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: aiam3265OpenMr. Robert A. Eddy, Manager, Quality Assurance, McCreary Tire & Rubber Company, Indiana, PA 15701; Mr. Robert A. Eddy Manager Quality Assurance McCreary Tire & Rubber Company Indiana PA 15701; Dear Mr. Eddy: This is in response to your letter of March 7, 1980, asking whethe ASTM E501 and E524 tires must be graded in accordance with the Uniform Tire Quality Grading (UTQG) Standards (49 CFR 575.104). You state that these tires are manufactured in limited quantities as standards for traction testing and are not manufactured for general highway use. It is the National Highway Traffic Safety Administration's understanding that these tires are used only on a test trailer designed for use in skid testing.; The UTQG regulation applies to new pneumatic tires for use on passenge cars (49 CFR 575.104(c)(1)). Thus, ASTM E501 and E524, which are manufactured solely for use on a traction test trailer, would not fall within the application of the UTQG Standards.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0146OpenMr. Sam W. Folsom, Jr., Gold Cross Ambulance Service, Inc., 304 Northwest Tenth, Oklahoma City, OK 73103; Mr. Sam W. Folsom Jr. Gold Cross Ambulance Service Inc. 304 Northwest Tenth Oklahoma City OK 73103; Dear Mr. Folsom: This is in reply to your letter of January 18, 1969, to Dr. Willia Haddon, Jr., requesting information on Federal Motor Vehicle Safety Standards (FMVSS) applicable to ambulances.; If the ambulance is built on a passenger car chassis, all of the FMVS applicable to passenger cars would apply. However, if the ambulance is built on a truck chassis, the FMVSS applicable to multi-purpose passenger vehicles would apply. There have been no special exceptions granted for ambulances.; Enclosed for your information and guidance are copies of the Nationa Traffic and Motor Vehicle Safety Act of 1966 and the FMVSS established thereunder.; Sincerely, Francis Armstrong, Director, Office of Performance Analysis Motor Vehicle Safety Performance Service; |
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ID: aiam1178OpenMr. Donald W. Taylor, Engineering Liaison Representative, Volvo of America Corporation, Rockleigh, NJ 07647; Mr. Donald W. Taylor Engineering Liaison Representative Volvo of America Corporation Rockleigh NJ 07647; Dear Mr. Taylor: This is in reply to your letter of July 11, 1973, asking for a waive of 49 CFR S575.6(c) with respect to consumer information that Volvo of America would like to supply to prospective purchasers of 500 passenger cars beginning July 30, 1973.; There is no provision in the Consumer Information Regulation empowering the Administrator to waive the 30 day requirement and therefore we are unable to grant this request. We do not view the lack of this authority as unjust, given the purpose of the requirement 'so that there may be an evaluation and dissemination to the public of this information if deemed appropriate' (34F.R.11501).; We received your material on July 12, and the 30 day period will expir on August 11.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam3266OpenMr. Robert A. Eddy, Manager, Quality Assurance, McCreary Tire & Rubber Company, Indiana, PA 15701; Mr. Robert A. Eddy Manager Quality Assurance McCreary Tire & Rubber Company Indiana PA 15701; Dear Mr. Eddy: This is in response to your letter of March 7, 1980, asking whethe ASTM E501 and E524 tires must be graded in accordance with the Uniform Tire Quality Grading (UTQG) Standards (49 CFR 575.104). You state that these tires are manufactured in limited quantities as standards for traction testing and are not manufactured for general highway use. It is the National Highway Traffic Safety Administration's understanding that these tires are used only on a test trailer designed for use in skid testing.; The UTQG regulation applies to new pneumatic tires for use on passenge cars (49 CFR 575.104(c)(1)). Thus, ASTM E501 and E524, which are manufactured solely for use on a traction test trailer, would not fall within the application of the UTQG Standards.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1030OpenMr. Bill B. Wiggins, Wiggins & Christian, 602 First Federal Building, Post Office Box 994, Fort Smith, AR 72901; Mr. Bill B. Wiggins Wiggins & Christian 602 First Federal Building Post Office Box 994 Fort Smith AR 72901; Dear Mr. Wiggins: This is in response to your letter of February 27, 1973, concerning th application of the new Federal Odometer Disclosure Requirements to transfers between dealers.; The Federal requirements apply, with certain exceptions, to eac transfer of ownership of a motor vehicle. Some types of vehicles, such as heavy trucks and antique vehicles, are exempt. Passenger cars and lighter vehicles, however, are exempted only in the case of transfers of *new* vehicles from a manufacturer or a distributor to a dealer or from one dealer to another. The transfer of a *used* car or light truck, whether from dealer to dealer, dealer to wholesaler, or dealer to customer, must be accompanied by a disclosure statement.