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: aiam3132OpenMr. H. J. T. Young, Vice President - Technical Affairs, SEV Corporation, 33201 Harper Avenue, St. Clair Shores, MI 48082; Mr. H. J. T. Young Vice President - Technical Affairs SEV Corporation 33201 Harper Avenue St. Clair Shores MI 48082; Dear Mr. Young: This is in reply to your letter of September 24, 1979, to Mr. Vinson o this office asking for an interpretation of Federal Motor Vehicle Safety Standard No. 108.; You referred to the SAE standard on motorcycle headlamps, J584, whic specifies that the 'bulb or unit shall be operated at its rated voltage during the [photometric] test.' You asked whether the 'rated voltage' of J584 is the same rated voltage of ECE Regulation 37 when the bulb in question is a European bulb bearing an E mark signifying compliance with Regulation 37.; The term 'rated voltage' is not defined by J584 or by the correspondin standard on sealed beam headlamps, J579c. It is our opinion, however, that 'rated voltage' is the equivalent of 'design voltage' on the basis of the SAE standard that covers bulbs used in sealed beam headlamps, J573d, *Lamps Bulbs and Sealed Units*. Table 2 of J573d lists voltages for such headlamps under the heading of 'Design.'; We realize that your question arises in the context of recent testin by NHTSA of Cibie headlamps, incorporating European H4 halogen bulbs, for compliance with the requirements of Standard No. 108 for motorcycle headlighting. NHTSA tested these headlamps at 12.8 volts and discovered that the maximum allowable 5000 candela at test point 4D-V was exceeded by many of the lamps tested. You raised the question whether NHTSA should not have tested at 12 volts, the 'rated value' given by Regulation 37 for the H4 bulb, at which value all lamps tested by NHTSA would have complied at test point 4D-V.; We do not believe that NHTSA is required by J584 to test the H4 bulb a 12 volts. Regulation 37 specifies a 'test voltage' of 13.2 for the H4 bulb, a point apparently recognized by EFPE Company's catalogue 'Turned on Lighting' which gives wattage figures for the headlamps in question 'at 13.2 design volts as specified by the bulb manufacturer.' If anything, NHTSA was overly conservative in testing its lamps at 12.8 volts, for it is apparent that had it tested at 13.2 volts even more failures would have occurred.; As Roman Brooks explained to you, it has been the European practice a nearly as we can determine to test the H4 bulb at 12.8 volts, apparently in recognition that the higher voltage levels are closer to those generated by the electrical systems of the motor vehicles on which the headlamps are installed. Given this fact and Regulation 37's specification of 13.2 test volts, we do not believe that a lamp manufacturer could successfully argue in court that J584 was ambiguous and should be construed against NHTSA in any attempt by this agency to enforce motorcycle headlighting requirements on the basis of results of test conducted at 12.8 volts.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3562OpenConfidential; Confidential; Dear: This is in reply to your letter of March 23, 1982, asking for 'confidential interpretation' of the applicability of certain Federal motor vehicle safety standards to sidecars.; The agency does not provide 'confidential interpretations.' You questions are of public interest and a copy of this letter will be placed in the interpretations file that is available for public review. However, because it relates to 'specific future model product plans,' we are deleting your name and address from the copy of our response made available to the public.; You first ask for confirmation of your understanding that no Federa motor vehicle safety standard is applicable to a sidecar 'sold independently as an aftermarket item.' It is true that there are no 'sidecar' standards. But certain of its equipment items are themselves covered by Federal equipment standards and must independently comply. Specifically, brake hoses, lighting equipment, tires and glazing (if provided) would have to meet Standards Nos. 106, 108, 119, and 205 as they apply to motorcycle equipment. In addition, because a sidecar is an item of motor vehicle equipment, the manufacturer of any sidecar sold in the aftermarket would be responsible for notification and remedy in the event his product was determined to contain a safety-related defect.; You have presented the hypothetical situation of a motorcycle supplie to a retail dealership with the sidecar attached by the manufacturer and asked whether it is considered to be a three-wheeled motorcycle or a two-wheeled motorcycle with an attachment of motor vehicle equipment. You point out that the former interpretation raises questions of practicability of compliance with the standards.; The definition of a motorcycle encompasses both two- and three-wheele vehicles, and we believe that the questions you have raised subsequently with respect to Standards Nos. 108, 119, 120, and 122 should be answered on a common sense basis. For lighting equipment on the front and rear of a motorcycle the vertical center line of a motorcycle with sidecar attached is the vertical center line of the two-wheeled motorcycle. However, the side reflex reflector should be placed on both the motorcycle and the sidecar. Standards Nos. 119 and 120 must be met by the motorcycle with the sidecar attached. In addition, a motorcycle whose original equipment includes a sidecar must meet Standard No. 122 with the sidecar attached. If a motorcycle with sidecar is capable of meeting Standard No. 122 without the sidecar being equipped with a brake, then the sidecar need not have a brake.; I hope this answers your questions. