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: aiam5371OpenMr. Donald F. Lett Lett Electronics Company 410 North Plum Hutchinson, KS 67501; Mr. Donald F. Lett Lett Electronics Company 410 North Plum Hutchinson KS 67501; "Dear Mr. Lett: This responds to your letter to me in which you aske whether any 'pre- necessary authorization' is needed for molding white sidewalls onto existing passenger car tires. We assume 'pre-necessary authorization' means this agency's prior approval or permission to modify the tires in the manner you propose. You explained in your letter that you intend to modify existing radial passenger car blackwall tires by grinding a recess into one sidewall between 1/8 and 3/16 inches deep by 2 inches wide, then vulcanizing white rubber into that recess to transform a 'D.O.T. approved radial blackwall tire' into a white sidewall tire. You would then market those tires, as modified, for classic cars of the 1955-1960 era. By way of background, the National Traffic and Motor Vehicle Safety Act of 1966, 15 U.S.C. 1381, et seq. (Safety Act), gives the National Highway Traffic Safety Administration (NHTSA) the authority to issue Federal motor vehicle safety standards (FMVSS) applicable to new motor vehicles and new items of motor vehicle equipment. Tires are considered motor vehicle equipment. The Safety Act establishes a self-certification system in which vehicle and equipment manufacturers certify that their products comply with all applicable FMVSSs in effect on the date of manufacture. Because of this self- certification system, neither NHTSA nor the Department of Transportation (DOT) approves, endorses, certifies, or gives assurances of compliance of any product. Rather, NHTSA enforces its standards by testing products in accordance with the test procedures set forth in applicable FMVSSs. If the product meets the requirements of the standard, no further action is taken. If the product fails to comply, the manufacturer must notify the purchasers of the product and remedy the noncompliance without charge to the purchaser(s). Failure to comply with any FMVSS can also result in civil penalties of up to $1,000 per violation, up to a maximum of $800,000 for a series of related violations. We assume from your letter that you propose to modify new radial passenger car tires. Whether the process you described is permissible depends on whether it adversely affects the tire's compliance with FMVSS No. 109, New Pneumatic Tires (copy enclosed). This standard specifies the performance requirements applicable to passenger car tires, which include tubeless tire resistance to bead unseating, tire strength, tire endurance, and high speed performance. It does not appear that radial tires can be modified as you propose and still meet the requirements of Standard 109. The average radial tire sidewall is approximately 3/16 inch thick at the shoulder, gradually increasing to approximately 1/2 inch where the sidewall meets the bead. The radial sidewall is unsupported by cords, belts, or other material contributing to the strength of that sidewall. To achieve a 2 inch whitewall, at least some of the whitewall would extend into the tire shoulder. Therefore, cutting into a radial tire sidewall at the shoulder to a depth of 3/16 inch would cut through the sidewall. Cutting into the sidewall at the shoulder to a depth of 1/8 inch would leave approximately 1/16 inch of rubber on the shoulder of the tire. That would, obviously, have the effect of destroying the tire. Section 108(a)(1)(A) of the Safety Act, 15 U.S.C. 1397 (a)(1)(A), prohibits any person from manufacturing or selling any new item of equipment that does not conform to all applicable FMVSSs. A new noncomplying tire that is sold to a retail customer would constitute a violation of 108(a)(1)(A), and is subject to the recall and civil penalties described above. In addition, 108(a)(2)(A) of the Safety Act, 15 U.S.C. 1397(a)(2)(A), prohibits a manufacturer, distributor, dealer, or motor vehicle repair business 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 Federal motor vehicle safety standard. Accordingly, modifying previously-complying tires by removing them from compliance with the strength requirements of FMVSS 109 could violate 108(a)(2)(A), again subjecting the violator to the civil penalties described above. Standard No. 109 also requires that certain information be molded into or onto the sidewalls of tires in certain specified locations and that the letters 'DOT' appear on each tire sidewall to indicate the manufacturer's certification that the tire complies with all applicable FMVSSs. In addition, the Uniform Tire Quality Grading Standards (UTQGS), 49 CFR Part 575.104, provides that the ratings required by that section will be molded onto or into the sidewalls of tires. Therefore, if the modification you propose obliterates or removes any of the required labeling, that could violate FMVSS 109 and the UTQGS, again subjecting the violator to penalties. In addition to the safety implications of grinding and filling recesses in tires, we also note that the suspension systems of older motor vehicles may not be compatible with radial tires. The handling and stability of those