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: aiam1484OpenMr. Tatsuo Kato, Staff, Safety, Nissan Motor Company, Ltd., 560 Sylvan Avenue, Englewood Cliffs, NJ 07632; Mr. Tatsuo Kato Staff Safety Nissan Motor Company Ltd. 560 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Kato:#This is in reply to your letter of April 23, 1974 asking for an interpretation of Standard No. 101, as proposed in the *Federal Register* on September 27, 1973. You reference that portion of Paragraph S4.3.3 which states 'If illumination of controls and displays not listed in Paragraph S4.1 is provided, its intensity shall be variable in a manner that complies with this paragraph'.#The basic requirement of S4.3.3 is that 'A control shall be provided to adjust the intensity of control and display illumination. . . .' We interpret the basic requirement as applying to *all* control and display illumination, not just illumination of the minimum number of controls and displays specified in Tables I and II. Thus if the manufacturer chooses to provide illumination for *any* control or display, even those not related to safety such as the radio or clock, its intensity shall be variable in accordance with Paragraph S4.3.3.#Yours truly, Richard B. Dyson, Assistant Chief Counsel; |
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ID: aiam0631OpenMr. Thomas S. Pieratt, Jr., Executive Secretary, Truck Equipment & Body Distributors Association, 602 Main Street, Cincinnati, OH 45202; Mr. Thomas S. Pieratt Jr. Executive Secretary Truck Equipment & Body Distributors Association 602 Main Street Cincinnati OH 45202; Dear Mr. Pieratt: This is in reply to your letter of February 23, 1972, concerning th application of the Certification regulations (49 CFR Part 567) to certain vehicles and components.; You describe a device, called a 'converter gear', which is used t convert a semi-trailer into a trailer, and ask whether this unit is considered to be a trailer which must be certified. You also ask whether all lamps and reflectors specified for trailers are required. We believe this device to be a trailer, and it appears from your description that it is a 'trailer converter dolly' under the Motor Vehicle Safety Standards (49 CFR S571.3). Trailer converter dollies are specifically exempt from the requirements of Motor Vehicle Safety Standard No. 108, 'Lamps, Reflective Devices, and Associated Equipment,' and are consequently not required to meet the lighting requirements applicable to other trailers. In addition, there are presently no other motor vehicle safety standards applicable to trailers and consequently, trailer converter dollies need not be certified. This will no longer be the case, however, after the effective date of Standard No. 121, 'Air Brake Systems.' Trailer converter dollies manufactured on or after that standard's effective date will be required to comply with its requirements, and to be certified in accordance with Part 567.; You also ask how manufacturers are to determine the GVWR fo semi-trailers, and whether such a figure can be based solely on the semi-trailer's axle or axles. The GVWR of a semi-trailer should not be based on the vehicle's axles. The definition of GVWR calls for the weight *of a fully loaded vehicle*, and normally the capacity of a semi-trailer is greater than that of its rear axles.; You describe another device, a 'Jo-Dog' or detachable tab axle to b attached to a truck tractor, asking whether this unit is a 'trailer' which must be certified and whether the use of such a device would alter the truck tractor to the extent that an altered certification label is required. It appears from your description of this device that it is also a 'trailer converter dolly.' As in the case of the 'converter gear' described above, certification by the manufacturer (at the present time) is not required. Moreover, we would not consider the use of such a device to be 'manufacturing' within the National Traffic and Motor Vehicle Safety Act, and no certification of any kind by a user (as distinguished from a manufacturer) would be required.; Finally you describe additional devices, a 'drom,' and an auxiliar cargo-carrying platform, both of which can be added to truck tractors between the cab and the fifth wheel. You ask whether the installation of such devices would constitute re-manufacturing of the vehicle and if additional certification is required when compliance to a standard is not altered.; We would consider the addition of such components to a new vehicle t be manufacturing under the National Traffic and Motor Vehicle Safety Act, and certification by the vehicle manufacturer would be required regardless of whether compliance of the vehicle to any standard is affected.; We are pleased to be of assistance. Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3862OpenHonorable Jim Burnett, Chairman, National Transportation Safety Board, Washington, DC 20594; Honorable Jim Burnett Chairman National Transportation Safety Board Washington DC 20594; Dear Mr. Chairman: This is in further response to recommendations H-83-44 and H-83-4 which your agency made to the National Highway Traffic Safety Administration (NHTSA) regarding the Highway Accident Report, 'Jonesboro School District Schoolbus Run-Off-Road and Overturn, State Highway 214 at State Highway 18, near Newport, Arkansas, March 25, 1983' (NTSB/HAR-83/03).; NHTSA agrees with the National Transportation Safety Board tha properly inspected and repaired school buses are essential to the safe transportation of school children. We also believe that the current provisions in Highway Safety Program Standard 1, Periodic Motor Vehicle Inspection, and Highway Safety Program Standard 17, Pupil Transportation Safety, as well as the relevant Federal Motor Vehicle Safety Standards, provide for an adequate level of safety when children are transported to and from school.; Of the 15,840 school districts in the United States, about 15,00 provide pupil transportation. Over 400,000 buses are involved in transporting the nation's 22 million public, private and parochial school children to and from school each day. These buses are maintained by a number of persons having diverse backgrounds ranging in skill from 'grease monkey' to those certified by the national institute for Automotive Service Excellence (ASE). This fleet travels over three billion miles a year, and is remarkably free of problems. Information reported at national meetings indicates that accidents due to mechanical failure are estimated to be between three and five percent and very few result in injury or death.; With respect to the specific recommendations, we have the followin comments:; >>>*RECOMMENDATION H-83-44* (Class II, Priority Action) *Include in Highway Safety Program Standard (HSPS) 17--Pupi Transportation Safety and in the Program Manual' for HSPS 17 the requirement that the States institute quality control procedures for schoolbus repairs to determine if needed repairs have been performed adequately or if major repairs are required.; COMMENT* State Directors of Transportation, school business officials and flee supervisors with whom NHTSA has talked agree that school buses should be kept in good repair. They questioned, however, how quality control procedures could be applied to the repair of school buses when almost every repair is different. Most school buses currently undergo at least two inspections a year, as suggested by Standard 17, which procedure helps to detect major defects that require repair. In addition to this inspection, we understand that most drivers conduct a daily inspection which identifies the need for minor repairs. One supervisor observed that school bus drivers act as a form of practical quality control because they check to determine if the school bus is operating safely after the repair has been made.; A survey of almost 1,000 fleets by the National School Transportatio Association revealed that 49 percent operated fewer than 10 buses. To institute quality control procedures for these small fleets would quickly exhaust the limited resources of most States. Instituting formal quality control procedures would be costly to the States, no matter whether facilities were built and equipment purchased, or alternative checking procedures were utilized.; *Recommendation H-83-45* (Class II, Priority Action) This five part recommendation would include in the Program Manual o Highway Safety Program Standard 17-Pupil Transportation Safety, the program areas listed below.; *1. Specific, well-defined qualifications for hiring schoolbu mechanics,; 2. Specific skill areas for schoolbus mechanics for which certificatio of proficiency is required,; 3. A bibliography of available courses that can be attended or cours curricula that can be used as an example to obtain certification of proficiency in the required skill areas, *Comment*; NHTSA plans to use a portion of staff resources to review th literature that pertains to school bus mechanic qualifications and skill areas needed for certification. Upon completion we will disseminate the appropriate information to State and local governments.; Many schools, colleges and vocational training centers offer variou courses in auto-mechanics, but few people ever master all the major areas of vehicle repair and become master-mechanics. The majority of small fleet operators could not afford to hire such a skilled mechanic. Car dealers employ many skilled mechanics but many are neither equipped nor do they desire to repair school buses. It is highly unlikely that owners of small fleets would or could hire an ASE certified mechanic. It is also unlikely that most of the garages or service stations that maintain school buses have such a person in their employ because they are small independent private entrepreneures (sic). The extreme diversity of the school bus fleet in the United States would be a major complication for a practical certification program.; In 1978, hearings were held by the House Subcommittee on Consume Protection and Finance, of the Committee on Interstate and Foreign Commerce, to examine State and local as well as private sector approaches to the problem of unnecessary, incompetent, or fraudulent repair practices. Senator Philip Hart also held hearings in the late 1960s on Mechanic Training and Licensing. In spite of the adverse findings by these two committees, neither