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: aiam4538OpenMr. Frank Reynolds F.E. Reynolds Associates P.O. Box 703 Marysville, OH 43040; Mr. Frank Reynolds F.E. Reynolds Associates P.O. Box 703 Marysville OH 43040; "Dear Mr. Reynolds: This is in response to your telephone conversatio with Marvin Shaw of my staff, seeking a clarification of my June 16, 1988 letter concerning school bus mirrors under Highway Safety Program Guideline No. 17. Specifically, you asked about the meaning of the phrase, 'area in front of the bus,' as used in section S9.2(b) of Standard No. 111, Rearview Mirrors (49 CFR 571.111). In your telephone conversation, you stated that a NHTSA staff person told you in a previous telephone conversation that NHTSA had defined this phrase to mean 'the area three feet in front of the bus.' NHTSA has never so interpreted this phrase in Standard No. 111. For your information, I am enclosing a June 20, 1980 letter to James Tydings that sets forth the agency's interpretation of S9.2(b) of Standard No. 111. This letter notes that the area of concern in S9.2(b) is the region in front of the bus where a driver is not able to see directly a school age child. As explained in the letter and an earlier notice (40 FR 33829, August 12, 1975), the purpose of a crossview mirror is to 'address special problems of driver visibility associated with pupil transportation,' and this type of mirror 'allows the bus driver to see the area immediately in front of a stopped bus to be sure there are no children there before moving the bus.' This letter then explains: 'The agency used the word 'view' in its ordinary, dictionary sense to mean within the range of sight. Thus, most, but not literally all, of the front bumper must be visible to the driver by use of the crossview mirror to ensure that he or she can see children standing in front of the bus.' This is still an accurate expression of the agency's interpretation of the purpose of a crossview mirror and this phrase. In your telephone conversation, you also expressed concern about the 'legal effect' of Standard No. 111. You should be aware of 108 (a)(1)(A) of the Safety Act which states that No person shall manufacturer for sale, sell, offer for sale, or introduce or deliver for introduction in interstate commerce, or import into the United States, any motor vehicle or item of motor vehicle equipment manufactured on or after the date any applicable Federal motor vehicle safety standard takes effect under this title unless it is in conformity with such standard except as provided in subsection (b) of this section. I hope this information is useful. If you have any additional questions, or need further information on this subject, please feel free to contact Mr. Shaw at this address or by telephone at (202) 366-2992. Sincerely, Erika Z. Jones Chief Counsel Enclosure"; |
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ID: aiam0828OpenMr. J. W. Kennebeck, Manager, Safety & Development, Volkswagen of America, Inc., Englewood Cliffs, NJ, 07632; Mr. J. W. Kennebeck Manager Safety & Development Volkswagen of America Inc. Englewood Cliffs NJ 07632; Dear Mr. Kennebeck: This is in reply to your letter of July 27, 1972, requesting a interpretation of S4.3 of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials', and an opinion regarding the applicability of Standard No. 302 to your Model 15 convertible top cover.; You ask whether the basic burn rate of not more than 4 inches pe minute or the burn rate of 2 inches in less than 60 seconds should be applied to material which self-extinguishes after 55 seconds at a burn distance of 3 inches. The answer to this question is that the basic burn rate of not more than 4 inches per minute applies to this case. The basic burn rate requirement, calculated according to the formula given in S5.3(g), applies whenever the tested material burns more than 2 inches or more than 60 seconds. This 2-inch, 60-second burn rate provided in the second sentence of paragraph S4.3 is given to simplify the calculation of certain self-extinguishing materials, not for the purpose of imposing an additional requirement.; In regard to your graphic illustrations and you request for our opinio with respect to the validity of your Figure 3, you are correct in assuming that materials falling under the B-line are acceptable and that the portions of the shaded area under the B-line in Figure 2 represent an overlap that is in the acceptable area. The second burn rate was intended as a means for rapid qualification of test specimens that, because of their specified flammability limits, would be acceptable without further calculation to determine the burn rate. Any materials falling outside of the 2-inch or 60-second limits require calculation. It would, as you suggest, be a further simplification to say that material that self-extinguishes before burning 2 inches meets the performance requirement and is acceptable.; You ask further whether Standard No. 302 applies to your Model 1 convertible top cover. We consider for