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: aiam2486OpenMr. Jack D. Gross, Jr., National Sales Manager, Marchal America, 14622 Southlawn Lane, Rockville, MD 20850; Mr. Jack D. Gross Jr. National Sales Manager Marchal America 14622 Southlawn Lane Rockville MD 20850; Dear Mr. Gross: This is in reply to your letter of December 17, 1976, asking whether 1 U.S.C. 1392(d) permits the installation of quartz halogen headlamps on State-owned vehicles. It is understood that these headlamps are manufactured in France, and are not of sealed beam construction. Thus they do not conform to Motor Vehicle Safety Standard No. 108. Your letter also commented that certain 'state highway and law enforcement agencies . . . have indicated . . . that they prefer the quartz halogen units but are reluctant to install these units in their state vehicles because they are not of an approved type.'; Importation and sale of nonconforming motor vehicle equipment i expressly forbidden by Section 108 (a) (1) (A) of the National Traffic and Motor Vehicle Safety Act. A civil penalty of up to $1,000 may be imposed for each violation. Therefore, quartz halogen headlamps that do not conform to Standard No. 108 may not be imported into the United States and sold to State agencies.; Your inquiry appears premised that such may be allowable pursuant t Section 1392(d) which reads in pertinent part:>>>Nothing in the section shall be construed to prevent. . . the government of any State or political subdivision thereof from establishing a safety requirement applicable to motor vehicle or motor vehicle equipment procured for its own use if such requirement establishes a higher standard of performance than that required to comply with the otherwise applicable federal standard.; << |
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ID: aiam0141OpenMr. T. Sudderth, Post Office Box 757, Laurens, SC 29360; Mr. T. Sudderth Post Office Box 757 Laurens SC 29360; Dear Mr. Sudderth: Thank you for your letter of January 22, 1969, concerning safet glazing in your motor home.; We do not know what is meant by the description 'Windows-Double Densit - glass - set.'; Glazing materials in a motor home must be in accordance with Federa Standard No. 205. Glass in the windshield must be AS1, not AS2 as your letter states. The windows on either side of the driver's compartment may be AS2, and AS2 may be used in the balance of the windows when needed for driver visibility or AS3 may be used in the balance of the windows when not needed for driver visibility.; The markings of glazing materials cited in your letter indicate tha the materials used in your motor home are in accordance with Federal Standard No. 205, with the exception that you state that AS2 is marked on the windshield.; Please advise if AS1 is not installed in the windshield of your moto home.; Sincerely, Clue D. Ferguson, Director, Office of Standards o Crash-Injury Reduction, Motor Vehicle Safety Performance Service; |
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ID: aiam4801OpenMr. Lawrence W. Rusk Project Engineer, Drum Brakes Bendix Automotive Systems Allied-Signal, Inc. P.O. Box 4001 South Bend, IN 46634-4001; Mr. Lawrence W. Rusk Project Engineer Drum Brakes Bendix Automotive Systems Allied-Signal Inc. P.O. Box 4001 South Bend IN 46634-4001; "Dear Mr. Rusk: This responds to your recent inquiry concernin adjustment procedures for hydraulic brakes during testing in accordance with Federal Motor Vehicle Safety Standard No. 105, Hydraulic Brake Systems. You asked whether, following the revisions effective September 1, 1991, the Standard will authorize manual brake adjustment on a vehicle equipped with duo-servo brakes and automatic brake adjusters following the initial burnish and three subsequent reburnishes. Although your letter did not specify that the focus of your inquiry is vehicles with a GVWR of 10,000 pounds or less, based on the context of your letter, I am assuming that this is the case. The answer to your question is yes, if manual adjustment is the published procedure recommended by the vehicle manufacturer. Standard 105 currently provides that where automatic brake adjusters have been locked out during testing, the brakes may be manually adjusted following the initial burnish and each subsequent reburnish. Where the automatic adjusters have not been locked out, the Standard requires that the brakes be adjusted at these points by making stops in accordance with the manufacturer's recommendations. See, S7.4.1.2, S7.6, S7.12 and S7.14. On September 29, 1989, NHTSA published a final rule (54 FR 40080) which requires that as of September 1, 1991, for all vehicles equipped with automatic brake adjusters being tested to Standard No. 105, that the automatic adjusters be operational during the test. In addition, the rule revises the provisions in S7.4 governing brake adjustment after burnish to delete language requiring that vehicles equipped with automatic adjusters be adjusted by making stops in accordance with the manufacturer's recommendations. These provisions are revised to state that following each specified burnishing, the brakes are to be adjusted in accordance with the manufacturer's published recommendations (e.g. recommendations set forth in service literature). Thus, if the manufacturer recommends that the brakes be adjusted manually, notwithstanding the automatic adjusters, they are to be manually adjusted. Alternatively, if the manufacturer recommends