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4702OpenMr. Satoshi Nishibori Nissan Research & Development, Inc. 750 17th Street N.W., Suite 902 Washington, D.C. 20006; Mr. Satoshi Nishibori Nissan Research & Development Inc. 750 17th Street N.W. Suite 902 Washington D.C. 20006; "Dear Mr. Nishibori: This responds to your January 16, 1990 letter t Mr. Robert Hellmuth, the Director of this agency's Office of Vehicle Safety Compliance, seeking an interpretation of Standard No. 120, Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars (49 CFR 571.120). Specifically, S5.1.2 of Standard No. 120 provides that when a passenger car tire is used on vehicles other than passenger cars, the tire's load rating shall be reduced by dividing it by 1.10 before calculating the sum of the load ratings of all of the original equipment tires on the vehicle. S5.3.2 through S5.3.5 establish requirements for certain information about the tires and rims to be labeled on the vehicle. S5.3.2 sets forth lettering size and format requirements for the labeling. S5.3.3 through S5.3.5 require the labeling to provide the following information: the 'size designation of tires....appropriate (as specified in S5.1.2) for the GAWR' be given on the label, the size and type designation of rims 'appropriate for those tires', and the 'cold inflation pressure for those tires'. Your question was whether the cold inflation pressure set forth on the label in response to S5.3.5 of Standard No. 120 must reflect the 1.1 reduction factor set forth in S5.1.2 for passenger car tires. You suggested in your letter, and in your January 18, 1990 meeting with agency staff, that S5.3.5 does not require the 1.1 reduction factor to be taken into account when determining the cold inflation pressure to be specified. Instead, you suggested that Standard No. 120 requires the vehicle manufacturer to specify an inflation pressure that is adequate to support the tire's share of the gross axle weight rating (GAWR), without regard to the 1.1 reduction factor. I cannot agree with your suggested interpretation. You asserted that S5.3.5 merely requires the label to include the 'cold inflation pressure for those tires,' without referring to S5.1.2 and its 1.1 reduction factor. You contrasted this requirement with that in S5.3.3, which expressly refers to S5.1.2 and the 1.1 reduction factor. You asserted that this difference in wording showed that the 1.1 reduction factor need not be considered when specifying the cold inflation pressure on the label in response to S5.3.5. This argument is not persuasive. The load-carrying capability of a tire generally varies with the inflation pressure of that tire, i.e., a tire can carry a greater load at a higher inflation pressure and a lesser load at a lower inflation pressure. Hence, a reference to inflation pressure alone, without any corresponding load-carrying capability to which that inflation pressure applies would be meaningless. If S5.3.5 of Standard No. 120 were interpreted to require the manufacturer to specify some inflation pressure, without regard to any load that must be borne by the tire at that inflation pressure, the vehicle manufacturer could specify an extremely high or low inflation pressure. Such a specification would be useless or even dangerous for the consumer, and contrary to the purposes of the labeling requirements. You implicitly recognize that such an interpretation is unacceptable when you argue on page 1 of your January 16, 1990 that S5.3.5 of Standard No. 120 must be interpreted to require the manufacturer to recommend an inflation pressure 'that will permit the tires to safely carry Gross Axle Weight Rating loads and will provide good vehicle ride characteristics.' In other words, Nissan agrees that the inflation pressure specified in response to S5.3.5 cannot be an extreme value such as 1 psi, instead, it must be determined with reference to some load that the tires will carry. The question then becomes what loading must be considered to determine if the specified inflation pressure complies with S5.3.5. This question is answered by reading the labeling requirement of S5.3.5 in connection with the other labeling requirements in S5.3, instead of considering S5.3.5 in a vacuum. S5.3.2 sets forth the format and lettering size for the labels to be placed on all vehicles manufactured on or after December 1, 1984. The information that must appear on such labels is set forth in S5.3.3, S5.3.4, and S5.3.5 of Standard No. 120. S5.3.3 specifies that the label shall include information on 'the size designation of tires (not necessarily those on the vehicle) appropriate (as specified in S5.1.2) for the GAWR.' (Emphasis added). On any reading of this emphasized language, it is beyond dispute that the 1.1 reduction factor set forth in S5.1.2 must be considered when specifying