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
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ID: aiam2454OpenMr. Rex R. Redhair, Shughart, Thomson and Kilroy, 922 Walnut Street, P. O. Box 13007, (sic); Mr. Rex R. Redhair Shughart Thomson and Kilroy 922 Walnut Street P. O. Box 13007 (sic); Dear Mr. Redhair: Your October 20, 1976, letter to the U.S. Department of Transportation Federal Highway Administration, has been referred to this office for reply.; You request data concerning the 10.00-02 'Inland Deep Drive 300,' tha was manufactured by the Mansfield Tire and Rubber Company, Mansfield, OH. Tire Identification Number WLZJAVN 503.; We have enclosed all the Federal Motor Vehicle Safety Standards for: >>>o New Pneumatic Tires, Passenger Cars, Federal Motor Vehicle Safet Standard No. 109; o New Pneumatic Tires for Vehicles Other Than Passenger Cars, Federa Motor Vehicle Safety Standard No. 119; o Part 574 - Tire Identification and Recordkeeping o Tire Code Numbers Assigned New Tire Manufacturers. o Tire Size Codes<<< The tire identification number stated in your letter can be explaine by the use of the above data.; >>>'WL' - is the plant code for the Mansfield, Ohio plant. 'ZJ' - is the tire size code for the 10.00-20 tire size designation. 'AVN' - is an internal code for Mansfield. '503' - means the tire was cured the 50th week of 1973.<<< You also request design and construction information. We do not hav this type of information because it is proprietary. Also enclosed are copies of tire 'Care and Service of Bias and Radial Ply Truck Tires.'; We hope the above has been of some help to you. Sincerely, E. T. Driver, Director, Office of Crash Avoidance, Moto Vehicle Programs; |
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ID: aiam4996OpenMs. Eileen Mathews Industry Manager, Hose and Tubing General Electric Company 2 Summit Park Dr. Suite 410 Independence, OH 44131; Ms. Eileen Mathews Industry Manager Hose and Tubing General Electric Company 2 Summit Park Dr. Suite 410 Independence OH 44131; "Dear Ms. Mathews: This concerns your letter to the Federal Highwa Administration (FHWA) asking about FHWA's regulation 393.45 (49 CFR 393.45) and NHTSA's Federal Motor Vehicle Safety Standard No. 106, Brake Hoses. FHWA provided us a copy of its March 6, 1992 response on regulation 393.45. This letter answers your question about Standard 106. You ask about S7.3.6, 7.3.10 and 7.3.11 of the standard. Those sections set forth performance requirements for limiting the amount a hose may change in length under specified conditions (S7.3.6), for the tensile strength of a hose assembly (S7.3.10), and for the tensile strength of an assembly after immersion in water (S7.3.11). Each of these sections excludes certain items from the requirement. Your question relates to those exclusions. S7.3.6 excludes coiled nylon tubes for use in assemblies that meet the FHWA requirements of 393.45. S7.3.10 excludes coiled nylon tube assemblies that meet 393.45. S7.3.11 excludes coiled tube assemblies that meet 393.45. You ask whether those exclusions in S7.3.6, 7.3.10 and 7.3.11 'require compliance with 393.45.' The answer is no. Standard 106 does not require tubing to meet 393.45. Instead, compliance with 393.45 is a condition for excluding the item from S7.3.6, 7.3.10 or 7.3.11. The other condition, relevant for S7.3.6 and 7.3.10, is that the brake hose be coiled nylon tubing. According to your letter, the brake hose (tubing) of your concern would be made from a material other than nylon. Since the second condition would not be satisfied, such hose would not qualify for the S7.3.6 exception, and an assembly made from such hose would not qualify for the 7.3.10 exception, regardless of whether the hose meets regulation 393.45. Thus, S7.3.6 and 7.3.10 would apply to hose and assemblies made from your product, without exception. S7.3.11 does not specify that the coiled tubing must be nylon to qualify for the exception. While NHTSA intended to specify nylon (see, preamble to rule adopting the exclusion, 39 FR 28436, August 7, 1974), as adopted, S7.3.11 excludes a 'coiled tube assembly' that meets regulation 393.45 from its requirements. I hope this information is helpful. If you have any further questions, please contact Deirdre Fujita of my staff at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam2141OpenInterps. file, Parts 575.104(d)(1)(ii) and 575.6; Interps. file Parts 575.104(d)(1)(ii) and 575.6; Office visit by Pat Raher, Hogan and Hartson I received an office visit on December 8, 1975, from Mr. Raher of Hoga and Hartson (representing Mercedes-Benz). He showed me a sample information sheet of the type that Mercedes proposes to use to indicate the quality grades of tires with which its vehicles are equipped. We discussed the vehicle manufacturer's information requirement of the Uniform Tire Quality Grading Standards, and I indicated that a formal interpretation would follow our receipt of his letter, which is en route.; Mark I. Schwimmer, Attorney- Advisor |