the Federal Government nor any State has gone so far as to require certification of mechanics doing work on cars or school buses. Because of the complexity of this problem, and the lack of Congressional action, NHTSA is of the opinion that it cannot go beyond publishing qualifications for school bus mechanics and identifying available training centers.; States whose accident records show the need for better maintenance car can be expected to take remedial action. Michigan, for example, provided workshops especially designed for school bus mechanics for over 10 years.; *4. A requirement to institute and enforce procedures to prevent schoo activity groups from organizing, beginning, or continuing trips in mechanically unsafe vehicles,; Comment* A requirement to institute and enforce procedures to prevent schoo activity groups from organizing, beginning or continuing trips in mechanically unsafe vehicles is commendable. Such a requirement, however, would be effective only if it were enforced. Standard 17 currently suggests pre-trip inspections and a written report of any defect or deficiency discovered. We believe a reminder to the States of this suggestion would encourage them to give the proper attention to this safety area.; *5. Requirements to place fire extinguishers at the front and rear o school buses, post signs in school buses on the location and use of emergency equipment, and brief passengers on the location and use of emergency equipment, both periodically and before beginning activity trips.; Comment* The placement of additional fire extinguishers outside the bus driver' compartment has led to increased theft and vandalism. These essential pieces of emergency equipment need to remain under the watchful eyes of the bus driver. The benefits of placing a second fire extinguisher in the rear of the school bus are so few as to make this requirement unwarranted. In case of a fire, a bus driver's first responsibility is to get the pupils to a place of safety. Having the personal skill and the equipment to handle a small fire are helpful, but not a necessity.; NHTSA suggests that all pupils who ride school buses should hav instruction twice a year in safe riding procedures and emergency drills. This should provide sufficient information to students concerning the location and use of emergency equipment carried on the school bus. The location and use of fire extinguishers should be a part of this instruction.; Thank you for the opportunity to comment on these safet recommendations. If NHTSA can supply any additional information, please let me know.; |
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ID: aiam1715OpenMr. Randall D. Bartlett, 225 Ginger Drive, Auburn, CA, 95603; Mr. Randall D. Bartlett 225 Ginger Drive Auburn CA 95603; Dear Mr. Bartlett: This is in reply to your letter of November 27, 1974, asking about th legality of rectangular headlamps, particularly with respect to the aftermarket.; Federal Motor Vehicle Safety Standard No. 108, *Lamps, Reflectiv Devices and Associated Equipment*, permits the use of a four-headlamp system with rectangular lenses of specified dimensions (approximately 4-1/4 by 6-1/2 inches), on vehicles manufactured between January 1, 1974, and August 31, 1976. The standard also permits manufacture of replacement headlamps for this system for sale in the aftermarket. The standard does not allow rectangular headlamps of other sizes, or a two-headlamp system, either as original equipment or for sale in the aftermarket.; I enclose a copy of that portion of Standard No. 108 covering th rectangular headlamps.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam2813OpenMr. E. M. Ryan, Chief Design Engineer, Ward Industries, Inc., P.O. Box 849, Highway 65 South, Conway, AR 72032; Mr. E. M. Ryan Chief Design Engineer Ward Industries Inc. P.O. Box 849 Highway 65 South Conway AR 72032; Dear Mr. Ryan: This responds to your April 27, 1978, letter asking whether a sampl certification label that you submitted complies with the National Highway Traffic Safety Administration's (NHTSA) Part 567, *Certification*.; Military vehicles are exempted from compliance with Federal safet standards. Therefore, the application of the safety standards to these vehicles is a matter of contract between a manufacturer and the military. Since the NHTSA does not mandate Federal safety standards for these vehicles, it is not necessary to put certification labels on them. If you choose to include a label with a vehicle, the label would not be required to comply with any Federal regulations.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam2814OpenMr. E. M. Ryan, Chief Design Engineer, Ward Industries, Inc., P.O. Box 849, Highway 65 South, Conway, AR 72032; Mr. E. M. Ryan Chief Design Engineer Ward Industries Inc. P.O. Box 849 Highway 65 South Conway AR 72032; Dear Mr. Ryan: This responds to your April 27, 1978, letter asking whether a sampl certification label that you submitted complies with the National Highway Traffic Safety Administration's (NHTSA) Part 567, *Certification*.; Military vehicles are exempted from compliance with Federal safet standards. Therefore, the application of the safety standards to these vehicles is a matter of contract between a manufacturer and the military. Since the NHTSA does not mandate Federal safety standards for these vehicles, it is not necessary to put certification labels on them. If you choose to include a label with a vehicle, the label would not be required to comply with any Federal regulations.