this purpose a convertible top cover, or boot, to be part of the convertible top itself and consequently subject to the standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2815OpenColonel James C. Crawford, Chief, Minnesota State Patrol, Department of Public Safety, Saint Paul, MN 53155; Colonel James C. Crawford Chief Minnesota State Patrol Department of Public Safety Saint Paul MN 53155; Dear Col. Crawford: Jim Downey of our regional office has forwarded for reply your lette of May 3, 1978, in which you asked whether a single beam headlighting system is permissible on mopeds.; The answer is yes. The portion of SAE Standard J584 that you hav quoted only establishes an option to the specific requirements of J574. Table 1 of J584 permits motor driven cycles to be equipped with a single (upper) beam headlamp. We consider mopeds to be 'motor driven cycles' as defined by 49 CFR 571.3(b) and J584 as they are invariably powered by a motor developing less than 5 horsepower.; I hope this answers your question. Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3707OpenMr. William E. Meiter, Middletown Van Pool Association, 60 Wallace Road, Middletown, NJ 00748; Mr. William E. Meiter Middletown Van Pool Association 60 Wallace Road Middletown NJ 00748; Dear Mr. Meiter: This responds to your note of May 27, 1983, attaching correspondenc between yourself and a District Manager for Ford Motor Company. You requested that we investigate the Ford E-150 van (which you state is a 15-passenger van) to determine if the stated Gross Vehicle Weight Rating of that vehicle is accurate.; Each manufacturer of a motor vehicle is required by the agency' regulations to place a certification label on the vehicle specifying that the vehicle is in compliance with all Federal motor vehicle safety standards and regulations (issued pursuant to the National Traffic and Motor Vehicle Safety Act of 1966). This certification label must include information regarding the vehicle's Gross Vehicle Weight Rating, as specified in 49 CFR 567.4(g)(3):; >>>(3) 'Gross Vehicle Weight Rating' or 'GVWR', followed by th appropriate value in pounds, which shall not be less than the sum of the unloaded vehicle weight, rated cargo load, and 150 pounds times the vehicle's designated seating capacity. However, for school buses the minimum occupant weight allowance shall be 120 pounds.'<<<; Thus, you are correct in your assumption that the GVWR for 15-passenger vehicle would have to include 2,250 pounds for occupant weight. Further, if a 15- passenger vehicle has a stated GVWR of 6,200 pounds, its unloaded vehicle weight could not exceed 3,950 pounds. I cannot state whether the Ford E-150 van has an unloaded vehicle weight in excess of this figure. However, I am sending a copy of your correspondence to our Office of Enforcement so that they may review this matter.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0081OpenMr. Carl W. Ruegg, Selma Trailer & Manufacturing Company, P. O. Box 120, Selma, CA 93662; Mr. Carl W. Ruegg Selma Trailer & Manufacturing Company P. O. Box 120 Selma CA 93662; Dear Mr. Ruegg: Thank you for your letter of May 2, 1968, which included additiona information for certification under Public Law 89-563 and your comments.; You will note that Federal Motor Vehicle Safety Standard 108 does no restrict the height of the identification lamps from the roadway. You may find it suitable to mount these lights at a lower level than indicated in your illustrations.; With respect to the requirements of Standard No. 108, I must point ou that this Bureau does not issue approvals on items of lighting equipment or on vehicle designs incorporating this equipment. Therefore, the above comments are for your information only and in no way relieve the vehicle manufacturer from his responsibility for certifying that the assembled vehicle meets the requirements of the standard.; I am enclosing a copy of the National Traffic and Motor Vehicle Safet Act of 1966 which defines the vehicles to which it applies.; Sincerely, Joseph R. O'Gorman, Acting Director, Office of Performanc Analysis, Motor Vehicle Safety Performance Service; |
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ID: aiam5283OpenMr. Matt Gerrity 7624 Rohrer Dr. Downers Grove, IL 60516; Mr. Matt Gerrity 7624 Rohrer Dr. Downers Grove IL 60516; "Dear Mr. Gerrity: This responds to your letter, forward to us o December 9, 1993, by Representative Harris W. Fawell, regarding the removal of the air bag in your 1990 Coupe de Ville. Because you have a physical handicap, you had your vehicle modified by the installation of a hand control system over the steering wheel. You are concerned that, in the event the air bag should activate, the steering device would probably pop off causing serious injury. You also stated that dealers and other mechanics are reluctant to disconnect the air bag because of Federal law. As discussed below, in certain limited situations, the National Highway Traffic Safety Administration (NHTSA) has exercised its discretion in enforcing our