the appropriate tire size designation pursuant to S5.3.3. Following this, S5.3.4 requires information on the size and type designation of rims 'appropriate for those tires' to appear on the label. The reference to 'those' tires in S5.3.4 indicates that the tires are the tires previously specified in S5.3.3. Similarly, when S5.3.5 requires the cold inflation pressure for those tires to appear on the information label, the language is referring back to the tires specified in S5.3.3. Since NHTSA agrees with your statements that S5.3.3 incorporates the 1.1 reduction factor of S5.1.2 to determine compliance with S5.3.3, and since S5.3.5 refers to the tires specified in S5.3.3, the 1.1 reduction factor set forth in S5.1.2 must be considered to determine ocmpliance with S5.3.5 of Standard No. 120. Sincerely, Stephen P. Wood Acting Chief Counsel"; |
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ID: aiam5425OpenMs. Doris Hull Owner Sikeston Trailer Sales, Inc. Route 2, Box 2291 Sikeston, MO 63801; Ms. Doris Hull Owner Sikeston Trailer Sales Inc. Route 2 Box 2291 Sikeston MO 63801; Dear Ms. Hull: This responds to your letter of May 16, 1994, addresse to Mr. Robert Hellmuth, whom you identified as Chief Counsel. For your future information, Mr. Hellmuth is Chief of the Office of Vehicle Safety Compliance of this agency. I am the Acting Chief Counsel. Your letter referred to a May 13, 1994 telephone conversation that you and Mr. David McCormick had with Walter Myers of my staff concerning new and used tires on trailers. You asked for confirmation of your understanding of what was said during that conversation, as follows: (a) That as a trailer manufacturer you can sell to a dealer new trailers that are stacked one on top of the other, with new tires on the bottom trailer but no tires or wheels on the stacked trailers, (b) That you can sell used tires and rims but not installed on the new trailers, and (c) That you can separately sell used tires and rims to the purchaser of a trailer, then install them on the new trailer if the purchaser so requests. FMVSS No. 120, Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars (copy enclosed) provides that vehicles equipped with pneumatic tires for highway service shall be equipped with tires that meet the requirements either of FMVSS 109, New Pneumatic Tires, or FMVSS No. 119, New Pneumatic Tires for Other Than Passenger Cars. Both those standards specify requirements for new tires. As an exception to those requirements, however, paragraph S5.1.3 of FMVSS No.120 provides that: A truck, bus, or trailer may at the request of the purchaser be equipped at the place of manufacture of the vehicle with retreaded or used tires owned or leased by the purchaser, . . . Used tires employed under this provision must have been originally manufactured to comply with Standard No. 119, as evidenced by the DOT symbol (emphasis added). With that background in mind, your understanding (a) above is correct. You stated to Mr. Myers that it is common practice in the industry to stack completed trailers one on top of another for shipment, with the bottom trailer being equipped with new tires. This office stated in a letter to Mr. Steve Thomas dated April 14, 1993 (copy enclosed), that new trailers may be sold without tires and wheels. Accordingly, it is permissible to ship trailers without tires and wheels, with new tires on the bottom trailer that is carrying the others. Your understanding (b) is also correct, but with a caveat. No provision of Federal law or regulation prohibits you from separately selling used tires and wheels that you own to anyone you want, including dealers. However, the practice you describe implies that the dealer will be installing the used tires you've provided on the new trailers, which would amount to a violation of Standard No. 120. The standard specifically provides that used or retreaded tires may be installed on new vehicles only at the place of manufacture, the dealer is not permitted to install used tires on new trailers, whether or not owned and requested by the purchaser. Further, a manufacturer that includes used tires with new vehicles, even though not installed on the new vehicle, could be considered to be contributing to a potential violation of the Federal motor vehicle safety standards by the dealer. With respect to understanding (c), S5.1.3, as noted above, requires that used or retreaded tires installed on a new vehicle be owned or leased by the purchaser of the vehicle. The standard, however, does not specify any length of time that the used or retreaded tires must be owned or leased by the vehicle purchaser, nor does the standard specify the source(s) from which the purchaser must have acquired the used or retreaded tires. Therefore, there is no prohibition against the purchaser of a trailer purchasing used or retreaded tires from a trailer manufacturer or from any other source, then requesting the manufacturer to install