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: aiam0659OpenMr. Edward L. Adams, Route 4, Union Hill, Carbondale, IL 62901; Mr. Edward L. Adams Route 4 Union Hill Carbondale IL 62901; Dear Mr. Adams: This is in reply to your letter of February 17, 1972, in which you as for information on safety specifications as they would apply to travel trailers.; All trailers manufactured for use on the public roads are required t meet applicable Federal Motor Vehicle Safety Standards (FMVSS) in effect on the date of manufacture. Part 567 of Title 49 of the Code of Federal Regulations requires that a certification label be attached to the left front of the trailer. A specific conformity statement is required, among other things, on the label. A copy of the regulation is enclosed.; We do not have information at this time that would add to the articl in the St. Louis Post Dispatch.; Thank you for your interest in the program of the National Highwa Traffic Safety Administration.; Sincerely, Francis Armstrong, Director, Office of Standard Enforcement, Motor Vehicle Programs; |
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ID: aiam2664OpenMr. Noel C. Ice, Cantey, Hanger, Gooch, Munn & Collins, 1800 First National Bank Building, Fort Worth, TX 76102; Mr. Noel C. Ice Cantey Hanger Gooch Munn & Collins 1800 First National Bank Building Fort Worth TX 76102; Dear Mr. Ice: This responds to your August 9, 1977, letter asking whether a alterer's responsibility for ensuring the compliance of a vehicle with Federal safety standards, as required in Part 567, *Certification*, extends only to those aspects of performance that could have been affected by the alteration or whether it extends to the compliance of the entire vehicle with all Federal standards.; The intent of the alteration regulation is to make vehicle alterer responsible for the continued compliance of the vehicles they modify. Therefore, an alterer would be held responsible for any noncompliance of a vehicle caused by his alterations. The National Highway Traffic Safety Administration would not hold the alterer liable for noncompliances in a vehicle that were the responsibility of the original vehicle manufacturer and not affected by the alterer's conduct.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3976OpenMs. Melinda Maggs, 243 Washington Ave., Scotia, NY 12302; Ms. Melinda Maggs 243 Washington Ave. Scotia NY 12302; Dear Ms. Maggs: Thank you for your March 25, 1985, letter asking about Federal moto vehicle safety regulations that might affect an aftermarket product you wish to manufacture. You described your product as a pad to cushion safety belts. The pad, which is removable, is made of 1/4 inch foam and is attached with velcro to the safety belt. I regret the delay in our response.; You first asked for confirmation of information received in a phon conversation with Paul Bauer of this office. As Mr. Bauer explained, section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act (Safety Act) may affect the sale of your product. As you requested, I have enclosed a copy of the Act for your reference. That section provides that manufacturers, distributors, dealers, and motor vehicle repair businesses may not render inoperative any safety device installed in accordance with any Federal safety standard. Since safety belts are safety devices installed in accordance with Safety Standards No. 208 and 209, those types of businesses may not install any other products which would impair the effective operation of the belts. Individual consumers may purchase and install additional products in their vehicles or otherwise modify existing equipment, without risk of violating the 'render inoperative' provision.; I should emphasize that we are unable to offer any opinion on whethe your product would impair the effectiveness of safety belts. We do recommend that manufacturers carefully consider that possibility before placing their products on the market.; You also asked whether any Federal regulations relating to materia content and flammability affect your product. Although no Federal Motor Vehicle Safety Standards directly govern material content, Standard No. 302 does provide flammability requirements for components of new vehicle occupant compartments, including safety belts. Thus, your product would need to meet the flammability standard if it was installed as original equipment in new vehicles.; Standard No. 302 would not apply directly to your product if it is sol only as aftermarket equipment. However, section 108(a)(2)(A) of the Safety Act, discussed above, could affect your product as it relates to the flammability standard. NHTSA would consider the installation of safety belt pads that do not meet the requirements of Standard No. 302 as 'rendering inoperative' an element of design (flammability resistance) installed in accordance with an applicable Federal safety standard. Again, this provision prohibits only manufacturers, dealers, distributors, and repair businesses from installing such products, it does not prohibit consumers from purchasing and installing those products on their own.; Again, we are not offering any opinion