regulations to provide some allowance when making modifications to accommodate the special needs of persons with disabilities. While the disconnection of an air bag by a dealer or motor vehicle repair business would ordinarily be a violation of Federal law, this is to advise you that this agency would not institute enforcement proceedings against a dealer or repair business that disconnected the driver side air bag in your vehicle. If you show this letter to your dealer or mechanic, you should be able to get this work performed. By way of background information, NHTSA is authorized to issue Federal motor vehicle safety standards that set performance requirements for new motor vehicles and new items of motor vehicle equipment. Manufacturers are required by the National Traffic and Motor Vehicle Safety Act (Safety Act) to certify that their products conform to our safety standards before they can be offered for sale. Manufacturers, distributors, dealers and repair businesses modifying certified vehicles are affected by 108(a)(2)(A) of the Safety Act. It prohibits those businesses from knowingly rendering inoperative any elements of design installed on a vehicle in compliance with a safety standard. Removal or disconnection of an air bag by any of the named commercial entities would violate the 'render inoperative' prohibition, since air bags are installed to comply with Federal Motor Vehicle Safety Standard No. 208, Occupant Crash Protection. However, in certain situations where a vehicle must be modified to accommodate the needs of a particular disability, NHTSA has been willing to consider any violation of 108(a)(2)(A) a purely technical one justified by public need, and indicated that it would not institute enforcement proceedings. We will take this position for the specific factual situation cited above. We caution, however, that only necessary modifications should be made. For example, S4.5.2 of Standard No. 208 requires a readiness indicator for an air bag system which is clearly visible from the driver's seating position. After the air bag is removed, this indicator would show that the air bag system is not operative. The readiness indicator should not be modified, so other drivers who may expect an air bag will be aware that the air bag is not functional. I would also like to caution your dealer or mechanic to contact the vehicle manufacturer concerning the proper procedure for any air bag disconnection as this procedure could cause it to deploy and injure the mechanic. As a final caution, I note that the purpose of the 'render inoperative' provision is to ensure, to the degree possible, that current and subsequent owners and users of a vehicle are not deprived of the maximum protection afforded by the vehicle as newly manufactured. Your letter states that you would have the air bag reconnected before selling the car. I urge you to have this work performed so that future users of the vehicle will have the protection the air bag affords. I hope you find this information helpful. If you have any other questions, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel cc: Representative Harris W. Fawell United States House of Representatives 2342 Rayburn House Office Building Washington, DC 20515-1313"; |
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ID: aiam2546OpenMr. Dick Rechlicz, Executive Secretary, Wisconsin School Bus Association, Box 403, Brookfield, WI 53005; Mr. Dick Rechlicz Executive Secretary Wisconsin School Bus Association Box 403 Brookfield WI 53005; Dear Mr. Rechlicz: This responds to your March 5, 1977, letter asking for a interpretation concerning the definition of school bus. In particular you ask how the National Highway Traffic Safety Administration determines the seating capacity of a motor vehicle which in turn determines whether that vehicle will be considered a school bus for purposes of our regulations.; You are correct in your interpretation that a van designed to carr fewer than 10 passengers may transport children to or from school and need not comply with the new school bus safety standards. The NHTSA determines the seating capacity of a motor vehicle by the number of designated seating positions in the vehicle. The term 'designated seating position' is defined in Part 571.3 of our regulations (49 Code of Federal Regulations) to mean: '...any plan view location intended by the manufacturer to provide seating accommodation while the vehicle is in motion for a person at least as large as a 5th percentile adult female, except auxiliary seating accommodations such as temporary or folding jump seats.' Thus, as long as a van purchased for pupil transportation has fewer than 10 designated seating positions for passengers, it is not considered a school bus and need not comply with school bus safety standards.