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: aiam4823OpenThe Honorable John D. Dingell Chairman, Subcommittee on Oversight and Investigations Committee on Energy and Commerce House of Representatives Washington, DC 20515; The Honorable John D. Dingell Chairman Subcommittee on Oversight and Investigations Committee on Energy and Commerce House of Representatives Washington DC 20515; "Dear Mr. Chairman: Your letter of July 10, 1990 about th applicability of NHTSA's safety standards to replacement parts was misplaced. This is indeed unfortunate, embarrassing, and I can assure you extraordinary. You asked me to review an April 9, 1990 interpretation letter from our Office of Chief Counsel to Mr. Rowghani, which indicated that Standard No. 214, Side Door Strength, applies only to new vehicles, and not to doors sold as replacement parts. In view of your concern about replacement parts, we have reviewed that interpretation, and our authority regarding replacement parts. Many of our safety standards apply only to complete vehicles, while others apply only to the individual components (whether original or replacement equipment). Some apply both to vehicles and to the components involved. Each of our standards includes an 'Application' section, which clearly defines the scope of coverage, based on the nature of the safety issue and the vehicle/equipment items involved. NHTSA's standards which apply to equipment (both original and replacement equipment) generally cover those types of items which can be used in many different vehicle lines, which are frequently replaced or sold separately, and which can be independently tested. These include such items as brake hoses (Standard 106), lamps and reflectors (Standard 108), tires (Standards 109, 117 and 119), windows and windshields (Standard 205), safety belt assemblies (Standard 209), child safety seats (Standard 213), and motorcycle safety helmets (Standard 218). Other safety systems require testing in a full-vehicle context, and our safety standards are applied to the vehicle rather than the component. Examples include brake performance (Standards 105 and 121), occupant crash protection (Standard 208), head restraints (Standard 202) and roof-crush resistance (Standard 216), as well as side-door strength. As noted in the April 9 letter, Standard 214 applies only to whole cars, not to replacement parts, as stated in the application section (see S2 of Standard 214, copy enclosed). While most manufacturers have chosen to meet the Standard by adding reinforcement beams, we are aware of at least one vehicle (a gray-market imported Mercedes-Benz) which passed the standard's compliance test without such a beam. Further, while intuitively it seems that doors without a reinforcement beam are not as safe as ones with a beam, efforts to document a safety problem have been unsuccessful. The current compliance procedures specify testing a door as part of a new vehicle (see S4 of Standard 214), since it does not appear feasible to specify an appropriate procedure for testing an individual new door (whether original or replacement) by itself. The reason for this is that a door's performance in resisting intrusion is dependent not only on the structure of the door itself, but also other factors such as the vehicle frame into which the door fits, and the hinges and latches which hold the door in place within the frame. In addition, vehicle seats may help resist intrusion and protect occupants. The current standard reflects these factors. While the current standard does not apply to replacement doors, NHTSA has full authority to pursue any alleged safety problems with doors or any other vehicle components under the 'defects' provision of the Safety Act. If evidence demonstrated that certain replacement doors presented an unreasonable risk to motor vehicle safety, the agency could order the manufacturer of such doors to repair or replace such doors. At the present time, however, we are not aware of a safety problem with replacement doors that would warrant the commencement of a defects investigation. I appreciate your interest in the safety of vehicle parts and hope this information is helpful. For further discussion of the legal issues regarding the applicability of standards, your staff should feel free to contact our Chief Counsel, Mr. Paul Jackson Rice, at 366-9511. Sincerely, Jerry Ralph Curry Enclosure"; |
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ID: aiam0533OpenMr. William C. Bottger, Jr., Latham & Watkins, 615 South Flower Street, Los Angeles, CA 90017; Mr. William C. Bottger Jr. Latham & Watkins 615 South Flower Street Los Angeles CA 90017; Dear Mr. Bottger:This is in reply to your letter of November 16, 1971 in which you ask whether a manufacturer may add certain statements to the Certification label required pursuant to Part 567 of Title 49, Code of Federal Regulations. You state that the manufacturer in question is engaged in the manufacture and mounting of concrete mixer assemblies. Because, as you state, the weight of the concrete may vary according to the mix formula, and because the volume of mix loaded into a mixer can also vary, the manufacturer wishes to add to his Certification label a declaration of the vehicle's cargo load and an indication of the maximum volume of mix that could be safely hauled within the rated cargo load limit.; There is no prohibition to this additional information being added t the Certification label as long as (1) it appears after the required information, and (2) it is stated in such a way that it cannot be confused with the information, particularly the GVWR and GAWR, required to be placed on the label.; We are pleased to be of assistance. Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1288OpenMr. Howard Levine, Ft. Lauderdale Police Dept., 1300 W. Broward Boulevard, Fort Lauderdale, FL (zip code missing); Mr. Howard Levine Ft. Lauderdale Police Dept. 1300 W. Broward Boulevard Fort Lauderdale FL (zip code missing); Dear Mr. Levine: This is in reply to your inquiry of October 18, 1973, concerning th legal consequences of disconnecting the seat belt interlock systems in the new cars your department is purchasing.; The dealer or distributor from whom you buy the cars is required unde subsection 108(a)(1) of the National Traffic and Motor Vehicle Safety Act, Public Law 89-563 (15 U.S.C. 1397(a)(1)), to deliver them to you with the interlocks operational. However, subsection 108(b)(1) of the act provides that the requirements of subsection 108(a)(1) do not apply after the first purchase of a vehicle for purposes other than resale. As a purchaser who intends to use the cars, rather than resell them, your department is therefore not obliged to keep the interlocks operational.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4570OpenJ.W. Lawrence, Manager, Compliance Volvo GM Heavy Truck Corporation 7825 National Service Road Airpark West, P.O. Box 26115 Greensboro, NC 27402-6115; J.W. Lawrence Manager Compliance Volvo GM Heavy Truck Corporation 7825 National Service Road Airpark West P.O. Box 26115 Greensboro NC 27402-6115; "Dear Mr. Lawrence: This is a response to your letter of October 5 1988, asking this agency to 'reconsider and rescind' an interpretation of Standard 124, Accelerator Control Systems (49 CFR /571.124). The interpretation which was the subject of your request was addressed to Mr. Leon Steenbock and dated March 17, 1988. Mr. Steenbock asked whether it is permissible under Standard 124 to install a locking hand throttle control in a new motor vehicle. In our response to Mr. Steenbock, we stated that while nothing in the Standard prohibits installing a hand-throttle control in a new vehicle, ''locking hand throttle controls' are expressly prohibited by Standard 124.' In your letter, you stated that most (and perhaps all) heavy truck manufacturers install hand throttles for engine warm-up, extended idle periods, and for vocational applications such as pumping, compacting, and mixing. You also stated that your company installs only locking hand throttle controls and that these locking hand throttle controls hold the driver-selected engine idle speed until such time as the driver selects a new idle speed, or disengages the throttle. In support of your position that the letter to Mr. Steenbock was incorrect, you referred to the agency's response to petitions for reconsideration of Standard 124. NHTSA's response to requests that special provisions be made for hand throttles was as follows: Mack and Alfa Romeo petitioned that 'hand-throttles' and throttle positioners be specifically excluded from the definition of 'idle position.' Petitioners stated that in the event such a device is used a return to the preset throttle position occurs upon release of the driver-operated accelerator control system. This request is granted. If a driver choose to raise the lowest engine speed threshold by the use of a throttle positioning device, the throttle should return to that new position within the same time requirements specified in section S5.3. Accordingly, the NHTSA is amending the definition of 'idle position' to provide for the use of throttle positioners. (37 FR 20033, September 23, 1972.) In accordance with this stated intent, the definition of 'idle position' in S4.1 of Standard 124 was amended to read: (T)he position of the throttle that will provide the lowest engine speed for existing conditions according to the manufacturers' recommendations. These conditions include, but are not limited to, engine speed adjustments for cold engine, air conditioning equipment, and emission control equipment, and the use of throttle setting devices. Because of this language, we agree with your position that Standard 124 permits the installation of hand throttles, including locking hand throttle controls, provided that the vehicle's engine returns to the lowest engine speed threshold as adjusted by use of the hand throttle within the time and under the conditions set forth in S5 of Standard 124. To the extent that our March 17, 1988 letter is inconsistent with this interpretation, it is incorrect. I hope you find this information helpful. If you have further questions, please call Joan F. Tilghman of my staff at (202) 366-2992. Sincerely, Erika Z. Jones Chief Counsel cc: Mr. Leon Steenbock Administrative Manager, Engineering FWD Corporation Clintonville, WI 54929-1590"; |
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ID: aiam0860OpenMr. Satoshi Nishibori, Engineering Representative, Nissan Motor Co., Ltd., 560 Sylvan Avenue, Englewood Cliffs, NJ, 07632; Mr. Satoshi Nishibori Engineering Representative Nissan Motor Co. Ltd. 560 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Nishibori: This is in reply to your letters of August 8, and August 28, 1972 requesting interpretation of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials'.; In your August 8th letter, as we understand your first question, yo ask whether the adhesive, sound-proofing material used on the floor panels of your cars should be tested together with the few insulating fibers which become embedded in this material when the insulation which covers the sound- proofing material is removed. The Standard provides a list of the interior components which must meet its requirements and the manner in which those components are to be tested. Since the sound-proofing material