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: aiam0485OpenMr. E. M. Ryan, Chief Design Engineer, Ward School Bus Mfg., Inc., P. O. Box 849, Conway, AR, 72032; Mr. E. M. Ryan Chief Design Engineer Ward School Bus Mfg. Inc. P. O. Box 849 Conway AR 72032; Dear Mr. Ryan: Your letter of October 28, 1971, to Mr. Stan Haranski, Truck Body an Equipment Association, Inc., concerning switching arrangements for school bus red signal lamps, has been forwarded to this Office for reply.; Paragraph S4.1.4(a) of Federal Motor Vehicle Safety Standard No. 10 requires that the four red signal lamps be controlled by a manually actuated switch. A two-way switch, whereby all four lamps are activated when the switch is in one position, and the two rear lamps only are activated when the switch is in the opposite position, would not be in violation of this requirement of Standard No. 108.; Sincerely, E. T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
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ID: aiam2512OpenMr. Raymond Titsworth, Project Engineer, Ward School Bus Mfg., Inc., P. O. Box 849, Highway 65 South, Conway, AR 72032; Mr. Raymond Titsworth Project Engineer Ward School Bus Mfg. Inc. P. O. Box 849 Highway 65 South Conway AR 72032; Dear Mr. Titsworth: This responds to your December 7, 1976 and January 8, 1977, question whether 53 described intersections of bus body components qualify as 'body panel joints' subject to the requirements of Standard No. 221, *School Bus Body Joint Strength*. This also responds to your question whether the seating reference point in Standard No. 222, *School Bus Passenger Seating and Crash Protection*, can be located using nominal seat cushion deflection.; The terms which establish the applicability of the requirements of th standard to a particular section of a school bus body are defined in S4 of the standard. Read together, they establish the following test. If the edge of a surface component (made of homogeneous material) in a bus that encloses the bus' occupant space comes into contact or close proximity with any other body component, the requirements of S5 apply, unless the area in question is designed for ventilation or another functional purpose or is a door, window, or maintenance access panel. Applying this test to the 53 intersections of bus body components you describe, it appears that the areas corresponding to the following numbered paragraphs of your letter are bus body joints and therefore must meet the 60-percent joint strength requirements: 1 through 34, 36, 37, 39, 42, 44, 45, 46, 51. Additionally the joint described in your January 8, 1977, submission must comply with the standard.; The illustration accompanying paragraph 16 shows a second joint betwee a door post and exterior trim panel with the notation that this joint is 'Not Required To Meet Std.' The agency concludes that this joint also must meet the requirements of the standard, because it is a connection of a body component with a body panel that encloses occupant space.; The lower skirt section described in paragraph 35 is not a body pane that encloses occupant space, because it is located entirely below the level of the floor line and, therefore, is excluded from the standard's requirements.; In the control console area, the interior side panel described i paragraph 38 and the shoulder cap (wire cover) described in paragraph 43 are considered maintenance access panels, whose joining with the bus body is excluded from the requirements only if a wire is installed behind them.; The turn signal housings described in paragraphs 40 and 41 are no considered to have a function in enclosing the occupant space and are therefore not considered body components for purposes of the requirements.; The front and rear headers described in paragraphs 47 and 48 ar considered primarily structural and have only an incidental role in enclosing the occupant space and, therefore, are not considered 'body panels' for purposes of the requirements.; The rubrail described in paragraph 49 is not considered to have function in enclosing the occupant space and, therefore, is not considered a body component for purposes of the requirements. For purposes of testing the complex joints to which it is fastened, it should be modified as necessary to prevent it from affecting testing of the underlying joint.; Because the plywood described in paragraph 50 is attached to a floo panel and is only added to some buses for insulation purposes, it is not considered to have a function in enclosing the occupant space and is therefore not considered a body component for purposes of the requirements.; The NHTSA concludes that parts A, E, and F of paragraph 52 describ joints between maintenance access panels and the bus body. The heater ducts in parts B, C, and D are the type of ventilation space that is not subject