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: aiam1338OpenMr. W. R. Nelson, Chief of Police, City of San Marcos, P.O. Box 725, San Marcos, TX 78666; Mr. W. R. Nelson Chief of Police City of San Marcos P.O. Box 725 San Marcos TX 78666; Dear Mr. Nelson: This is in reply to your letter of November 14, 1973, concerning th permissibility of installing trailer hitches which prevent the proper function of a vehicle's shock absorbing bumper device.; The attachment of trailer hitches to motor vehicle bumpers will no constitute a violation of any Federal motor vehicle safety standard. The testing requirements of Standard No. 215, which are here applicable, specify that trailer hitches are to be removed prior to testing for compliance. Thus, it is only necessary that the vehicle comply with the regulation when the trailer hitch is not attached. Further, the requirements of the standard do not apply after the first purchase of the vehicle for purposes other than resale, which removes the welding company and the vehicle owner from the standard's coverage once the initial sale has occurred.; Thank you for your inquiry. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3305OpenMr. J. Bill Simpson, Simpson Sports, 22630 South Normandie Avenue, Torrance, CA 90502; Mr. J. Bill Simpson Simpson Sports 22630 South Normandie Avenue Torrance CA 90502; Dear Mr. Simpson: This responds to your May, 1980, letter asking whether the Departmen of Transportation preempts State approval programs designed to enforce State standards on equipment regulated by Federal safety standards. In a subsequent conversation with Roger Tilton of my staff, you indicated that several States require you to obtain advance approval from them prior to sale of your motorcycle helmets. You further stated that each of these advance approvals can be very costly.; The National Traffic and Motor Vehicle Safety Act of 1966 (the Act) (1 U.S.C. 138 *et* *seq*.) in section 1392(d) preempts States from having any safety standard applicable to the same aspect of performance as a Federal standard unless the State standard imposes a higher level of performance and applies only to vehicles or equipment purchased for the State's own use. The Act is silent with respect to the preemption of State enforcement procedures, such as approval schemes that require State permission prior to the sale of vehicles or equipment in their jurisdictions.; We note that the issue of advance approval schemes was litigated i *Truck Safety Equipment Inst. v. Kane*, 466 F.Supp. 1242 (D.C., Pa. 1979). In that case (copy enclosed) the court held that a State advance approval scheme was preempted by the Act. We suggest that you bring this case to the attention of the appropriate officials in the States in question. If either you or officials from those States have further questions, you can contact Mr. Tilton at 202-426-9511.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3610OpenMr. Darnley M. Howard, Director, Office of Safety and Health, United States Postal Service, 475 L'Enfant Plaza, S.W., Washington, DC 20260; Mr. Darnley M. Howard Director Office of Safety and Health United States Postal Service 475 L'Enfant Plaza S.W. Washington DC 20260; Dear Mr. Howard: This responds to your August 18 letter to Roger Fairchild of thi office, regarding the use of cross-view mirrors on certain Postal Service vehicles. These mirrors are convex and have a non-uniform radius of curvature. They would be used to assist drivers in viewing the area immediately in front of the vehicle.; Federal Motor Vehicle Safety Standard No. 111 sets forth rear vie mirror requirements for new motor vehicles. Vehicles such as Postal Service trucks are required to comply with one of three specified alternative sets of requirements for mirror systems. The first alternative requires a plane inside mirror providing a specified field of view and a plane exterior driver side mirror, also providing a specified field of view. The second alternative is the same as the first, except that it permits the interior mirror to have a more narrow field of view as long as the vehicle also uses an exterior mirror on the passenger side. The third alternative requires two plane exterior mirrors of at least 19.5 square inches surface area each, with one placed on the driver's side and the other on the passenger's side of the vehicle.; The agency has taken the position that mirrors used on a vehicle i addition to the required mirrors are not subject to any requirements of FMVSS 111. If the cross-view mirrors you wish to use would supplement mirrors which fully comply with one of the alternatives in the standard, the installation of the cross-view mirrors on new Postal Service trucks is in