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: aiam3860OpenMichael S. Rosenthal, Esq., Assistant Attorney General, State of Georgia Department of Law, 132 State Judicial Building, Atlanta, GA 30334; Michael S. Rosenthal Esq. Assistant Attorney General State of Georgia Department of Law 132 State Judicial Building Atlanta GA 30334; Dear Mr. Rosenthal: This is in response to your letter of October 21, 1983 inquiring as t policy of the National Highway Traffic Safety Administration with respect to routine use by dealers of the 'unknown' block on Odometer Disclosure Statements when there is no actual knowledge that the mileage shown on the odometer is not accurate. I apologize for the delay in answering your inquiry.; On several occasions in the past, this office has issued interpretatio letters expressing disapproval of the practice you describe. I have enclosed copies of three such letters, dated November 14, 1978, February 3, 1978, and October 28, 1976, for your information. It is our position that a statement by the transferor on the odometer disclosure statement that the mileage is unknown when he has no actual knowledge that the mileage is inaccurate significantly inhibits enforcement of the Federal odometer law (Title IV of the Motor Vehicle Information and Cost Savings Act, 15 U.S.C. SS1981-19991 (sic)) by making it more difficult to trace violations through the chain of title.; I hope you find this information helpful. Sincerely, David W. Allen, Assistant Chief Counsel |
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ID: aiam2772OpenMr. James J. Kearney, Vice President, Baltimore Cycles, Inc., 6020 Eastern Avenue, Baltimore, Maryland 21224; Mr. James J. Kearney Vice President Baltimore Cycles Inc. 6020 Eastern Avenue Baltimore Maryland 21224; Dear Mr. Kearney: This is in reply to your letter of January 12, 1978, asking whether th braking system on your Casal mopeds meets Federal requirements.; Table 1 of Federal Motor Vehicle Safety Standard No. 123, *Motorcycl Controls and Displays*, requires that the control for read brakes on motorcycles shall be located at the right foot control (with the option of the left handlebar permissible for motor driven cycles such as mopeds) and operate by depressing to engage. The rear brake on the Casals moped in operated by 'back peddling, similar to a bicycle.' We understand that this is accomplished by application of force to the right foot pedal.; We have concluded that this system meets the requirements of th standard, since the brake is engaged by depressing the right foot pedal.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam2288OpenMr. Thomas Kupensky, 4136 Loganway, Youngstown, OH, 44505; Mr. Thomas Kupensky 4136 Loganway Youngstown OH 44505; Dear Mr. Kupensky: This is in reply to your letter of April 8 to the Department o Transportation, regarding your CAUTION and THANK YOU signals which would flash simultaneously with the turn signal lamps on trucks and trailers.; Since such signs, flashing CAUTION or THANK YOU when actually 'turn' i intended, may be confusing in many circumstances, they would be prohibited by paragraph S4.1.3 of Federal Motor Vehicle Safety Standard (FMVSS) No. 108, 'Lamps, Reflective Devices and Associated Equipment,' (copy enclosed), because they would appear to impair the effectiveness of the turn signals. If these signs were manually operated by the driver, separately from the turn signals, at appropriate times, whether flashing or steady burning, they would be considered auxiliary devices which did not impair the effectiveness of the turn signals, and would be permitted by Standard No. 108. In this situation, however, they would be subject to the motor vehicle regulation of the individual States.; Sincerely, E. T. Driver, Director, Office of Crash Avoidance, Moto Vehicle Programs; |
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ID: aiam5058OpenMr. C. Morris Adams 1201 Rockford Road High Point, NC 27260; Mr. C. Morris Adams 1201 Rockford Road High Point NC 27260; "Dear Mr. Adams: This responds to your FAX of September 24, 1992 requesting a ruling regarding the legality of lap belts at the passenger seats on school buses. As explained below, Federal law has long required lap or lap/shoulder belts to be installed at every passenger seating position on small school buses. Federal law has also long permitted, but not required, lap or lap/shoulder belts to be installed at passenger seating positions on large school buses, provided that those belts do not adversely affect the large school bus's compliance with the applicable safety standards. This is still the agency's position. As you know, in 1977, NHTSA issued Federal Motor Vehicle Safety Standard No. 222, School