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3098OpenMr. Dietmar K. Haenchen, Administrator, Vehicle Regulations, Volkswagen of America, Inc., 7111 E. Eleven Mile Road, Warren, Michigan 48090; Mr. Dietmar K. Haenchen Administrator Vehicle Regulations Volkswagen of America Inc. 7111 E. Eleven Mile Road Warren Michigan 48090; Dear Mr. Haenchen: This is in response to your letter of September 25, 1979, requesting a interpretation of the term 'restraint system type' as contained in Table I of S4.5.2 of Federal Motor Vehicle Safety Standard No. 115. In addition, this is in confirmation of Volkswagen's statement of the conclusions reached in the meeting with Messrs. Carson, Parker and Schwartz of the National Highway Traffic Safety Administration.; The agency has carefully considered your request that 'restraint syste type' not be interpreted to require a distinction between active and passive belt systems. The agency must deny your request. As the introduction of mandatory passive restraints approaches, information concerning restraint system type is of exceptional importance to the agency. It is important not only to evaluate the overall effectiveness of the various types of passive restraint system types. Consequently, it is necessary that passive belt systems be differentiated from other restraint systems types by decoding the vehicle identification number (VIN).; The agency has also considered the alternative Volkswagen suggeste which is to submit this information separately to the agency on a magnetic tape. Motor vehicle safety research is carried out by many organizations aside from the NHTSA, however, and Standard No. 115 is intended to make information available to these other researchers as well. Consequently, the agency can not accept the alternative you suggest.; As regards the other questions raised in the meeting with NHTSA staff this is to confirm that paragraphs 2 through 4 of our November 20, 1978, letter remain the position of the agency despite the changes in Standard No. 115 since that time. A copy of that letter is enclosed. Likewise, the agency can confirm that the World Manufacturer Identifiers assigned to Volkswagen by the Society of Automotive engineers fulfill the requirements of S6.1 of Standard No. 115.; As requested, the agency has reviewed the VIN format Volkswagen intend to utilize (attachments 2-4 of this letter) and has determined that it meets the requirements of the standard. As explained at the meeting, specific details concerning an engine need not be encoded so long as the information is available from the manufacturer and different engine types can be differentiated by means of the VIN (S4.5.2).; Volkswagen also pointed out to the agency at the meeting that the firs eight characters of the VIN for a particular model might remain the same for several model years, although the characteristics of the vehicle which they codify might change from model year to model year. For example, a 1981 Dasher might have a different engine that a 1982 Dasher, yet that part od the VIN which contained this information would remain the same. This is authorized by Standard No. 115, so long as the correct information for each model year is submitted to the agency. Volkswagen also asked at the meeting what the correct procedure would be for submitting information to the agency concerning vehicles whose line is not subdivided into several series. In this instance, indicate that the line and series are the same. However, even if the series is not divided into more than one body type, this body type must be reported to the agency (S4.5.2). The engine displacement may be indicated in cubic centimeters, and the horsepower in H.P. SAE net (S3). If only one engine make is used, this information must be submitted to the agency, but need not be directly reflected in the VIN (S6.3).; Volkswagen has also asked when information concerning vehicles importe into the United States must be submitted to the agency. Manufacturers of imported vehicles are required to report VIN codes 60 days before the vehicles are imported into the United States to comply with S6.2.; The agency is considering the petitions of a number of manufacturers t establish engine horsepower groupings for reporting purposes and to establish a flexible effective date for vehicles whose model year begins between September 1, 1980 and December 31, 1980. We expect to respond shortly to the petitions.