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam5329OpenMr. Perry McGlothan Quality Assurance Test Specialist Century Products Company 9600 Valley View Road Macedonia, OH 44056; Mr. Perry McGlothan Quality Assurance Test Specialist Century Products Company 9600 Valley View Road Macedonia OH 44056; Dear Mr. McGlothan: This responds to your letter to me about the hea impact protection and protrusion limitation requirements of Federal Motor Vehicle Safety Standard (FMVSS) No. 213, Child Restraint Systems. We received under separate cover the three child seats you sent for illustration purposes, samples of Models 4560, 4590 and the STE 1000. You discuss in your letter a new method you would like to use to attach the head impact protection foam to the child restraint shell. The foam would be attached to the shell by means of two push-in pins, each 1/2 inch in length and with a 3/4 inch diameter head, as distinguished from the padding being glued to the shell as in the past. You stated that this change would better secure the foam padding to the shell and help your manufacturing process. You asked us whether the new method would meet the head impact protection requirement of S5.2.3 (for restraints recommended for children weighing less than 20 pounds) and the protrusion limitations of S5.2.4. As you know, the National Traffic and Motor Vehicle Safety Act establishes a self-certification system under which manufacturers are responsible for ensuring that their products comply with all applicable FMVSSs. We do not approve, endorse, or give assurances of compliance of any product. NHTSA may examine the manufacturer's certification in the course of any enforcement action. In response to manufacturers' requests for interpretations of the FMVSS's, we try, to the extent possible, to provide information that will help them make their determinations of compliance. However, these responses are based on information provided by the manufacturer, and is subject to the findings of actual compliance testing by the agency. Should the agency, in the future, examine production units of these models and detect an apparent noncompliance or defect, those results will control. You first inquire, 'Please advise as to compression deflection,' which we understand as asking whether S5.2.3.2 would permit you to secure the foam with the pins. S5.2.3.2 states that each system surface, except for protrusions that comply with S5.2.4, which is contactable by a dummy head must be covered with slow recovery, energy absorbing material with specified characteristics. As explained in the next paragraph, the pins we examined appear to satisfy S5.2.4. Further, the pins might not be contactable by the dummy head in Standard 213's dynamic test. However, whether they are contactable can only be determined in the standard's dynamic test. S5.2.4 requires that any portion of a rigid structural component within or underlying a contactable surface, or any portion of a child restraint system surface that is subject to S5.2.3 shall meet specified limits on height and radius of exposed edge. Based on our visual inspection, the pins we saw appear to be within those limits. Again, however, the Vehicle Safety Act places the responsibility for determining compliance in the first instance on you, the manufacturer of the child restraint. We still have the three seats that you sent us. We plan to dispose of them unless we hear from you. I hope this information is helpful to you. Should you have any further questions or need further information, please feel free to contact Walter Myers of this office at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam2116OpenHonorable Jamie L. Whitten, House of Representatives, Washington, D.C. 20515; Honorable Jamie L. Whitten House of Representatives Washington D.C. 20515; Dear Mr. Whitten: This is in further reply to your letter of October 3, 1975, for Mr Charles Russell of WJLJ,regarding tire failures on ambulances in Tupelo, Mississippi.; Pursuant to the national Traffic and Motor Vehicle Safety Act of 1966 the Department's National Highway Traffic Safety Administration (NHTSA) has issued Federal Motor Vehicle Safety Standard No. 109, 49 CFR 571.109, which specifies performance and labeling requirements for new tires for use on passenger cars. Among the labeling requirements is that such tires must have their load ratings molded into or onto both sidewalls. Standard No. 119, 49 CFR 571.119, establishes similar requirements for new tires for use on trucks, buses, trailers, motorcycles, and multipurpose passenger vehicles (MPV's). The choice of standard applicable to a given tire depends on that tire's primary intended use. These standards apply to tires, and not to vehicles.; To ensure that new vehicles are equipped with proper tires, the NHTS has also issued Standard No. 110 for passenger cars and a proposed new Standard No. 120 that would apply to vehicles other than passenger cars. Briefly, Standard No. 110 requires each new passenger car to be equipped with tires which meet Standard No. 109 and which are sufficient load carrying capacity, as evidenced by the load ratings found on the sidewalls. As proposed, Standard No. 120 would require MPV's (including ambulances) to be equipped with tires which meet either Standard