that the brakes be adjusted by completing a series of specified stops, that procedure must be followed. In conclusion, under the new provisions in Standard No. 105, brakes on a vehicle with automatic brake adjusters and a GVWR of 10,000 pounds or less should be manually adjusted at the end of the initial and subsequent burnishes if the manufacturer's published recommendations call for manual adjustment. I hope you find this information helpful. If you have further questions, please do not hesitate to contact David Greenburg of my staff, at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam0511OpenMr. Vincent G. Grey, Engineering Manager, Truck Trailer Manufacturers Association, 1413 K Street, N.W., Washington, DC 20005; Mr. Vincent G. Grey Engineering Manager Truck Trailer Manufacturers Association 1413 K Street N.W. Washington DC 20005; Dear Mr. Grey: This is in reply to your letter of November 11, 1971, concerning th application of GVWR and GAWR (49 CFR Parts 567, 568) to semitrailers.; Your position is that the term 'gross vehicle weight rating' is no meaningful when applied to semitrailers because the amount of cargo a semitrailer can carry depends upon the tractor that pulls it. You request that a different expression, 'rating based on load-carrying capability' be used 'for purposes of certification' (assumedly on the certification label). If that alternative is found unsatisfactory you request our concurrence with the following: 'For semitrailers, GVWR shall be taken to mean the structural capability of the vehicle when supported by the king-pin and axles with the load uniformly distributed throughout its length.' You also mention that gross vehicle weight rating has particular industry meaning and note that confusion' will certainly arise when state and Federal governmental authorities are using the same term to mean two different things.'; As we indicated in our meeting with you of November 4, 1971, we do no agree that the concept of GVWR is meaningless when applied to a semitrailer. The definition of GVWR, 'the value specified by the manufacturer as the loaded weight of a single vehicle' (49 CFR S 568.3), can be applied to a semitrailer without considering the load-carrying ability of a tractor. The fact that certain tractors should not be attached to a particular semitrailer loaded to its GVWR does not mean that the trailer cannot be so rated.; With regard to your first question, 'rating based on load-carryin capability,' while we do not grant your request that this language be substituted on the label, we believe that a GVWR based on operational load- carrying capability, as long as the weight of the vehicle is included, would be within the definition of GVWR in 49 CFR 568.3. Similarly, your other statement, 'For semitrailers, GVWR shall be taken to mean the structural capability of the vehicle when supported by the king-pin and axles with the load uniformly distributed throughout its length' is likewise consistent with the definition of GVWR. With reference to your claim concerning confusion of State and Federal regulation, we believe that if problems in this regard are properly presented to State government, any ambiguities can be satisfactorily resolved.; You also ask, with reference to Gross Axle Weight Rating, whether spee limitations can be included on the certification label. The regulation does not allow such weight limitations to be included within the listing of the required information, although it may be placed on the vehicle in any other location.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2039OpenMr. Edward L. J. Young, Director, Engineering, Lear Siegler, Inc., Neway Division, P.O. Box 425, Muskegon, MI 49443; Mr. Edward L. J. Young Director Engineering Lear Siegler Inc. Neway Division P.O. Box 425 Muskegon MI 49443; Dear Mr. Young: I appreciate your letter of August 13, 1975, forwarding a copy o Neway's publication on Standard No. 121, *Air Brake Systems*. The efforts of companies like Neway to assist final-stage manufacturers in their certification responsibility has been an important part of the implementation of the air brake systems standard.; You asked for review of the booklet, which consists mainly o instructions to manufacturers concerning systems that must be tested and how to establish a basis for certification. This is an area which our statutory scheme leaves to the manufacturer, and in which, aside from discussions of general principles, this agency declined to issue statements of approval. While we appreciate the usefulness of the advice contained in your booklet, we regret that we can not judge the adequacy of a certification program in the abstract.