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: aiam0998OpenMr. Walter S. McPhail, President, Lectron Products, Inc., 1810 Stephenson Highway, Troy, MI 48084; Mr. Walter S. McPhail President Lectron Products Inc. 1810 Stephenson Highway Troy MI 48084; Dear Mr. McPhail: This is in reply to your letter of January 29, 1973, concerning you safety belt interlock system.; Paragraph S7.4.1 of Federal Motor Vehicle Safety Standard No. 208 Occupant Crash Protection, requires that the belt system at each occupied seating position be operated after the occupant is seated in order to start the engine. It is our opinion that a system such as yours, which senses whether the safety belt is properly buckled around the occupant before allowing the engine to start would meet the above requirements and could be used under the option described in S4.1.2.3.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1370OpenMr. M. L. Higgins, Truck Trailer Manufacturers Association, 2430 Pennsylvania Avenue, N.W., Washington, DC 20037; Mr. M. L. Higgins Truck Trailer Manufacturers Association 2430 Pennsylvania Avenue N.W. Washington DC 20037; Dear Mr. Higgins: This is in reply to your letter of November 26, 1973, asking whethe motor vehicle new or used car dealers are prohibited from selling vehicles mounted on regrooved or recapped tires. You indicated in a phone conversation with Michael Peskoe of this office that your concern is with motor vehicles generally, and not passenger cars alone.; New passenger cars are required to be sold with tires meeting th requirements of Motor Vehicle Safety Standard No. 109 (49 CFR 571.110). New vehicles other than passenger cars are not presently required by NHTSA regulations to be sold with particular tires, but requirements in this regard have been proposed (36 F.R. 14273, August 3, 1971).; This agency has no requirements regarding the sale of used moto vehicles equipped with recapped or retreaded tires. However, buses subject to Bureau of Motor Carrier Safety regulations are prohibited from operating with recapped, retreaded, or regrooved tires on their front wheels (49 CFR S 393.75(d)).; Trucks and truck tractors subject to Motor Carrier Safety requirement may not be operated with regrooved tires on the front wheels which have a load carrying capacity equal to or greater than that of 8.25-20 8 ply-rating tires (49 CFR 393.75(e)). For more inforamtion regarding the applicability of these requirements you should contact, Regualtions Division Bureau of Motor carrier Safety, Federal Highway Administration, United States Department of Transportation, Washington, DC 20590.; The sale of regrooved tires is subject to regulations issued by thi agency (49 CFR Part 569). the recent opinion issued by the United States Court of Appeals (*NAMBO* v. *Brinegar*, D.C. Dir., Case No. 71-1268, July 26, 1973) appears to allow the sale of regrooved tires under these regulations in certain circumstances. We believe the opinion is unclear in this regard, and as a result we have determined to seek additional judicial review to further clarify the matter.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3382OpenMr. T. Shimada, Senior Technical Manager, MMC Services Inc., 3000 Town Center, Suite 1960, Southfield, MI 48075; Mr. T. Shimada Senior Technical Manager MMC Services Inc. 3000 Town Center Suite 1960 Southfield MI 48075; Dear Mr. Shimada: This responds to your letter of October 14, 1980, regarding the warnin devices required by Safety Standard No. 114, *Theft Protection*, and Safety Standard No. 208, Occupant Crash Protection. You ask whether the sound of a voice repeating the phrase 'please pull out the ignition key' or 'please fasten seat belt' at 2-3 second intervals could be used to satisfy the requirements of Standard No. 114 and Standard No. 208. You also ask whether a buzzer or chime that signals an unfastened seat belt or the presence of the key in the ignition could also be used to give the driver other warnings, such as turning off the headlights.; Standard No. 114 does not specify the nature of the warning that mus be given to the driver in the event that the ignition key is left in the locking system. Thus the system you describe would comply with the rule. Notre that the signal must be activated whenever the key has been left in the ignition and the driver's door is opened.; Standard No. 208 requires that the driver's seating position b equipped with a warning system that activated a continuous or intermittent audible signal for a period of not less than four (4) seconds and not more than eight (8) seconds. The signal must begin when the vehicle's ignition switch is in the 'on' or 'start' position and the driver's belt is not in use. If the system you have devised stops the warning only when the belt has been fastened, it would not comply with this rule. The signal must end within eight (8) seconds, irregardless(sic) of whether the driver's belt has been fastened. Regardless your specific question, an audible 'voice' signal would be permitted under the standard.; The buzzers or chimes that are installed in accordance with Standar No. 214 or Standard No. 208 may also be used to warn the driver of other conditions.; We hope you find this information helpful. Please contact this offic if you have any other questions.