no way prohibited by our standard.; Further, our requirements do not apply to aftermarket modifications t the original equipment mirror system, when those modifications are performed by the vehicle owner. Modifications to the required system would be deemed unlawful only if done by vehicle manufacturers, distributors, dealers, or motor vehicle repair businesses. Thus, the use of the cross-view mirrors is permissible in any case, so long as one of these designated businesses does not perform the modification. However, we recommend that the cross-view mirror be used in addition to the original equipment mirrors, and not as a substitute for those mirrors. Based on our experience with non-uniform radius mirrors, these mirrors should not be used when the vehicle is in motion, since the mirror produces an image which can distort distances. Rather, the mirror should be used to detect people in front of the vehicle while the vehicle is stopped.; NHTSA would appreciate the opportunity to review the results of you test program once it is completed. If we can be of assistance to you in evaluating the mirrors, please feel free to contact us.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2719OpenMr. Paul Jones, Kentucky Department of Education, Frankfurt, KY 40601; Mr. Paul Jones Kentucky Department of Education Frankfurt KY 40601; Dear Mr. Jones: This responds to your oral request to Roger Tilton of my staf concerning the applicability of the new Federal school bus safety standards to vans transporting 10 or more school children to or from school or related events.; The National Highway Traffic Safety Administration (NHTSA) promulgate safety standards applicable to all school buses. School bus is defined in Part 571.3 of our regulations (Volume 49 of the Code of Federal Regulations, Part 571.3) to mean a bus sold or introduced in interstate commerce for purposes that include carrying students to and from school or related events. In turn, bus is defined as 'a motor vehicle with motive power, except a trailer, designed for carrying more than 10 persons.' More than 10 person means 10 passengers or more plus a driver. Accordingly, any vehicle sold or introduced in interstate commerce to transport school children which carries 10 or more passengers to or from school or related events must comply with all of the new Federal school bus requirements. This includes vans which fall within that passenger capacity.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam1836OpenMr. W. G. Milby, Staff Engineer, Blue Bird Body Company, P.O. Box 937, Fort Valley, GA 31030; Mr. W. G. Milby Staff Engineer Blue Bird Body Company P.O. Box 937 Fort Valley GA 31030; Dear Mr. Milby: This is in reply to your letter of February 6, 1975, asking whethe paragraph S5.5.1 of Motor Vehicle Safety Standard No. 217 (49 CFR 571.217) permits the words Emergency Exit' to be placed above the emergency door in a school bus, or whether they must be within six inches of the emergency door release mechanism. You argue that placing the nomenclature above the door provides a more prominent identification of the exit than does placing it within 6 inches of the release mechanism.; We believe the interpretation of S5.5.1 which you suggest i appropriate when applied to rear door emergency exits in school buses. We have not previously considered school buses containing this type of emergency exit labeling to fail to conform to the standard. In addition, our recent proposal regarding school bus emergency exits (39 FR 8569, copy enclosed) would specifically require emergency exit labeling of this type.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5526OpenMs. Merridy R. Gottlieb 4 Duchess Court Baltimore, MD 21237; Ms. Merridy R. Gottlieb 4 Duchess Court Baltimore MD 21237; Dear Ms. Gottlieb: This responds to your letter of February 14, 1995 requesting an 'exemption' from the National Highway Traffic Safety Administration (NHTSA) to allow a business to modify your motor vehicle. Your letter states: I am disabled and need 3-4' of additional room for the passenger seat to allow my legs to straighten on long trips. I have two replaced hips and arthritis in my knees. If I leave my legs slightly bent for long periods of time, I suffer too much pain to be active at the end of the drive. By allowing my legs to straighten all the way out, there is no pain at all. You state that you were told that this modification cannot be done as it would 'interfere with the functionality of the air bag.' In summary, our answer is that you may have your vehicle modified. NHTSA will not institute enforcement proceedings against a repair business that modifies the seat on your vehicle to accommodate your condition. A more detailed