vehicles could be adversely affected by mounting radial tires on them, or by the mixing radial and bias ply tires, without appropriate modifications to their suspension systems. Finally, I note that you used the term 'previously D.O.T. approved' tire in your letter. As explained above, NHTSA does not use that term because neither NHTSA nor the Department of Transportation 'approves' tires or any other motor vehicle product. We assume that by using that expression you mean that the tires you select for modification contain the 'DOT' code that signify the manufacturer's, not NHTSA's, certification. Nevertheless, since the meaning of the term is unclear and might be misleading to consumers, we ask that you not use that term in any of your promotional materials. I hope this information is helpful to you. Should you have any further questions or need any additional information, please feel free to contact Walter Myers of my staff at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosure"; |
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ID: aiam0173OpenStanley Hoffman, Esq., Attorney at Law, 270 Park Avenue, New York, New York 10017; Stanley Hoffman Esq. Attorney at Law 270 Park Avenue New York New York 10017; Dear Mr. Hoffman: This in further response to your letter of July 14 enclosing a engineering drawing of a hub cap 'incorporating a decorative device designed to create an impression of spinning at the center of the wheel during operation of the vehicle', and requesting an interpretation of Federal Motor Vehicle Safety Standard No. 211 with respect thereto.; Standard No. 211 specifies the requirement that hub caps, wheel nuts and wheel discs shall not incorporate winged projections. that is the sole requirement of this Standard. The drawing submitted by you depicts a hub cap which, in our judgement, incorporates a winged projection. The Standard does not regulate vehicle width, and thus your observation that 'it would not broaden or extend the front (or top or rear) profile of automobiles...' is not a factor to be considered.; I enclose (sic) the engineering drawing you furnished us. Sincerely, Lawrence R. Schneider, Acting Assistant Chief Counsel fo Regulations; |
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ID: aiam4999OpenMr. Al Twyford Suite 1200 140 Mayhew Way Pleasant Hill, CA 94523; Mr. Al Twyford Suite 1200 140 Mayhew Way Pleasant Hill CA 94523; "Dear Mr. Twyford: This responds to your letter of April 21, 1992, t the Federal Highway Administration, which has been forwarded to this agency for reply. You wish to complain 'about some makes of new cars that have two sets of headlights (4) which operate at the same time.' If this agency plans to do nothing about it, you 'plan to take this matter up with Congressmen and U.S. Senators.' You are not alone in your concern about headlamp glare created by new motor vehicles. Other citizens have brought the subject to the attention of Members of Congress. I enclose a copy of a recent letter from the Deputy Administrator of this agency to Senator Cohen of Maine which is representative of our views on this issue. You will see that a number of factors may be responsible for creating a perception of glare. We note that you have already been in touch with the Department of California Highway Patrol, and that California has no periodic motor vehicle inspection. With respect to the specific comments in your letter, the agency does not 'approve' specific headlamp designs. Standard No. 108 sets forth photometric performance requirements to be met on both the upper and lower beam, and does establish maximum limitations at some of the photometric test points. Further, in a four-headlamp system, the upper and lower beams may be provided by all headlamps. Headlamp manufacturers must ensure that their products meet these requirements, and certify that each headlamp complies by placing a 'DOT' mark on the lamp. There is no requirement that a manufacturer obtain permission from this agency before introducing the lamps into the market. We appreciate your concern. Sincerely, Paul Jackson Rice Chief Counsel Enclosure"; |
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ID: aiam4130OpenRobert Bosch GmbH, Postfach 50, 7000 Stuttgart 1, Germany, Attention: Herr Berg; Robert Bosch GmbH Postfach 50 7000 Stuttgart 1 Germany Attention: Herr Berg; Gentlemen: This is in response to a letter from Robert Bosch GmbH dated March 13 1986, with reference to 'Approval for exemption from Humidity test S6.8' of Federal Motor Vehicle Safety Standard No. 108.; You have asked that vented replaceable bulb headlamps produced b Robert Bosch be exempted from compliance with paragraph S6.8 of Standard No. 108 on the grounds that failure to comply would be inconsequential noncompliance. You request that this exemption continue until such time as S6.8 is modified, presumably in accordance with the petition for its amendment which you filed in October 1985. The purpose of your request is to allow you 'to test headlamps with ventilation openings pursuant to the procedure described on page 4' of your petition, and in the event that that test is successful 'we request authority to use the headlamps in motor vehicles.'; I should