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4650OpenMr. David G. Gould Legislation Department Lotus Engineering Hethel, Norwich, Norfolk NR14 8EZ ENGLAND; Mr. David G. Gould Legislation Department Lotus Engineering Hethel Norwich Norfolk NR14 8EZ ENGLAND; "Dear Mr. Gould: Thank you for your letter asking whether a worl manufacturer identifier (WMI) assigned by the Society of Automotive Engineers (SAE) pursuant to a contract with this agency may be deleted from SAE's register of assigned WMIs upon request of a foreign national governmental agency, but without the consent of the holder of the WMI. Absent some extraordinary circumstances, the answer to your question is no. 49 CFR Part 565, Vehicle Identification Number - Content Requirements, sets forth format and content requirements for vehicle identification numbers (VINs). Section 565.4(a) specifies that the first three characters of the VIN shall be the manufacturer's WMI, which is 'assigned in accordance with /565.5(c) of this part.' Section 565.5(c) specifies that the SAE assigns WMIs to vehicle manufacturers under contract with the National Highway Traffic Safety Administration (NHTSA). No provision in NHTSA's regulations sets forth any procedures for deleting assigned WMIs from the SAE register upon the request of any party, even the manufacturer assigned the WMI. Similarly, no provision in the contract specifically addresses the issue of deleting assigned WMIs for any reason. In its contract with NHTSA, SAE has agreed to 'furnish the facilities, materials, personnel and services necessary to accomplish the work...' We contacted the SAE's WMI Coordinator to learn how they have handled this situation in the past. We were informed that the WMIs are assigned by the SAE for an indefinite period with no express provision for revocation of the assignment. There have been a few isolated instances in which the party to whom a WMI was assigned has contacted SAE and asked that the WMI assignment be revoked. In those instances, the SAE has granted the manufacturer's request but the revoked WMI is never reassigned to another manufacturer. To date, SAE has never been asked to delete an assigned WMI by any party other than the manufacturer to whom the WMI was assigned. If a situation arose in which the SAE was asked to delete an assigned WMI without the knowledge and consent of the manufacturer to whom the WMI was assigned, the SAE assures us that they would not act on the request without consulting this agency. If and when we are ever consulted by SAE for our opinion on how to handle such a request, we would carefully consider the circumstances of the particular case before advising SAE on how to respond to the request. As a general matter, however, NHTSA does not favor the deletion of assigned WMIs for any reason. Sincerely, Stephen P. Wood Acting Chief Counsel"; |
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ID: aiam3195OpenMr. Brian Gill, Manager, Certification Department, American Honda Motor Co., Inc., P.O. Box 50, 100 W. Alondra Boulevard, Gardena, California 90247; Mr. Brian Gill Manager Certification Department American Honda Motor Co. Inc. P.O. Box 50 100 W. Alondra Boulevard Gardena California 90247; Dear Mr. Gill: This is in response to your letter of November 18, 1979, requesting a interpretation as to whether the VIN plate samples you enclosed with your letter comply with the requirements of Standard No. 115, *Vehicle identification number*.; You enclosed two proposed VIN plates in your letter, one fo automobiles and one for motorcycles.The VIN plates themselves and the pre-printed lettering which appears on them seem to conform to the requirement of Standard No. 115. The lettering is clear and indelible, as required by S4.3, in that it cannot be removed without damage to the surface on which it is printed. Further, the plate when riveted to the vehicle would be considered to be permanently affixed in that it cannot be removed without damage (S4.3). The type face utilized for the lettering consists of capital, sans serif characters with a minimum height of 4 mm as required by S4.3.1.; The letters stamped on the automobile VIN plate 'SL5322AS000001', ca hardly be seen, and would not appear to meet the requirements of S4.3 and S4.4.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1452OpenMr. J.K. White,Domi Racer Distributors, inc.,5218 Wooster Road,Cincinnati, Ohio 45226; Mr. J.K. White Domi Racer Distributors inc. 5218 Wooster Road Cincinnati Ohio 45226; Dear Mr. White:#This responds to your March 19, 1974, request to kno if aircraft hydraulic hose is suitable for motor vehicle use under Standard 106, *Brake hoses*.#Standard No. 106, *Brake hoses*, presently applies to hydraulic brake hose for use in passenger cars, and therefore sale of aircraft hydraulic hose for use in motorcycles is presently legal. However, Standard 106 has been recently amended to require extensive performance testing and labeling of all motor vehicle brake hose manufactured after September 1, 1974. Sale of an aircraft hose manufactured after that date which has not been certified to conform to Standard 106 would violate S108 (a)(1) of the National Traffic and Motor Vehicle Safety Act of 1966. This means that the hose must be properly tested for conformity to the standard, and labeled according to the standard, before it can be sold as motor vehicle hose.#Yours truly,Richard B. Dyson,Assistant Chief Counsel; |
