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: aiam3037OpenMr. A. M. Dahm, President, Macdonald Equipment Company, P.O. Box B, 7333 Highway 85, Commerce City, CO 80022; Mr. A. M. Dahm President Macdonald Equipment Company P.O. Box B 7333 Highway 85 Commerce City CO 80022; Dear Mr. Dahm: This responds to your January 2, 1979, letter asking whether it i permissible to mount a snow plow on a vehicle when the weight of the snow plow will cause the vehicle to exceed its gross axle weight rating (GAWR). The answer to your question is no.; The GAWR of a vehicle is determined and established by a vehicle' manufacturer and represents a manufacturer's assessment of the maximum weight that each axle can safely sustain. When this weight rating is exceeded by the addition of equipment to a vehicle, the safety of a vehicle is jeopardized. Over a period of time, the excessive weight borne by the axle could result in unusual wear and eventual failure of the axle.; The National Highway Traffic Safety Administration require manufacturers to label their vehicles with GAWR's to avoid the overload problem that you mention in your letter. The NHTSA has not granted exceptions from this requirement for snow plows. If you mount a snow plow on a new vehicle prior to first purchase, you must be sure that the vehicle continues to comply with all Federal safety standards and regulations. If the weight of the plow exceeds the GAWR of the vehicle, the vehicle would no longer comply with Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*. Further, the compliance of other safety standards could be impacted by the addition of that weight.; In the case of used vehicles on which you mount a snow plow, manufacturer, repair business, distributor, or dealer may not knowingly render inoperative the compliance of a vehicle with the safety standards. The attachment of a snow plow that exceeds the gross axle weight rating would render inoperative the compliance of the vehicle with Standard No. 120. Accordingly, whether a vehicle is new or used, the additional weight of a snow plow that would exceed the GAWR of a vehicle would not be permissible.; The NHTSA understands the budgetary constraints of municipalities However, financial considerations must be balanced against the potential loss of life that can occur when vehicles are routinely overloaded. Accordingly, vehicles that have snow plows or other devices mounted on them should have sufficient GAWR's to carry their intended load.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4658OpenMr. Samuel Kimmelman Product Engineering Manager Ideal Division Parker Hannafin Corporation 3200 Parker Drive St. Augustine, FL 32084; Mr. Samuel Kimmelman Product Engineering Manager Ideal Division Parker Hannafin Corporation 3200 Parker Drive St. Augustine FL 32084; "Dear Mr. Kimmelman: This is in reply to your letter to Taylor Vinso of this office. I regret the delay in responding. You express your understanding that Standard No. l08 'allows vehicles with combined function rear stop and turn signal/hazard lamps to operate in either of two modes when both the hazard switch and brake switch have been actuated.' You have expressed these two modes as follows: 'l. The hazard switch is the major control for operation of the combined rear stop and turn signal/hazard lamps. a. Actuating the hazard switch some period of time after actuation of the brake switch will cause the rear lamps to change from steady on, stop signal, to flashing, hazard signal. b. Actuating the brake switch some period of time after actuation of the hazard switch will not change the flashing lamps, hazard signal, to steady on, stop signal. 2. The brake switch is the major control for operation of the combined rear stop and turn signal/hazard lamps. a. Actuating the brake switch some period of time after actuation of the hazard switch will cause the rear lamps to change from flashing, hazard signal, to steady on, stop signal. The front flashing hazard lamps will also become steady on. b. Actuating the hazard switch some period of time after actuation of the brake switch will not change the rear steady on lamps, stop signal, to flashing, hazard, while the front hazard lamps go from off to steady on.' You ask for confirmation of your understanding, and if it is correct, whether NHTSA is presently considering rulemaking 'to specify a specific signal from the combined function rear stop and turn signal/hazard lamps when both the hazard and brake switches are actuated.' Neither of these modes are correct, for the reasons discussed below. Initially we note that systems with combined-function lamps are those that use red lenses for the rear turn signals lamps, and not the amber lenses that Standard No. l08 allows. The second point we wish to make is that you may have confused hazard warning lamps with turn signal lamps. The basic Federal requirements for stop lamps are those of SAE Standard J586c Stop Lamps, August l970, which is incorporated by reference in Standard No. l08. Paragraph 4.2 of J586c states 'When a stop signal is optically combined with the turn signal, the circuit shall be such that the stop signal cannot be turned on in the turn signal which is flashing.' The identical provision is found in paragraph 4.4 of SAE Standard J588e Turn Signal Lamps, September l970, which is also incorporated by reference in Standard No. l08. This