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: aiam1993OpenMr. Daniel W. Lang, Suite 600, 9440 Santa Monica Boulevard, Beverly Hills, CA 90210; Mr. Daniel W. Lang Suite 600 9440 Santa Monica Boulevard Beverly Hills CA 90210; Dear Mr. Lang: This is in response to your letter of July 15, 1975, in which yo inquire as to the applicability of the National Traffic and Motor Vehicle Safety Act and the regulations promulgated thereunder to your client, Star Vision, as a manufacturer and installer of see-through fiberglass replacement tops.; Section 108(a) (2) (A) prohibits a manufacturer, distributor, dealer or motor vehicle repair business from knowingly rendering inoperative any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard. This means that the installation of the top by Star Vision must not take a vehicle out of compliance with Safety Standard No. 216 or any other applicable safety standard. You should note that the requirements of section 108(a) (2) (A) apply to modifications of vehicles following their sale to a purchaser for purposes other than resale. It appears from the literature accompanying your letter that the tops are not installed on vehicles prior to their first sale. If they are, then Star Vision is subject to the notification, remedy, certification, and record-keeping requirements of section 108(a) (1).; There is no specific requirement for testing the replacement tops i order to determine compliance with Standard No. 216. However, since the Act prohibits knowingly rendering inoperative any vehicle or part of a vehicle in compliance with an applicable safety standard, Star Vision is under an obligation to test its product if it has reason to believe that installation of the tops will substantially degrade the performance of the vehicle roofs. If the company has no reason to believe that installation will affect the safety characteristics of the vehicle, it is not obligated to conduct compliance tests.; The replacement tops appear to be subject to Safety Standard No. 205 *Glazing Materials* (49 CFR 571.205). As a result, Star Vision must certify the tops in accordance with section 114 of the Act (15 U.S.C. S 1403).; If the tops do not comply with Standards Nos. 205 or 216 or any othe applicable safety standard, or if they contain a malfunction or defect related to motor vehicle safety, the company will be obligated by sections 151-160 of the Act to notify the purchasers of the kits and to remedy the defect or noncompliance without charge. In addition, section 108(c) of the Act provides that compliance with the Act will not exempt a person from common law liability.; We trust that this information will be of assistance. Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam5179Open"Dr. Thomas L ckemeyer Dept VER/LB SWF Auto-Electric GmbH"; "Dr. Thomas L ckemeyer Dept VER/LB SWF Auto-Electric GmbH"; "Dear Dr. L ckemeyer: As you have requested, we are responding by FA to your letter of April 28, 1993, to Taylor Vinson of this Office. You have asked two questions with respect to the acceptability of a multiple rear turn signal lamp under Federal Motor Vehicle Safety Standard No. 108, and have enclosed a sketch of the lamp. Your first question is: 'Is it allowed to split the turn signal lamp in two parts with the dimensions given in the sketch . . . where the bigger part (4.5 sq. in.) is on the body of the car. The distance does not exceed 22 in.' Your question indicates that the turn signal lamp array of two lamps that is illustrated in the sketch is intended for installation on passenger cars or other vehicles whose overall width is less than 80 inches. Standard No. 108 incorporates by reference the SAE standard applicable to such vehicles, J588 NOV84. Paragraph 5.1.5.2 of SAE J588 NOV84 permits the use of multiple rear turn signal lamps to meet the photometric requirements of Standard No. 108. When multiple lamps are used to meet the photometric requirements of a rear turn signal lamp, paragraph 5.3.3 of SAE J588 NOV84 requires that the functional lighted lens area of each lamp shall be at least 22 sq. cm, provided the combined area is at least 37.5 sq. cm. Your sketch shows that the functional lighted lens area of one lamp is 23 sq. cm, and of the other, 30 sq. cm, with a combined area of 53 sq. cm. Therefore, Standard No. 108 permits you to use the turn signal lamp array shown in your sketch. Your second question is: 'Is it allowed to use the combination of the two lamps to meet the photometric requirements.' Because the distance between the two adjacent light sources in the array does not exceed 560 mm (the sketch indicates that it is less than 550 mm), paragraph 5.1.5.2 of SAE J588 NOV84 requires that the combination of the lamps be used to meet the photometric requirements for the corresponding number of lighted sections, two in this case. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam0681OpenMr. K. Krueger, Technical Development, Liaison Engineer, Volkswagen of America, Inc., Englewood Cliffs, NJ, 07632; Mr. K. Krueger Technical Development Liaison Engineer Volkswagen of America Inc. Englewood Cliffs NJ 07632; Dear Mr. Krueger: In reviewing our response of March 1, 1972, to your letter of Decembe 6, 1971, we have noted that one of our answers contains an error. On page 2, our answer to question 1(b) should read:; >>>'The provisions of S4.3 that you refer to are intended to reflec the performance of samples described in the test procedures of S5. These requirements are intended to provide an exemption for self-extinguishing materials, and not to exempt small samples that are consumed by fire before *one minute* elapses. The standard establishes burn-rate requirements, and manufacturers should keep this in mind in determining whether particular components comply. If your component is such that it is consumed by fire because of its size before the *one-minute* period, then we would expect modifications to the procedure, of a nature described above, to be made in order that a determination of the burn rate of the material is obtained.' (Emphasis added.)<<<; We regret any inconvenience this error may have caused. Yours truly, Richard S. Dyson, Assistant Chief Counsel |
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ID: aiam2346OpenHonorable Bob Sikes, House of Representatives, Washington, DC 20515; Honorable Bob Sikes House of Representatives Washington DC 20515; Dear Mr. Sikes:#This is in response to your May 10, 1976, communicatio enclosing a letter from Mr. John C. Richardson concerning the importation of passenger cars with 'metric instrumentation.' Your communication was forwarded to this agency by the National Bureau of Standards for reply.#Mr. Richardson has encountered difficulty in importing a 1976 model 911 Porsche with metric instrumentation. He has received a letter from Volkswagen of America, Inc., suggesting that 'such instrumentation would be illegal and not certified with the appropriate U.S. Government agencies.' While the precise meaning of 'metric instrumentation' is not clear from either letter, I assume that Mr. Richardson is referring to the marking of the speedometer (in kilometers per hour) and the calibration of the odometer (in kilometers traveled).#The Federal motor vehicle safety standards administered by the National Highway Traffic Safety Administration do not presently require any particular form of marking for speedometers or odometers. While we are considering the establishment of a requirement that English units be used, such a rule would permit metric units as an optional addition. Furthermore, such a rule would only be applied prospectively.#Sincerely, Frank A. Berndt, Acting Chief Counsel; |
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ID: aiam5483OpenMessrs. Jim Cawse and Fred Diehl Plastics Technology Division General Electric Company One Plastics Ave. Pittsfield, MA 01201; Messrs. Jim Cawse and Fred Diehl Plastics Technology Division General Electric Company One Plastics Ave. Pittsfield MA 01201; Gentlemen: We have received your letter of January 2, 1995, asking fo a confirmation of the appropriateness of your proposed test procedures for plastic materials, as you wish to 'continue to adhere to the SAE testing protocol as delineated in SAE J576C.' Paragraph S5.1.2 of Standard No. 108 requires, with certain exceptions, that plastic materials used for optical parts such as lenses and reflectors shall conform to SAE J576c. It has been the agency's position over the years that 49 U.S.C. Chapter 301 (formerly the National Traffic and Motor Vehicle Safety Act) does not establish a requirement that a manufacturer actually conduct compliance testing, but requires only that a vehicle or equipment item conform to any applicable Federal motor vehicle safety standard if tested in the manner set forth in the standard. We have advised that a manufacturer may exercise due care in certifying compliance of its product on bases other than the test procedures that are set forth in the Federal motor vehicle safety standards, whether the procedures are incorporated by reference, as with J576c, or directly expressed in the standards themselves, although NHTSA itself will conduct its tests according to the procedures set forth in the standards. For this reason, we have no comment on the merits of your suggested approach. Because the agency has proposed amending Standard No. 108 to substitute SAE J576 JUL91 for J576c, we are filing your letter in Docket No. 94-37 as a comment to be considered in this rulemaking. Enclosed is a copy of the proposal with which you are probably already familiar. Although the comment period closed on January 3, it is the agency's practice to consider late-filed comments to the extent practicable. Sincerely, Philip R. Recht Chief Counsel Enclosure; |
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ID: aiam5529OpenMr. Paul D. Kelly Albertson, Ward & McCaffrey 36 Euclid Street Woodbury, NJ 08096; Mr. Paul D. Kelly Albertson Ward & McCaffrey 36 Euclid Street Woodbury NJ 08096; "Dear Mr. Kelly: This responds to your letter of February 2, 1995 requesting permission or a waiver from the National Highway Traffic Safety Administration (NHTSA) to allow one of your clients, a 'corporation specializing in modification of vehicles for handicapped and disabled citizens,' to modify a vehicle for one of its customers. You explained that the customer 'suffers from a neuromuscular disorder which renders her partially paralyzed.' You further explained that '(s)he cannot turn the factory steering wheel because it is too thick for her to hold and too wide for her to see the