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ID: aiam4200OpenMr. W. Alex Cantrell, President, C&A Control Systems, Inc., 7117 Commercial Park Drive, Knoxville, TN 37918; Mr. W. Alex Cantrell President C&A Control Systems Inc. 7117 Commercial Park Drive Knoxville TN 37918; Dear Mr. Cantrell: This responds to your letter regarding the LA-Z-START, a remote contro device which you manufacture for starting automobiles. You ask whether your device is compatible with Standard No. 114, *Theft Protection*. I regret the delay in responding to your letter.; For your information, this agency does not approve motor vehicles o motor vehicle equipment. Instead, NHTSA relies on the self-certification process in the National Traffic and Motor Vehicle Safety Act of 1966, as amended, which requires each manufacturer to certify that a motor vehicle or item of motor vehicle equipment complies with all applicable safety standards.; The product information enclosed with your letter indicates that thi device permits a person to use a remote control device to send a coded signal to start or stop a vehicle engine up to 500 feet away. Your device will shut off the engine immediately if any of the following events occur: (1) the transmission is removed from the park position, (2) the brake pedal is depressed, (3) the engine overspeeds or overheats, or (4) the hood is raised. In addition, the device will not start the engine if the transmission is in forward or reverse gear. The device automatically shuts off the engine after 12 to 14 minutes running time and allows remote shut-off at any time.; Standard No. 114 requires that passenger cars as well as trucks an multipurpose passenger vehicles with a gross vehicle weight rating of 10,000 pounds or less have a key locking system. When the key is removed, the system must prevent normal activation of the vehicle's engine and prevent either steering or forward self-mobility or both. You state that starting a vehicle with your device does not permit normal activation of the vehicle's engine and either forward motion or steering until the key is inserted into the ignition and turned to the on position. Therefore, the question is whether your device, which permits activation of the engine when the ignition key is removed, permits 'normal activation' of the vehicle.; In previous interpretations, the agency has determined that automotiv remote starting devices with characteristics similar to yours were outside the concept of 'normal activation.' These characteristics have included automatic deactivation of the remotely started engine when a vehicle door is opened, maintenance of the steering column or gear shift locking feature until the ignition key is inserted in the vehicle, and automatic deactivation of the remotely started engine after 15 minutes unless the key is inserted into the ignition.; Your device apparently has some of these same characteristics, as wel as other automatic deactivation features which are comparable in nature. Therefore, we conclude that your device does not conflict with the requirements of Standard No. 114, since it does not permit normal activation of the engine without the ignition key.; Although not related to compliance with Standard No. 114, the agency i concerned about the possibility that a child could accidentally press the transmitter button on your device and, thus, start a car by remote control. This situation could clearly raise safety problems. Therefore, we suggest that you add language to the purchasers' instructions making them aware of this possibility and urging them to take precautions to avoid use of the product by anyone who is not authorized to drive the car.; I hope this information is helpful to you. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1002OpenMr. Spencer O. Moore, Merino and Moore, 651 Town and Country Village, Post Office Box 1334, Sunnyvale, CA 94086; Mr. Spencer O. Moore Merino and Moore 651 Town and Country Village Post Office Box 1334 Sunnyvale CA 94086; Dear Mr. Moore: This is in reply to your letter of February 1 to Mr. B.M. Crittenden Regional Administrator, concerning emergency flashers.; Effective January 1, 1969, all new automobiles were required to mee Federal Motor Vehicle Safety Standard No. 108, 'Lamps, Reflective Devices and Associated Equipment,' which in turn required the vehicular hazard warning signal operating unit to meet Society of Automotive Engineers Standard J910, January 1966. Prior to January 1, 1969, automobiles were required to