Bus Passenger Seating and Crash Protection, which established minimum levels of crash protection that must be provided for occupants of all school buses. For large school buses (those with a gross vehicle weight rating GVWR of more than 10,000 pounds), the standard requires occupant protection through a concept called 'compartmentalization' -- strong, well-padded, well- anchored, high-backed, evenly spaced seats. Small school buses (those with a GVWR of 10,000 pounds or less) must provide 'compartmentalization' and be equipped with lap or lap/shoulder belts at all passenger seating positions. The agency believes that safety belts are necessary in addition to 'compartmentalization' in small school buses because of their smaller size and weight, which are closer to that of passenger cars and light trucks. Ever since 1977, NHTSA has indicated that Federal law permits lap or lap/shoulder belts to be installed at the passenger seating positions on large school buses as long as the vehicle would still comply with all applicable safety standards, including Standard No. 222. NHTSA has no information to indicate that installation of seat belts at the passenger seating positions on a large school bus would affect the bus's compliance with any safety standard.The allegations in your FAX that using seat belts in large school buses will result in crash forces producing concentrated loading on the head, instead of being spread evenly over the upper torso as is the case without a seat belt, are nearly identical with the explanations included in a 1985 Transport Canada report on school bus safety. NHTSA carefully evaluated and considered the Canadian report and these explanations in connection with its rulemaking action considering whether to specify requirements for voluntarily installed seat belts on large school buses. 54 FR 11765, March 22, 1989. After fully considering the Canadian report, the agency stated at 54 FR 11770: NHTSA shares commenters' concerns about any implications that safety belts negatively affect the protection provided to passengers on large school buses. However, the agency is not aware of accident data showing an injury caused or made more serious by the presence of safety belts on a school bus. Furthermore, NHTSA cannot conclude from the Canadian report's findings that belts actually degrade the benefits of compartmentalization to the extent that the supplemental restraint system renders inoperative the safety of large school buses, but the possibility exists that the occupant kinematics shown in the Canadian tests could occur. The agency then identified some possible safety benefits that could result from seat belts in large school buses, benefits that were not considered in the Canadian tests. The agency concluded that, 'Although these benefits are not significant enough to justify a Federal requirement for the installation of safety belts on all large school buses, they are enough to provide a basis upon which the agency will decline to prohibit the installation of belts on large school buses.' 54 FR 11765, at 11770, March 22, 1989. I have enclosed a copy of this notice for your information. As you can see, NHTSA has carefully considered the subject raised in your FAX and reviewed all available information in this area. After that review, the agency concluded that there was no justification for changing its longstanding position that persons that wish to do so should be permitted to install seat belts at passenger seating positions in large school buses. Your letter did not provide any data that NHTSA had not already considered. Hence, there is no basis for the agency to change its longstanding position in this area. I hope you find this information helpful. If you have any other questions, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosure"; |
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ID: aiam2267OpenMr. W. G. Milby, Staff Engineer, Blue Bird Body Company, P.O. Box 937, Fort Valley, GA 31030; Mr. W. G. Milby Staff Engineer Blue Bird Body Company P.O. Box 937 Fort Valley GA 31030; Dear Mr. Milby: This responds to Blue Bird Body Company's March 22, 1976, request fo interpretation of the provision of Standard No. 217, *Emergency Exits*, that requires unobstructed passage of a described parallelepiped through the opening provided by an open rear emergency door in the case of a school bus with a gross vehicle weight rating of more than 10,000 pounds (S5.4.2(a)). The dimensions of the parallelepiped are 45 inches by 24 inches by 12 inches, and it is oriented so that the 45-inch dimension is vertical, the 24-inch dimension is parallel to the opening, and the lower surface is in contact with the bus floor.; You point out that