answer to your letter is provided below. I would like to begin by clarifying that there is no procedure by which persons petition for and are granted an exemption from NHTSA to have a motor vehicle repair business modify their motor vehicle. Repair businesses are permitted to modify vehicles without obtaining permission from NHTSA to do so, but are subject to certain regulatory limits on the type of modifications they may make. In certain limited situations, we have exercised our discretion in enforcing our requirements to provide some allowances to a repair business which cannot conform to our requirements when making modifications to accommodate the special needs of persons with disabilities. Since your situation is among those given special consideration by NHTSA, this letter should provide you with the relief you seek. Our agency is authorized to issue Federal Motor Vehicle Safety Standards (FMVSS) that set performance requirements for new motor vehicles and items of motor vehicle equipment. Manufacturers are required to certify that their products conform to our safety standards before they can be offered for sale. Manufacturers, distributors, dealers, and repair businesses are prohibited from 'knowingly making inoperative' any device or element of design installed on or in a motor vehicle in compliance with an applicable FMVSS. In general, the 'make inoperative' prohibition would require repair businesses which modify motor vehicles to ensure that they do not remove, disconnect, or degrade the performance of safety equipment installed in compliance with an applicable FMVSS. Violations of this prohibition are punishable by civil fines up to $1,000 per violation. Moving a seat could affect compliance with Standard No. 208, Occupant Crash Protection. Standard No. 208 sets forth requirements for occupant protection at the various seating positions in a vehicles. Standard No. 208 requires that cars be equipped with automatic crash protection at the front outboard seating positions. Automatic crash protection systems protect their occupants by means that require no action by vehicle occupants. Compliance with the automatic crash protection requirements of Standard No. 208 is determined in a dynamic crash test. That is, a vehicle must comply with specified injury criteria, as measured on a test dummy, in a 30 mph barrier crash test. The two types of automatic crash protection currently offered are automatic safety belts (which help to assure belt use) and air bags (which supplement safety belts and offer some protection even when safety belts are not used). Based on the information in your letter, it appears that the manufacturer of your vehicle installed air bags as the means of complying with Standard No. 208's requirement. Your modifier is concerned that the modification of the seat would 'make inoperative' the air bag. I would like to note that accident data would suggest that a person is at greater risk of injury from an air bag from sitting too close to the air bag, rather than further away from the air bag. However, I understand that, due to the dynamic testing requirement, the modifier will be unable to ensure that the vehicle continues to comply with Standard No. 208's requirements. In situations such as yours where a vehicle must be modified to accommodate the needs of a particular disability, we have been willing to consider any violations of the 'make inoperative' prohibition a purely technical one justified by public need. As I have already noted above, NHTSA will not institute enforcement proceedings against a repair business that modifies the seat on your vehicle to accommodate your condition. We caution, however, that only necessary modifications should be made to the seat, and the person making the modifications should consider the possible safety consequences of the modifications. For example, in moving a seat, it is critical that the modifier ensure that the seat is solidly anchored in its new location. You should also be aware that an occupant of a seat which has been moved rearward may have less protection in a crash if the seat is too far rearward relative to the anchorages of the safety belts for that seat. Finally, if you sell your vehicle, we encourage you to advise the purchaser of the modifications. I hope this information has been helpful. If you have any other questions or need some additional information in this area, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam0374OpenMr. Richard I. Moss, Washington Representative, Trailer Coach Association, 1800 North Kent Street, Suite 922, Arlington, VA 22209; Mr. Richard I. Moss Washington Representative Trailer Coach Association 1800 North Kent Street Suite 922 Arlington VA 22209; Dear