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: aiam1146OpenMr. Louis C. Lundstrom,Executive Director,Environmental Activities Staff,General Motors Corporation,General Motors Technical Center,Warren, Michigan 48090; Mr. Louis C. Lundstrom Executive Director Environmental Activities Staff General Motors Corporation General Motors Technical Center Warren Michigan 48090; Dear Mr. Lundstrom:#This is in reply to your letter of may 11, 1973 asking for confirmation of your interpretation of paragraph S7.9 of Standard No. 105a in term of General Motors' air vacuum power brake.#Your interpretation is correct. Your system with its 'two separate and independent energy sources in the power head...is equivalents to two entirely duplicate systems', and disconnection of one source at a time would be the correct test procedure under S7.9, provided the requirements of S5.1.3 are satisfactorily met under both conditions.#Sincerely,James E. Wilson,Associate Administrator,Traffic Safety Programs; |
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ID: aiam4344OpenMr. Rudy van Kreuningen, Kraco Enterprises, Inc., 505 E. Euclid Ave., Compton, CA 90224; Mr. Rudy van Kreuningen Kraco Enterprises Inc. 505 E. Euclid Ave. Compton CA 90224; Dear Mr. van Kreuningen: This responds to your letters asking about the effect of Federal law o regulations on or aftermarket steel 'shelf' which you have designed for installation in the area above the windshield where the sun visors are located. The shelf would be used to hold small items such as maps or glasses and woud(sic) be provided with visors on its underside to replace the vehicle's original visors. I apologize for our delay in replying.; The National Traffic and Motor Vehicle Safety Act authorizes our agenc to issue Federal motor vehicle safety standards which apply to new motor vehicles and items of motor vehicle equipment. It also authorizes us to require the recall and remedy of any motor vehicle or item of motor vehicle equipment which contains a safety defect.; The sun visor in a new vehicle is regulated by Federal Motor Vehicl Safety Standard No. 201., *Occupant protection in interior impact*, which requires that the Visor be 'constructed of or cover with energy-absorbing material' and that the visor's mounting must 'present no material edge radius of less than 0.125 inch that is statically contactable by a spherical 6.5-inch diameter head form.' The purpose of the standard is to reduce the injuries that occur when unrestrained occupants strike the visor or its mounting with their heads. If your shelf were installed by the manufacturer of a new motor vehicle, the visor attached to it would have to comply with the visor requirements of the standard, and the shelf would have to meet the mounting requirements. I am enclosing a copy of the standard for your review.; Although you propose to sell your shelf in the aftermarket, no as a item of original equipment, the standard can nonetheless affect persons who install the shelf. The Act provides that a person who manufactures, distributes, sells or repairs motor vehicles cannot 'render inoperative' a regulated device such as a sun visor or its mounting. If a repair shop were to remove a vehicle's sun visor and replace it with your shelf, the shop would be in violation of the Act unless your shelf complied with the standard. The sole exception to this rule is the individual owner, who may install a shelf i his own vehicle without regard to the standard.; In addition to the requirements of the standard, our safety defec authority could have a bearing on your sale of the shelf. If the shelf would normally be installed so that its rear edge could be hit by an occupant's head in a crash, it would seem likely to cause serious injury. It is thus possible that the shelf would be determined to contain a safety defect subject to recall. I urge you to examine the possibility of such injury before you make further plans to market the shelf.; I hope this information is helpful to you. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3481OpenMr. Donald W. Vierimaa, Director of Engineering, Truck Trailer Manufacturers Association, 2430 Pennsylvania Avenue, N.W., Washington, DC 20037; Mr. Donald W. Vierimaa Director of Engineering Truck Trailer Manufacturers Association 2430 Pennsylvania Avenue N.W. Washington DC 20037; Dear Mr. Vierimaa: This is in reply to your letter of October 6, 1981, asking for ou concurrence that front clearance lamps 'located at the frame level (about 50 inches above the ground) on platform trailers with permanent front bulkheads conforms with FMVSS 108.'; Clearance lamps are required by Standard No. 108 'to indicate th overall width' of a vehicle, and to be 'as near the top thereof as practicable.' As you noted, NHTSA has commented before that the indication of overall width