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ID: aiam0486OpenDavid J. Humphreys, Esq., Recreational Vehicle Institute, Inc., Suite 406, 1140 Connecticut Avenue, Washington, DC 20006; David J. Humphreys Esq. Recreational Vehicle Institute Inc. Suite 406 1140 Connecticut Avenue Washington DC 20006; Dear Mr. Humphreys: As we have advised Ed Bernett of your office from time to time durin the fall, a response to your letter on the treatment of removable foam seat cushions under Standard No. 207 has been under review for some time.; Standard No. 207 is essentially a test of the strength of the sea structure. As such it does not prohibit the use of removable seat cushions of the type described in your letter.; We consider it to be the intent of the standard, however, that when th momentum of a cushion is transferred in any way to the seat structure during the course of an acceleration in a given direction, the weight of the cushion must be added to the weight of the seat structure in calculating the force to be applied in that direction under S4.2 and S4.3.2.; Please advise us if you have further questions. Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2511OpenMr. Dave Murray, Harley Murray, Inc., 1754 E. Mariposa Road (So. Highway 99), Stockton, CA 95206; Mr. Dave Murray Harley Murray Inc. 1754 E. Mariposa Road (So. Highway 99) Stockton CA 95206; Dear Mr. Murray: This responds to your January 25, 1977, question whether a row of eigh wheels arranged in a line that is perpendicular to the longitudinal axis of a vehicle constitute an 'axle' as that word is used in S3(b) of Standard No. 121, *Air Brake Systems*. You note that the wheels are not mounted on a single solid axle but rather are mounted on two walking beam assemblies that also constitute the suspension for a separate set of eight wheels across the vehicle.; The answer to your question is yes. When asked for a definition o 'axle system' in connection with Standard No. 121, the National Highway Traffic Safety Administration stated:; >>>In answer to Wagner's request for a definition of 'axle system,' th term is used in the same sense as it is used in the definition of GAWR found at 49 CFR 571.3. 'Axle system' is used instead of 'axle' to avoid confusion in situations where a suspension system does not employ an axle. The term has not created difficulty in the GAWR definition (39 FR 17553, May 17, 1974).<<<; The agency's use of 'axle' in S3 is intended to be identical to its us of the phrase 'axle system.' Thus, 'axle' means the arrangement of wheels that lie across the vehicle in a line that is perpendicular to the longitudinal centerline of the vehicle. This understanding of 'axle' and 'axle system' is used regularly in the assignment of gross axle weight ratings (GAWR) on vehicles that employ independent suspensions in place of solid axles.; From your description, it appears that each row of eight wheels on you trailer constitutes an 'axle' or 'axle system' that could be rated at a GAWR in excess of 29,000 pounds, qualifying the vehicle for exclusion from Standard No. 121.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam2842OpenHonorable John Glenn, United States Senate, Washington, DC 20510; Honorable John Glenn United States Senate Washington DC 20510; Dear Senator Glenn: This is in response to your letter of June 7, 1978, pertaining to you constituent's, Mrs. Carl A. Koch, concerns regarding motor vehicle seat backs that do not permanently lock.; Federal Motor Vehicle Safety Standard No. 207, Seating Systems, cop enclosed, requires that a hinged or folding occupant seat or occupant seat back shall be equipped with a self-locking device for restraining the hinged or folding seat or seat back and a control for releasing that restraining device. The industry is currently installing two types of seat back latches, a manual conventional type of latch and a new inertial locking device. The standard requires that the locks withstand a load 20 times the weight of the hinged portion of the seat and is not required to withstand the load of an occupant striking the seat back. Rear occupants are expected to be restrained by the rear seat belts, however, seat backs in locked position, because of some padding, do provide some protection for unrestrained occupants.; The seat back latch referred to by your constituent is an inertial sea back latch which is neither required nor prohibited by the standard. The industry, in an effort to facilitate rapid egress from a motor vehicle in emergency situations, such as a fuel fire, have introduced inertial seat back latches. The seat back latch will lock when the low forces of a panic breaking situation occurs or a high impact force occurs, releasing itself automatically when the inertial forces drop to a predetermined force, normally approximately .5g, allowing rapid occupant egress.; We believe there can be positive post-crash escape advantages for th inertial type seat back latches, however, it would appear from Mrs. Koch's experience that it may be warranted to initiate an investigation of the type of inertial latches installed in the 1978 Ford Granada. Accordingly, I am forwarding a copy of your letter to our Office of Defects Investigation for their action to determine if and what corrective action may be warranted.; I hope this information is helpful to you in responding to Mrs. Koch' inquiry. If I can be of further assistance, please let me know.; Sincerely, Michael M. Finkelstein, Acting Associate Administrator fo Rulemaking; |