clearly means that a turn signal cannot be overriden by a stop lamp. In addition, you should note that regulations of the Federal Highway Administration's Bureau of Motor Carrier Safety forbid the optical combination of a stop lamp with a turn signal lamp unless the stop lamp function is deactivated when the turn signal lamp is activated (49 CFR 393.22(b)(2). Assuming, however, that you meant hazard warning system lamps, there is no provision in Standard No. l08 for hazard warning system operation (those of SAE Recommended Practice J945 Vehicular Hazard Warning Signal Flasher, February l968, incorporated by reference in Standard No. l08) specifying priority of operation with respect to the stop lamp system. Because paragraph S5.5.4 of Standard No. l08 requires the stop lamps to be activated upon application of the service brakes, we interpret this as allowing the stop lamp system to override the hazard warning system. This opinion, of course, relates only to the rear lamps. The hazard warning system at the front of a vehicle must operate at any time the system is actuated. In response to your question about the possibility of rulemaking, please note that the agency does not plan any rulemaking on this subject. Sincerely, Stephen P. Wood Acting Chief Counsel"; |
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ID: aiam3467OpenKenneth R. Brownstein, Counsel, Paccar, Inc., P.O. Box 1518, Bellevue, WA 98009; Kenneth R. Brownstein Counsel Paccar Inc. P.O. Box 1518 Bellevue WA 98009; Dear Mr. Brownstein: This responds to your letter of September 16, 1981, in which yo requested our views on whether Paccar may use its name on the certification label of vehicles manufactured by its Mexican affiliate.; This agency's regulations provide that each vehicle's certificatio label must contain 'the full corporate or individual name of the actual assembler of the vehicle.' See 49 CFR 567.4(g)(1). The only relevant exception to that requirement is set forth in section 567.4(g)(1)(i), which states that if 'a vehicle is assembled by a corporation that is controlled by another corporation that assumes responsibility for conformity with the standards, the name of the controlling corporation may be used.' Thus, the answer to your question depends upon whether Paccar 'controls' Kenworth Mexicana, the Mexican affiliate.; Your letter states that Paccar effectively owns a 49 percent interes in Kenworth Mexicana, the maximum permitted under Mexican law. Based on your telephone conversations with Roger Fairchild of this office, we understand that the vehicles to be produced in Mexico are of Paccar design, with Paccar control over all matters relating to compliance with safety standards. In fact, any design changes in the vehicle must apparently be approved by Paccar under your agreement with the Mexican company.; In these circumstances, we conclude that Paccar may use its corporat name on the Mexican vehicles' certification labels notwithstanding the less than majority equity interest in the Mexican company. The 'controlling corporation' exception to the general requirement that the vehicle assembler's name must appear on the certification label was enacted in recognition of the fact that 'particularly in some foreign countries, assembly of a vehicle may be performed by a subsidiary corporation controlled by a parent that is the generally known 'nameplate company.'' The agency determined that in such a situation, 'no important purpose is served by requiring the name of a lesser-known subsidiary corporation on the label.' See 34 FR 11360, July 9, 1969. Further, the agency has previously stated in one of its interpretations that the 'purpose of the manufacturer's designation in the certification regulations is to identify the company that has primary technical responsibility for conformity of the design and quality control of the assembly.' Particularly with respect to the design aspects, Paccar meets this test.; If you have further questions in this area, please feel free to contac us.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0498OpenMr. A. C. Rudd, Director, Engineering, Lotus Cars Ltd., Norwich NOR 92W, England; Mr. A. C. Rudd Director Engineering Lotus Cars Ltd. Norwich NOR 92W England; Dear Mr. Rudd: This is in reply to your letter of November 16, 1971, in which yo asked whether Standard No. 208 would require seat belt retractors to be installed after January 1, 1972, for the rear occasional seats of the Lotus Elan Plus Two. Our answer is that retractors will be required if the rear seats are 'designated seating positions' as defined in our regulations at 49 CFR 571.3(b). The definition provides, among other things, that to be a designated seating position a seat must accomodate (sic) a 5th percentile adult female. To define an occupant of this size, the regulations incorporate a U.S. Public Health Service publication that includes the following specifications: weight, 104 pounds, standing height, 59 inches, sitting height, 30.9 inches, knee height, 17.9 inches, buttock-knee length, 20.4 inches. If the Elan Plus Two cannot accomodate (sic) a person of this size in the rear seat, it need not have a seat belt retractor for that seat. If such a person can be accomodated (sic), then retractors will be required unless the seat is otherwise exempt by the definition as an 'auxiliary seating accomodation (sic) such as [a (sic) temporary or folding jump seat.' We do not have the information necessary to judge whether the seat is exempt as an auxiliary seating accomodation (sic).; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5360OpenMr. Nicholas S. Copass Sales Manager Titeflex Industrial Americas 170 Tapley Street Springfield, MA 01104-2893; Mr. Nicholas S. Copass Sales Manager Titeflex Industrial Americas 170 Tapley Street Springfield MA 01104-2893; Dear Mr. Copass: This responds to your letter to Mr. David Elias formerly of this office, concerning the manufacture of hydraulic brake hose assemblies by Titeflex and Russell Performance Products. I regret the delay in responding. We recently responded to a letter from Mr. Jim Davis of Russell about the labeling of the hose assemblies. I have enclosed a copy of that letter for your information. In that letter, we explain that both Titeflex's and Russell's designations need not be marked on the assembly. Instead, since Russell is manufacturing the assemblies and will market the assemblies, Russell's designation must be marked. The designation will identify Russell as the manufacturer of the assembly in the event of a possible noncompliance or defect with the assembly. I hope this information is helpful. If you have any questions, please do not hesitate to call Ms. Deirdre Fujita of my staff at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosure; |
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ID: aiam4988OpenMr. George F. Reuss Reuss Engineers, Inc. P.O. Box 22 Waltz's Mills Madison, PA 15663; Mr. George F. Reuss Reuss Engineers Inc. P.O. Box 22 Waltz's Mills Madison PA 15663; "Dear Mr. Reuss: This responds to your letter addressed to Barr Felrice, NHTSA's Associate Administrator for Rulemaking, concerning your recently patented vehicle that is designed to transport passenger cars. You requested information about which specific regulations and standards would be applicable to your vehicle. I am pleased to have this opportunity to explain our regulations. I am also enclosing the agency's general information fact sheet for new manufacturers and a booklet entitled 'Federal Motor Vehicle Safety Standards and Procedures,' which summarizes the basic requirements of our safety standards and shows which standards apply to various vehicle types. You explained that your vehicle consists of a chassis with a gross vehicle weight rating (GVWR) greater than 10,000 pounds and a structural frame between the cab and rear wheels. This frame includes moveable forks that can be extended from the framework and inserted beneath a passenger car's tires. The forks can be raised and retracted into the framework, thus allowing your vehicle to transport the passenger car. The National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1397(a)(2)(A), the Safety Act) authorizes this agency to issue safety standards applicable to new motor vehicles and new items of motor vehicle equipment. All motor vehicles and items of motor vehicle equipment manufactured or imported for sale in the United States must comply with all applicable safety standards. Manufacturers of motor vehicles must certify compliance of their products in accordance with 49 CFR Part 567, Certification. I note that you may be considered a 'final-stage manufacturer' under Part 568, Vehicles Manufactured in Two or More Stages, because you purchase the chassis. Section 102(3) of the Safety Act defines the term 'motor vehicle' as follows: 'any vehicle driven or drawn by mechanical power manufactured primarily for use on the public streets, roads, and highways, except any vehicle operated exclusively on a rail or rails.' Based on the description in your letter, it appears that your vehicle is a motor vehicle under the Safety Act. More specifically, it appears that your vehicle would be considered a 'truck' under the agency's regulations. The term 'truck' is defined, at 49 CFR Part 571.3, as 'a motor vehicle with motive power, except a trailer, designed primarily for the transportation of property or special purpose equipment.' Accordingly, your vehicle must comply with all Federal motor vehicle safety standards that are applicable to trucks with a GVWR greater than 10,000 pounds and be certified as conforming to those standards. I hope this information is helpful. If you have any further questions about NHTSA's safety standards, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosure"; |
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ID: aiam0162OpenGeorge M. Hilgendorf, Esq., One North La Salle Street, Suite 400, Chicago, Illinois 60602; George M. Hilgendorf Esq. One North La Salle Street Suite 400 Chicago Illinois 60602; Dear Mr. Hilgendorf: Mr. Frank Coy, Special Assistant to the Under Secretary o Transportation has asked that I respond to your letter of April 16, 1969, in which you ask whether a station wagon purchased in March of 1968, equipped with two ply tires, violates Federal Motor Vehicle Safety Standard No. 109.; The vehicle you purchased was apparently manufactured prior to April 1 1968, and therefore, it was not required to be equipped with tires conforming to Standard No. 109. However, even if the standards were applicable, because a tire is labeled '2-ply' it is not necessarily a non-conforming tire. Standard No. 109 does not specifically require tires to have a given number of plies. It does require that irrespective of any ply rating tires pass minimum performance tests. As to passenger cars, Standard No. 110 requires that passenger cars manufactured after April 1, 1968, (1) must be equipped with tires that comply with Standard No. 109, and (2) the vehicle must not place a load on any of the tires greater than the load capacity of the tire specified in Standard No. 109.; Very truly yours, Howard A. Heffron, Chief Counsel |
