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: aiam1841OpenHonorable Lawton Chiles, United States Senator, Federal Building, Lakeland, FL 33801; Honorable Lawton Chiles United States Senator Federal Building Lakeland FL 33801; Dear Senator Chiles: This is in response to your letter of March 5, 1975, forwarding a inquiry from one of your constituents, Mr. Vincent Tetuan, concerning a proposed amendment to the Federal bumper standard.; On January 2, 1975, the National Highway Traffic Safety Administratio (NHTSA) issued a Federal Register notice (copy enclosed) proposing to reduce the current 5 mph bumper impact requirements to 2.5 mph until the 1979 model year. The impact requirements would then have been increased to 4 mph for 1979 and later model year cars.; The proposal was based primarily on the results of two agency-sponsore studies which indicated that the cost and weight of many current production bumpers, in light of inflation and fuel shortages, made the bumpers no longer cost beneficial. Information presented at public hearings on the bumper notice and comments submitted to the docket in response to the proposal have brought to light additional data. The NHTSA has carefully examined all of this evidence and reviewed its studies in light of the new information. As a result, the agency has concluded that the 5 mph protection level should not be reduced. This decision is contained in a Federal Register notice that was published March 12, 1975 which is enclosed (Docket No. 74-11, Notice 7, Docket No. 73-19, Notice 6).; Mr. Tetuan appears to be directing his comments to what he believes t be a proposed requirement that vehicles manufactured in the future be equipped with plastic bumper systems. Such an understanding of the proposal is incorrect. The January 2, 1975 proposal was aimed at enabling a reduction in vehicle weight. In the preamble to that notice, the NHTSA cited soft face bumpers as one type of system that could produce a significant weight reduction. However, no proposal was made to require the use of soft face systems. The March 12, 1975 notice reiterates the agency's position that bumpers which are lighter in weight than those currently in mass production could and probably would be developed. The requirements proposed in the March notice, however, ensure that a wide variety of materials could continue to be used in bumper systems.; Sincerely, James C. Schultz, Chief Counsel |
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ID: aiam2447OpenMr. Byron Crampton, Truck Body and Equipment Association, 5530 Wisconsin Ave., Suite 1220, Washington, D.C. 20015; Mr. Byron Crampton Truck Body and Equipment Association 5530 Wisconsin Ave. Suite 1220 Washington D.C. 20015; Dear Mr. Crampton: This responds to the Truck Body and Equipment Association's November 8 1976, question whether any provision of Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other than Passenger Cars*, prohibits the certification of a vehicle following the addition of an axle system (typically known as a 'tag' or 'pusher' axle) that is not equipped with tires or rims at the time of sale and delivery to the first purchaser for purposes other than resale.; The answer to your question is no. The requirement of S5.1.1 tha '...each vehicle equipped with pneumatic tires for highway service shall be equipped with tires that meet [specified requirements]...' prohibits the installation of tires that do not meet certain performance requirements, but it is not a requirements that tires be fitted to every axle of a vehicle prior to certification and sale.; I would like to point out that S567.4(g) (4) of Part 567 *Certification*, requires that a gross axle weight rating be assigned to each axle system. Section S5.1.2 of Standard No. 120 specifies that the GAWR be not more than the sum of the maximum load ratings of the tires fitted to the axle in question. While the agency interprets Standard No. 120 to permit the assignment of a GAWR on the basis of tires listed on the certification plate for that GAWR, the assignment of an arbitrarily high (or low) GAWR for purposes such as avoiding a Federal motor vehicle safety standard (such as Standard No. 121, *Air Brake Systems*), would constitute a violation of S 108(a) (1) (D) of the National Traffic and Motor Vehicle Safety Act:; >>> S108(a) (1) No person shall (A) ........... (c) Fail to issue a certificate required by section 114 of this title or issue a certificate to the effect that a motor vehicle or item of motor vehicle equipment conforms to all applicable Federal motor vehicle safety standards, if such person in the exercise of due care has reasons to know that such certificate is false or misleading in a material respect,..............