is the primary function of clearance lamps, with a secondary purpose of indicating overall height. However, because trailers are not required to have identification lamps on their front, the secondary purpose of clearance lamps on trailers is important, especially if the top of the trailer is substantially higher than that of the truck tractor towing it.; You have stated that the top of the trailer is substantially highe than that of the truck tractor towing it.; You have stated that the top of the typical front bulkhead is 8 to feet above the ground, and the identification lamps of truck tractors are typically 10 feet above the ground. We will assume also that the tractor's clearance lamps are also typically 10 feet above the ground. You have also stated that the mounting height of truck tractor rear view mirrors and bulkhead-mounted clearance lamps are essentially the same, and that as a result 'drivers remove the bulb from the clearance lamps or place tape over the lamps.'; The determination of practicability is one that is made by th manufacturer of the trailer. NHTSA will accept a determination that mounting of clearance lamps at the top of the bulkhead is not practicable if such lamps are reflected into the driver's eyes by way of the side view mirror. But if the configuration of a trailer with a permanent front bulkhead is such that the clearance lamps may be located at the top of the bulkhead from without interfering with the vision of the truck tractor's operator, that location would appear to be 'practicable' within the meaning of Standard No. 108 and the situation your letter addresses.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4153OpenMr. Terry W. Wagar, Technical Services Bureau, Division of Vehicle Safety Services, Department of Motor Vehicles, State of New York, Albany, NY 12228; Mr. Terry W. Wagar Technical Services Bureau Division of Vehicle Safety Services Department of Motor Vehicles State of New York Albany NY 12228; Dear Mr. Wagar: This is in reply to your letter of December 27, 1985, with reference t the 'Pulse' and 'Litestar' motor vehicles. You have asked several questions regarding the registration category and highway safety records of these vehicles. I hope the following information will be helpful.; There are no Federal categories for vehicle registration. Each State i free to define vehicles as it wishes for registration purposes. The State definition need not conform to the Federal categorization assigned for purposes of the safety standards. However, regardless of how a State defines a vehicle, under the preemption clause of the National Traffic and Motor Vehicle Safety Act (15 USC 1392(d)) a State may not require compliance of that vehicle with a State standard that differs from a Federal safety standard covering the same aspect of conformance. Such a State standard must be identical with the Federal one. For example, a State could require a horn as a prerequisite to registration since there is no corresponding Federal requirement, but it could not require a motorcycle to be equipped with two headlamps, since Federal Standard No. 108 allows a manufacturer a choice of one or two headlamps.; With reference to the Litestar and Pulse vehicles, we understand tha both vehicles have small outrigger wheels, which support the vehicles at rest. For purposes of compliance with the Federal motor vehicle safety standards, a 'motorcycle' is a motor vehicle that is designed to travel on not more than three wheels in contact with the ground. If the outrigger wheels are used only to provide stabilization in turns while the vehicle is in motion, then we would view the vehicle as a 'motorcycle' since it is designed to travel on not more than three wheels in contact with the ground. However, if this type of vehicle is designed to travel on all four wheels, or capable of it according to outrigger adjustment, the vehicle would not be a motorcycle, but would be a 'passenger car' for purposes of compliance with the Federal motor vehicle safety standards. (See definition of 'motorcycle' at 49 CFR Sec. 571.3(b)). We have not formally investigated these vehicles for compliance, nor do we have any information regarding their highway safety records.; You also asked whether the 'Litestar' had been brought to our attentio previously. The answer is yes. James Bede, the apparent originator of this type of vehicle, brought one to the headquarters of the Department some years ago and obtained our informal concurrence that it could be classified as a 'motorcycle.'; I hope that this is of assistance to you. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3696OpenMr. Ken Alexander, Engineering Manager, Sylvania GTE Products Corporation, 1231 'A' Avenue North, Seymour, IN 47274; Mr. Ken Alexander Engineering Manager Sylvania GTE Products Corporation 1231 'A' Avenue North Seymour IN 47274; Dear Mr. Alexander: This is in reply to your letter of April 8, 1983, following conversation with Mr. Vinson of this office, with reference to Standard No. 108 *Lamps, Reflective Devices, and Associated Equipment*.; You are concerned with the 'design to conform' language as it relate to headlamps, and have asked for an interpretation that it 'does not mean that every lamp produced is required to have every photometric point in.'; I am not certain what you mean by 'every photometric point in' However, a manufacturer is expected to design his headlamps so that each will meet the minimum photometric output in candela set forth by SAE J579C for each test point. The agency does not pursue random occasional photometric failures at individual test points. But if a manufacturer's products show a pattern of failures to meet the minimum at any individual test point, the agency could consider this as an indication that the headlamp was, in fact, not 'designed to conform'.; I hope this answers your question. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2984OpenMs. Barbara A. Loureiro, International Salt Co., Clarks Summit, PA 18411; Ms. Barbara A. Loureiro International Salt Co. Clarks Summit PA 18411; Dear Ms. Loureiro: This responds to your letter of January 29, 1979, asking whethe folding front seats on a two-door, 1978 Chevrolet Malibu are required to have locking devices.; The answer to your question is yes. Federal Motor Vehicle Safet Standard No. 207, *Seating Systems*, (49 CFR 571.207) specifies in paragraph S4.3 that 'a hinged or folding occupant seat or occupant seat back shall be equipped with a self-locking device for restraining the hinged or folding seat or seat back and a control for releasing that restraining device.'; You stated in a telephone conversation with Hugh Oates of my offic that your 1978 Malibu does not have such a restraining device, either manual or inertia-activated. Our Office of Vehicle Safety Compliance has found, however, that the front seating system of the 1978 Chevrolet Malibu two door sedan does in fact have a seat back locking device that is actuated by an inertia system. This system has been certified by General Motors Corporation as meeting the performance requirements of Federal Motor Vehicle Safety Standard No. 207. A description of this system is found on page four of section one in the owner's manual. If the inertia restraint system in your vehicle does not perform as described, you should contact your Chevrolet dealer.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam1351OpenMs. Deborah A. Henderson, Crisp & Henderson, Attorneys at Law, 119 West Third Street, Post Office Box 91, Greenville, North Carolina 27834; Ms. Deborah A. Henderson Crisp & Henderson Attorneys at Law 119 West Third Street Post Office Box 91 Greenville North Carolina 27834; Dear Ms. Henderson: This is in reply to your letter of November 19, 1973, inquiring whethe there are Federal or State regulations that contain labeling requirements for rubber used in retreaded tires.; There are to our knowledge no Federal regulations that either establis quality levels or require labeling for rubber used in retreaded tires.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4503OpenMr. Robert Cuzzi Breda Transportation, Inc. 275 Madison Avenue, Suite 1711 New York, NY 10016; Mr. Robert Cuzzi Breda Transportation Inc. 275 Madison Avenue Suite 1711 New York NY 10016; Dear Mr. Cuzzi: This responds to your letter asking whether buses wit a gross vehicle weight rating (GVWR) greater than 10,000 pounds are excluded from coverage under Federal Motor Vehicle Safety Standard No. 301, Fuel System Integrity. I regret the delay in responding to your letter. The answer to your question is yes. Safety Standard No. 301 applies to new passenger cars, multipurpose passenger vehicles, trucks, and buses having a GVWR of 10,000 pounds or less and to all new school buses. The buses you manufacture for sale as municipal transit buses are excluded from Standard No. 301 because their GVWR is greater than the 10,000 pound limit established for the standard. You asked also whether there are any other Federal standards that might apply to the fuel tanks on your transit buses. I have forwarded a copy of your letter to the Federal Highway Administration (FHWA) and the Urban Mass Transit Administration (UMTA) for their direct reply as to the applicability of any FHWA or UMTA regulations to your transit vehicles. You might also contact the Environmental Protection Agency (EPA) to see whether that agency has any requirements affecting the fuel tanks on your buses. The general telephone number for the EPA is (202) 382-2090. Sincerely, Erika Z. Jones Chief Counsel; |