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ID: aiam4095OpenMr. Earnest Farmer, Director of Pupil Transportation, Tennessee Department of Education, Nashville, TN 37219-5335; Mr. Earnest Farmer Director of Pupil Transportation Tennessee Department of Education Nashville TN 37219-5335; Dear Mr. Farmer: This responds to your February 19, 1986 letter to the National Highwa Traffic Safety Administration (NHTSA) asking whether Federal motor vehicle safety standards prohibit commercial businesses from using fiberglass on the exterior of school buses. As explained below, the answer to your question is no.; The National Traffic and Motor Vehicle Safety Act authorizes NHTSA t issue minimum performance standards for school buses. Our safety standards do not specify the materials to be used for the exterior of school buses. However, the materials chosen by a manufacturer must be strong enough to enable the bus to meet the requirements of those standards. Among those requirements are the rollover protection ones of Standard No. 220, fuel system requirements of Standard No. 301, and strength requirements of Standard No. 221, *School Bus Body Joint Strength*, for body panel joints on school buses with gross vehicle weight ratings over 10,000 pounds. Manufacturers of new school buses using fiberglass for school bus exteriors must certify that their vehicles conform to the requirements of all applicable school bus safety standards.; I hope this information is helpful. Please contact my office if yo have further questions.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3750OpenMr. Philip H. Wong, Deltana Enterprises, Inc., 12871 S.W. 117 Street, Miami, Florida 33186; Mr. Philip H. Wong Deltana Enterprises Inc. 12871 S.W. 117 Street Miami Florida 33186; Dear Mr. Wong: This responds to your letter to this office asking for information o regulations applicable to the importation of new tires, retreaded tires, and used tire casings from Japan into this country. It is not clear from your letter whether you are interested in importing passenger car tires or tires for use on other motor vehicles. To ensure that you get the information of concern to you, I will discuss the three situations you asked about for both passenger car tires and tires for use on other motor vehicles.; Generally speaking, all tires which are subject to a Federal moto vehicle safety standard must have the symbol 'DOT molded into the sidewall by the manufacturer or retreader, if those tires are to be imported into the United States. This symbol represents a certification by the manufacturer or retreader that the tire complies with all requirements of the applicable safety standard. The importation of any item without the DOT certification symbol on the sidewall would be a violation of 15 U.S.C. 1397(a)(1)(A), and the importer would be subject to a civil penalty of $1000 for each tire he imported without a DOT symbol on the sidewall.; *New passenger car tires*. Section S4.3.1 of Safety Standard No. 10 (49 CFR S571.109) (copy enclosed) requires that all new passenger car tires have the DOT symbol molded into the sidewall by the manufacturer. Tires without this symbol may not legally be imported into this country.; *New tires for use on motor vehicles other than passenger cars* Section S6.5(a) of Standard No. 119 (49 CFR S571.119) (copy enclosed) requires that all new tires for use on motor vehicles other than passenger cars have the DOT symbol molded into the sidewall by the manufacturer. Tires without this symbol may not legally be imported into this country.; *Retreaded passenger car tires*. Sections S6.1 of Standard NO. 117 (4 CFR S571.117) (copy enclosed) requires that all retreaded passenger cars tires have the symbol DOT molded into the sidewall by the retreader. Retreaded passenger car tires without this symbol may not legally be imported into this country.; *Retreaded tires for use on motor vehicles other than passenger cars* No Federal safety standard is applicable to these tires. They may be imported without certification of compliance by the retreader. However, these tires must have a tire identification number marked on the sidewall, per the requirements of 49 CFR Part 574 (copy enclosed), if they are to be legally sold in the United States. It would be a violation of 15 U.S.C. 1397(a)(1)(E) to sell tires without an identification number.; *Used passenger car tires*. 