<<<; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam3722OpenMs. Mary Ruth Harsha, Office of General Counsel, 3M Center, P.O. Box 33428, St. Paul, MN 55133; Ms. Mary Ruth Harsha Office of General Counsel 3M Center P.O. Box 33428 St. Paul MN 55133; Dear Ms. Harsha: This responds to your company's recent letter regarding th applicability of Federal motor vehicle safety regulations to the sale and application of sun control films on motor vehicles. You ask whether our November 10, 1976, letter to your company on this same subject is still applicable, as well as several other questions.; Our November 1976 letter is still current. Solar films themselves ar not considered glazing materials under Safety Standard No. 205. As stated in that letter, however, the application of such films to motor vehicles by certain persons does give rise to responsibilities under Federal law. I am enclosing a copy of a recent letter of interpretation which discusses the pertinent Federal law on this subject.; I am also enclosing a copy of a telegram that we recently sent to th Hawaii Department of Transportation which discusses the preemptive effect of Safety Standard No. 205 over State laws governing the same aspect of motor vehicle performance, under the National Traffic and Motor Vehicle Safety Act, as amended (15 U.S.C. 1381, et *seq*. (sic)). The Hawaii legislature has passed a law which attempts to allow dealers and businesses in that State to apply solar films on motor vehicles. Those films are allowed to reduce transmittance down to 35 percent. As pointed out in the enclosed telegram, Safety Standard No. 205 preempts that State statute in certain respects. The letter of interpretation and the telegram should answer all of your questions.; Please note that under Safety Standard No. 205 all windows in passenger car are considered requisite for driving visibility. Thus, all windows in a passenger car must have a light transmittance of at least 70 percent. In vehicles other than passenger cars, typically, only the windshield and front side windows are considered requisite for driving visibility. This means, for example, that a van could have solar films installed on windows behind the driver, since no transmittance requirements are specified for those windows.; I hope this has answered all your questions. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2811OpenMr. Doug Mills, Rt. 1 Box 149, Tellico Plains, TN 37385; Mr. Doug Mills Rt. 1 Box 149 Tellico Plains TN 37385; Dear Mr. Mills: This responds to your recent letter asking additional question concerning the responsibilities of a person converting a pick-up truck into a dump truck, under Federal motor vehicle safety standards and regulations. This office explained the general responsibilities of a person who alters a certified vehicle in a letter to your associate, Mr. Henry Brown, dated February 1, 1978. You now ask questions regarding specific aspects of the conversion operating and whether they can be accomplished without destroying a vehicle's compliance with safety regulations.; Unfortunately, it is impossible for the National Highway Traffic Safet Administration (NHTSA) to answer your specific questions. It is the responsibility of the manufacturer or vehicle alterer to determine whether his vehicle is in compliance with applicable safety standards and to certify that vehicle. The NHTSA cannot review an alteration procedure such as the one with which you are concerned and state that it can or cannot be done in compliance with Federal regulations. There are no safety regulations which require a specific number of bolts or specific bolt locations, for instance. Likewise, Safety Standard No. 301-75, *Fuel System Integrity*, is specified only in terms of performance requirements, so the NHTSA cannot tell you whether a modified fuel filler neck will destroy a vehicle's compliance with the standard.; As stated in our previous letter, a person who alters a pick-up truc to convert it to a dump truck must certify that the truck remains in compliance with all applicable safety standards. Further, the person who makes the conversion must assure that the alterations do not result in any 'safety related defects' whether or not there is a specific safety standard that is applicable. Therefore, you must determine for yourself whether the number of bolts you use, the bolt strengths and the bolt locations will result in safety hazards.; I can answer your question number 8 regarding possible liability fo removal and alteration of the truck bumper. The Federal safety standard for bumpers is only applicable to passenger cars, so you may alter a truck bumper with impunity provided the action does not result in a safety related defect.