as to whether your product woul meet those flammability standards, but we recommend that you consider that aspect.; The agency believes that all Federal motor vehicle safety standards ar important and that all manufacturers should strive to meet those standards, whether required by law or not. Additionally, if noncomplying pads were to catch fire in a situation where a pad complying with Standard No. 302 would not have caught fire, a manufacturer might face possible product liability consequences under state law. Likewise, a manufacturer might face product liability consequences if its product impaired the effectiveness of the safety belts. You may wish to consult a local attorney in this regard to discuss your product.; I am enclosing copies of Safety Standards Nos. 208, 209 and 302. W appreciate your interest in devices which may encourage safety belt usage, and I hope this letter has addressed your concerns. If you have any further questions, please feel free to contact me.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam0209OpenMr. Michael G. Curran, G. F. Pierce Company, Marion Building, Cleveland, OH 44113; Mr. Michael G. Curran G. F. Pierce Company Marion Building Cleveland OH 44113; Dear Mr. Curran: This is in reply to your letter of January 13, 1970, to Mr. W. S Scott, and to your recent inquiry to Mr. James Gilkey, concerning your safety belt system.; Federal Motor Vehicle Safety Standard No. 210 specifies the number o belt anchorages that must be provided and the performance and location requirements of these anchorages in passenger cars. This standard does not apply to seat belt assemblies.; Seat belt assembly performance requirements are specified in Federa Motor Vehicle Safety Standard No. 209.; I am enclosing copies of Standards Nos. 209 and 210 for your reference. Thank you for your interest in motor vehicle safety. Sincerely, Clue D. Ferguson, Director, Office of Standards o Crash-Injury Reduction, Motor Vehicle Safety Performance Service; |
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ID: aiam2234OpenMr. Robert Fisher, Sales Engineer/Coordinator, Bock Products, Inc., 1901 West Hively Avenue, P.O. Box 1208, Elkhart, IN 46514; Mr. Robert Fisher Sales Engineer/Coordinator Bock Products Inc. 1901 West Hively Avenue P.O. Box 1208 Elkhart IN 46514; Dear Mr. Fisher: This responds to your February 11, 1976, question whether two traile designs you describe would qualify as 'Heavy Hauler Trailer[s]' as defined in Standard No. 121, *Air Brake Systems*. A copy of that definition is enclosed for your information.; Both of your trailer designs include a primary cargo-carrying surfac that inclines from a height of 24 inches in the rear to a height of 47 inches in the front of the trailer. In one case, part of the inclined portion is removable, leaving a 6-foot length of the surface that is flat and 40 inches above the ground in the unloaded condition. In both cases somewhat more than one-half of the primary cargo-carrying surface is 40 inches or less in height.; The exclusion from Standard No. 121 for heavy hauler trailers applie (in relevant part) only to trailers 'whose primary cargo-carrying surface is not more than 40 inches above the ground in an unloaded condition.' The trailer designs you describe would not qualify for the exclusion, because only a portion of the surface qualifies as 'not more than 40 inches above the ground.'; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam2721OpenMr. David M. Thompson, Kelsey-Hayes Company, Romulus, MI 48174; Mr. David M. Thompson Kelsey-Hayes Company Romulus MI 48174; Dear Mr. Thompson: This responds to Kelsey-Hayes' September 2, 1977, request to kno whether Standard No. 121, *Air Brake Systems*, allows a burnish of the brake friction elements immediately prior to the parking brake tests of S5.6, and whether the service line air pressure limitation of 100 p.s.i. specified in S5.4.2.1 can be exceeded momentarily.; A burnish prior to the parking brake test is not permitted by Standar No. 121, except that S6.1.8 specifies burnish of the parking brake friction elements before testing in those cases where the parking brake system does not utilize the service brake friction elements. The National Highway Traffic Safety Administration (NHTSA) would consider a provision to deal with the condition of the brake linings prior to the parking brake test upon receipt of technical data showing justification for such an action.; Section S5.4.2.1 of the standard specifies a procedure that state '[t]he service line air pressure shall not exceed 100 p.s.i. during any deceleration.' You describe a condition in which the service line pressure exceeds 100 p.s.i. for a short period (typically 0.1 seconds), which might be traced to characteristics of the friction material, brake mechanism, dynamometer, or instrumentation.; The NHTSA recognizes that peak pressure may be momentarily increased b the initial rush of air pressure into the brake chamber, or by other anomolies (sic). In the case of such momentary pressure increases, the NHTSA interprets S5.4.2.1 to mean that the source of air pressure for applying the brake must never exceed 100 p.s.i. Thus, it would be permissible to experience momentary pressures above 100 p.s.i. in the service line as long as the pressure source never exceeds that level. Sustained periods of pressure above 100 p.s.i. would not be permissible.