gauges.' You described previous modifications done for this customer as follows: the steering box on a stock vehicle (would be) removed and the steering mechanism would be adjusted at a machine shop to a low effort or zero effort steering gear. From this point after-market steering wheels and column adapter kits would be installed to accept this new steering wheel. You explained that your client was concerned that they would no longer be permitted to make such modifications as removal of the original steering wheel also results in removal of the air bag. During an April 4, 1995 phone call with Mary Versailles of my staff you explained that the vehicle is also equipped with a wheelchair lift and that the floor of the vehicle has been lowered. As explained in this letter, replacement of the steering wheel is permitted provided that a lap/shoulder safety belt is installed at the driver's position. By way of background, the National Highway Traffic Safety Administration is authorized to issue Federal Motor Vehicle Safety Standards that set performance requirements for new motor vehicles and items of motor vehicle equipment (49 USC 30111). Manufacturers are required to certify that their products conform to all applicable safety standards before they can be offered for sale (49 USC 30112). If a certified vehicle is modified, other than by the addition, substitution, or removal of readily attachable components, prior to its first retail sale, the person making the modification is an alterer and is required to certify that, as altered the vehicle continues to conform to all applicable safety standards (49 CFR 567.7). After the first retail sale, there is one limit on modifications made to vehicles. 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 safety standard (49 USC 30122). In general, the 'make inoperative' prohibition would require a business which modifies motor vehicles to ensure that they do not remove, disconnect, or degrade the performance of safety equipment installed in compliance with an applicable safety standard. NHTSA has exercised its authority to issue Standard No. 208, Occupant Crash Protection (49 CFR 571.208). Standard No. 208 requires light trucks and vans manufactured on or after September 1, 1991 to be capable of providing occupant crash protection to front seat occupants when the vehicle is crash tested at 30 miles per hour (mph) into a concrete barrier. A vehicle that provides this crash protection will increase the safety of vehicle occupants. The air bag installed in the customer's vehicle is one means of complying with this requirement. As a result of this new requirement, this agency received a number of phone calls and letters, from both van converters and individuals suggesting that the new light truck and van crash testing requirement will, in effect, prohibit van converters from modifying vehicles to accommodate the special needs of persons in wheelchairs. The agency also received a petition asking for an amendment to the light truck and van crash test requirement in Standard No. 208 to address this problem. As a result on that petition, on March 2, 1993, this agency amended Standard No. 208 to allow manufacturers of light trucks and vans an alternative to complying with the existing requirement (58 FR 11975). Under the amendment, 'vehicles manufactured for operation by persons with disabilities' are excluded from the light truck and van automatic crash protection requirement. Instead, these vehicles must be equipped with a Type 2 manual belt (integrated lap and shoulder belt) or Type 2A manual belt (non-integrated lap and shoulder belt) at the front outboard seating positions. A 'vehicle manufactured for operation by persons with disabilities' is defined as vehicles that incorporate a level change device (e.g., a wheelchair lift or a ramp) for onloading or offloading an occupant in a wheelchair, an interior element of design intended to provide the vertical clearance necessary to permit a person in a wheelchair to move between the lift or ramp and the driver's position or to occupy that position, and either an adaptive control or special driver seating accommodation to enable persons who have limited use of their arms or legs to operate a vehicle. For purposes of this definition, special driver seating accommodations include a driver's seat easily removable with means installed for that purpose or with simple tools, or a driver's seat with extended adjustment capability to allow a person to easily transfer from a wheelchair to the driver's seat. Based on the information you provided, the customer's van would come within this definition. Therefore, if your client would be considered an alterer, it may certify that, with the air bag removed, the vehicle continues to conform to all applicable safety standards, provided that the safety belts are not removed. If the modification is done after the first retail sale, removal of the air bag would not violate the 'make inoperative' prohibition, provided that the safety belts are not removed. I hope this information has been helpful. If you have other questions or need some additional information, please contact Mary Versailles at this address or by phone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam1839OpenMr. H. W. Gerth, Assistant Vice