unobstructed passage' through the opening could b considered to occur when the rearmost surface of the parallelepiped coincides with a vertical transverse plane that intersects the outer surface of the bus body at either the top or the bottom of the opening, or intersects the inner surface of the bus body at either the top or the bottom of the opening.; The NHTSA considers unobstructed passage of the parallelepiped to occu when its rearmost surface coincides with the vertical transverse plane that intersects the outer surface of the bus body at the bottom of the opening in question. Thus, your intention to assure compliance by measuring unobstructed passage at the point when the rearmost surface is flush with the bus body outer surface appears justified. The agency does not consider the bus body outer surface to include rub rails or trim materials for purposes of this measurement.; Yours truly, Frank Berndt, Acting Chief Counsel |
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ID: aiam5408OpenMrs. Carmen Colet Vice President John Russo Industrial, Inc. 575 West San Carlos Street San Jose, CA 95126; Mrs. Carmen Colet Vice President John Russo Industrial Inc. 575 West San Carlos Street San Jose CA 95126; "Dear Mrs. Colet: This responds to your request for an interpretatio whether Standard No. 115, Vehicle identification number - basic requirements or any other Federal Motor Vehicle Safety Standard (FMVSS) applies to your 'aircraft rescue and fire- fighting vehicle.' As explained below, the answer is no. Your letter states that your company is constructing the vehicle 'to satisfy proposed U.S.A.F. and D.O.D.' specifications. The vehicle is made to operate on airfields. You described the unusual configuration of the vehicle as having a 'cockpit' that is 'similar to 117A Stealth Fighter,' having bumpers that are 5 feet high, and having a 'power water turret on top.' You further stated that vehicle uses tires 54 inches high and over two feet wide, that are made to be run on only for 20 minutes, at a speed of up to 65 miles per hour. Enclosed with your letter is a picture of the vehicle, which you asked be kept confidential. Although your request for confidentiality does not comply with NHTSA's regulations at 49 CFR part 512 Confidential Business Information, in order to save time, I will not publicly disclose the picture. The FMVSSs apply only to 'motor vehicles,' within the meaning of 49 U.S.C. 30102(a)(6). 'Motor vehicle' is defined at section 30102(a)(6) as: a vehicle driven or drawn by mechanical power and manufactured primarily for use on public streets, roads, and highways, but does not include a vehicle operated only on a rail line. We have interpreted this language to mean that vehicles designed and sold solely for off-road use are not considered motor vehicles, even though they may be operationally capable of highway travel. In an interpretation letter of December 28, 1979, to Walter Motor Truck Company, NHTSA determined that the Walter airport crash-fire-rescue vehicle does not qualify as a motor vehicle subject to the FMVSS. Your description of your aircraft rescue vehicle indicates that the vehicle is to be used only within an airfield. In particular, the size and 20 minute running time of the tires, appears to make the vehicle impracticable for highway use. Based on the information you have provided, and our understanding that your vehicles are neither used on public roads nor suitable for such use, we conclude that the 'aircraft rescue and fire-fighting vehicle' is not a 'motor vehicle' within the meaning of the National Traffic and Motor Vehicle Safety Act. Thus, your vehicle is not subject to Standard No. 115. Since you are not a manufacturer of a 'motor vehicle,' you do not have to furnish NHTSA with information pursuant to 49 CFR part 566 Manufacturer Identification. Enclosed with this letter is your picture of the aircraft rescue and fire- fighting vehicle. If you have any questions, please contact Dorothy Nakama of my staff at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosure"; |