Mr. Moss: This is in reply to your letter of June 7, requesting interpretation of Standard No. 207, Seating Systems, and Standard No. 208, Occupant Crash Protection.; First, with respect to Standard No. 207, you have asked whethe designated seating positions must be labeled as such. Our response is that the labeling section requires labels on seats not designated for occupancy while the vehicle is in motion but does not require designated seating positions to be labeled.; With respect to the nature and content of the label on a seat no designated for occupancy, the standard states that the seat must be 'conspicuously labeled to that effect.' There are thus two general requirements: that the label be conspicuous and that it indicate that the seat is not to be occupied while the vehicle is in motion. The requirement for conspicuousness relates to the location of the label and the prominence of its lettering. Generally speaking, it would have to be located so that it could be seen by a person preparing to occupy the seat and of a size that could be read by the occupant in the normal motion of sitting. The statement on the label must clearly indicate that the seat is not to be occupied while the vehicle is in motion, but the exact wording is left to the manufacturer.; Standard No. 208 requires that MPV's and trucks with a GVWR of les than 10,000 pounds, manufactured from January 1, 1972 to August 15, 1975, must elect either a passive protection system or a seat belt system that requires Type 2 seat belt assemblies at outboard designated seating positions that include the windshield header within the head impact area. A similar requirement, without the passive option, goes into effect July 1, 1971, for these vehicles. Your question is whether, if a seating position does not have the windshield header within the head impact area, it is permitted to have a Type 1 seat belt assembly. Our response is that the standard permits a Type 1 belt for such a position.; Please advise us if we can be of further assistance. Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam2349OpenMr. Russell H. Berry, Jr., Marketing Specialist, 'Lucite' Acrylic Sheet Products, 1007 Market Street, Wilmington, DE 19898; Mr. Russell H. Berry Jr. Marketing Specialist 'Lucite' Acrylic Sheet Products 1007 Market Street Wilmington DE 19898; Dear Mr. Berry: This is in response to your letter of April 9, 1976, concerning th certification and marking requirements for glazing specified in Section 6 of Standard No. 205, *Glazing* Materials. You asked whether the standard prohibits use of the 'DOT' symbol and manufacturer's code number by anyone other than a 'prime glazing material manufacturer,' as that term is defined in paragraph S6.1.; Our letter to Dupont explained the separate certification and markin requirements that are applicable to glazing prepared by prime glazing material manufacturers, distributors, and vehicle manufacturers. The standard specifies that the 'DOT' symbol shall be placed on glazing that is designed by the prime glazing material manufacturer as a component of any specific motor vehicle. The agency's interpretations of several years ago pointed out that the standard requires a person other than a prime glazing manufacturer who cuts glazing materials to mark it in accordance with section 6 of ANS Z26 and to certify it in accordance with section 114 of the National Traffic and Motor Vehicle Safety Act of 1966. These interpretations emphasized that a person who cuts and shapes the glazing material received from a prime glazing manufacturer should not include the 'DOT' symbol in his marking and certification.; At the time of the earlier interpretations, the NHTSA considered i necessary from the standpoint of enforcement to distinguish between glazing that had been manufactured by the prime glazing manufacturer for use in specific motor vehicles and glazing that had been cut, shaped, or otherwise altered by another party before installation. The agency was also concerned that the use of the 'DOT' symbol by anyone other than the prime glazing manufacturer would be misleading and could create confusion.; Since that time, the certification procedures have become more widel understood and uniformly practiced throughout the industry, and this has aided the 'traceability' of glazing materials for enforcement purposes. Therefore, the agency no longer prohibits the use of the 'DOT' symbol and the prime glazing manufacturer's code number by the distributor or manufacturer who cuts the glazing, if the prime glazing manufacturer grants permission for such use of his code number to the distributor or manufacturer.