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ID: aiam4822OpenMr. S.V. Kaaria 70 E. Heather #3 Midvale, UT 84047; Mr. S.V. Kaaria 70 E. Heather #3 Midvale UT 84047; Dear Mr. Kaaria: Our Denver Regional Office has forwarded your lette of January 3, l99l, to this Office for reply. You are 'the designer of the taillights placed near the rear window of passenger cars.' In attempting to negotiate a settlement with vehicle manufacturers, you have been informed that because 'elevated brake lights' are required by our agency, the government 'should negotiate with me for l% of replacement cost of these taillights.' You have asked that we clarify our position in this matter. Federal Motor Vehicle Safety Standard No. 108 requires that every passenger car manufactured on or after September 1, l985, be equipped with a high-mounted stop lamp, mounted on the rear vertical centerline of the vehicle. The only requirement relating to design is that the lens have an effective projected luminous lens area of not less than 4 1/2 square inches, but the standard does not specify the shape of the lens. Within these parameters, manufacturers have located their lamps both inside and outside of the car, from the roof to the deck, and have equipped them with circular and rectangular lenses of varying sizes. Our standards are generally expressed in performance terms so that manufacturers have the freedom to design their vehicles in the manner most suited to them to meet the performance requirements, and so that a specification that appears to favor a proprietary device (e.g., mandating a specific design solution to a standard's requirements) is avoided. Because of the latitude in design that Standard No. 108 affords, we do not regard the lamp as having any single inventor or designer. While it is possible that you have designed a lamp with some proprietary elements, your search for recovery is properly directed towards lamp and vehicle manufacturers. You have been ill-advised to seek recovery from the government, for you have no legal basis to do so. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam0532OpenMr. Rozie M. Turner, Engineering Department, Hackney Bros. Body Company, P. O. Box 920, Wilson, NC 27893; Mr. Rozie M. Turner Engineering Department Hackney Bros. Body Company P. O. Box 920 Wilson NC 27893; Dear Mr. Turner: This is in reply to your letter of December 6, 1971, in which yo requested our opinion on the application of Standard No. 207 to swivel type pedestal seats.; Your problem arises from the method specified in S5.1.1 for th application of the force required by S4.2(a) of 20 times the weight of the seat. Although your letter does not state the problem directly, it appears that when a forward force is applied from behind the seat, as shown in the figures accompanying S5.1.1, the seat will tend to swivel. Your solution is to attach a T-shaped structure to the seat and to apply the force to the leg of the T forward of the swivel point.; The initial question raised by your letter is whether a seat tha swivels under the application of a force through its back as shown in Figure 1, will be considered to fail to withstand the force and thereby fail the standard.; On the basis of our present information, we cannot say that such swiveling action would result in a failure of the standard. The engineering staff has expressed uncertainty as to the effects on the occupant if the seat swivels in a side or angular crash, but they are not prepared to say that it would present a hazard. Since the swiveling itself is not a failure, the remaining question is one of test procedure. Our opinion is that the procedure you describe, using a T shaped structure, appears to be an acceptable means of applying the test force to the seat.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1289OpenMr. T.J. Wagner, 1409-119th Street, Whiting, Indiana 46394; Mr. T.J. Wagner 1409-119th Street Whiting Indiana 46394; Dear Mr. Wagner: #This is in reply to your letter of September 18 1973, concerning you recent purchase of tires that were marked 'Blemtube type must use tube,' but which were installed on your car without tubes. #The NHTSA does consider the mounting of 'tube type' tires without to involve at least a potential violation of the National Traffic and Motor Vehicle Safety Act. However, the establishment of a violation by the agency involves the purchase and testing of new tires, a time-consuming and costly process. The agency would not, moreover, under its authority, be able to take any action with respect to the tires sold to you. We will, however, inquire into the matter by contacting the dealer who sold you the tires in the hope that we may prevent a recurrence of the problem. #Thank you for bringing this matter to our attention. #Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicle Programs; |
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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.