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ID: aiam3925OpenMr. Jeffrey Richard, JBR Manufacturing, P.O. Box 415, Fairfield, IA 52556; Mr. Jeffrey Richard JBR Manufacturing P.O. Box 415 Fairfield IA 52556; Dear Mr. Richard: This responds to your letter inquiring about the Federal safet standards that would apply to a product you are planning to sell. You stated that the product is a 6 inch by a 4 inch sheet of 1/8 inch thick semi-transparent rubber that is held on a side window of a vehicle by four suction cups. The purpose of the sheet is to shield vehicle occupants from the sun. The following discussion explains the applicability of our safety standards to your sun screen.; Pursuant to the National Traffic and Motor Vehicle Safety Act, we hav issued Federal Motor Vehicle Safety Standard No. 205, *Glazing Materials,* (49 CFR 571.205) which specifies performance and location requirements for glazing used in vehicles. These requirements include specifications for minimum levels of light transmittance (70% in areas requisite for driving visibility, which includes all windows in passenger cars).; Any manufacturer, dealer or other person who installs tinting films o other sun screen devices, such as those described in your letter, in *new* vehicles must certify that the vehicle as altered, continues to comply with the requirements of the standard. Thus, for example, the light transmittance through the combination of the sun-screening material and the glazing must be at least 70 percent in the case of glazing used in windows requisite for driving visibility. Similarly, the combination must also meet the other applicable requirements of the standard, such as the abrasion resistance requirements.; After a vehicle is sold to the consumer, owners may alter thei vehicles as they please, so long as they adhere to all State requirements. Under Federal law, an owner may install any device regardless of whether the installation adversely affects light transmittance. The agency does, however, urge owners not to install equipment which would render inoperative the compliance of a vehicle with our standards. Individual States govern the operational use of vehicles by their owners and therefore it is within the authority of the States to preclude owners from applying sun screens on their vehicles.; If a manufacturer, dealer, distributor or motor vehicle repair busines installs the sun screen device for the owner of a used vehicle, then S108(a)(2)(A) of the Vehicle Safety Act may apply. That section provides that none of those persons may knowingly render inoperative any 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. Violation of the 'render inoperative' provision can result in Federal civil penalties of up to $1,000 for each violation.; I am enclosing the sample of your product you sent with your letter. I you need further information, the agency will be glad to provide it.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam1918OpenMr. A. L. Aslan, Aslan Truck Service, P.O. Box 291, Kingsburg, CA 93631; Mr. A. L. Aslan Aslan Truck Service P.O. Box 291 Kingsburg CA 93631; Dear Mr. Aslan: Thank you for your letter of April 15, 1975, explaining your reason for not purchasing bulk agricultural commodity trailers that conform to the requirements of Standard No. 121, *Air brake systems*. You said that you expect that the new systems will be disabled or destroyed by rough usage in the fields, and that you intend to manufacture trailers that do not conform to the standard.; We have no reason to believe that the new axle systems will be mor susceptible to field hazards than are present systems. Most antilock systems are designed so that the outboard sensor is enclosed in the hub and the wiring harness is routed inside the axle to the antilock module. There are antilock systems that incorporate the antilock module and air valve in the same location as the relay valve found on pre-121 vehicles. We therefore expect little change in the susceptibility of these vehicles to field hazards.; You stated that you intend to manufacture air-braked trailers for you own use which do not comply with Standard No. 121. The National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1391, et seq.) prohibits the manufacture of non-complying vehicles after the effective date of an applicable standard as follows:; >>>S 1397(a)(1) No person shall -- (A) manufacture for sale, sell, offer for sale, or introduce or delive for introduction in interstate commerce, or import into the United States, any motor vehicle or item of motor vehicle equipment manufactured on or after the date any applicable Federal motor vehicle safety standard takes effect under this subchapter unless it is in conformity with such standard except as provided in subsection (b) of this section, . . .<<<; From your description, your plans to build vehicles which woul subsequently be introduced in interstate commerce (i.e., driven on the public highway) would appear to be in violation of this section. Civil penalties of up to $1,000 per violation can be assessed under S 1398 of the Act.; I am interested in hearing form you on your experience with Standar No. 121 if you choose to purchase any complying vehicles. In any case, I would like to assure you that the National Highway Traffic Safety Administration (NHTSA) is in the process of monitoring the standard's economic impact. The NHTSA will attempt to identify any modifications that would lower the standard's cost while achieving comparable levels of safety.; Sincerely, James B. Gregory, Administrator |