to requirements for joint strength.; In response to your question concerning the effect of seat cushio deflection on the location of the seating reference point, the NHTSA has determined that the definition of seating reference point contemplates some deflection of seat cushions to simulate compression of padding material under the weight of a human torso and thigh. As noted in the preamble of the second proposal for a school bus seating standard (39 FR 27585, July 30, 1974), 'It can be seen that the manufacturer's freedom to locate the point is sharply restricted by the definition which specifies that it actually simulate the position of the pivot center of the human torso and thigh, following SAE placement procedures.' However, since the seating reference point is an approximation of the pivot center, the NHTSA permits the manufacturer to locate the point based upon nominal seat cushion deflection.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam0169OpenMr. H.J. Hempel, Vice President, Interamerican Motor Corporation, 14721 Calvert Street, Van Nuys, California 91401; Mr. H.J. Hempel Vice President Interamerican Motor Corporation 14721 Calvert Street Van Nuys California 91401; Dear Mr. Hempel: This is in reply to your letter of May 27 in which you reques information necessary to obtain a D.O.T. number and import 'Pneumant' tires. The information furnished below concerns only those requirements of the Department of Transportation.; Regulations promulgated pursuant to Section 110(e) of National Traffi and Motor Vehicle Safety Act of 1966 (15 U.S.C. S1391 *et seq.*, 1399(e)) require any manufacturer, assembler, or importer of a motor vehicle before offering a motor Vehicle or item of motor vehicle equipment for importation into the United States to designate a permanent resident of the United States as his agent upon whom service of all processes, notices, orders, decisions, and requirements may be made.; The manufacturer of 'Pneumant' tires is therefore required to designat an agent as prescribed in the regulations (49 C.F.R. S351.45) and I enclose a copy of them, as well as a copy of the National Traffic and Motor Vehicle Safety Act, for your information.; Please note that these regulations require the designation to be mad in a specific manner. The designation should contain the following:; >>>(1) a certification by the signer of the designation that it i binding on the manufacturer of 'Pneumant' tires under the laws, corporate by-laws, or other requirements governing the making of the designation by the manufacturer of 'Pneumant' tires at the place and time where it is made,; (2) the full legal name, principal place of business, and mailin address of the manufacturer of 'Pneumant' tires,; (3) trade names, or other designations of origin of the products of th manufacturer of 'Pneumant' tires which do not bear its legal name,; (4) a provision that the designation remains in effect until withdraw or replaced by the manufacturer of 'Pneumant' Tires,; (5) a declaration of acceptance duly signed by the designated agent and; (6) the full legal name and mailing address of the designatio agent.<<<; In addition, the designation should be signed by one with authority t appoint the agent for the manufacturer of 'Pneumant' tires, and this authority should be so indicated.; In your letter you state that it is your understanding that 'all tire used in this Country are subject to approval which will be given in form of a D.O.T. number.' This is incorrect. There is no provision in the National Traffic and Motor Vehicle Safety Act which provides that motor vehicles and motor vehicle equipment are to be approved by the United States Government. On the contrary, under this Act the manufacturer o(sic) the motor vehicle or item of motor vehicle equipment bears the responsibility for complying with Federal Motor Vehicle Safety Standards promulgated pursuant to the Act, and, pursuant to Section 114 of the Act for certifying that his product so complies. In the case of tires, the applicable standard is Standard No. 109 and I enclose a copy of it with applicable amendments for your reference. Standard No. 109 contains requirements for new pneumatic tires for passenger cars, and in order to meet the requirements of the Act, 'Pneumant' tires must comply with Standard No. 109. Furthermore, the manufacturer of these tires must certify in the prescribed manner that such tires so comply.; The 'D.O.T. number' to which you refer is required by Section 201 o the Act and the labelling section (S.4.3 and 'Figure 1') of Standard No. 109. As specified in the standard, the letters 'D.O.T.', when permanently molded into or onto the tire so that the tire is conspicuously labelled on both sidewalls, indicate pursuant to S.4.3(1) and Figure 1 of Standard No. 109, that the tire has been manufactured to conform to