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam1314OpenMr. Rudolfo H. Schroeter, Suite 2600 Equitable Plaza, 3435 Wilshire Boulevard, Los Angeles, California 90010; Mr. Rudolfo H. Schroeter Suite 2600 Equitable Plaza 3435 Wilshire Boulevard Los Angeles California 90010; Dear Mr. Schroeter: This is in reply to you letter of October 24, 1973, in which you as the following questions:; 1. Is it true that Standard Nos. 109 and 110 are not applicable to 1/2-ton pickup truck with camper because such vehicle is not a 'passenger car' as defined in Standards 109 and 110?; 2. Is it true that in Appendix A of Standard 110 no 'alternative rims are listed for the L70-15 tire simply because no one has requested (in the manner provided in Appendix A to Standard 110) inclusion of such additional or alternative rim widths.; With respect to question 1, a pickup truck is not a passenger car but 'truck' (as defined in 49 CFR S571.3) for purposes of all the Federal motor vehicle safety standards, including Standard Nos. 109 and 110. Standard No. 110 (49 CFR S571.110) applies only to passenger cars, not to pickup trucks.; In response to your second question, the answer is not an unequivoca 'yes', and I regret that you may have drawn that conclusion from your conversation with Michael Peskoe of this office. In order for alternative rims to be listed with a tire size designation in the Appendix of Standard No. 110, data showing that the tire and rim combination meets the requirements of both Standard No. 109 and 110 must first be submitted to the agency. Once that data has been provided, the NHTSA will publish the alternative rim size in Standard No. 110, and if no objections are received within a 30-day period, the tire/rim combination becomes part of the standard. Thus, there are not one but two possible reasons way a rim size is not listed in Standard No. 110:; >>>The tire/rim combination fails to meet either Standard No. 109 o 110, or; It does meet both standards, but no one has requested approval of th combination. This could occur simply if the combination was not intended to be used as original equipment on a passenger car.<<<; Sincerely, Lawrence, R. Schneider, Chief Counsel |
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ID: aiam5395OpenMr. Donald P. Green 809 Huasna Road Arroyo Grande, CA 93420; Mr. Donald P. Green 809 Huasna Road Arroyo Grande CA 93420; Dear Mr. Green: This responds to your letter to this agency askin whether there is a State or Federal regulation prohibiting the use of passenger radial tires on recreational 'pull type' trailers. I regret the delay in responding. You explain that you were told by various tire dealers that radial tires should not be used on trailers because the soft sidewalls of radial tires could cause an uncontrollable swaying that could result in a serious accident. You then state that while towing a trailer mounted with four radial tires, you were caught in a crosswind which caused the trailer to jackknife, resulting in a serious accident. To begin, I am sorry to hear about your accident but am thankful that no one was hurt. The tire safety standards and regulations issued by the National Highway Traffic Safety Administration (NHTSA) require tires to be able to safely carry the load on a vehicle and to be labeled with important safety information, such as tire size, construction, and inflation pressure. There is nothing in our standards or regulations that prohibits the use of passenger car radial tires on trailers. In fact, Federal Motor Vehicle Safety Standard No. 120, 'Tire selection and rims for motor vehicles other than passenger cars,' expressly permits the use of passenger car tires on vehicles like trailers, provided that adjustment is made to the tire's load-carrying capacity. NHTSA also issues consumer advisories to alert consumers to certain practices that should be avoided, such as mixing radial and non-radial tires. However, we have never issued a consumer advisory on the use of passenger car radial tires on trailers, and we are not aware of any widespread hazard due to the use of such tires on trailers. Your State could have requirements for the use of tires on trailers. We suggest that you check with the California Highway Patrol for information on that issue. We regret we are unable to be more helpful. Should you have any further questions, please feel free to contact Walter Myers of my staff at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam1729OpenHonorable Birch Bayh, United States Senate, Washington, DC 20510; Honorable Birch Bayh United States