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: aiam2593OpenMr. James M. Beach, Director of Engineering, Collins Industries, Inc., P.O. Box 58, Hutchinson, KS 67501; Mr. James M. Beach Director of Engineering Collins Industries Inc. P.O. Box 58 Hutchinson KS 67501; Dear Mr. Beach: This responds to your April 28, 1977, letter in which you ask severa questions concerning Standard No. 222, *School Bus Passenger Seating and Crash Protection*, and the definition of school bus.; You first ask whether the seat spacing requirements found in S5.2.1 o the standard are applicable to buses with gross vehicle weight ratings (GVWR) equal to or less than 10,000 pounds. Buses in this weight classification do not have to comply with the mandatory seat spacing requirements. Since these buses are equipped with seat belts, the mandatory seat spacing is not necessary to provide adequate occupant crash protection.; Your second question concerns those areas required to meet the hea protection zone requirements. You ask whether the window frame, window supporting structure, and window glass are included within the head protection zone requirements.; The NHTSA issued an amendment of the standard (Notice 6, 41 FR 28506 in an attempt to clarify those portions of the bus subject to the head protection zone requirements. In this notice (copy enclosed), we stated that the sidewall, window and door structures were never intended to be included within the zone and are not subject to the requirements for head protection. However, the roof structure, if it falls within the zone, is subject to the requirements. If you need further information to determine the portions of your bus that would be included within the head protection zone requirements, I suggest that you send the agency sketches of your bus interior depicting those areas of concern.; Concerning seat orientation, you question whether the requirements fo forward facing seats found in S5.1 of the standard applies to buses with GVWR's of 10,000 pounds or less. S5(b) of the standard lists the paragraphs of the standard applicable to buses in the above-mentioned weight classification. S5(b) does not refer to S5.1 which contains the requirement for forward facing seats. This omission was an oversight that occurred during the drafting of the regulation. The agency intended that seats in all school buses be forward facing, unless designed for handicapped or convalescent passengers as permitted in Notice 6. This intent is obvious since, as you note, we require these seats to comply with forward and rearward performance requirements. The NHTSA will soon issue an amendment of the standard to correct this omission.; Your final question concerns the definition of school bus whic excludes common carriers in urban transportation. Your interpretation of this exclusion is correct. These buses are permitted to transport children to and from school but need not comply with the school bus construction standards.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam5256OpenThe Honorable Phil Gramm United States Senate 2323 Bryan Street, #1500 Dallas, TX 75201; The Honorable Phil Gramm United States Senate 2323 Bryan Street #1500 Dallas TX 75201; "Dear Senator Gramm: Thank you for your inquiry on behalf of you constituent, Mr. Thomas J. Devon of Longview, Texas. The Federal Highway Administration (FHWA) referred your inquiry to this office, since the National Highway Traffic Safety Administration (NHTSA) administers Federal safety standards for tires. In his communication with you, Mr. Devon expressed concern about separated treads from retreaded large truck tires. He referred to the deaths of two young women reportedly caused when they lost control of their vehicle after striking a separated tread in the road. Mr. Devon is concerned that retreaded tires do not meet the same standards as new tires and requested data on accidents caused by separated tire tread sections on the roadway. By way of background information, the National Traffic and Motor Vehicle Safety Act of 1966, 15 U.S.C. 1381, et seq. (Safety Act) authorizes NHTSA to issue safety standards applicable to new motor vehicles and new items of motor vehicle equipment. Pursuant to that authority, NHTSA has issued various Federal Motor Vehicle Safety Standards (FMVSS) applicable to tires: FMVSS Nos. 109 and 110 for new pneumatic passenger car tires, FMVSS Nos. 119 and 120 for new pneumatic tires for other than passenger cars, and FMVSS No. 117 for retreaded passenger car tires. There is currently no standard applicable to retreaded tires for vehicles other than passenger cars. This is because the agency is not aware of any data suggesting a safety need for such a standard. With respect to tire tread separation, examination of actual tire scraps from the nation's highways have indicated that about 60 percent came from