meet the standards and regulations of the individual States. Since New York required hazard warning signals (4-way flashers) in 1966, most automobiles manufactured for sale throughout the United States were similarly equipped.; SAE J910 did not contain requirements relating the activation of th signal to the position or rotation of the steering wheel. Several States prohibited the operation of the subject signal on a moving vehicle, therefore, on many cars, this signal was cancelled by the rotation of the steering wheel, and consequently could not be activated even with the vehicle stopped with the steering wheel in certain positions.; We are unaware of similar complaints on the activation of the hazar warning signals.; Sincerely, E. T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
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ID: aiam3896OpenMr. H. Moriyoshi, Executive Vice President and General Manager, Mazda (North America), Inc., 24402 Sinacola Court, Farmington Hills, MI 48016; Mr. H. Moriyoshi Executive Vice President and General Manager Mazda (North America) Inc. 24402 Sinacola Court Farmington Hills MI 48016; Dear Mr. Moriyoshi: This is in reply to your letter of November 21, 1984, asking for a interpretation of Motor Vehicle Safety Standard No. 108 as it would apply to a contemplated parking lamp system.; Usually passenger cars are designed with two parking lamps, one on eac side of the vehicle front. Mazda would have two such lamps on each vehicle side, each of the two lamps flanking the headlamp. You have asked whether, in determining the H-V axis, one takes the axis as the center of each lamp, or should one consider the pair a single device and place the H-V axis at the midpoint between them.; Standard No. 108 requires passenger cars to be equipped with a minimu of two parking lamps, located 'as far apart as practicable.' Therefore, the outermost parking lamp, (the one located between the turn signal lamp and the headlamp is the lamp that must meet the parking lamp requirements of Standard No. 108, and the H-V axis for purposes of compliance would be determined at the center of the lens of that lamp. Supplementary lighting equipment is permissible under Standard No. 108 and does not have to meet the Standard's requirements, but it must not impair the effectiveness of the lighting equipment required by the standard (paragraph S4.1.3). Because of the difference in candela between parking lamps and headlamps, information available to us does not indicate that your supplementary parking lamp would have this effect, and consequently, the design would be permitted.; I hope that this answers your questions. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2784OpenMr. Karsten J. Vieg, Governor's Representative for Highway Safety, Illinois Department of Transportation, 2300 South Dirksen Parkway, Springfield, IL 62764; Mr. Karsten J. Vieg Governor's Representative for Highway Safety Illinois Department of Transportation 2300 South Dirksen Parkway Springfield IL 62764; Dear Mr. Vieg: This is in reply to your letter of September 22, 1977, to th Administrator asking whether an Illinois standard applicable to school bus lighting is neither preempted by nor violates Federal Motor Vehicle Safety Standard No. 108, *Lamps, Reflective Devices, and Associated Equipment*.; Paragraph S4.1.4(b) (ii) of Standard No. 108 requires that: '>>>The [school bus signal lamp] system shall be wired so that th amber signal lamps are activated only by manual or foot operation and, if activated, are automatically deactivated and the red signal lamps automatically activated when the bus entrance door is opened.'<<<; Under the Illinois requirement (4.2.18.2) the amber signal lamps appea to be activated only by manual or foot control (4.2.18.2(d)), and are automatically deactivated when the bus entrance door is opened (4.2.18.2(e) and (f)). The red signal lamps are activated before the bus entrance door is opened (4.2.18.2(e)) and remain activated when the door is opened (4.2.18.2(f)). Thus, these portions of the Illinois requirement comply with Standard No. 108.; As for the remaining portions of 4.2.18.2, they dictate sequentia operational requirements of the 8-lamp system and stop arm (an item of equipment not required by Standard No. 108). To accomplish this operation, 4.2.18.2 requires that 'A separate circuit breaker and a master switch shall be provided for this signal system.' You have asked whether this is preempted by Standard No. 108.; The aspect of performance involved here is that of wiring requirement for school bus warning lamps. Standard No. 108 specifies the manner in which these lamps shall operate but it is silent as to the ways this performance shall be achieved. Therefore Illinois is not preempted from requiring a separate circuit breaker and master cylinder in school bus lighting systems, a specification which is one of good engineering practice and probably used as a matter of course by most school bus manufacturers.; Sincerely, Joseph J. Levin, Jr., 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.