President, Mercedes-Benz of North America, Inc., One Mercedes Drive, Montvale, NJ 07645; Mr. H. W. Gerth Assistant Vice President Mercedes-Benz of North America Inc. One Mercedes Drive Montvale NJ 07645; Dear Mr. Gerth: This is in response to your letter of March 3, 1975, requestin approval of your proposed owner notification letter for your defect notification campaign (NHTSA No. 75-0005) involving the front wheel bearings on some model L1113 trucks.; The letter which you propose sending to owners of the subject vehicle satisfactorily meets the requirements of the National Traffic and Motor Vehicle Safety Act of 1966, as amended. Based on the information provided by you, your plan of notification appears to be adequate.; Sincerely, Andrew G. Detrick, Director, Office of Defect Investigation, Motor Vehicle Programs; |
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ID: aiam3804OpenMr. Stephen Underwood, Mazda (North America), Inc., 23777 Greenfield Road, Suite 462, Southfield, MI 48075; Mr. Stephen Underwood Mazda (North America) Inc. 23777 Greenfield Road Suite 462 Southfield MI 48075; Dear Mr. Underwood: This is to follow up on your phone conversation with Stephen Oesch o my staff on Standard No. 203, *Impact Protection for the Driver From the Steering Control System*. You asked how the steering wheel should be positioned when it is tested in accordance with the standard. As explained below, the steering wheel should be positioned at its design angle, as specified by the manufacturer.; Standard No. 203 incorporates by reference Society of Automotiv Engineers Recommended Practice J944, Steering Wheel Assembly Laboratory Test Procedure, December 1965. Section 6.2 of SAE J944 provides that the steering wheel is to be mounted 'at the proper angle as determined by the package drawing.' Therefore, the agency would mount the column at the design angle specified by the manufacturer.; If you have any further questions, please let me know. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2716OpenMr. Robert Kurre, Director of Engineering, Wayne Corporation, Industries Road, Richmond, IN 47374; Mr. Robert Kurre Director of Engineering Wayne Corporation Industries Road Richmond IN 47374; Dear Mr. Kurre: This responds to your oral request to Roger Tilton of my staff for th reasons that the National Highway Traffic Safety Administration (NHTSA) exempted buses with gross vehicle weight ratings of 10,000 pounds or less from the requirements of Standard No. 221, *School Bus Body Joint Strength*.; As you know, the NHTSA promulgated the joint strength standard t prevent injuries resulting from the impact of children with the sharp protruding edges of body panel sheets that become unfastened in school bus accidents. This problem, according to the information available to the agency, was particularly acute with respect to large school buses. The agency has no similar data indicating that the joint severance problem is a major factor contributing to injuries in accidents involving smaller school buses. Accordingly, the agency exempted those vehicles from the requirements. Should the NHTSA discover in the future that such problems exist with respect to smaller buses, it would consider extending the requirements to them.; I am enclosing a copy of our last notice on Standard No. 221 that full outlines our reasons for exempting smaller school buses.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam2203OpenMr. David E. Martin, Director, Automotive Safety Engineering, General Motors Corporation, General Motors Technical Center, Warren, MI 48090; Mr. David E. Martin Director Automotive Safety Engineering General Motors Corporation General Motors Technical Center Warren MI 48090; Dear Mr. Martin: This is in response to your letter of February 10, 1976, concerning th definition of 'daylight opening' (DLO) as specified in Motor Vehicle Safety Standard No. 219, *Windshield Zone Intrusion*, 49 CFR 571.219, and concerning the procedure used by General Motors to determine DLO.; Your letter states that General Motors is concerned about th definition of DLO as stated in Standard No. 219, and 'believes that the wording is not easily understood.' The definition of DLO as stated in the Standard is based upon the definition found in paragraph 2.3.12 of Section E, Ground Vehicle Practice, SAE Aerospace Automotive Drawing Standards, September, 1963. The SAE definition was slightly modified to reflect the particular characteristics of Standard No. 219. The last phrase of the SAE definition was changed to read 'as measured parallel to the outer surface of the glazing material,' because there was concern that there might be some confusion if the definition directed measurement by means of a 'vertical projection'.; Your letter describes General Motors' procedure for obtaining DLO, an asks if this procedure is consistent with the definition of DLO as specified in Standard No. 219. The answer to your question is yes. Your illustration (Figure 1) shows that you are measuring 'parallel to the outer surface of the glazing material'. Your Figure 1 is a simplified illustration, of course, since nearly all windshields are curved.; Please contact us if we can be of any further assistance. Yours truly, Richard B. Dyson, Assistant 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.