them on the new trailer. However, we have the following observations about the practice. The used/retreaded tire exception in S5.1.3 was included in the standard to accommodate bus and truck fleets who either purchase or lease tires on a mileage contract basis or who maintain tire banks. A mileage contract purchaser or lessor is one who purchases or leases tires on a per-mile basis. A tire bank is composed of serviceable tires that have been removed from vehicles no longer in service. Mileage contract purchases and tire banks are standard practices in the transportation industry and the agency assumed that those purchasers would select only safe, serviceable tires from their inventories for installation on their new vehicles. The agency also assumed that those purchasers would have owned and used those tires for some length of time prior to their being selected for installation on new vehicles. Thus, the practice of a new vehicle purchaser purchasing used tires from a trailer manufacturer and then asking the manufacturer to install them on the new vehicle was not envisioned by this agency when issuing Standard No. 120. None of the above would relieve trailer manufacturers from their responsibility to attach the required labels with the recommended tire and rim sizes and inflation pressures in accordance with 49 CFR Part 567. I hope this information is helpful to you. Should you have any further questions or need additional information, please feel free to contact Mr. Myers at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosure; |
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ID: aiam4435OpenThe Honorable Beverly B. Byron Member of Congress U.S. House of Representatives Westminster District Office 6 North Court Street Westminster, MD 21157; The Honorable Beverly B. Byron Member of Congress U.S. House of Representatives Westminster District Office 6 North Court Street Westminster MD 21157; "Dear Ms. Byron: Thank you for your recent letter on behalf of you constituent, Mr. Joseph L. Ciampa, Jr., who received a citation from the Maryland State Police, Automotive Safety Enforcement Division, for noncomplying window tinting. You asked us to review Mr. Ciampa's letter and provide you with our comments and appropriate information. I am pleased to have the opportunity to do so. Mr. Ciampa suffers from diabetes, which makes his eyes extremely sensitive to sunlight. Because of this, the side windows on his passenger automobile apparently were tinted such that the tinted glazing no longer complied with State of Maryland requirements. There is no indication whether Mr. Ciampa did the tinting on his own or had an aftermarket business do it. According to Mr. Ciampa's letter, he was previously given a medical exemption by the State of Maryland that permitted him to drive with windows tinted differently than Maryland law permits. However, Mr. Ciampa stated that Maryland officials have now told him that the Federal government will not allow Maryland to grant any more medical exemptions. This information is inaccurate. Some background information on the Federal requirements in this area may be helpful. Our agency, the National Highway Traffic Safety Administration (NHTSA) is authorized, under the National Traffic and Motor Vehicle Safety Act, to issue safety standards applicable to new motor vehicles and certain items of motor vehicle equipment. The safety standard that specifies performance and location requirements for glazing used in vehicles is Standard No. 205, Glazing Materials (49 CFR 571.205). These requirements include specifications for minimum levels of light transmittance (70 percent in areas requisite for driving visibility, which includes all windows in passenger cars). Under Standard 205 no manufacturer or dealer is permitted to install solar films and other sun screen devices in a new vehicle, without certifying that the vehicle continues to be in compliance with the light transmittance and other requirements of the standard. Federal law does not permit States to grant any exemptions, including medical exemptions, from the safety standards. Thus, we assume that Mr. Ciampa's car as delivered to him complied with Standard No. 205's requirement for at least 70 percent light transmittance in all of its windows, including the side windows that are now the subject of dispute. The requirement that a car comply with all applicable safety standards applies only until the car is first sold to a consumer. After a vehicle is first sold to a consumer, any modifications to the vehicle's windows, including the tinting performed on the side windows of Mr. Ciampa's car, are affected by section 108(a)(2)(A) of the Safety Act. That section prohibits any manufacturer, dealer, distributor, or repair business from 'rendering inoperative' any device or element of design installed in a vehicle in compliance with any safety standard. In the case of windows in a passenger car, this means that no