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3833OpenB. R. Belsches, Captain, Safety Office, Department of State Police, Commonwealth of Virginia, P.O. Box 27472, Richmond, VA 23261-7472; B. R. Belsches Captain Safety Office Department of State Police Commonwealth of Virginia P.O. Box 27472 Richmond VA 23261-7472; Dear Captain Belsches: This is in response to your letter of April 20, 1984, asking for a interpretation of paragraph S4.6(b) of Motor Vehicle Safety Standard No. 108 and 'a history relative to the inclusion of such function of headlamps and marker lamps.'; Paragraph S4.6(b) allows means to be provided for the automati flashing of headlamps and side marker lamps for signaling purposes, as an exception to the general rule that vehicle lamps (other than turn and hazard warning signals, and school bus warning lamps) be steady-burning in use. This confirms your understanding of the wording of the standard and its effect. It does not allow, however, modulating headlamps which do not flash on and off, but deviate between a higher intensity and a lower one.; Originally, paragraph S3.5 of the standard (see *e.g.* 49 CFR 371.21 Standard No. 108 rev. as of January 1, 1970) stated that 'normally steady-burning lamps may be capable of being flashed for signaling purposes.' On January 3, 1970, the agency proposed paragraph S4.6 (35 F.R. 106) as it exists today. It was adopted on October 31, 1970 (35 F.R. 16840). The agency observed that some commenters requested that additional lamps be permitted to flash and some requested that flashing headlamps be prohibited. It also noted that, with the exceptions set forth in S4.6(a), flashing lamps should be reserved for emergency and road maintenance-type vehicles, and that flashing lamps are otherwise prohibited in the Uniform Vehicle Code. The agency further noted that lamps could be flashed by the driver merely by turning the switch on and off, and that it could not prohibit that type of operation, but that the definition of 'Flash,' also adopted in the amendments, made clear that automatic flashers for use with steady-burning lamps other than headlamps and side marker lamps were prohibited.; This is the rulemaking history of paragraph S4.6. I hope that this wil answer your questions.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2371OpenWilliam K. Rosenberry, Esq., Attorney at Law, Parkway Central Plaza, 611 Ryan Plaza Dr., Suite 713, Arlington, TX 76011; William K. Rosenberry Esq. Attorney at Law Parkway Central Plaza 611 Ryan Plaza Dr. Suite 713 Arlington TX 76011; Dear Mr. Rosenberry: This is in reply to your letter of July 14, 1976, to George Shifflet of the Office of Standards Enforcement, on behalf of a client who intends to install a different type of seat, carpeting, and headliner in a pick-up truck, which would then be sold to the general public. You asked whether a fabric supplier must test each fabric lot for flammability before certification to Motor Vehicle Safety Standard No. 302 can be given, and whether your client 'may rely on the warranty of a fabric manufacturer that the fabric sold meets the requirements ' of Standard No. 302.; You are correct in your understanding that the provisions of th National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 *et seq*) apply to your client. His basic responsibility is to ensure that the vehicles he modifies are in compliance with the Federal standards when delivered to dealers for sale to the public. (15 U.S.C. 1397(a)(1)(A)) A temporary noncompliance during modifications is permissible if the vehicle is not used on the public roads while noncompliant (15 U.S.C. 1397(a)(2)(A)). Standards which would appear to be affected by your client's modifications include: Standard No. 207 *Seating Systems*, No. 208 *Occupant Crash Protection*, No. 210 *Seat Belt Assembly Anchorages* and No. 302 *Flammability of Interior Materials*.; As a person who alters a certified vehicle other than by the additio of readily detachable (sic) components, your client is also required to attach his own certification of compliance to each modified truck (49 CFR 567.7). Should a noncompliance be discovered as a result of an alterer's modification, the alterer would be liable for a civil penalty unless he could establish that he did not have actual knowledge of the noncompliance, and that he did not have reason to know in the exercise of due care that the vehicle did not comply (15 U.S.C. 1397(b)(2)).; With respect to Standard No. 302, there is no requirement that a fabri supplier 'test each fabric lot for flammability before certification.' In point of fact, 49 CFR 571.302 Motor Vehicle Safety Standard No. 302 does not apply to suppliers but only to vehicle manufacturers (or alterers) and it is they who are required to certify compliance with Standard No. 302. Generally, at a minimum, a vehicle manufacturer will require by contract with the supplier that