retreaded tires and 40 percent from original tires. Because of the many complaints about heavy truck tire tread scraps on and around the highways, the University of Michigan conducted a study in the mid-1980s entitled 'Large Truck Accidents Involving Tire Failure.' That study concluded that most large truck tire failures are caused by vehicle overload and/or tire underinflation. Underinflation causes excessive flexing of the tire. The friction resulting from that flexing causes excessive heat buildup which can, in turn, result in tread separation or other tire failure. Indeed, the heat buildup has been known to be so extreme as to cause the tire to burst into flame. The findings from the Michigan study led the FHWA to prohibit the operation of commercial motor vehicles with overloaded and underinflated tires, unless the vehicle is operated pursuant to a special permit issued by a state. That permit, however, requires a reduced speed to compensate for the increased tire loading. In addition, the vehicle and the tires must be maintained in a safe operating condition at all times. FHWA conducts roadside inspection programs to ensure that such requirements are being met. While scraps of tires on the roadway could pose a safety hazard to motorists, this agency has no real world crash data to indicate what percentage of motor vehicle crashes could be attributed to separated tire treads. Our crash data are limited to the general category of tire failure. Please be assured that NHTSA and FHWA, as well as the tire industry itself, are engaged in ongoing efforts to alleviate this problem by appropriate publicity to large truck owners and operators regarding proper tire care and maintenance and by vigorous vehicle inspection programs. I hope this information is helpful. If your constituent has any further questions, he may contact Walter Myers of this office at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosure Constituent's Correspondence"; |
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ID: aiam1215OpenMr. Keitaro Nakajima, 1099 Wall Street, West, Lyndhurst, NJ 07071; Mr. Keitaro Nakajima 1099 Wall Street West Lyndhurst NJ 07071; Dear Mr. Nakajima: This is in reply to your letter of July 24, 1973, concerning th meaning of the phrase 'remain in adjustment' in S5.3.5 of Motor Vehicle Safety Standard No. 215. You ask whether this criterion, when applied to the alignment of the front wheels, would permit misalignment as a result of the test, so long as the misalignment could be corrected to within the 'inspection limit' under which vehicle operation is considered to be normal.; Our reply is that impact-related misalignment beyond the inspectio limit is considered to be a noncompliance with S5.3.5, even though a mechanic could bring the wheel within the inspection limit without recourse to extraordinary techniques. Some variance in alignment would be permitted, in that tests are begun with the wheels aligned as closely as possible to the manufacturer's nominal adjustment limit which may be tighter than the inspection limit. This variance, however, is considerably less than what you envision in your letter.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3228OpenMr. David Williams, Box 4091, Wilmington, DE 19807; Mr. David Williams Box 4091 Wilmington DE 19807; Dear Mr. Williams: I would like to clarify my remarks of March 17, 1980, with respect t the applicability of Federal motor vehicle safety standards to imported vehicles.; In that letter I implied that there was a prohibition against importin cars that didn't meet Federal standards and that such vehicles had to comply with standards in effect on the date of importation. Actually, a non-conforming vehicle may be imported under bond if it will be brought into compliance within 120 days of entry with all applicable standards in effect on the date of its manufacture.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4017OpenMr. K. Douglas Scribner, President, Mini City Ltd., 876 Turk Hill Road, Fairport, NY 14450; Mr. K. Douglas Scribner President Mini City Ltd. 876 Turk Hill Road Fairport NY 14450; Dear Mr. Scribner: This responds to your recent letter seeking an interpretation o Standard No. 109, *New Pneumatic Tires--Passenger Cars* (49 CFR S571.109). Specifically, you were interested in learning whether that standard applies to tires for use on 'antique and classic automobiles.' You stated that your firm deals in tires which are authentic replacement tires for antique and classic cars, and that none of those tires has ever been marked with a DOT number. Standard No. 109 requires that all new pneumatic tires for use on passenger cars manufactured after 1948 be marked with DOT numbers, among other things, and there is no exception to this requirement for tires designed for 'classic' cars.; It is unclear when you refer to a 