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam5176OpenSt. F. Steiner Consultant AET Network 2190 3rd Street San Francisco, CA 94107; St. F. Steiner Consultant AET Network 2190 3rd Street San Francisco CA 94107; "Dear Sir or Madam: We have received your 'Dear Mr. Van Orden' lette of May 4, 1993, which was addressed to me. You wish to import 3- and 4-wheeled vehicles from Europe 'for research and exploration', and have asked several questions relating to U.S. laws and D.O.T. requirements. Your first question is: 'Are there any safety standards and regulations for the above mentioned automobiles?' The answer is yes. All 3-wheeled motor vehicles are considered 'motorcycles' for purposes of compliance with the Federal motor vehicle safety standards that apply to motorcycles. Depending upon their configuration, but not upon their weight, 4-wheeled vehicles are either 'passenger cars', 'multipurpose passenger vehicles', 'trucks', or 'buses' for purposes of the safety standards. However, motor vehicles intended solely for purposes of research may be imported without the necessity of conforming them to the safety standards under the terms and conditions that the agency has set out in 49 CFR Part 591. Your second and third questions are whether there is a minimum speed standard regulation or weight limitations for the vehicles you wish to import. The answer is no. However, a motorcycle with 5-horsepower or less is considered a 'motor-driven cycle', and some of the motorcycle standards impose lesser requirements for motor-driven cycles, and motor-driven cycles whose speed attainable in l mile is 30 mph or less. Your fourth question relates to the conversions required to meet U.S. specifications and standards. As indicated previously, no conversion is required when the importation is solely for the purpose of research. If you wish to import vehicles that have been originally manufactured to meet the Federal motor vehicle safety, bumper, and theft prevention standards, the manufacturer will find those standards at 49 CFR Parts 571, 581, and 541, respectively. If you wish to import nonconforming vehicles for conversion after importation, then the agency must determine that the vehicles are eligible for entry pursuant to 49 CFR Part 593, and importation and conversion accomplished through a Registered Importer pursuant to 49 CFR Part 592. Your final question is whether the vehicles will be permitted on highways. This is a question that is not answerable under Federal law. Each State determines the criteria for licensing motor vehicles for use on the roads under its jurisdiction. If a State does not license a vehicle for on-road use (all terrain vehicles, minibikes, golf carts are examples), a basis exists for a manufacturer to determine that its vehicles are not 'motor vehicles.' If a vehicle is not a motor vehicle, i.e. one manufactured primarily for on-road use, then no Federal safety standards apply to it. If you have any further questions about the importation process, you should refer them to Mr. Van Orden at our Office of Vehicle Safety Compliance, Office of Enforcement. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam0499OpenMr. Robert W. Etter, G & D Communications Corporation, 12997 Merriman Road, Livonia, MI 48150; Mr. Robert W. Etter G & D Communications Corporation 12997 Merriman Road Livonia MI 48150; Dear Mr. Etter: This is in reply to your letter of October 22, 1971, and your phon call to Michael Peskoe of November 15, 1971, requesting a copy of the Consumer Information regulations and asking what penalties may be imposed on manufacturers if their vehicles cannot perform as well as the figures they provide pursuant to the regulation. You stated in the above conversation that you have obtained the volume entitled 'Performance Data for New 1971 Passenger Cars and Motorcycles' which contains a copy of the Consumer Information requirements. I have enclosed certain amendments to the Consumer Information regulations which will bring the regulations as they appear in this volume up to date.; With reference to your question regarding penalties for violations o the Consumer Information requirements, Sections 108 and 109 of the National Traffic and Motor Vehicle Safety Act of 1966 (15 U.S.C. SS 1397, 1398) authorize the imposition of civil penalties of up to $1,000 per violation, and up to $400,000 for any related series of violations, against manufacturers whose vehicles cannot perform at least as well as the data they supply indicates. In addition, injunctive proceedings may be utilized pursuant to section 110 of the Act (15 U.S.C. S 1399).; I trust this answers your question. We regret that it was overlooked i our first response to your letter.; Sincerely, Lawrence R. Schneider, 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.