applicable Federal Motor Vehicle Safety Standards. This satisfies the certification requirement referred to above.; The code mark *number* is included as part of the label (as illustrate in Figure 1) pursuant to Section 201 of the Act, when the tire contains a brand name other than the name of the manufacturer, and is included for the purpose of permitting the seller of the tire to identify the manufacturer to the purchaser upon his request.; A code mark number con be obtained from the Department o Transportation by any tire manufacturer on request, but is only necessary when a name other than the manufacturer's is used on the tire. Such a request should be directed to Secretary of Transportation, Attention: Motor Vehicle Safety Performance Service, National Highway Safety Bureau, Federal Highway Administration, U.S. Department of Transportation, Washington, D.C. 20591. Issuance of the code mark number by the Department of Transportation in no way indicates approval by the government that tires manufactured by the one to whom it is issued meet Federal requirements. As indicated above, the code mark number is to be used purely for labeling purposes.; I am also enclosing a copy of Federal Highway Administration Impor Regulations, (19 C.F.R. S12.80) which are promulgated jointly with the Treasury Department pursuant to Section 108(b) (3) of the Act for your information.; Should you have further questions, please feel free to contact me. Sincerely, Lawrence R. Schneider,Acting Assistant Chief Counsel fo Regulations; |
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ID: aiam1328OpenMr. H. W. Gerth, Ass't. Vice President, Mercedes-Benz of North America, Inc., One Mercedes Drive, P.O. Box 350, Montvale, NJ 07645; Mr. H. W. Gerth Ass't. Vice President Mercedes-Benz of North America Inc. One Mercedes Drive P.O. Box 350 Montvale NJ 07645; Dear Mr. Gerth: This is in reply to your letter of September 24, 1973, concerning th conformity of an emergency feature of Mercedes-Benz's interlock system to S7.4.3 of Standard No. 208.; The feature you describe would permit the engine starting system to b operated without belt use for a period of 3 minutes after an activation knob inside the engine compartment is depressed. If the vehicle stalls, the driver would have to leave his seat, open the hood, depress the knob, close the hood, and return to his seat, at which point the interlock would be deactivated for the 3-minute period. This bypass feature would apparently supplement other convenience aspects provided pursuant to S7.4.3.; After review of the Mercedes system we have determined that it woul not result in bypassing the interlock in situations where that would not be permissible under S7.4.3 or S7.4.4. We therefore conclude that it is an allowable system and that it may be installed.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3315OpenMr. Brian Gill, American Honda Motor Co., Inc., 100 W. Alondra Blvd., P.O. Box 50, Gardena, CA 90247; Mr. Brian Gill American Honda Motor Co. Inc. 100 W. Alondra Blvd. P.O. Box 50 Gardena CA 90247; Dear Mr. Gill:#This responds to your letter of April 22, 1980, askin two questions about Standard No. 101-80, *Controls and Displays*.#Your first question concerns whether a display incorporated in the tachometer instrument face that shows which gear position has been selected by the automatic transmission control lever is an 'informational readout display.' You explained that the display 'consists of 5 stacked transparent screens on which are printed 'D', '2', 'N', 'P', 'R' to identify the transmission control lever positions. Each screen is illuminated by an incandescent bulb which is energized selectively through contacts at the control lever.'#The display which you have described is not an informational readout display. Section 4 of the standard defines 'informational readout display' as 'a display using light-emitting diodes, liquid crystals or other electro illuminating devices where one or more than one type of information or message may be displayed.' As explained in the June 26, 1978, preamble to the final rule establishing Standard No. 101-80, the agency did not want to inhibit the development of electronic 'readout' panels which present the driver with specific information concerning vehicle and environmental conditions affecting safety. The preamble further described these devices as displays 'capable of exhibiting information and warning with word messages and not with symbols.' The device you have described uses symbols instead of words and conventional incandescent bulb technology instead of electronic technology and thus is not an informational readout display.