Senate Washington DC 20510; Dear Senator Bayh: This is in response to your letter requesting information concernin correspondence from Mr. James A. Graham, commenting on a proposed amendment to the Federal bumper standard.; On January 2, 1975, the National Highway Traffic Safety Administratio (NHTSA) issued a *Federal Register* notice (copy enclosed) proposing to reduce the current 5-mph bumper impact requirements to 2.5 mph until the 1979 model year. The impact requirements would have been increased to 4 mph for 1979 and later model year cars.; The proposal was based primarily on the results of two agency-sponsore studies which indicated that the cost and weight of many current production bumpers, in light of inflation and fuel shortages, made the bumpers no longer cost beneficial. Information presented at public hearings on the bumper notice and comments submitted to the docket in response to the proposal have brought to light additional data. The NHTSA has carefully examined all of this evidence and reviewed its studies in light of the new information. As a result, the agency has concluded that the 5-mph protection level should not be reduced. This decision is contained in a *Federal Register* notice that was published March 12, 1975, which is enclosed (Docket No. 74-11, Notice 7, Docket No. 73-19, Notice 6).; In his letter Mr. Graham objects to the standard's regulation o surface damage, such as dents, stating that this is not the type of damage which should be addressed by an agency developing safety standards. The surface damage criteria are proposed as part of a standard being promulgated under Title I of the Motor Vehicle Information and Cost Savings Act (Pub. L. 92-513). The Cost Savings Act directs the National Highway Traffic Safety Administration to develop a bumper standard that will obtain the maximum feasible reduction of costs to the public and the consumer. As such, the standard is not to be limited to affecting safety- related damage. Factors such as insurance costs and consumer time and inconvenience are to be considered in the rulemaking as well.; Mr. Graham's comments will be placed in the public docket where the will receive every consideration.; We appreciate your interest and that of Mr. Graham in this area o motor vehicle safety and performance.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam2007OpenMr. Fred Long, South Texas Tire Test Fleet, Drawer J, Devine, TX 78016; Mr. Fred Long South Texas Tire Test Fleet Drawer J Devine TX 78016; Dear Mr. Long: This is to confirm your telephone conversation of July 31, 1975, wit Mark Schwimmer concerning the treadwear test procedures specified in 49 CFR Part 575.104, *Uniform Tire Quality Grading Standards* (UTQGS).; You had previously pointed out that the A78-13 and other tires ar available neither as original equipment nor as recommended replacement options on any 1975 model passenger cars, although they are available as replacement options for the 1974 Ford Pinto. You had asked whether it is permissible for a tire manufacturer to conduct treadwear testing for such tires on a 1975 Pinto, in light of the National Highway Traffic Safety Administration's (NHTSA) statement that; >>>tires will be tested for compliance only on vehicles for which the are available as original equipment or recommended replacement options. (40 FR 23076, May 28, 1975)<<<; As Mr. Schwimmer explained to you, the UTQGS rules does not dictate th method by which a tire manufacturer must conduct his testing to assign grades. It merely specifies the procedures which the NHTSA will follow when testing tires for compliance with the rule. While the surest way for the tire manufacturer to be confident of compliance would be to follow these procedures in every detail, he is not legally obligated to do so. His obligation is simply to ensure that, when tested by the NHTSA according to the specified procedures, his tires are capable of achieving the grades which he has assigned to them. He may fulfill this obligation by whatever means he believes reliable and necessary. Thus, for example, he might choose a 1975 Pinto to test an A78-13 tire, if he is confident that the model year change in the Pinto will have no effect on the tire's treadwear performance. This decision is his, however. The NHTSA, in its compliance testing, would test such a tire on a 1974 Pinto or on some other passenger car for which it is original equipment or a recommended replacement option.