15 U.S.C.d 1397(a)(1)(A) reads in part a follows: 'No person shall...import into the United States...any item of motor vehicle equipment manufactured on or after the date any applicable Federal motor vehicle safety standard takes effect under this title unless it is in conformity with such standard...' The effect of this language is to require that passenger car tires manufactured on or after the date Standard No. 109 took effect (January 1, 1968) be certified as complying with that standard, whether the tire is now new or used. To be legally imported into the United States, used passenger car tires must either have a DOT symbol molded into the sidewall by the original manufacturer or be accompanied by proof that they were manufactured before January 1, 1968.; *Used tires for use on motor vehicles other than passenger cars*. Th same reasoning applied above in the case of used passenger car tires applies to these tires as well. Standard No. 119 took effect on March 1, 1975, so used tires to be imported into the United States must either have a DOT symbol on the sidewall or proof that they were manufactured before March 1, 1975.; Used tires for use on motor vehicles other than passenger cars whic have less than 2/32 inch of tread remaining and which are imported solely for the purpose of being retreaded in this country prior to resale may be imported without a DOT symbol on the sidewall. I have enclosed a copy of a letter to Mr. Roy Littlefield, which explains in detail the requirements of this narrow exception to the requirement that used tires have a DOT symbol on the sidewall to be legally imported.; You also asked for any other information which your supplier might nee to export tires to the United States. I have enclosed a copy of a letter to Mr. Yang Ru-tang, which sets forth the requirements which must be satisfied in order for a foreign manufacturer to export tires to this country.; If you need any further information on this subject, please feel fre to contact me.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1297OpenThomas N. O'Leary, Esq., Messrs. Pain & Julian, 1940 East Camelback, Phoenix, AZ 85016; Thomas N. O'Leary Esq. Messrs. Pain & Julian 1940 East Camelback Phoenix AZ 85016; Dear Mr. O'Leary: In your letter of October 8, 1973, to the Department of Transportatio you ask whether it is true that DOT requires trailer braking systems to have stainless steel conduits rather than copper ones.; Neither the Federal motor vehicle safety standards nor the regulation of the Bureau of Motor Carrier Safety contain such a requirement, and we are unaware of any Federal regulation of this nature.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3300OpenHonorable John P. Murtha, Member, U.S. House of Representatives, Post Office Building, Room 15, 201 North Center Avenue, Somerset, PA 15501; Honorable John P. Murtha Member U.S. House of Representatives Post Office Building Room 15 201 North Center Avenue Somerset PA 15501; Dear Mr. Murtha: This responds to your recent request for information on behalf of you constituent, Mr. Steve Zufall. Mr. Zufall is interested in the specifications applicable to the manufacture of propane tanks to be used in the conversion of gasoline-powered vehicles. He asked how to obtain 'numbers' to be listed on the tanks and mentioned the designation '4VA-240', which someone had discussed with him.; The enclosed discussion sets forth the implications under Federal la of converting gasoline-powered vehicles to use propane, as well as a general discussion of auxiliary fuel tanks. The applicable statutory authority is the National Traffic and Motor Vehicle Safety Act, as amended 1974 915 U.S.C. 1381, *et seq*.). The discussion first looks at the Federal Motor Vehicle Safety Standard (FMVSS) applicable to fuel systems and then at the defect responsibilities that might be involved. Next, a brief mention is made of the possibility of product liability suits.; There are no requirements under the Federal motor vehicle safet regulations that specify 'numbers' which must be stamped on propane gas tanks. The designation mentioned by Mr. Zufall, 4VA- 240', is actually '4BA-240' and refers to specifications under the Bureau of Motor Carrier Safety regulations relating to fuel systems on commercial vehicles or to tanks used for shipment of propane gas in interstate commerce. These regulations would not apply, however, to tanks or fuel systems on private vehicles. For further information regarding these regulations, Mr. Zufall should contact Mr. W. R. Fiste of the Bureau of Motor Carrier Safety (202-426-0033).; Sincerely, Frank Berndt, Chief Counsel |
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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.