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: aiam4787OpenSamson Helfgott, Esq. Helfgott & Karas, P.C. 60th Floor Empire State Building New York, NY l0ll8-0ll0; Samson Helfgott Esq. Helfgott & Karas P.C. 60th Floor Empire State Building New York NY l0ll8-0ll0; Dear Mr. Helfgott: This is in reply to your letter of June ll, l99 (Your file CAIN 8877), with respect to the permissibility under Standard No. 108 of the use of amber lamps on the rear of motor vehicles. You have referenced our letter to you of March 30, l989, on the use of a single amber lamp adjacent to, but separate from, the center highmounted stop lamp. Your client wishes to utilize the amber center lamp in conjunction with rear amber turn signal lamps to provide an amber triangular array on the rear. The array would be activated when the ignition is turned on, and remain activated except when the stop lamps were activated (which, with the red center lamp, provide a red triangular array). With respect to the triangular amber lamp array you have asked the following four questions: 'l. The possibility of utilizing the amber turn signals as tail lights, instead of the red tail lamps. This is the same as is now in effect on the front of all vehicles.' Standard No. 108 requires that the color of taillamps be red. Therefore amber turn signal lamps could not serve as substitutes for taillamps. Your comment about frontal lighting is not exactly in point. A turn signal lamp may be combined with a parking lamp (provided the requirements for each are met) but Standard No. 108 requires that both be amber in color. '2. The possibility of supplementing existing tail lamps with the presence of the amber lamps.' We do not regard this as a true supplement because the color of the array differs from that of the taillamps required by Standard No. 108. However, like taillamps, the array is intended to indicate the presence of a vehicle. The question is, whether an array of three amber lamps would impair the effectiveness of the required two red taillamps. As we advised in our letter of March 30, l989, additional lighting equipment is permissible as long as it does not impair the effectiveness of the lighting equipment that the standard requires. We cautioned that you should consider whether steady-burning amber lamps might confuse following drivers, who would probably be unused to seeing steady burning amber lamps on the rear of a vehicle. Because you have not informed us as to the intended candela of the array, we cannot advise with any assurance whether the amber array would impair the effectiveness of the required red taillamps. Certainly if the candela of the triple amber arrray exceeded that of the red taillamps a basis would appear to exist for a judgment of impairment. '3. The possibility of using the amber lamps as daytime running lamps on the rear of a vehicle.' Under this scenario, the amber array would function as daytime presence lamps, a function not provided by any rear lighting system required by Standard No. 108. The question therefore is whether such a system would impair the effectiveness of the signal lamps required by Standard No. 108. These are hazard warning signals, turn signals, and stop lamps. With respect to the hazard warning signals, these operate through the turn signal lamps, and, although operable when the vehicle is in motion, they are designed to operate when the ignition is not on (i.e., when the triple array would be deactivated). Therefore, we do not believe that the triple array would impair the effectiveness of the hazard warning signals. As for impairment of the turn signals, we must distinguish between those that are amber and those that are red. Again, we raise the possibility that confusion could exist if the candela of the triple array exceeds that of an amber turn signal system. It is imperative that following drivers understand without hesitation the signals provided by other vehicles in front of them. Confusion may be less likely to exist if the required signal lamp and the triple array differ in color. Concerning the stop lamps, you have informed us that the triple array is deactivated when the stop lamps come on. In this event, there would be appear to be no impairment of the stop signals. '4. The possibility of utilizing the 'amber triangular array' as described above.' In our view, no specific Federal rulemaking appears required for your client to offer its system for installation on motor vehicles, subject to the constraints expressed in this letter and the letter of March 30, l989. As the earlier letter explains, the determination of whether there is impairment is initially made by a manufacturer who wishes to offer the system as new vehicle equipment. In the aftermarket, installation of the system must not, in effect, result in impairment of required lighting equipment, but nevertheless the system is subject to State and local lighting laws. We have forwarded a copy of your letter and our response to the agency's Office of Research and Development for their information. We appreciate your client's interest in motor vehicle safety. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam1585OpenMr. Joseph G.M. Vidoli, Attorney at Law, The Chadamy Corporation, 5241 Southwyck Blvd., Toledo, OH 43614; Mr. Joseph G.M. Vidoli Attorney at Law The Chadamy Corporation 5241 Southwyck Blvd. Toledo OH 43614; Dear Mr. Vidoli: This responds to your August 8, 1974, request for our opinion of th legality of the manufacture and sale of a device which frustrates the ignition function of seat belt assemblies in 1974 model passenger cars. The device, to be manufactured by the Chadamy Corporation under the name 'Buzz-Off', consists of two devices that are inserted in the ends of a seat belt assembly to simulate a buckling action.; The National Highway Traffic Safety Administration has promulgated n safety standard regulating the manufacture of your product. A standard does exist, however, which specifies requirements for occupant restraint systems. If one of your devices were installed in a vehicle prior to its first purchase for purposes other than resale, causing the interlock system not to be in compliance with the occupant crash protection standard, the person installing the device or offering the vehicle for sale would be in violation of Section 108(a)(1) of the National Traffic and Motor Vehicle Safety Act. That section prohibits the manufacture for sale, sale, or offer for sale of any motor vehicle or item of motor vehicle equipment that does not comply with applicable safety standards in effect on the date of their manufacture.; I would like to point out, that we estimate 10,000-15,000 individual died needlessly during 1973 because they were not wearing their seatbelts. Obviously, any device which disconnects a seat belt interlock could gravely increase the risk faced by the occupants of the motor vehicle. We cannot agree with your conclusion that people would not utilize your device to frustrate the interlock in highway driving.; I would also like to point out the recent Congressional action in whic the House of Representatives passed a law which would prevent a requirement for ignition interlock systems in future passenger cars. The final form of this law, pending Senate action, is not clear.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam0547OpenMr. Thomas E. Toney, III, Fordyce, Wayne, Hartman, Renard & Stribling, Attorneys and Counselors, 818 Olive Street, Saint Louis, MO 63101; Mr. Thomas E. Toney III Fordyce Wayne Hartman Renard & Stribling Attorneys and Counselors 818 Olive Street Saint Louis MO 63101; Dear Mr. Toney: This is in reply to your letter of October 10, 1972, requestin information on requirements applicable to the trucking industry regarding the reporting of numbers of vehicles produced. You also ask whether a person who adds a fifth wheel to complete a truck is a manufacturer who is subject to the requirements.; Section 573.5(5) of NHTSA 'Defects Reports' regulation (49 CFR Par 573) requires manufacturers of motor vehicles to report, on a quarterly basis, the total number of the manufacturer's vehicles by make, model, and model year, if appropriate, produced or imported during that quarter. This requirement applies to all manufacturers of complete or incomplete motor vehicles, including manufacturers of trucks. A person who adds a fifth wheel to an incomplete vehicle and completes the vehicle is considered to be a manufacturer under section 573.3 of the regulation, and is required to report production figures as part of his quarterly reports.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2080OpenMr. John F. McCuen, Counsel, Kelsey-Hayes Company, Romulus, MI 48174; Mr. John F. McCuen Counsel Kelsey-Hayes Company Romulus MI 48174; Dear Mr. McCuen: This responds to Kelsey-Hayes Company's July 28, 1975, question askin whether the requirements of S5.1.6 of Standard No. 121, *Air Brake Systems*, that specify a warning signal 'in the event of a total electrical failure of the antilock system' would permit installation on a vehicle of an antilock-equipped axle that has no capability signal electrical failure of its antilock system. You state that the vehicle would be equipped with antilock systems on other axles that would provide a warning signal in the event of their electrical failure.; The answer to your question is yes. As you noted in your letter, th National Highway Traffic Safety Administration has interpreted the specifications of S5.1.6 to require a signal only in cases where electrical failure within the antilock electrical system circuity causes loss of antilock control of every wheel on the vehicle. In the design you describe, the signal which activates upon loss of antilock control at one or more wheels on the vehicle would fulfill this requirement, because it would always activate by the time antilock control had been lost at every wheel on the vehicle. Under our interpretation of S5.1.6, a failure of antilock only on the axle described by you would not constitute 'loss of antilock control of every wheel on the vehicle' and would not be required to be signaled.