number required pursuant to Part 574 be allowed to be placed on the lower sidewall of the tire*. Your statement to the effect that no problems are presented if the number 'wears off' ignores the fact that the number must be retained on the tire for purposes of identification should a defect notification or recall campaign be instituted.; With reference to your request for modification of the minimum siz factor for the tire size designations which you list, *we believe B. F. Goodrich should petition, in accordance* with *guidelines published October 5, 1968 (33 F.R. 14964)*, to *amend the Appendices of Standards Nos. 109 and 110 to provide that folding sidewall-reduced tread tires be added as a separate tire type, including new size designations* and *corresponding values for section width and minimum size factor that you consider appropriate*.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam2186OpenMr. David Warfield, Box 1207, Easton, Maryland 21601; Mr. David Warfield Box 1207 Easton Maryland 21601; Dear Mr. Warfield: This is in response to your January 21, 1976, request for a interpretation of Federal Motor Vehicle Safety Standard No. 117, *Retreaded Pneumatic Tires*.; You asked whether a retreaded tire may be manufactured with a casin from which the original manufacturer's tire identification number (required by 49 CFR Part 574 and Standard No. 109) has been buffed off, provided the original DOT symbol remains. The answer to your question is yes. The only items of information that are required to be retained from the original casing are the following:; >>>(a) the symbol DOT, (b) the size of the tire, and (c) the actual number of plies or ply rating.<<< A retreaded tire must also, of course, be labeled with the DOT-R symbo and with the retreader's tire identification number, pursuant S6.1 of Standard No. 117 and 49 CFR Part 574.; 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.