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0004OpenMr. Jeffrey S. Malinowski Small Business Center 407 Avalon Marine City, MI 48039; Mr. Jeffrey S. Malinowski Small Business Center 407 Avalon Marine City MI 48039; "Dear Mr. Malinowski: This responds to your letter on behalf of Mr. Le McCallum, asking whether any Federal Motor Vehicle Safety Standard applies to his invention, a tie rod 'safety bracket.' You stated that the product would typically be installed by a vehicle owner to reduce tie rod end wear. As explained below, while no Federal safety standard directly applies to your client's product, he may nevertheless have certain responsibilities under this agency's regulations. As way of background information, the National Traffic and Motor Vehicle Safety Act of 1966, as amended (the 'Safety Act') authorizes the National Highway Traffic Safety Administration (NHTSA) to issue safety standards applicable to motor vehicles and items of motor vehicle equipment. The Safety Act also requires that these safety standards establish minimum levels of performance for vehicles or equipment. Once the necessary performance level has been established, vehicle or equipment manufacturers are free to choose any means they wish to achieve the required level of performance. In other words, the safety standards do not require the use of any particular manufacturer's product or particular materials, the standards permit the use of any manufacturer's product that achieves the necessary performance level. Section 114 of the Safety Act (15 U.S.C. 1403) requires manufacturers to certify that each of its vehicles or items of motor vehicle equipment complies with all applicable safety standards. NHTSA does not approve, endorse, or certify any motor vehicle or item of motor vehicle equipment. NHTSA has no safety standard directly about tie rods or safety brackets used with tie rods. As for installation of your client's device on vehicles in the aftermarket, such installations may be limited by section 108(a)(2)(A) of the Safety Act (15 U.S.C. 1397(a)(2)(A)). That section prohibits any manufacturer, distributor, dealer, or motor vehicle repair business from knowingly rendering inoperative any device or element of design installed on or in a motor vehicle in compliance with an applicable safety standard. If installation of your client's product resulted in a vehicle no longer complying with a safety standard, a manufacturer, distributor, dealer, or repair business that installed the product would have rendered inoperative a device or element of design installed on the vehicle in compliance with a standard. To avoid a 'rendering operative' violation, your client should examine his product to determine if installing his product would result in the vehicle no longer complying with a standard's requirements. Section 109 of the Safety Act (15 U.S.C. 1398) specifies a civil penalty of up to $1,000 for each violation of the 'render inoperative' provision. Please note that the Safety Act does not establish any limitations on an individual vehicle owner's ability to alter his or her own vehicle. Under Federal law, individual owners can install any device they want on their own vehicles, regardless of whether that device renders inoperative the vehicle's compliance with a safety standard. Other statutory provisions in the Safety Act could affect your client's product. Manufacturers of motor vehicle equipment such as the 'tire rod safety bracket' are subject to the requirements in sections 151-159 of the Safety Act (15 U.S.C. 1411-1419) on the recall and remedy of products with defects related to motor vehicle safety. The Safety Act specifies that if either the manufacturer or this agency determines that a safety-related defect exists in your client's product, your client as the manufacturer must notify purchasers of the safety-related defect and must either: (1) repair the part so that the defect is removed, or (2) replace the part with an identical or reasonably equivalent part which does not have a defect. Whichever of these options is chosen, the manufacturer must bear the full expense and cannot charge the owner for the remedy if the equipment was purchased less than eight years before the notification campaign. I hope this information is helpful. If you have any further questions, 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"; |
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ID: aiam5206OpenMr. Dave Beidleman Arizona Department of Transportation Equipment Services; Mr. Dave Beidleman Arizona Department of Transportation Equipment Services; FAX 602-258-5193 Dear Mr. Beidleman: We have received your FAX of Jul 2, 1993, to the attention of Taylor Vinson of this Office, asking for an interpretation of Motor Vehicle Safety Standard No. 108 as it pertains to the location of rear identification lamps. The rear configuration of l0 dump trucks that are being constructed for the Arizona DOT is such that you would like to raise the center lamp of the three- lamp identification lamp cluster approximately 1 1/2 inches, the two outer lamps of the array cannot be raised due to the positioning of the underbody tailgate release mechanism. Table II of Standard No. 108 requires that the identification lamps be mounted 'as close as practicable to the top of the vehicle, at the same height, and as close as practicable to the vertical centerline.' In our opinion, the lamps in an identification lamp cluster must be equally spaced laterally and mounted at the same height in order for the identification lamp system to perform its intended purpose. Therefore, I am afraid the agency cannot accept a lamp display that differs. Although the lamps could be mounted on the rear of the cab, we understand that in that position they could be obscured by the top lip of the dump body. We realize that the contractor has pre-punched holes for the lamps, which would be flush-mounted in the rear cross sill of the truck body. If a way were found to cover the holes, there are surface-mounted lamps available which could be mounted at the same height (your desired height for the center lamp) in a manner than should not affect the positioning of the underbody tailgate release mechanism. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam2469OpenInterps. File, 49 CFR Part 575.104, (UTQGS); Interps. File 49 CFR Part 575.104 (UTQGS); Subject: Tread Label Format: *Uniform Tire Quality Grading Standards* On December 16, 1976, I received a telephone call from Mr. Calvi Schaffner of B.F. Goodrich Co. (216 379-3470) concerning Figure 2 of the Uniform Tire Quality Grading Standards, 49 CFR S 575.104. That figure depicts the format of the tread label required by the rule.; Mr. Schaffner referred to Figure 2 as it appears in Notice 21 (41 F 54205, December 13, 1976). I explained that, because Notice 21 is a notice of proposed rulemaking rather than final rulemaking, the inclusion of the warnings in the traction and temperature grades is not yet certain. I further explained, however, that (i) in all other respects, the depiction of Figure 2 in that notice was correct, (ii) the appearance of Figure 2 was incorrect in both Notices 17 and 18, due to printing errors at the Federal Register, and (iii) this point would be clarified in a final rulemaking notice.; Mark Schwimmer, Attorney-Advisor |
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ID: aiam0454OpenMr. J.T. Flynt, President, Cox Tire Machinery Company, Inc., 1101 W. First Street, Charlotte, North Carolina 28201; Mr. J.T. Flynt President Cox Tire Machinery Company Inc. 1101 W. First Street Charlotte North Carolina 28201; Dear Mr. Flynt: Your letter of September 29, 1971, to the National Highway Traffi Safety Administration requesting an interpretation of Federal Motor Vehicle Safety Standard No. 117, has been referred to this office for reply.; Within S5 of Standard No. 117, it states that retreaded tires mus conform to S4.2.1 of Standard No. 109 requires a treadwear indicator that will provide a visual indication that the tire has worn to a tread depth of 1/16 inch. For your information, we have enclosed copies of Standard No. 109 and No. 117.; Sincerely, E.T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
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ID: aiam2193OpenHonorable John E. Moss, Chairman, Subcommittee on Oversight and Investigations, Committee on Interstate and Foreign Commerce, House of Representatives, Washington, DC 20515; Honorable John E. Moss Chairman Subcommittee on Oversight and Investigations Committee on Interstate and Foreign Commerce House of Representatives Washington DC 20515; Dear Mr. Moss: Thank you for your January 19, 1976, letter asking for furthe explanation of the National Highway Traffic Safety Administration's (NHTSA) position on a school bus seating standard that specifies both passive compartmentalization and the installation of seat belt anchorages.; The NHTSA has issued its school bus seating standard (Standard No. 222 *School Bus Seating and Crash Protection*) in a form that requires compartmentalization of vehicle occupants but does not require installation of seat belt anchorages. There is not sufficient information in the record on which to determine what percentage of school districts would utilize seat belts. The limited evidence available to the NHTSA indicates that only a small fraction of school buses would have belts installed and properly used, and that the decision to mandate seat belt anchorage installation should await further information as to the extent to which belts would be installed and properly used.; The issue of whether the NHTSA is on 'safe legal ground in mandating requirement that in itself does not contribute to motor vehicle safety but requires further action on the part of local officials' has become less urgent in view of the standard's promulgation without anchorage requirements. I would like to respond generally that the NHTSA has always held the opinion in construing the National Traffic and Motor Vehicle Safety Act (the Act) that safety performance requirements that require further action by vehicle users are entirely appropriate. While some safety devices (such as bumpers) are in place and operate passively, most devices, (such as lights and seat belts) require occupant action to gain protection. Seat belt anchorages require more action than simple use to gain their benefits, but this does not appear to be a legally significant distinction. In this case, I decided that substantial controversy over the appropriateness and legality of this protection should not continue to create uncertainty over the ultimate form of the standard, endangering the ability of manufacturers to comply with Congress' maximum 9-month leadtime for upgrading school bus seating systems. We have, of course, left the issue of restraints in school buses.; While the decision on passive restraints could negate the value of sea belt training during the adult years, it should be noted the NHTSA is not proposing passive protection for the rear seats of passenger cars where children are encouraged to ride. They would need to use the seat belts provided to increase their protection in a crash.; Sincerely, James B. Gregory, Administrator |
Request an Interpretation
You may email your request to Interpretations.NHTSA@dot.gov or send your request in hard copy to:
The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590
If you want to talk to someone at NHTSA about what a request for interpretation should include, call the Office of the Chief Counsel at 202-366-2992.
Please note that NHTSA’s response will be made available in this online database, and that the incoming interpretation request may also be made publicly available.