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam4857OpenMr. Rueben K. Brown Product Engineer Crane Carrier Company P.O. Box 582891 1925 North Sheridan Tulsa, OK 74158; Mr. Rueben K. Brown Product Engineer Crane Carrier Company P.O. Box 582891 1925 North Sheridan Tulsa OK 74158; Dear Mr. Brown: This responds to your letter of March 12, 199 requesting an interpretation of the applicability of the spike stop requirement in Standard No. 105 to school buses with GVWR greater than 10,000 lbs. While school buses are required by S5.1 to be capable of meeting the requirements of S5.1.1 through S5.1.6, the spike stop requirement in S5.1.6 is only applicable to vehicles with a GVWR of 10,000 lbs. or less. Therefore, school buses with a GVWR greater than 10,000 lbs are not required to be capable of meeting the spike stop requirement. I hope this information has been helpful. If you have further questions, please contact Mary Versailles of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam0117OpenMrs. Jerry E. Anderson, Tejas Campers, 5125 College, Beaumont, TX 77707; Mrs. Jerry E. Anderson Tejas Campers 5125 College Beaumont TX 77707; Dear Mrs. Anderson: Thank you for your letter of August 19, 1968, concerning glazing an lighting requirements in campers.; The amendment to Standard No. 205 to which you refer, Docket No. 23, i enclosed along with a copy of FHWA Ruling 68-1. The amendment does not allow AS2 tempered glass to be placed in forward facing windows of campers. Forward facing windows of campers must be AS1, AS2 laminated that meets the requirements of test no. 26 of ASA Standard Z26.1 - 1966, or AS3 laminated that meets the requirements of test no. 26 of ASA Standard Z26.1 - 1966. Rigid plastics may be used in other windows.; With respect to your question on vehicle lighting requirements enclosed is a copy of Federal Motor Vehicle Safety Standard No. 108, effective January 1, 1969. You will note from the standard that clearance lamps are not required on vehicles less than 80 inches in overall width. The specified requirements for side marker lamps and side reflex reflectors on vehicles of less than 80 inches in overall width are contained in paragraphs S3.1.1.6 and S3.1.1.8 and Tables III and IV of Standard No. 108.; I have had your name added to our mailing list for all rulemaking related to multipurpose passenger vehicles and trailers and I have also enclosed information on subscribing to the *Federal Register* should you so desire.; Sincerely, Clue D. Ferguson, Director, Office of Standards o Crash-Injury Reduction, Motor Vehicle Safety Performance Service; |
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ID: aiam5315OpenMr. William D. McIntosh Quality Assurance Manager Perstorp Components Kitchener, Ontario, Canada K2G 4R9; Mr. William D. McIntosh Quality Assurance Manager Perstorp Components Kitchener Ontario Canada K2G 4R9; "Dear Mr. McIntosh: This responds to your inquiry about whethe Standard No. 302, Flammability of Interior Materials (49 CFR 571.302), applies to your product. You state that you manufacture a 'composite assembly acoustical abatement product' that is installed against vehicle sheet metal and is then covered by carpet, trim, or the instrument panel. You had further questions about testing your product and certifying its compliance if the Standard applies to it. I apologize for the delay in responding. By way of background information, NHTSA is authorized to issue Federal Motor Vehicle Safety Standards that set performance requirements for new motor vehicles and items of motor vehicle equipment. NHTSA does not, however, approve or certify any vehicles or items of equipment. Instead, the National Traffic and Motor Vehicle Safety Act (The 'Safety Act') establishes a 'self- certification' process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. Since Standard No. 302 is a vehicle standard, the manufacturer of the vehicle, and not the manufacturer of the individual component, is responsible for certifying compliance with Standard No. 302. The agency periodically tests new vehicles and items of equipment for compliance with the standards. Under the Safety Act's authority, NHTSA