#The display you have described is a gauge. Section 4 of the standard defines 'gauge' as 'a display that is listed in S5.1 or in Table 2 and is not a telltale.' Section 5.1 and Table 2 do not identify the automatic gear position as a telltale. Likewise, an automatic gear position display does not meet the definition of 'telltale.' Section 4 of the standard defines 'telltale' as 'a display that indicates, by means of a light-emitting signal, the actuation of a device, a correct or defective functioning or condition, or failure to function.' In this case, the display does not indicate the activation of a device since a transmission is always activated. Likewise, the display does not indicate that the transmission is functioning correctly or improperly or has failed to function. Section 5.3.3 provides that the light intensity of each gauge shall be continuously variable. The display you have described does not comply with section 5.3.3, since it only has two light intensities.#Your second question concerns 'a display adjacent to the shift control lever which shows the transmission shift level sequence. The identifying characters 'P', 'R', 'N', '2', 'D', are shown on a transparent screen, the position selected is indicated by a colored panel which moves with the shift control level.' You explained that the 'colored panel *only* is illuminated when the headlights are switched on showing which position is selected, the other positions on the display are not illuminated.' [Emphasis in the original]#You asked whether the display is exempt from the illumination requirements of the standard because it is 'a hand- operated control mounted upon a...floor console' or because it is a 'telltale.' Section 5.1 and Table 2 of the standard classify an automatic gear position indicator as a display. Thus, an automatic gear position indicator cannot be a 'hand-operated vehicle control.'#Further, the display that you have described is not a 'telltale.' As explained above, an automatic gear position display is a gauge. According to your description, the display '*only* is illuminated when the headlights are switched on.' Section 5.3.3 of the standard requires the light intensity for gauges to be continuously variable. Since the illumination for the display you have described apparently is not variable, it would not comply with the standard.#If you have any further questions, please let me know.#Sincerely, Frank Berndt, Chief Counsel; |
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ID: aiam1282OpenMr. Jerry R. Freed, 3115 Prairie, Elkhart, IN 46514; Mr. Jerry R. Freed 3115 Prairie Elkhart IN 46514; Dear Mr. Freed: Your letter of September 24, 1973 has been referred to the Region Office of the National Highway Traffic Safety Administration, by the Federal Trade Commission.; Enclosed is a copy of Title IV of the Motor Vehicle Information an Cost Savings Act, Public Law 92-513. This information should provide you and your counsel with adequate information to resolve your problem. If, after having gone over the law, you still have technical questions regarding this law, please forward them to Lawrence R. Schneider, Chief Counsel, N40-30, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590. I am forwarding a copy of your letter to Mr. Schneider's office for appropriate action.; If this office can be of further assistance to you in the future please let us know.; Sincerely, Gordon G. Lindquist, Regional Administrator |
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ID: aiam2857OpenMr. D. L. Haines, The B. F. Goodrich Company, Engineered Systems Division, P.O. Box 340, Troy, OH 45373; Mr. D. L. Haines The B. F. Goodrich Company Engineered Systems Division P.O. Box 340 Troy OH 45373; Dear Mr. Haines: This responds to B. F. Goodrich's August 2, 1978, question whether th specified temperature for brake burnish in S6.1.8.1 of Standard No. 121, *Air Brake Systems*, should be maintained by reducing maximum vehicle speed during snubs even if the reduced maximum speed does not appear among the snub conditions listed in Table IV of S6.1.8.1.; The answer to your question is yes. The snub conditions listed in Tabl IV represented the agency's best estimate of appropriate speeds for obtaining the specified burnish temperature, given the state-of- the-art of brake technology when the standard was issued. If you have under development a brake design that achieves the specified burnish temperature at a lower speed, it would be correct to reduce vehicle speed below the 40-mph level specified in Table IV to achieve and maintain that temperature.