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3831OpenMr. John B. McMillan, Manning, Fulton, and Skinner, Raleigh, NC; Mr. John B. McMillan Manning Fulton and Skinner Raleigh NC; Dear Mr. McMillan: This is in response to your March 5, 1984 letter regarding the exten to which an automotive remote starting device which one of your clients wishes to market is compatible with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) 114, *Theft Protection*. This device would permit a vehicle to be started from a remote location using a signal transmitter, provided the vehicle's gear shift is in the park position, the emergency brake is set, the hood is closed, and all the vehicle doors are closed. Further, should any of these failsafe systems become deactivated (e.g., gear shift level moved out of the park position), the engine would automatically shut off.; FMVSS 114 requires that passenger cars as well as trucks an multipurpose passenger vehicles with a gross vehicle weight rating of 10,000 pounds or less must have a key locking system that, when the key is removed, will prevent normal activation of the vehicle's engine and either steering or forward self-mobility. We presume that the steering/transmission lock feature is unaffected by your client's device. Therefore, the question presented by your client's system is whether that device, which permits activation of the engine when the ignition key is removed, permits 'normal activation' of the vehicle.; In a previous agency interpretation (copy enclosed), the agenc described certain characteristics of a remote starting system similar to your client's which we concluded were outside the concept of 'normal activation.' These characteristics were automatic deactivation of the remotely started engine when a vehicle door is opened, maintenance of the steering column or gear shift locking feature until the ignition key is inserted in the vehicle, and automatic deactivation of the remotely started engine after 15 minutes (unless the key is inserted in the ignition).; Your client's device apparently has some of these same characteristic as this previously considered device, as well as other automatic engine deactivation features which are comparable in nature. Therefore, we conclude your client's device does not conflict with the requirements of FMVSS 114, since it does not permit normal activation of the engine without the ignition key.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2723OpenMr. Lawrence F. Henneberger, Arent, Fox, Kinter, Plotkin & Kahn, Federal Bar Building, 1815 H Street, N.W., Washington, DC 20006; Mr. Lawrence F. Henneberger Arent Fox Kinter Plotkin & Kahn Federal Bar Building 1815 H Street N.W. Washington DC 20006; Dear Mr. Henneberger: This responds to your December 1, 1977, request for agreement by th National Highway Traffic Safety Administration that the installation as original or aftermarket equipment of an electric retarder on the driveline of an air- braked vehicle would not affect its compliance with Standard No. 121, *Air Brake Systems*.; Section 108(a)(1)(A) of the National Traffic and Motor Vehicle Safet Act (15 U.S.C. S 1397(a)(1)(A)) requires, among other things, that no person manufacture or sell any motor vehicle manufactured on or after the date any applicable Federal motor vehicle safety standard takes effect unless it is in conformity with such standard. As your letter indicates, you are aware that this provision makes it impossible for the NHTSA to 'approve' the compliance of a vehicle configuration in advance of manufacture of the vehicle, because there can be no certainty that the vehicle as manufactured will actually comply. In this case, for example, the retarder's weight or the manner in which it is mounted would affect the actual compliance of the vehicle in which it is installed.; Jacobs' September 20, 1977, analysis evaluated the likelihood tha certain retarders to be imported or manufactured by Jacobs would affect compliance. With regard to these retarders, it appears that their installation as original equipment or in the aftermarket in the fashion described would not affect compliance of the vehicle with Standard No. 121. This finding is of necessity limited to the retarders evaluated in the September 20, 1977, analysis.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam2373OpenMr. George R. Semark, Manager, Vehicle Safety Activities, Sheller-Glove Corporation, Vehicle Planning and Development Center, 3555 St. Johns Avenue, Lima, OH 45804; Mr. George R. Semark Manager Vehicle Safety Activities Sheller-Glove Corporation Vehicle Planning and Development Center 3555 St. Johns Avenue Lima OH 45804; Dear Mr. Semark: This responds to Sheller-Globe's July 7, 1976, request for revision o the requirements of S5.4.2.1 of Standard No. 217 *Bus Window Retention and Release*, so that passage of the described parallelepiped through the emergency door can be effected with its lower surface several inches above the bus floor. Section 5.4.2.1 requires that the 45-inch dimension of the parallelepiped remain vertical, that the 24-inch dimension remain parallel to the