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 |
|---|---|
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: 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: aiam3406OpenMr. H. Hayashi, Manager for Safety Standards, Tire Quality Assurance Dept., Bridgestone Tire Co., Ltd., 2800-1, Ogawa, Higashi-Cho, Kodairai-Shi, Tokyo, JAPAN; Mr. H. Hayashi Manager for Safety Standards Tire Quality Assurance Dept. Bridgestone Tire Co. Ltd. 2800-1 Ogawa Higashi-Cho Kodairai-Shi Tokyo JAPAN; Dear Mr. Hayashi: This is in response to your letter of March 26, 1981, requesting, (sic an interpretation of the Uniform Tire Quality Grading (UTQG) Standards (49 CFR S575.104). You ask whether a tire designed for service as a temporary use spare tire, and labeled on its sidewall with the inscription: TEMPORARY USE ONLY FOR SPARE TIRE, INFLATE TO 40 PSI, MAX. SPEED 50 MPH, is exempt from the requirements of the UTQG Standards.; As you note, the 'Application' section of the UTQG regulation does no apply to space-saver or temporary use spare tires. Thus, the UTQG Standards would not apply to the tire you describe, which is designed as a temporary use spare tire and is so labeled.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam0724OpenMr. B. Fechner: (sic), FMC Corporation, Recreational Vehicles Division, 333 Brokaw Road, Box 664, Santa Clara, CA 95052; Mr. B. Fechner: (sic) FMC Corporation Recreational Vehicles Division 333 Brokaw Road Box 664 Santa Clara CA 95052; Dear Mr. Fechner:#This is in reply to your letter of May 25 inquirin about compliance of your planned motorhome with Federal Motor Vehicle Safety Standards Nos. 101 and 104.#Standard No. 101 requires certain controls to be illuminated. We interpret this to mean sufficiently illuminated that the control identification, if verbal, can be read, or if pictorial, can be understood. Therefore, illumination from any course is satisfactory as long as the basic requirement of comprehension is met.#Standard No. 104 does not describe the type of windshield wiping system that must be used to meet its requirements. It is the manufacturer's responsibility to insure, whatever system is used and whatever configuration of windshield is employed, that the wiped and washed area requirements are met.#Yours truly, Richard B. Dyson, Assistant Chief Counsel; |
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ID: aiam0725OpenMr. B. Fechner: (sic), FMC Corporation, Recreational Vehicles Division, 333 Brokaw Road, Box 664, Santa Clara, CA 95052; Mr. B. Fechner: (sic) FMC Corporation Recreational Vehicles Division 333 Brokaw Road Box 664 Santa Clara CA 95052; Dear Mr. Fechner:#This is in reply to your letter of May 25 inquirin about compliance of your planned motorhome with Federal Motor Vehicle Safety Standards Nos. 101 and 104.#Standard No. 101 requires certain controls to be illuminated. We interpret this to mean sufficiently illuminated that the control identification, if verbal, can be read, or if pictorial, can be understood. Therefore, illumination from any course is satisfactory as long as the basic requirement of comprehension is met.#Standard No. 104 does not describe the type of windshield wiping system that must be used to meet its requirements. It is the manufacturer's responsibility to insure, whatever system is used and whatever configuration of windshield is employed, that the wiped and washed area requirements are met.#Yours truly, Richard B. Dyson, Assistant Chief Counsel; |
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ID: aiam1778OpenMr. C. H. Waterman, President, C. H. Waterman Industries, White Pond Road, Athol, MA 01331; Mr. C. H. Waterman President C. H. Waterman Industries White Pond Road Athol MA 01331; Dear Mr. Waterman: We have received your letter of January 7, 1975, and a notic concerning your petition will appear shortly in the *Federal Register*.; Although we will not identify the manufacturer of the basic vehicle i the notice, your letter with that information will be part of the public docket. Section 567.4(g)(1) requires that the name of the 'actual assembler' of the vehicle be placed on the vehicle certification label which must be affixed before the vehicles are offered for sale. Notwithstanding your modifications to the vehicles we regard the Dutch manufacturer as the 'actual assembler' who must be identified as such on the label. (The same regulation requires your corporate name to appear directly below the name of the assembler.); If your review of Section 555.9(c)(1) and Section 567.4(g) raises an questions about the content of the label or your responsibilities, I will be happy to answer them.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam3909OpenMr. Fred W. Bowditch, Vice President, Technical Affairs Division, Motor Vehicle Manufacturers Association, 300 New Center Building, Detroit, MI 48202; Mr. Fred W. Bowditch Vice President Technical Affairs Division Motor Vehicle Manufacturers Association 300 New Center Building Detroit MI 48202; Dear Mr. Bowditch: On October 29, 1984, the Motor Vehicle Manufacturers Association file a petition for rulemaking to amend Motor Vehicle Safety Standard No. 108, *Lamps, Reflective Devices, and Associated Equipment*. The petition requested 'removal from section 4.1.1.36(a)(2) of the limitation requiring the three aiming pads to be located on the exterior face of the headlamp lens.' You have suggested the mounting flange at the lens-reflector joint as an acceptable alternative location for the aiming pads. The language suggested in the petition for amendment of S4.1.1.36(a)(2) would also allow all three legs to be adjustable on the headlamp aimers.; The agency has proposed amendments to Standard No. 108 (49 FR 47880) t delete the final sentence of paragraph S4.1.1.36(a)(2) with reference to aiming locating plates, and to delete Figures 9-1 and 9-2. Thus, this aspect of your petition has already been granted. We have filed your petition as a comment in the docket to be considered in future rulemaking action on this subject. Further, we interpret the words 'The exterior face of each...lens' in paragraph S4.1.1.36(a)(2) to mean all portions of the lens face including the mounting flange which is a molded and indivisible part of the lens. Thus, no rulemaking is considered necessary to implement this item of your petition. Your request also included a suggestion that the minimum height of the lettering for the adjustment of the legs on the aimer adapter should be reduced from 0.25 inch to 4 mm. This is being addressed in pending rulemaking. Therefore, no further action is necessary at this time.; Sincerely, Barry Felrice, Associate Administrator for Rulemaking |