'DOT number' whether you ar referring to just the tire identification number, which is required to appear on all new tires for use on passenger cars manufactured after 1948 by 49 CFR Part 574, *Tire Identification and Recordkeeping*, or that identification number together with the symbol 'DOT.' The DOT symbol is a certification by the tire manufacturer that the tire complies with all the requirements of Standard No. 109. I have enclosed copies of both Standard No. 109 and Part 574 for your information.; In any event, Standard No. 109 applies to *all* new pneumatic tires fo use on passenger cars manufactured after 1948. Section S4.3.1 of the standard requires the DOT symbol to be permanently marked on the tire, while section S4.3.2 requires the tire identification number assigned to a manufacturer in accordance with Part 574 to be permanently marked on the tire. Standard No. 109 contains no provisions making an exception to these requirements.; Accordingly, if the antique and classic cars to which you refer wer manufactured in or before 1948, the tires are not subject to Standard No. 109 or Part 574. Sale of such tires would not violate any of this agency's requirements.; If, however, the tires are designed for use on cars manufactured afte 1948, the tires must comply with all requirements of Standard No. 109, including the requirements to have a DOT symbol and a tire identification number marked permanently on the sidewall. If you sell tires which are subject to, but do not comply with, the requirements of Standard No. 109, you would violate section 108(a)(1)(A) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1397(a)(1)(A)). Section 109 of that Act (15 U.S.C. 1398) specifies a maximum civil penalty of $1,000 for each violation of section 108, and this agency would consider each sale of a noncomplying tire to be a separate violation.; If you need any further information on this subject, please contac Steve Kratzke of my staff at this address or by telephone at (202) 426-2992.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1645OpenMr. Byron Crampton, Manager of Engineering Services, Truck Body and Equipment Association, Inc., 5530 Wisconsin Avenue, Suite 1220, Washington, DC 20015; Mr. Byron Crampton Manager of Engineering Services Truck Body and Equipment Association Inc. 5530 Wisconsin Avenue Suite 1220 Washington DC 20015; Dear Mr. Crampton: This responds to your October 3, 1974, questions whether the exemptio for 24,000-pound axle vehicles from Standard No. 121, *Air brake systems*, until September 1, 1976, applies to fire fighting vehicles, and whether a tandem axle assembly consists of two 'axle systems' for purposes of our definition of 'Gross axle weight rating.'; The answer to both of your questions is yes. A fire fighting vehicl would qualify for exemption until 1976 if any of its axles has a gross axle weight rating of 24,000 pounds or more.; A tandem axle assembly, which we understand to mean a running rea assembly consisting of two axles and associated components, comprises two 'axle systems.' As we pointed out in the preamble to Notice 2 of Docket No. 74- 10, the term 'axle system' is used only to avoid confusion in situations where a suspension system does not employ an axle (39 FR 17550, May 17, 1974).; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam3678OpenMr. T. J. Brown, Mohawk Rubber Company, Roanoke, VA 24017; Mr. T. J. Brown Mohawk Rubber Company Roanoke VA 24017; Dear Mr. Brown: This is in response to your March 28, 1983, letter to Roger Fairchil of this office, requesting confirmation of your understanding of the effective dates for the recent suspension of treadwear grading under this agency's Uniform Tire Quality Grading Standards.; Your understanding of the effective dates is correct. Tires produced i molds manufactured on or after August 8, 1983, must have the new grading format which excludes treadwear information. Tires produced in molds manufactured before that date may either use the new format as soon as feasible, to minimize the dissemination of misleading information with regard to tire treadwear.; With regard to labels, the requirement that such labels must contai information regarding treadwear grades was suspended effective February 7, 1983. The preamble to the final rule states that manufacturers will be permitted to exhaust inventories of labels which were in existence as of the date of the suspension. Thereafter, manufacturers should begin using labels without treadwear information.; If you have further questions on this matter, please feel free t contact us.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0957OpenMr. A. P. Hoynck Van Papendrecht, Technical External Relations, Van Doorne's Automobielfabrieken N. V., Endhoven, Holland; Mr. A. P. Hoynck Van Papendrecht Technical External Relations Van Doorne's Automobielfabrieken N. V. Endhoven Holland; Dear Mr. Van Papendrecht:#This is in reply to your letter of Novembe 12, 1972, about compliance of DAF cars with Federal Motor Vehicle Safety Standard No. 102.