opening, and that the lower surface remain in contact with the floor of the bus at all times.; The three specifications for passage of the parallelepiped through th opening are intended to describe, for the benefit of the manufacturer, how the NHTSA will conduct its compliance testing. These specifications do not represent a requirement that the opening be constructed without a threshold or corner obstructions. As the agency interprets this requirement, minor obstructions that do not necessitate passage of the parallelepiped through the opening more than 1 inch above the floor are not prohibited by this requirement. Thus, in the case you describe, the NHTSA would move the parallelepiped through the opening with its sides vertical and the rear surface parallel to the rear surface of the bus, just above the obstructions, but no more than 1 inch above the bus floor.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam2689OpenMs. Charlotte A. Hayes, Satterlee, Mestayer & Freeman, 1606 First National Bank of Commerce Building, New Orleans, LA 70112; Ms. Charlotte A. Hayes Satterlee Mestayer & Freeman 1606 First National Bank of Commerce Building New Orleans LA 70112; Dear Ms. Hayes: This is in response to your letter of August 31, 1977, to our For Worth, Texas office and October 7, 1977, telephone conversation with Robert Churella of my staff concerning the existence of any Federal motor vehicle standard that would require doors on garbage trucks.; There are no Federal motor vehicle safety standards that requir vehicles to be equipped with doors. In fact, Federal Motor Vehicle Safety Standard No. 206 (49 CFR 571.206), which regulates door locks and door retention components, specifically exempts from its application those motor vehicles manufactured for operation without doors.; The National Highway Traffic Safety Administration has, however promulgated a standard requiring trucks manufactured after July 1, 1971, to be equipped with seat belts. This requirement would provide protection for an individual riding in a vehicle without a side door.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam5459OpenVincent Ugoletti, Chief Engineer Great Lakes Communications, Inc. 3514 State St. P.O. Box 860 Erie, PA 16512; Vincent Ugoletti Chief Engineer Great Lakes Communications Inc. 3514 State St. P.O. Box 860 Erie PA 16512; "Dear Mr. Ugoletti: This responds to your September 7, 1994 letter t this office in which you stated your intention to modify a 'conversion' van into a 'production' van by replacing the original front seats with seats that swivel. You stated in an October 4 telephone conversation with Walter Myers of my staff that the vehicle in question is a 1994 cargo van. The vehicle has two front seats, and a gross vehicle weight rating (GVWR) of 9,680 pounds (lbs.). You also explained that the work will be done by a commercial vehicle modification shop. You asked us about the requirements for swivel front seats. By way of background, 49 U.S.C. 30101, et seq. authorizes this agency to issue Federal motor vehicle safety standards (FMVSSs) applicable to new motor vehicles and new items of motor vehicle equipment. Under 49 U.S.C. 30112, each person selling a new vehicle must ensure that the vehicle is certified as complying with all applicable FMVSSs. NHTSA has five safety standards, described below, applicable to motor vehicle seats. The original seats and seat belts on your van were required to meet the requirements of those standards when the new van was sold to you. The five standards set performance criteria ensuring that seats and seat belts provide safety benefits in a crash. Standard No. 207, Seating systems (49 CFR section 571.207), establishes strength and other performance requirements for vehicle seats. The standard does not prohibit the installation of swivel seats in vans. Standard No. 208, Occupant Crash Protection (49 CFR 571.208), specifically section S4.2.3, sets forth occupant protection requirements at the various seating positions in vehicles such as yours manufactured after September 1, 1991, and with a GVWR not greater than 10,000 lbs. Standard No. 209, Seat Belt Assemblies (49 CFR 571.209), sets strength, durability, and other requirements for seat belts. Standard No. 210, Seat Belt Assembly Anchorages (49 CFR 571.210), establishes strength and location requirements for seat belt anchorages. Standard No. 302, Flammability of Interior Materials (49 CFR 571.302), specifies the flammability resistance of the seats and seat belts. Copies of those standards are enclosed, as well as a fact sheet explaining how to obtain copies of all FMVSSs. Generally speaking, once a motor vehicle is sold to its first retail purchaser, its use and any modifications made to it become a matter of state interest. Thus, owners of used vehicles may personally make any modifications or alterations they want to their vehicles without regard to the FMVSSs, subject only to applicable state requirements. There is, however, a limitation on modifications of used vehicles by commercial entities. 