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ID: aiam1701OpenMr. Charles O. Verrill, Jr., Messrs. Patton, Boggs & Blow, 1200 Seventeenth Street, N.W., Washington, DC, 20036; Mr. Charles O. Verrill Jr. Messrs. Patton Boggs & Blow 1200 Seventeenth Street N.W. Washington DC 20036; Dear Mr. Verrill: This is in reply to your two letters of November 8, 1974, on behalf o Trailer Manufacturers Association, requesting interpretations of Standard No. 108 as it applies to boat trailers.; Standard No. 108 requires that clearance lamps be located 'on the rear (Table II) but 'boat trailers need not be equipped with both front and rear clearance lamps, provided an amber (to front) and red (to rear) clearance lamp is located so as to indicate its extreme width' (paragraph S4.1.1.9). You enclose a drawing showing front and rear clearance lamps imbedded in the trailer fender and ask for an interpretation that 'where locating the clearance lamp on the front and rear of the vehicle would not mark the extreme width of the vehicle, the manufacturer shall have the option of locating the clearance lamps as close to the front or rear as practicable in order to mark the overall width of the trailer.'; Paragraph S4.1.1.9 contemplates the use of a double-faced lamp. Thi lamp is generally mounted atop the fender so that the visibility requirements at 45 degrees inboard may be met. Separate lamps also 'located at or near the mid point' would meet the same need for vehicle safety, and would be acceptable, provided that the visibility requirements are also met. This does not seem likely from your proposed configuration, unless the lamps are located above the trailer frame.; You also present the problem of boat trailers on which 'apparatus t hold, load and unload the boat extends from two to four feet beyond the rear frame.' The apparatus overhang may prevent lamps mounted on the rear frame from meeting the visibility requirements of paragraph S4.3.1.1.'You ask for an interpretation 'that would permit the use of detachable light bars where necessary to comply with the visibility requirements of S4.3.1.1.'; There are two solutions to your problem permissible under Standard No 108. The apparatus itself appears to be a permanent and rigid part of the vehicle within the meaning of paragraph S4.3.1, so that the lamps in question could be mounted there and comply with the requirements of the standard. You may not wish to do so, however, because of damage that might be incurred through unloading the immersion in water. In that instance paragraph S4.3.1.1 provides the answer: 'However, if motor vehicle equipment. . . prevents compliance with this paragraph by any required lamp or reflective device, an auxiliary lamp or device meeting the requirements of this paragraph shall be provided'. A detachable light bar would be acceptable as an auxiliary, provided that it complies with the wiring requirements of paragraph S4.5, and the required lighting is retained (in your hypothetical, lamps located at the end of the frame).; We have also received your petition of November 8, 1974, on behalf o Trailer Manufacturers Association to amend Standard No. 108 with respect to boat trailers. You will be informed in due course whether it merits initiation of rulemaking.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam0813OpenMr. Stan Haransky, Truck Body & Equipment Association, Inc., 5530 Wisconsin Avenue, Suite 1220, Washington, DC 20015; Mr. Stan Haransky Truck Body & Equipment Association Inc. 5530 Wisconsin Avenue Suite 1220 Washington DC 20015; Dear Mr. Haransky: This is in reply to your letter of July 20, 1972, concerning th Certification of vehicles having a dual purpose. You ask how you should determine weight ratings when a vehicle is intended to carry loads of varying weights, and cite as an example a vehicle designed to carry both gasoline and; 2 fuel oil. You indicate that you are presently placing a secon certification label on the vehicle, a copy of which you enclose, to inform the customer of the allowable weights.; The method you are using may not be consistent with the Certificatio regulations, as our position is that weight or axle values that may be confused with GAWR or GVWR cannot appear on the Certification (Part 567) label, or on adjoining labels. This will be the case if the 'total' in the 'chassis rated weight' column differs from the figure you provide on the Part 567 label for GVWR (assuming that the front and rear axle figures are identical to the GAWR figures on the Part 567 label). Gross vehicle weight rating is not necessarily the total of all axle weight ratings.; We recommend that the weight ratings be computed on the basis of th heaviest load that the vehicle is designed to carry, without attempting (for certification purposes) to anticipate the density of particular cargoes.; Yours truly, Richard B. Dyson, Assistant 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.