#Your question concerns the interpretation of paragraph S3.1.2. From your description in the letter and the description in the owner's manual, only one forward drive position is provided and engine braking can be achieved by actuating the transmission low ratio control switch. Under the conditions described above, the Variomatic transmission in DAF cars is not in violation with paragraph S3.1.2 of Standard No. 102. However, it appears that you do not comply with certain other paragraphs of the standard. For example, paragraph S3.1.1 requires that 'A neutral position shall be located between forward drive and reverse positions ....' and paragraph S3.1.3 requires that 'The engine starter shall be inoperative when the transmission shift lever is in a forward or reverse drive position.'#The DAF 66 owners manual dated September 1972, also indicates non-compliance with other standards, for example, 101, *Control Location, Identification and Illumination*, 114, *Theft Protection*, 115, *Vehicle Identification Number*, etc. It is recommended that all standards and regulations be checked for compliance.#A copy of 'Where to Obtain Motor Vehicle Safety Standards and Regulations' is enclosed for your review and information.#Sincerely, E. T. Driver, Director, Office of Operating Systems, Motor Vehicle Programs; |
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ID: aiam4447OpenMr. Jan Peter Kryger Vice President, Sales and Marketing Quickwheel, Inc. P.O. Box 39l Cos Cob, Connecticut 06830; Mr. Jan Peter Kryger Vice President Sales and Marketing Quickwheel Inc. P.O. Box 39l Cos Cob Connecticut 06830; "Dear Mr. Kryger: This responds to your letter asking whether an Federal safety standards apply to your product called 'Quickwheel' and whether you need approval from the Department of Transportation to market the product. You indicated that Quickwheel is similar to a roller skate and can be placed under a flat tire in a few seconds, enabling the driver to go on to a service station. You stated that the device has three little wheels and has been 'thoroughly tested' in Germany. The National Traffic and Motor Vehicle Safety Act (Safety Act) authorizes the National Highway Traffic Safety Administration (NHTSA) to issue 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. NHTSA does not provide approvals of motor vehicles or equipment. The Safety Act places the responsibility on the manufacturer to ensure that its vehicles or equipment comply with applicable requirements. The following represents our opinion based on the facts provided in your letter. NHTSA does not have any safety standards covering a roller-skate-like device intended to be placed under a flat tire in order to enable the driver to continue driving. However, should a safety-related defect be discovered in your device, whether by the agency or yourself, you as the manufacturer would be required by the Safety Act to notify purchasers and provide a remedy for the defect. While no Federal motor vehicle safety standards apply to Quickwheel, we note that the performance of the device is relevant to safety in many of the same respects as tires, which are covered by safety standards. Given this potential safety significance, we urge you to carefully review whether the testing conducted in Germany covered the full range of real-world driving conditions and experiences that may be encountered by Quickwheel, and if not, to conduct such additional testing and/or analysis as may be necessary to ensure that the product will perform in a safe manner. You also asked for an explanation of the Code of Federal Regulations. You will find such an explanation on the last page of an enclosed information sheet entitled 'Information for New Manufacturers of Motor Vehicles and Motor Vehicle Equipment.' You may also find other parts of the information sheet to be of interest. Sincerely, Erika Z. Jones Chief Counsel Enclosure"; |
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ID: aiam0462OpenMr. K. Krueger, Technical Development, Liason (sic) Engineer, Volkswagen of America, Inc., Englewood Cliffs, NJ 07632; Mr. K. Krueger Technical Development Liason (sic) Engineer Volkswagen of America Inc. Englewood Cliffs NJ 07632; Dear Mr. Krueger: This will serve to confirm your understanding that a retractor capabl of meeting the requirements for a vehicle-sensitive emergency-locking retractor under Standard No. 209 conforms to the Standard even though it is provided with a back-up webbing-sensitive retractor that locks only at webbing accelerations greater than those specified in Standard No. 209.; Sincerely, Lawrence R. Schneider, 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.