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam2882OpenMr. Richard H. Attenhofer, Manager - Tire Technical Relations, Dunlop Tire Company, P. O. Box 1109, Buffalo, New York 14240; Mr. Richard H. Attenhofer Manager - Tire Technical Relations Dunlop Tire Company P. O. Box 1109 Buffalo New York 14240; Dear Mr. Attenhofer: This responds to your July 10, 1978, letter asking whether it i permissible to label motorcycle tires with alternate speeds and load ratings appropriate for those speeds. You suggest that your tires be labeled with maximum speeds of 131, 137, and 143 miles per hour with the corresponding load ratings. The labeling of motor cycle (sic) tires is regulated by Standard No. 119, *New Pneumatic Tires for Vehicle Other Than Passenger Cars.*; Standard No. 119 requires that tires be marked with, among othe things, the maximum inflation pressure of the tire and the load rating applicable to that inflation pressure. Speed qualifications are permitted on tires when, for example, the tires are speed restricted. Otherwise, tires are not marked with speed criteria although they may be marked with the symbols S, H, or V as part of the tire identification number. These symbols, established by the European Tyre and Rim Technical Organization (ETRTO), indicate that the tire is an acceptable high-speed tire.; The National Highway Traffic Safety Administration considers i appropriate to permit the symbols S, H, or V to be marked on tires to indicate that such tires are appropriate for high-speed use. This permits, for example, a sophisticated purchaser of tires for emergency vehicles to know that the tires are suitable for the higher operational speeds necessary for those vehicles. The NHTSA, however, considers it inappropriate to mark motorcycle tires with maximum speeds of 131, 137, and 143 miles per hour with the corresponding safe load ratings. Such markings would appear to sanction the use of he tires at these speeds which far exceed the national speed limit.; Since Standard No. 119 regulates the permissible uses of spee designations on nonpassenger car tires, the agency interprets the standard to prohibit the marking of any other speed designations on a tire. The NHTSA considers the only appropriate speed designation on tires to be one that reflects a speed restricted tire or one that uses the symbols established by the ETRTO for tires that have been tested and can be operated at higher speeds.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam0098OpenMr. John W. Carlin, Calumet Corporation, P. O. Box 389, Kaukauna, WI 54130; Mr. John W. Carlin Calumet Corporation P. O. Box 389 Kaukauna WI 54130; Dear Mr. Carlin: Thank you for your letter of July 22, 1968, to Mr. George C. Nield concerning the applicability and effective date of Motor Vehicle Safety Standard 108.; Standard No. 108 is applicable to new vehicles manufactured on or afte the effective date of the standard. Initial Standard No. 108 was published on February 3, 1967, and became effective January 1, 1968. The initial standard is applicable only to vehicles that are 80 inches or more in overall width. Revised Standard No. 108 was published on December 16, 1967, and becomes effective January 1, 1969. The revised standard is applicable to passenger cars, multipurpose passenger vehicles, trucks, buses, trailers and motorcycles, regardless of overall width, however, the special requirements for vehicles that are 80 inches or more in overall width have been identified in the standard. Copies of the initial and revised standard are enclosed for your information.; In reply to your specific questions, information is provided a follows:; >>>1. With respect to your first question, Standard No. 108 i applicable to trailers manufactured for personal use by an individual and for commercial use.; 2. With respect to your second question, Revised Standard No. 108 effective January 1, 1969, specifies the lighting requirements for trailers that are less than 80 inches in overall width.; 3. With respect to your third question, the regulations of individua States and of the Bureau of Motor Carrier Safety (for vehicles engaged in interstate commerce) presently govern the lighting required on trailers that are less than 80 inches in overall width. Effective January 1, 1969, these trailers will be subject to the requirements of Revised Standard No. 108. Installation and location requirements for the individual lamps are contained in the referenced SAE standards (see Table III of Standard No. 108) and in Table IV of Standard No. 108.<<<; Also enclosed is a copy of the notice of 'Certification Requirement, which provides information on the manufacturer's certification of vehicles that are subject to the Federal motor vehicle safety standards.; Sincerely, Charles A. Baker, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service; |
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.