like to explain briefly our exemption authority because we ca not consider your request. You have asked us to excuse prospective conduct that would otherwise be a noncompliance with a Federal motor vehicle safety standard. Our laws and regulations do not permit this course of action. The inconsequentiality regulations (Part 556) excuse past conduct under which noncompliances have already occurred but which have ended at the time the petition is filed. A grant of an inconsequentiality petition means that the manufacturer of motor vehicles or of motor vehicle equipment is relieved of its obligation to notify purchasers of the existence of the noncompliance, and to remedy it.; Your petition for rulemaking is under evaluation, and you will b notified of the agency's decision in the near future. Until such time as the standard may be amended, all manufacturers are required to comply with all the requirements contained therein. Thus, an exemption such as you request is not possible.; As an aside, we note that the letter appears to have been signed by Herr Berg and another Bosch representative whose signature is illegible. It would be helpful to us if your letters to us would contain the name and title of the signers below their signatures, so that we can address our replies to the proper office. You may also wish to note for your records that Ms. Steed is the Administrator of NHTSA (since 1983, in fact) and that her first name is Diane, rather than Diana.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1332OpenMr. Adolph Kunasicwicz, 5644 Forest Avenue, Otter Lake, MI 48464; Mr. Adolph Kunasicwicz 5644 Forest Avenue Otter Lake MI 48464; Dear Mr. Kunasicwicz: Your request for information concerning the existence of penalties fo removal of the required certification label from a motor vehicle has been forwarded to us by the Federal Trade Commission.; The National Traffic and Motor Vehicle Safety Act requires that certification label, which under NHTSA regulations includes the name of the manufacturer and the date of manufacture, be permanently affixed to the motor vehicle. Although removal of this label does not carry a criminal penalty of either fine or imprisonment, a civil penalty of up to $1,000 is specified in certain situations.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1298OpenMr. H. Braun, Engineering Supervisor-Production, Motor Coach Industries, Inc., Pembina, ND; Mr. H. Braun Engineering Supervisor-Production Motor Coach Industries Inc. Pembina ND; Dear Mr. Braun: This is in reply to your letter of September 5, 1973, to Mr. Schneide asking whether you may furnsih (sic) side turn signal lamp for inter-city buses at the rear wheels, and if so, the required color.; It is correct that there are no Federal safety requirements for sid turn signal lamps. Therefore, there is no Federal prohibition against your providing such a lamp, and such restrictions as may exist would be those imposed by the States.; Rear mounted turn signal lamps under Federal Standard No. 108 may b either red or amber.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4560OpenMr. Jack McCroskey Ms. Glenda Swanson Lyle Regional Transportation District 1600 Blake Street Denver, CO 80202-1399; Mr. Jack McCroskey Ms. Glenda Swanson Lyle Regional Transportation District 1600 Blake Street Denver CO 80202-1399; "Dear Mr. McCroskey and Ms. Lyle: This responds to your letter o September 13, 1988, asking for our advice on potential safety hazards and legal liabilities that might result from ignoring the speed restrictions on the tires used on your transit buses. You stated that your entity operates three types of bus service in the State of Colorado. The first type is a local bus, operated primarily in areas where the speed limit is 35 miles per hour (mph), the second type is an express bus, operated primarily in areas where the speed limit is 55 mph, and the third type is a regional bus, operated primarily on freeways with speed limits of 55 to 65 mph. You were interested primarily in the tires used on your express buses. You stated that you use two types of speed-restricted tires 'almost interchangeably' on the express buses. One of your speed-restricted tire types is the XT, which is speed-restricted to a maximum speed of 55 mph. The other is the DXT, which is speed-restricted to a maximum speed of 35 mph. Since the express buses are operated primarily at speeds of 55 mph, you contacted the tire manufacturer to get its advice on the acceptability of using tires that are speed-restricted to 35 mph on these buses. You enclosed copies of correspondence you received from the manufacturer, stating that its DXT and XT tires are identical, except that the DXT tire has 7/32 of an inch more undertread. The manufacturer's advice was that the tire that is speed-restricted to a maximum of 35 mph 'may be used at higher speeds, but not for sustained operation.' You asked whether it is advisable for your entity to continue using the tires that are speed-restricted to 35 mph on your express buses, which operate primarily at 55 mph. We strongly recommend that you not do so. There are some notable advantages associated with speed-restricted tires, including enhanced load-carrying