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ID: aiam2637OpenMr. John B. White, Engineering Manager, Technical Information Dept., Michelin Tire Corporation, New Hyde Park P.O., P.O. Box 3467, New York 11040; Mr. John B. White Engineering Manager Technical Information Dept. Michelin Tire Corporation New Hyde Park P.O. P.O. Box 3467 New York 11040; Dear Mr. White: This responds to your June 7, 1977, letter asking who must mark a ri in accordance with the requirements of Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*, in those cases where the rim is manufactured by one manufacturer and then supplied to a wheel manufacturer who welds the rim to a disk making a completed wheel.; The National Traffic Safety Administration has determined that the ri marking must be undertaken by the rim manufacturer. The rim manufacturer is best able to supply the required rim information and undertake the certification required by S5.2 of the standard. The subsequent addition of the disc to the rim should not alter the information marked on the rim.; Sincerely, Joseph J., Levin, Jr., Chief Counsel |
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ID: aiam4649OpenMr. Jim Bowen Vice President of Quality, Service and Parts Gulf Stream Coach, Inc. P.O. Box l005 Nappanee, IN 46550; Mr. Jim Bowen Vice President of Quality Service and Parts Gulf Stream Coach Inc. P.O. Box l005 Nappanee IN 46550; "Dear Mr. Bowen: This responds to your letter concerning th installation of a television receiver in view of the driver of a vehicle. You asked whether the television is required to be off, when the ignition switch is turned on. I regret the delay in responding. Your question is responded to below. By way of background information, the National Highway Traffic Safety Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its vehicles and equipment meet applicable standards. The following represents our opinion based on the facts provided in your letter. I have enclosed a copy of a June 4, l987 letter, addressed to Panasonic, which discusses a number of issues relating to the installation of television receivers in motor vehicles. The letter notes that NHTSA does not have any safety standards specifically covering television receivers. The letter also explains that is possible that the installation of a television receiver could affect the compliance of a vehicle with some safety standards. With respect to your specific question concerning whether a television receiver installed in view of the driver of a vehicle is required to be off when the ignition is turned on, I would like to draw your attention to one requirement of Standard No. l0l, Controls and Displays. Section S5.3.5 of that standard reads as follows: Any source of illumination within the passenger compartment which is forward of a transverse vertical plane 4.35 inch (ll0.6 mm) rearward of the manikin 'H' point with the driver's seat in its rearmost driving position, which is not used for the controls and displays regulated by this standard, which is not a telltale, and which is capable of being illuminated while the vehicle is in motion, shall have either (l) light intensity which is manually or automatically adjustable to provide at least two levels of brightness, (2) a single intensity that is barely discernible to a driver who has adapted to dark ambient roadway conditions, or (3) a means of being turned off. This requirement does not apply to buses that are normally operated with the passenger compartment illuminated. The purpose of this requirement is to prevent glare visible to the driver. If a television receiver installed in view of the driver is capable of operation while the vehicle is in motion, it would be subject to this requirement. While NHTSA does not have any safety standards specifically covering television receivers, the installation of a television receiver in view of the driver which is capable of operation while the vehicle is in motion would raise obvious safety concerns related to possible driver distraction. If you are considering such installation, we recommend that you carefully evaluate the safety implications of such action. Finally, I note that state laws may cover the installation of television receivers in motor vehicles. The American Association of Motor Vehicle Administrators may be able to provide information on that issue. Its address is: 4200 Wilson Boulevard, Suite 600, Arlington, Virginia 22203. Sincerely, Stephen P. Wood Acting 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.