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam2823OpenMr. Don H. Pendergrass, Norris Industries, 1225 West Imperial Highway, Brea, California 92621; Mr. Don H. Pendergrass Norris Industries 1225 West Imperial Highway Brea California 92621; Dear Mr. Pendergrass: This responds to your January 7, 1978, letter asking whether final-stage wheel manufacturer is permitted to mark a rim in accordance with Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*. The standard currently specifies that rim marking shall be done by a rim manufacturer, not a final-stage wheel manufacturer.; The National Highway Traffic Safety Administration (NHTSA) ha previously determined that a rim manufacturer is the responsible party for rim marking. The language of the standard is specific in this requirement. The agency, however, is reviewing the standard with a view to its possible modification along the lines suggested in your letter. Should the agency decide to amend the standard, a notice proposing such change would first be published in the Federal Register. A final rule would only be issued following analysis of comments submitted by interested parties.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3652OpenMr. Kosti Shirvanian, President and Chairman of the Board, Western Waste Industries, P. O. Box 214, Gardena, CA 90247; Mr. Kosti Shirvanian President and Chairman of the Board Western Waste Industries P. O. Box 214 Gardena CA 90247; Dear Mr. Shirvanian: This is in reply to your letter of December 22, 1982, informing us tha the California Highway Patrol has advised one of your divisions to remove certain tires from service for failure to 'display the Department of Transportation's symbol on both sidewalls in violation of the Federal Motor Vehicle Safety Standard 119 effective March 1, 1975.' You have also stated that the tires are acceptable in all other respects.; Paragraph S6.5(a), requiring use of the DOT symbol on tires covered b the standard specifically states, 'This symbol may be used on only one sidewall.' Therefore, the tires in question would not fail to comply with Standard No. 119 by having the DOT symbol on only one of the two sidewalls.; If there should, in fact, be other items of information missing fro the tires which render them technically noncompliant with the standard, we would be pleased to advise you further.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2497OpenMr. Emilio Noriega, 3745 Winston Drive, El Monte, CA 91731; Mr. Emilio Noriega 3745 Winston Drive El Monte CA 91731; Dear Mr. Noriega: This responds to your November 3, 1976, question whether Standard No 121, *Air Brake Systems*, prohibits the installation in a towing vehicle of a service brake control that is designed to permit separate, sequential, or simultaneous actuation of the service brake systems of the towing vehicle and any towed vehicle.; Assuming that the valve for the towing vehicle represents a 'split service brake system as specified in S5.7 of Standard No. 121, such a service brake control design would not conflict with the Standard's requirements. Of course, the actual compliance of any vehicle with Standard No. 121 depends on the actual installation and performance of the system as well as its design.; I would like to note that the agency is not endorsing the service brak control in question by the issuance of this interpretation letter. In fact, the agency is unsure about the effect the control may have on safe braking in a panic situation. Any test information that you or a vehicle manufacturer may care to provide would be appreciated.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam2753OpenG. K. Pilz, Manager, Product Compliance, Mercedes-Benz of N.A., One Mercedes Drive, Montvale, NJ 07645; G. K. Pilz Manager Product Compliance Mercedes-Benz of N.A. One Mercedes Drive Montvale NJ 07645; Dear Mr. Pilz: This responds to your February 1, 1978, letter asking whether you certification label complies with the requirements of Part 567, *Certification*.Your certification would state the gross vehicle and axle weight ratings in both pounds and kilograms. In the past, the agency has permitted this approach for the purpose of international harmonization of measurements. Therefore, your proposed label appears to comply with the requirements.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
Request an Interpretation
You may email your request to Interpretations.NHTSA@dot.gov or send your request in hard copy to:
The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590
If you want to talk to someone at NHTSA about what a request for interpretation should include, call the Office of the Chief Counsel at 202-366-2992.
Please note that NHTSA’s response will be made available in this online database, and that the incoming interpretation request may also be made publicly available.