capabilities and greater resistance to tire damage from hitting objects in the road or curbs. However, the greater undertread on speed-restricted tires also means that the tires will generate higher temperatures at high speeds than a comparable non-restricted tire. Higher temperatures inside the tire increase the chances of a tire failure at high speeds. NHTSA carefully considered both the advantages of speed-restricted tires and the need to ensure that such tires are properly used when it was developing Standard No. 119, New Pneumatic Tires for Motor Vehicles Other Than Passenger Cars (49 CFR 571.119, copy enclosed). Every new bus tire must be certified by its manufacturer as complying with this standard. This agency decided that Standard No. 119 should permit the continued production of speed-restricted tires, but with appropriate safeguards to ensure that these tires would not be used at higher speeds. Accordingly, Standard No. 119 specifies less stringent high speed and endurance test requirements for speed-restricted tires. Speed-restricted tires for use on vehicles other than motorcycles are exempted from the high speed performance requirements of S6.3 of Standard No. 119. This exemption reflects the fact that the tires are not designed for high speed use. For the same reason, the endurance test schedule for speed-restricted tires consists of a lower test speed and fewer total revolutions of the test wheel, as shown in Table III of Standard No. 119. Hence, the manufacturer of these speed-restricted tires has not certified that these tires comply with the performance requirements of Standard No. 119 under conditions exceeding the speed-restriction marked on the tires. To ensure that the user of speed-restricted tires would not operate the tires at higher speeds than those at which the tires are designed to operate safely, section S6.5(e) of Standard No. 119 requires every speed-restricted tire to have the marking 'Max speed mph' on the sidewall. This marking is intended to alert the tire user of the limitations of this tire, so that it will not be repeatedly used at higher speeds. Since your express buses operate primarily at speeds of 55 mph, we urge you not to equip those buses with tires labeled 'Max speed 35 mph.' Similarly, since your express and regional buses typically operate at speeds exceeding 55 mph on their routes, we recommend only tires without speed restrictions for these buses. With respect to your question about potential legal liabilities in the event one of these speed-restricted tires fails while in service on one of your express buses, that is a question of State law. Since I am not familiar with the Colorado law on this subject, I must decline to offer an opinion. However, the Attorney General for the State of Colorado or other local counsel would be able to accurately advise you on Colorado's law in this area. Sincerely, Erika Z. Jones Chief Counsel Enclosure"; |
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ID: aiam1762OpenMr. Donald J. Gobeille,Volvo of America Corporation,Rockleigh, New Jersey 07647; Mr. Donald J. Gobeille Volvo of America Corporation Rockleigh New Jersey 07647; Dear Mr. Gobeille::#Please forgive the delay in responding to you letter of November 19, 1974, which requested an interpretation of the labeling requirements of Federal Motor Vehicle Safety Standard No. 106-74, *brake Hoses*, as applied to short lengths of vacuum brake hose.#To fit the information required by S9.1 of the standard on short lengths of hose, you have suggested a labeling format consisting of the required information presented in two lines,#>>>'each in block capital letters and numerals at least one eighth inch high, placed adjacent to one another and separated by the minimum space necessary to assure clarity. The label would occupy no more than three eighths of an inch on a hose approximately two inches in circumference (5/8 inch OD)'.<<<#Because the two lines would be close enough to prevent confusion with any optional labeling which might appear on the opposite side of the hose, it appears that the format you have described complies with the requirements of S9.1 of Standard No. 106-74. #Yours truly,Richard B. Dyson,Acting 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: aiam1277OpenMr. Donald Gary Hayes, Robertson Tank Lines Inc., P.O. Box 1505, Houston, Texas 77001; Mr. Donald Gary Hayes Robertson Tank Lines Inc. P.O. Box 1505 Houston Texas 77001; Dear Mr. Hayes: This is in reply to your letter of August 30, 1973, requesting a DO code number for retreaded tires you manufacture. It appears from your letter that the tires you retread are truck tires intended solely for your company's own use.; Any tires retreaded by and solely for use by Robertson Tank Lines ar exempt from NHTSA recordkeeping requirements and a code number is not required. As truck retreads are not subject to and Federal motor vehicle safety standard, you are also not required to place a 'DOT' symbol on them. If you retread passenger car tires, however, you are required to place a 'DOT' symbol on the tire sidewall (indicating conformity to Federal Motor Vehicle Safety Standard No. 117).; 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.