manufacturer, dealer, distributor, or repair business could install a sun screen device or window tinting that would result in a light transmittance of less than 70 percent for any window of the car, or otherwise cause the car to no longer comply with the other requirements of Standard No. 205. Violations of this 'render inoperative' prohibition can result in Federal civil penalties to the manufacturer, dealer, distributor, or repair business of up to $1000 for each noncomplying installation. Again, Federal law does not permit States to grant any exemptions, including medical exemptions, from the 'render inoperative' prohibition in Federal law. Thus, the State of Maryland does not have any authority to permit manufacturers, distributors, dealers, or repair businesses to install tinting on the side windows of passenger cars if such tinting causes those windows to have less than 70 percent light transmittance. Instead, the manufacturer, distributor, dealer, or repair business that installed such tinting on Mr. Ciampa's side windows would be liable for the civil penalty discussed above. Please note that Federal law does not affect vehicle owners. Vehicle owners may alter their own vehicles and operate them on the highways as they please, even if the vehicle's windows no longer comply with the requirements of Standard No. 205. Hence, no provision of Federal law or this agency's regulations prevents Mr. Ciampa himself from tinting his side windows. However, each of the individual States has the authority to regulate the modifications that may be made to vehicles by their owners and to establish requirements for vehicles to be registered or operated in that State. It would seem that the State of Maryland has exercised its authority to prohibit windows being tinted in the way that Mr. Ciampa's are. The wisdom and fairness of applying that prohibition to individuals with Mr. Ciampa's condition is something to be decided by the State of Maryland, not the Federal government. Contrary to the statement in Mr. Ciampa's letter, we have never told Maryland or any other State how to administer their laws and regulations with respect to the operational use of vehicles in the State. I hope this information is helpful. If you have any further questions or need some more information on this subject, please do not hesitate to contact Ms. Susan Schruth of my staff at this address, or by telephone at (202) 366-2992. Sincerely, Erika Z. Jones Chief Counsel cc: Washington Office Constituent's Correspondence"; |
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ID: aiam0199OpenMr. Bernard Belier, U. S. Resident Engineer, U. S. Technical Research Corporation, 801 Second Avenue, New York, NY 10017; Mr. Bernard Belier U. S. Resident Engineer U. S. Technical Research Corporation 801 Second Avenue New York NY 10017; Dear Mr. Belier: This is in reply to your letter, dated November 11, 1969, in which yo seek an interpretation as to how Federal Motor Vehicle Safety Standards (FMVSSs) 103 and 104 are applicable to cars equipped with right-hand drive or a central steering wheel.; For motor vehicles equipped with right-hand drive, the windshield area to be defrosted and wiped by FMVSSs 103 and 104 respectively, are mirror images of those areas required for vehicles equipped with left-hand drive.; More information is required before a reply can be given on vehicle equipped with a central steering wheel. Defrosting and wiping areas requirements would naturally vary depending on the number and location of the front seat passenger seating positions in the vehicle equipped with a central steering wheel.; We trust that we have been of assistance to you. Sincerely, Robert Brenner,Acting Director |
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ID: aiam2414OpenHonorable Leonor K. Sullivan, House of Representatives, Washington, DC 20515; Honorable Leonor K. Sullivan House of Representatives Washington DC 20515; Dear Mrs. Sullivan: This is in response to your September 20, 1976, letter concernin record keeping with respect to new passenger cars that are damaged prior to retail sale.; I would like to clarify the discussion of record requirements in m September 14, 1976, letter to you. While the National Highway Traffic Safety Administration (NHTSA) does not require vehicle manufacturers to create records of safety-related repairs that are made to new motor vehicles prior to sale, we do require the *retention* of all such records that are in fact created by the manufacturer. Through such records, the NHTSA can in many cases trace the history of vehicles suspected of containing safety- related defects. We have not to date found a safety need sufficient to justify further requirements specifically regarding identification of the vehicles in question.; A copy of the record retention regulation, 49 CFR Part 576, is enclose for your convenience.; Sincerely, John W. Snow, Administrator |
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.