No. 109 or No. 119, and which are of sufficient load carrying capacity. In the case of Standard 119 tires, sufficiency of load carrying capacity would be calculated directly from the tires' load ratings. In the case of Standard 109 (passenger car) tires mounted on an MPV, sufficiency would be determined by dividing the tire load ratings by a 110 percent correction factor before comparing these ratings with the vehicle's weight ratings. The use of passenger car tires on new ambulances would thus not be prohibited by the new standard, provided this load rating correction factor is applied. This provision would recognize an established practice which has not been found to present a safety hazard. Passenger car tires generally provide a softer, more comfortable ride than truck tires, because the latter operate at a higher inflation pressures, and thus may even be more desirable on ambulances, provided they are of adequate load carrying capacity. The NHTSA expect to issue Standard No. 120 in the near future.; For your convenience, I am enclosing copies of Standards Nos. 109, 110 119, and the proposed Standard No. 120.; Sincerely, William T. Coleman, Jr. |
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ID: aiam2638OpenNoel C. Ice, Esq., Cantey, Hanger, Gooch, Munn, & Collins, 1800 First National Bank Building, Fort Worth, TX 76102; Noel C. Ice Esq. Cantey Hanger Gooch Munn & Collins 1800 First National Bank Building Fort Worth TX 76102; Dear Mr. Ice: This responds to your March 1, 1977, letter asking whether your client a company that manufactures, distributes, and sometimes installs air conditioners and cruise control units on automobiles prior to first purchase for purposes other than resale, must comply with the certification and other requirements of the National Highway Traffic Safety Administration (NHTSA).; Section 114 of the National Traffic and Motor Vehicle Safety Act o 1966 (the Act) (15 U.S.C. 1381, 1403) requires that motor vehicle and motor vehicle equipment manufacturers certify that each vehicle or item of equipment conforms to all applicable Federal motor vehicle safety standards. There are no standards applicable to air conditioners or cruise controls. Thus, your client would not be required to certify the equipment he manufactures.; Your client may, however, have certification responsibilities a prescribed in the regulation issued under Section 114 (49 CFR Part 567, *Certification) in his capacity as installer of air conditioners or cruise controls if such installation places him within the status of 'alterer,' as that term is defined in Part 567.7. This would occur if the installation of the equipment, prior to the vehicle's first purchase for purposes other than resale, either altered the vehicle's gross vehicle weight rating or gross axle weight rating or was the installation of a nonreadily attachable component.; It is unlikely that the installation of an air conditioning unit woul alter the gross vehicle weight rating (GVWR). GVWR is defined in 49 CFR Part 571.3 as 'the value specified by the vehicle manufacturer as the loaded weight of a single vehicle.' The installation of air conditioners or cruise controls may, however, constitute an installation of equipment which is not readily attachable or may exceed the gross axle weight rating. If this is the case, your client would have to comply with the requirements of Part 567.7. To ascertain whether the installation involves readily attachable components such factors as the intricacy of installation, and the need for special expertise or tools must be taken into consideration.; You ask whether your client would be required to comply with 49 CF Part 566, *Manufacturer Identification*. This part applies to manufacturers of motor vehicles and motor vehicle equipment to which a safety standard applies. Since no safety standards apply to the equipment manufactured by your client, he would not be required to comply with this regulation in his capacity as an equipment manufacturer. Further, the NHTSA has determined by interpretation that vehicle alterers need not comply with Part 566. Similarly, 49 CFR Part 568, *Vehicles Manufactured in Two or More Stages*, may not apply to your client, since the installation of an air conditioner or a cruise control would not make your client an incomplete vehicle manufacturer, an intermediate manufacturer, or a final stage manufacturer of vehicles as those terms are defined in the regulation (568.3). Your client might have responsibilities under Part 568.8 as a vehicle alterer, however.; You should note that if your client is considered an alterer, a defined in Part 567 or Part 568 he would be considered a manufacturer for purposes of notification and recall for defects or noncompliances resulting from his installations (the Act, Section 151 *et seq.).; If we can be of further assistance do not hesitate to contact us. Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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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.