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam4080OpenThe Honorable Ted Stevens, United States Senate, Washington, DC 20510; The Honorable Ted Stevens United States Senate Washington DC 20510; Dear Senator Stevens: Thank you for your letter on behalf of your constituent, Ms. Kimberl Hallenbeck of Fairbanks, Alaska, concerning our regulations for safety belts on school buses. Your letter has been referred to my office for reply, since we are responsible for Federal regulations on school bus safety.; Your constituent asked whether our requirements for safety belts appl to the used school buses purchased by her company. As explained below, the answer is no.; We contacted Ms. Hallenbeck's company, Wilbur & Son, on February 13 t obtain more information about her inquiry. Wilbur & Son explained that it purchased two used 1980 large school buses for its shuttle service which had been certified by their manufacturer as meeting our school bus safety standards. The company has been requested to install safety belts in those vehicles, but believes this is unnecessary. The company requested us to clarify our requirements for safety belts on large school buses (i.e., school buses with gross vehicle weight ratings over 10,000 pounds). We appreciate this opportunity to do so.; The National Highway Traffic Safety Administration (NHTSA) i responsible for developing safety standards for all new motor vehicles, including school buses. NHTSA does not require safety belts in large new school buses because we issued a safety standard in 1977 (Standard No. 222, *School Bus Passenger Seating and Crash Protection*) to require those buses to provide improved crash protection to passengers through a concept called 'compartmentalization.' Compartmentalization requires that the interior of large buses be improved so that school children are protected without the need to fasten safety belts. The seating improvements include higher and stronger seat backs, additional seat padding, and better seat spacing and performance. Our safety standards do require safety belts for passengers in smaller school buses since those buses do not offer the same protection as that provided by compartmentalization.; Although we have determined that a safety standard *requiring* safet belts in those buses is not warranted at this time, NHTSA has tentatively determined that an amendment to Standard No. 222 might be necessary to set performance requirements for safety belts voluntarily installed on large new school buses. We recently issued such a proposal. If it is adopted, we would require manufacturers to ensure that safety belts voluntarily installed on new school buses meet performance criteria established by our safety standards. We emphasize that such a requirement would apply to the manufacture of new school buses only, and would not apply to persons retrofitting safety belts on large school buses already in use. A copy of our rulemaking notice is enclosed.; We are enclosing a copy of a report issued by NHTSA entitled 'Safet Belts in School Buses' (June 1985), which might be of interest to your constituents. In addition, we are providing your constituents with a copy of Safety Standard No. 222, and information sheets which describe our motor vehicle safety standards generally and how to obtain copies of individual safety standards or regulations.; I hope this information is helpful. Please feel free to contact m office if we can be of further assistance.; Sincerely, Erika Z. Jones, 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: aiam3745OpenMr. Otto Major, 219 West Bel Air Avenue, Aberdeen, MD 21001; Mr. Otto Major 219 West Bel Air Avenue Aberdeen MD 21001; Dear Mr. Major: This is in response to your letter of August 18, 1983, in which yo assert that the Maryland Certificate of Title does not comply with the Federal Odometer disclosure statement requirements.; Your assertion is incorrect. States are permitted to use their titl documents in lieu of a separate Federal form, provided that the State form contains the odometer disclosure information specified in 49 CFR Part 580. Maryland's Certificate of Title contains this information and, therefore, satisfies the Federal odometer disclosure statement requirements. For your information, I have enclosed a copy of Part 580.; You also requested an interpretation regarding whether the installatio of a replacement engine of unknown mileage will require the transferor to report the mileage on the certificate as being unknown. The answer is no.; Section 408 of the Motor Vehicle Information and Cost Savings Act, 1 U.S.C. S 1968, and its implementing regulations, require the transferor of a motor vehicle to disclose to the transferee the cumulative mileage registered on the odometer or, that the actual mileage is unknown, if the odometer reading is known to be different from the number of miles the *vehicle* has actually traveled.; The Act does not require the separate disclosure of the number of mile traveled by the motor vehicle components, nor is there a mechanism in motor vehicles to measure the distance traveled by each component. Therefore, the installation of a replacement engine will not change the disclosure requirements of the transferor.; Sincerely, Frank Berndt, 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.