has issued Standard No. 302 which specifies burn resistance requirements for materials used in the occupant compartment of new motor vehicles. Section S4.1 lists the components in vehicle occupant compartments that the vehicle manufacturer must certify as complying with the flammability resistance requirements of paragraph S4.3. The components listed include seat cushions, seat backs, seat belts headlining, convertible tops, arm rests, all trim panels including door, front, rear, and side panels, compartment shelves, head restraints, floor coverings, sun visors, curtains, shades, wheel housing covers, engine compartment covers, and any other interior materials, including padding and crash deployed elements, that are designed to absorb energy on contact by occupants in the event of a crash. Among the listed items that might be applicable to your acoustical abatement product are floor coverings and engine compartment covers. That is, the standard would apply to your product if the acoustical abatement material is a part of one of the covered items and is within 1/2' of the occupant compartment. You indicate in your letter that you are uncertain whether to test your product to Standard No. 302 as a composite with other materials. S4.2.2 of Standard No. 302 states, 'Any material that adheres to other material(s) at every point of contact shall meet the requirements of S4.3 when tested as a composite....' You indicate in your letter that your product has multiple layers that always adhere to each other. Accordingly, assuming your product is subject to Standard No. 302, the agency would test your product as a composite material, in accordance with S4.2.2. Please note that there are other NHTSA requirements that could affect the manufacture and sale of your product. A motor vehicle or equipment manufacturer incorporating your product in its vehicles or equipment would be subject to sections 151-159 of the Safety Act to ensure that its vehicles or equipment do not contain any safety related defect. If the manufacturer or NHTSA determines that a safety related defect exists, the manufacturer would be responsible for notifying purchasers of the defective vehicle or equipment and remedying the problem free of charge. In addition, section 108(a)(2)(A) of the Safety Act states: 'No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative...any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable motor vehicle safety standard...' Under this section, the entities mentioned above are required to ensure that the addition of your product would not adversely affect the compliance of any component or element of design on a vehicle with an applicable Federal safety standard. With respect to Standard No. 302, the addition of your product must not reduce the vehicle's overall flammability resistance. 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, John Womack Acting Chief Counsel"; |
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ID: aiam1356OpenMr. Alden G. Olson, Engineer/Transit Technology, Municipality of Metropolitan Seattle, 410 West Harrison Street, Seattle, WA 98119; Mr. Alden G. Olson Engineer/Transit Technology Municipality of Metropolitan Seattle 410 West Harrison Street Seattle WA 98119; Dear Mr. Olson: This responds to your April 2, 1974, request for a ruling on whethe trolley and motor buses equipped with air brake systems and dynamic electric or hydraulic devices are required to be equipped with antilock equipment.; Standard No. 121, *Air brake systems*, requires stopping distanc performance which must be met by any bus equipped with air brakes, whether or not it is equipped with supplementary dynamic braking means, and the stops must be made with only controlled wheel lockup over 10 mph. Although the standard does not require antilock devices, many manufacturers have indicated they will use antilock devices to meet this requirement.; In evaluating a vehicle's compliance with the stopping distanc performance requirements of S5.3 and S5.7.2.3, auxiliary braking devices may be utilized in making the stops provided such devices are engaged by means of the same service brake pedal or parking brake control that operates the air brakes. It should be noted, however, that these stops must be made with the transmission selector control in neutral or the clutch disengaged (S6.1.3).; It can be foreseen that at least one difficulty may arise in testin with supplementary brake systems. S6.3 requires that the transmission be in neutral or the clutch be disengaged during deceleration, which might eliminate the torque from your dynamic brake.; Please write again if this or other difficulties arise in th certification of your buses.