you have described would not be considered a floor covering and it is not otherwise included in S4.1 of the Standard, it is not subject to the requirements.; You ask further whether the 'seal screen' you glue peripherally on th inner, door panels to prevent water from penetrating the interior of the door must meet the requirements of the Standard. The 'seal screen', as you describe it, does not appear to be part of the panel and, accordingly, it would not be subject to the Standard.; In your August 28th letter, you ask whether the procedure you have fo testing the 'jute' insulating material used under the floor carpet of your cars conforms to the requirements of Standard No. 302. You state that this procedure includes removing the insulation and testing its top surface, which you designate as 'surface B', rather than testing its bottom surface, which you designate as 'surface A'. We are not sure what you mean by testing a 'surface', the Standard refers to a test for the entire specimen. You may be concerned with whether the specimen is oriented upward or downward. Under the Standard, the test specimen for each component is to be tested 'so as to provide the most adverse results'. Accordingly, the relevant test result is the most adverse one achieved in any horizontal orientation, either upward- or downward-facing. The fact that you remove the insulating material so as not to raise the nap on its bottom surface is consistent with existing test procedures.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1772OpenMs. Dianne Black, Liaison Engineer, British Leyland Motors Inc., 600 Willow Tree Road, Leonia, NJ 07605; Ms. Dianne Black Liaison Engineer British Leyland Motors Inc. 600 Willow Tree Road Leonia NJ 07605; Dear Ms. Black: This is in response to your letter of December 19, 1974, requestin interpretations of two test conditions contained in Standard No. 301-75, *Fuel System Integrity*.; Your first question relates to the static rollover test condition an asks whether it was the NHTSA's intention that the vehicle be rotated to three positions only for spillage measurement. (Paragraph S7.4 specifically refers only to increments of 90 degrees, 180 degrees, and 270 degrees.) The static rollover test is intended to test the amount of fuel spillage a vehicle experiences at each 90 degree increment in a full 360 degree rotation. The standard presumes that the test begin with the vehicle in an upright position. It is from this upright position that the vehicle begins its movement to the remaining three 90 degree increments.; Your second question asks for an interpretation of the section relatin to the operation of the vehicle's fuel pump during testing. Paragraph S7.1.3 of the standard requires that a electrically driven fuel pump be in operation during the barrier crash tests if it normally operates with the activation of the vehicle's electrical system. If pump operation requires the operation of the vehicle's engine, ten (sic) the pump should not be running during the barrier crash tests. If the fuel pump installed in your barrier is capable of independent operation as described in SF.1.3 it should be operating during the barrier crash tests even if it cuts off fuel at the moment of impact. Under the existing requirements, whether a pump out of fuel at impact would not be relevant to whether it must be operating at impact. Of course, over cutoff feature would be considered as pard of the bump's normal operation.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam4120OpenMr. Sidney K. Saksenberg, Manager of Regulatory Affairs, CSA Limited, Inc., P.O. Box 690347, Houston, TX 77269-0347; Mr. Sidney K. Saksenberg Manager of Regulatory Affairs CSA Limited Inc. P.O. Box 690347 Houston TX 77269-0347; Dear Mr. Saksenberg: This responds to your November 12, 1985 letter to NHTSA's Office o Vehicle Safety Compliance, concerning the packaging requirements of Federal Motor Vehicle Safety Standard No. 116, *Brake Fluid*, You asked whether the brake fluid container you enclosed would comply with the standard. Your letter has been referred to my office for reply.; By way of background information, I must explain that NHTSA does no pass approval on the compliance of any vehicle or equipment with a safety standard before the actual events that underlie certification. Under the National Traffic and Motor Vehicle Safety Act, it is your responsibility as a manufacturer to determine whether your products comply with all applicable safety standards and regulations, and to certify your products in accordance with that determination. Therefore, the following interpretation only represents the agency's opinion based on your letter and enclosure.; The sample container you enclosed is plastic and has a resealable scre cap. The cap is attached to a plastic band, or ring, encircling the opening of the container, and the attachment is broken when the cap is twisted open. The cap itself is lined with an inner seal which you have indicated is impervious to the packaged brake fluid.; Standard No. 116 specifies performance and labeling requirements fo motor vehicle brake fluids and their containers. Paragraph S5.2.1 of the standard sets forth specific requirements for container sealing of brake fluid packages:; >>>Each brake fluid or hydraulic system mineral oil container with capacity of 6 fluid ounces or more shall be provided with a resealable closure that has an inner seal impervious to the packaged brake fluid. The container closure shall include a tamper-proof feature that will either be destroyed or substantially altered when the container closure is initially opened.