49 U.S.C. 30122 provides that a manufacturer, distributor, dealer, or motor vehicle repair business may not knowingly make inoperative any device or element of design installed on or in a motor vehicle or equipment in compliance with an FMVSS. Since the seats and their safety belts are devices or elements of design that were installed in your van in compliance with applicable FMVSSs (particularly the five standards listed above), a business listed in section 30122 cannot modify the vehicle in such a manner as to remove the seats and/or safety belts from compliance. Accordingly, the vehicle modifier should ensure that the swivel seats and any seat belts it installs are installed in accordance with the requirements of the standards. You indicated that Great Lakes Communications wishes to maintain the safety of the original seats and seat belts. We commend that decision. NHTSA urges vehicle owners not to degrade the performance of the safety systems on their vehicles. I hope this information is helpful. Should you have any further questions or need additional information, feel free to contact Walter Myers or Mary Versailles of my staff at (202) 366-2992. Sincerely, Philip R. Recht Chief Counsel Enclosure"; |
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ID: aiam1949OpenMr. E. Alan Moss, Moss Motor, Ltd., P.O. Box 'MG', 5775 Dawson Avenue, Goleta, California; Mr. E. Alan Moss Moss Motor Ltd. P.O. Box 'MG' 5775 Dawson Avenue Goleta California; Dear Mr. Moss: #The President has asked me to reply to your letter o February 9, 1976, concerning the application of Federal Motor Vehicle Safety Standard No. 106-74, *Brake Hoses*, to replacement brake hoses for MG sports cars built from approximately 1945 to 1955. #All brake hose and brake hose end fittings manufactured on or after September 1, 1974, must meet the performance and labeling requirements of Standard No. 106-74. All brake hose assemblies manufactured on or after March 1, 1975, must meet those performance and labeling requirements in the standard that apply to assemblies and, with an exception noted below, must be constructed of conforming hose and end fittings. #The Federal motor vehicle safety standards are not applicable to classic or antique card in the following sense: a standard applies only to a motor vehicle or item of motor vehicle equipment that is manufactured after its effective date. Thus, for example, there is no requirement that MG's in question be retrofitted with conforming brake hose. However, any person manufacturing brake hose for use in such a vehicle must, on and after September 1, 1974, ensure that the hose conforms. #You may find some relief in S12 of the standard. To facilitate the depletion of inventories of hose manufactured before September 1, 1974, that conforms to all aspects of the standard except the labeling requirements, this provision permits the use of such hose in assemblies manufactured before September 1, 1976. #There are no Federal motor vehicle safety standards that apply to hydraulic brake system components other than Standard No. 106-74, *Brake Hoses*, and Standard No. 116, *Motor Vehicle Brake Fluids*. #Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicle Programs; |
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ID: aiam3974OpenThe Honorable John S. McCain, III, U.S. House of Representatives, Washington, DC 20515; The Honorable John S. McCain III U.S. House of Representatives Washington DC 20515; Dear Mr McCain: Thank you for bringing to our attention the problems experienced b your constituents due to conflicting State laws on motor vehicle window tinting.; The National Highway Traffic Administration (NHTSA) has issued Federal motor vehicle safety standard governing window tinting in new vehicles and replacement equipment, and Federal law also limits the extent to which certain commercial businesses may apply additional tinting. However, Federal law does not preclude individuals from tinting their vehicle windows. That matter is left to the States, and we understand the difficulties that may arise when the tinting laws of adjacent States are inconsistent.; Our agency has been discussing the issue of window tinting with th American Association of Motor Vehicle Administrators, in an effort to better explain the interaction of Federal and State laws in this area. That may also be an appropriate forum in which to consider ways to resolve conflicts between differing State tinting laws. While NHTSA and each state government has a valid interest in preserving its legal authority, we all share a common interest in promoting highway safety and in minimizing inconvenience to traveling motorists. In our view, a well-coordinated and cooperative approach among the various parties can help to address apparent problems in this area.; We will keep you advised of our progress in those discussions. appreciate knowing of your concern in this matter, and I hope you will feel free to contact me if this agency can be of further assistance.; Sincerely, Diane K. Steed |
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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.