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam3691OpenMr. Chuck Howard, President, Safety Alert Company, Inc., 1667 Ninth Street, Santa Monica, CA 90404, 213-452-2728; Mr. Chuck Howard President Safety Alert Company Inc. 1667 Ninth Street Santa Monica CA 90404 213-452-2728; Dear Mr. Howard: Thank you for your letter of May 6, 1983. You note that your Safet Alert device will blink the hazard warning lights four times in five seconds when the accelerator pedal is lifted when the car is moving at 30 mph or more.; We are glad to advise you that this device is not in violation o Federal Motor Vehicle Safety Standard Number 108, Lamps, Reflective Devices, and Associated Equipment - Passenger Cars, Multipurpose Vehicles, Trucks, Trailers, Buses and Motorcycles. For vehicles which predate having the hazard warning control, your device may blink the turn signals on both sides simultaneously.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4154OpenRussell F. Laurens, Investigating Case Coordinator, Office of Consumer Affairs, 2 Martin Luther King, Jr. Dr., S.E., Plaza Level, East Tower, Atlanta, GA 30334; Russell F. Laurens Investigating Case Coordinator Office of Consumer Affairs 2 Martin Luther King Jr. Dr. S.E. Plaza Level East Tower Atlanta GA 30334; Dear Mr. Laurens: This is in response to your letter of October 8, 1985, concernin Federal odometer disclosure requirements. It appears that Georgia car dealers have been *routinely* certifying that, to the best of their knowledge, the odometer reading is not the actual mileage and should not be relied upon. You asked whether this is a violation of the odometer requirements, by constituting a false statement or on any other grounds.; Congress found that purchasers rely on mileage as an indicator of th value and condition of vehicles and enacted Title IV of the Motor Vehicle Information and Cost Savings Act, 15 U.S.C. S 1981 *et seq*. Section 1988(a) of the Act requires the Secretary of Transportation to prescribe rules requiring any transferor to give a written disclosure (1) of the cumulative mileage registered on the odometer or (2) that the actual mileage is unknown, if the odometer reading is known to the transferor to be different from the number of miles the vehicle has actually travelled. To carry out this mandate, Federal regulation 49 C.F.R. Part 580 was promulgated. Furthermore, Section 1988(a) states that no transferor shall violate any rule prescribed under the section or give a false statement to a transferee in making any disclosure required by such rule.; A Senate report interprets Section 1988 as placing a duty on aut dealers to alert purchasers of irregularities in odometers when, in the exercise of reasonable care, they would have reason to know the odometer reading is inaccurate. S. Rep. No. 92-413, (92nd Cong., 2nd Sess.), 1972 U.S. Code Cong. Ad. & News 3971-3972. If a purchaser receives an odometer statement in which his transferor certified that the odometer reading does not reflect the actual mileage and should not be relied upon, that purchaser, when selling the vehicle, should certify the same. However, if a purchaser receives an odometer statement in which his transferor certified that to the best of his knowledge the odometer reading reflects the actual mileage the vehicle has been driven, and he has no reasonable suspicion that the reading is inaccurate, when selling the vehicle, he should not certify that the reading is inaccurate. If a transferor certifies the readings as inaccurate in the latter situation, it is the position of the National Highway Traffic Safety Administration that they violate the regulations prescribed under Section 1988, 49 C.F.R. S 580.4.; The Federal regulations provide for the inclusion of two sets o certifications on odometer disclosure statements. If the dealers truly wish to insulate themselves from liability when they have a reasonable suspicion that the mileage on the odometer has been altered, they *should* certify that the reading is not accurate, and check the third statement in the first set of certifications. However, none of the three statements in the second set covers a situation where a transferor suspects that an odometer reading is inaccurate, but the odometer was not altered, set back or disconnected in his possession. The Agency allows a transferor to check the first statement and cross out the lines which read, 'and I have no knowledge of anyone else doing so' provided that though crossed out it can still be read. Alternatively, we have no objection to a transferor writing and checking a fourth statement which would read:; >>>I hereby certify that the odometer of said vehicle was not altered set back, or disconnected while in my possession.; << |
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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.