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ID: aiam0703OpenMr. William V. Reynolds, National Association of School Bus Contract Operators, P.O. Box 324, 4616 Lawn Court, Fairfax, VA 22030; Mr. William V. Reynolds National Association of School Bus Contract Operators P.O. Box 324 4616 Lawn Court Fairfax VA 22030; Dear Mr. Reynolds: This is in reply to your letter of April 21, 1972, concerning problem some school bus manufacturers are having completing school buses manufactured with chassis ordered before January 1, 1972. You request our opinion as to whether these buses can be delivered even though they exceed by 350 pounds the GAWR specified for the rear axle of the chassis.; One purpose of the Certification requirements and the requirement regarding 'Vehicles Manufactured in Two or More Stages,' which went into effect January 1, 1972, and which require manufacturers to specify GAWR and GVWR, was to prevent the construction of motor vehicles of insufficient capability to carry anticipated loads. In our view, a manufacturer who completes a vehicle whose loaded weight or axle loads are in excess of its weight ratings is manufacturing a potentially unsafe vehicle which could be subject to the defect notification provisions of the National Traffic and Motor Vehicle Safety Act. The regulations apply to motor vehicles completed after January 1, 1972, and will apply to the school buses in question.; We do not consider the notice of December 28, 1971, to allow thes manufacturers to omit GAWR and GVWR from their certification labels. That notice allows this to be done only when a final-stage manufacturer, using a chassis manufactured before January 1, 1972, does not have and cannot obtain the gross axle and vehicle weight ratings for particular vehicles. These ratings have evidently been furnished to the school bus manufacturers who are the subject of your letter, and as a consequence they are responsible for placing these values on the labels of the completed vehicles.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2836OpenMr. Charles Pfaff, Motor Vehicle Administration, Maryland Department of Transportation, 6601 Ritchie Highway, N.E., Glen Burnie, MD 21062; Mr. Charles Pfaff Motor Vehicle Administration Maryland Department of Transportation 6601 Ritchie Highway N.E. Glen Burnie MD 21062; Dear Mr. Pfaff: Thank you for your letter of June 16, 1978, requesting our opinion o whether the Maryland Certificate of Title meets the Federal requirements for the odometer disclosure form as set forth in 49 CFR Part 580.; The proposed Certificate of Title which you enclosed with your lette differs from the Federal odometer disclosure form in the following ways:; (1) The Maryland Certificate of Title shortens the reference to th Federal law,; (2) the set of certifications relating to the distance that the vehicl has travelled are shortened by adopting language similar to that recommended by the American Association of Motor Vehicle Administrators,; (3) the certifications relating to alteration of the odometer ar deleted, and; (4) although the transferee is required to sign the statement, th signature does not specifically acknowledge receipt of a copy of the statement, as is required by the Federal law.; The National Highway Traffic Safety Administration (NHTSA) has reviewe Maryland's proposed Certificate of Title and has determined that it will further the goal of the Federal odometer law, despite its differences from the Federal form. Therefore, pursuant to 49 CFR S 580.4(f)(2), I hereby grant your request to use Maryland's Certificate of Title as a substitute for the Federal odometer disclosure form.; Sincerely, John Womack, Assistant Chief Counsel |
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ID: aiam0662OpenMr. Jimmy W. Gerlack, G. and W. Body Works, Post Office Box 585, Durant, OK 74701; Mr. Jimmy W. Gerlack G. and W. Body Works Post Office Box 585 Durant OK 74701; Dear Mr. Gerlack: Thank you for your 'Manufacturer Identification Registration Report with which you submitted a sample of a certification label that you intend to use to fulfill your obligations under Part 567 of Title 49 of the Code of Federal Regulations, soliciting our advice.; The nomenclature on the label fulfills the requirements. However, ther is some question as to whether the material would meet the permanency requirements of section 114 of the National Traffic and Motor Vehicle Safety Act of 1966 (the Act).; The subject is further addressed in the Preamble to the certificatio requirements that became effective on September 1, 1969, '. . . The intent of the requirement is that the label last for the life of the vehicle . . .' (34 F.R. 7031) copy enclosed.; You should assure yourself that the material used will meet thos requirements.; Sincerely, Francis Armstrong, Director, Office of Standard Enforcement, Motor Vehicle Programs; |
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.