the fabric meets Standard No. 302. In the exercise of 'due care' the manufacturer may wish to examine the basis for the supplier's assurance of compliance, and to require periodic testing of the fabric being supplied him. Since there is no requirement that each fabric lot be tested, such testing as is conducted should be sufficient to demonstrate in the event of a noncompliance that the vehicle manufacturer has exercised due care. As to whether your client may rely on the 'warranty' of his supplier, it has been our experience that simple reliance is insufficient to establish a 'due care' defense. That manufacturer should examine the supplier's test results to insure that the margin of compliance of the test fabric is great enough that production variables do not result in noncompliance. Some manufacturers even conduct their own test independent of the supplier.; Your client would also be responsible for conducting a notification an remedy campaign (15 U.S.C. 1411 *et seq*) if a noncompliance or safety-related defect occurs in the truck as a result of the alterations.; I enclose copies of the Act, 49 CFR Part 567, and Standards Nos. 207 208, 210, and 302 for your information.; Yours truly, Frank Berndt, Acting Chief Counsel |
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ID: aiam3999OpenStephen T. Waimey, Esq., Dean Hansell, Esq., Law Offices of Donovan, Leisure, Newton & Irvine, 333 South Grand Avenue, Los Angeles, CA 90071; Stephen T. Waimey Esq. Dean Hansell Esq. Law Offices of Donovan Leisure Newton & Irvine 333 South Grand Avenue Los Angeles CA 90071; Dear Mr. Waimey and Mr. Hansell: Thank you for your letter of April 15, 1985, concerning the automati restraint requirements of Federal Motor Vehicle Safety Standard No. 208, *Occupant Crash Protection*. I regret the delay in our reply.; You asked about the requirement in S4.1.3 of the standard concernin the minimum annual production of passenger cars that must be equipped with automatic restraints. You stated your assumption that the standard applies only to vehicles produced for sale in the United States and asked how a manufacturer is to determine if a vehicle is a part of its annual production for the United States. You pointed out that there are a number of possible sales transactions, beginning with the sale of a vehicle by Porsche to the U.S. importer and ending with the first sale to a consumer in the U.S. that can be used in determining at which point a vehicle becomes part of Porsche's annual production for the United States. I hope the following discussion answers your question.; As discussed in the agency's April 12, 1985, (50 FR 14596) notice o Standard No. 208, your assumption that the term 'average annual production' refers only to cars manufactured for sale in the United States is correct. S4.1.3 specifies that percentages of production are to be based on the number of cars *manufactured* between discrete dates. In the case of foreign cars, as in the case of domestic ones, 'manufactured' means produced or assembled. Part 567 *Certification* (49 CFR Part 567) of the agency's regulation requires all vehicles manufactured for sale in the United States to have a tag affixed to them certifying that they meet all Federal Motor Vehicle Safety Standards. Therefore, in determining which vehicles are to be counted as the manufacturer s average annual production, the manufacturer should determine how many vehicles were produced and certified in accordance with our regulation during the applicable time period. Using production and certification provides the agency and manufacturers with an easily verifiable event to determine which cars are to be counted.; I hope this information is of assistance to you. If you have furthe questions, please let me know.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam3130OpenMr. Roger E. Maugh, Director, Automotive Safety Office, Ford Motor Company, The American Road, Dearborn, MI 48121; Mr. Roger E. Maugh Director Automotive Safety Office Ford Motor Company The American Road Dearborn MI 48121; Dear Mr. Maugh: Re: Distribution of Imported Vehicles Brought Into Conformity Wit Applicable Federal Motor Vehicle Safety Standards; This is in reply to Mr. Eckhold's letter of September 28, 1979, to Mr Vinson of this office asking for our concurrence in Ford's wish to sell 60 1978 model Ford Fiestas on the American market.; According to Mr. Eckhold's letter, 56 of the cars did not comply wit the Federal motor vehicle safety standards at the time they entered the United States for use by Ford in testing and training programs. Ford represents that all these have now been brought into compliance. The four remaining Fiestas conformed at the time of entry but, presumably, because of the execution of the HS-7 importation form, were not certified.; We concur with Ford's opinion that all conforming vehicles may now b sold in the United States. However, since such sales are to first purchasers for purposes other than resale, a certification label must be attached to each that meets the requirements of 49 CFR Part 567.; Sincerely, Frank Berndt, 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.