<<<; The container you enclosed appears to be provided with a resealabl closure, i.e., the twist-off cap, and an impervious inner seal. The cap's tamper-proof feature is the attachment to the plastic ring that would be broken (and thus 'destroyed or substantially altered') when the cap is initially opened. Although not required by the standard. you have taken the commendable extra step of including a statement on the cap that warns purchasers not to accept the container if the seal is broken. We would suggest that you ensure that the warning is clearly legible.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1322OpenMr. William A. Teeling, Somerset Motors Inc., U.S. Highway 22, White House, NJ 08888; Mr. William A. Teeling Somerset Motors Inc. U.S. Highway 22 White House NJ 08888; Dear Mr. Teeling: This is in reply to your letter of October 15, 1973, concerning th means by which you can establish that the odometer on a car you have purchased has been reset.; Without detailed information about the car and about the circumstance which lead you to believe that the odometer has been altered, we can only offer a broad outline of the possible methods of proof. One source might be a former owner who had registered more miles on the odometer when he sold the car than are shown upon subsequent resale. Another source might be a repair shop or service station that had worked on the car and recorded its earlier mileage. A third source would be physical evidence on the car itself: excessive engine wear, excessive brake lining wear, or physical marks of tampering on the odometer or odometer cables. We would be interested to learn of the outcome of your situation.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2918OpenHonorable Bud Shuster, House of Representatives, Washington, DC 20515; Honorable Bud Shuster House of Representatives Washington DC 20515; Dear Mr. Shuster: This responds to your inquiry dated November 29, 1978, on behalf of on of your constituents, Mr. C. Stake, requesting information about Federal safety standards concerning door locks on automobiles. Specifically, Mr. Stake is concerned that the doors on his 1977 Mercury Monarch can be unlocked by a child from the inside by lifting the door handle.; I am enclosing a copy of Safety Standard No. 206 (49 CFR 571.206) which specifies performance requirements for side door locks and side door retention components to minimize the likelihood of occupants being thrown from the vehicle as a result of impact. That standard specifies that each door on a passenger car shall be equipped with a locking mechanism with an operating means in the interior of the vehicle. Paragraph S4.1.3.1 of the standard specifies that when the locking mechanism on a side *front* door is engaged, the outside door handle or other outside latch release control shall be inoperative. For side *rear* doors, however, paragraph S4.1.3.2 requires both the outside and inside door handles to be inoperative when the locking mechanism is engaged.; This latter requirement was specifically included in the standard t address Mr. State's concern, that is, to prevent children from unlocking rear doors by means of the door handle. The design restriction was limited to rear doors on the basis that the danger arises primarily with unattended children sitting in the rear seat. A child sitting in the front seat is likely under the watchful eye of the driver. Further, there is the consideration that in emergency situations the driver may need to unlock his front door as easily and quickly as possible.; Since the Standard No. 206 requirements have been in effect for som time, we assume that the situation Mr. Stake describes is true only of the front doors of his Mercury Monarch. As noted above, however, there are competing safety considerations involved with door locks on front side doors.; Please contact our office if your constituent has any further question concerning this matter, or have him contact us directly.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam0925OpenMr. Steven M. Sharp, Managing Director, Intercontinental Equipment Corp., 5383 Overland Avenue, San Diego, CA 92123; Mr. Steven M. Sharp Managing Director Intercontinental Equipment Corp. 5383 Overland Avenue San Diego CA 92123; Dear Mr. Sharp: This is in reply to your letter of September 25, 1972. You hav enclosed a copy of a letter from Suzuki Motor Company, Ltd., dated September 14, 1972, in which it objects to the certification label that you propose to attach to Suzuki trucks imported by you for sale. The label shows Suzuki as the manufacturer and Intercontinental Equipment Corporation (IEC) as the importer of the trucks.; Suzuki bases its objection on the fact that: >>>'. . . the vehicles as manufactured by Suzuki does (sic) not confor to all applicable Federal Motor Vehicle Safety Standards *in effect on the date of manufacture*, and it will be misrepresentation by our company to make such statement.'<<<; Suzuki also comments 'the responsibility for compliance rests sorel (sic) on both IEC and Yachiyoda but this fact is not clearly shown on the label.'; This agency's position is that the certification scheme you hav described is an appropriate one for imported vehicles that have been modified after manufacture to conform to the standards.; We do not consider the certification label necessarily to be representation by the original manufacturer. The question of who is responsible for the correctness of the certification, and for conformity, must be decided on the facts of the individual case. In this case, the representation is by IEC, not Suzuki, and IEC is responsible for conformity of the vehicle.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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.