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 |
|---|---|
| search results table | |
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 |
|
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 |
|
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 |
|
ID: aiam3941OpenDennis J. Slyman, Esq., 101 N. Main, Greensburg, PA 15601; Dennis J. Slyman Esq. 101 N. Main Greensburg PA 15601; Dear Mr. Slyman: Thank you for your letter of March 21, 1985 asking how the Nationa Traffic and Motor Vehicle Safety Act affects one of your clients. I hope the following discussion will explain the provisions of the Act.; You explained in your letter and a phone conversation of April 4, 1985 with Stephen Oesch of my staff that your client sold a new 1977 Dodge Van to Mon Valley United Health Services in March 1977. At the time of sale, the van was converted by Braun Corporation from a passenger van to a wheelchair van. Approximately two years after its purchase, Mon Valley requested your client to install a bench seat in the rear of the van. You stated that Mon Valley asked that the new seat not have safety belts and thus your client did not install them. Subsequently, a passenger sitting in the rear seat was injured in a crash and your client was sued for negligence.; I want to emphasize that our comments relate only to our interpretatio of the Safety Act from our vantage point as a Federal enforcement agency. The effect of Safety Act provisions in private products liability and negligence actions is a matter for state courts to determine.; You asked whether your client violated Section 108 and 125 of th Vehicle Safety Act (15 U.S.C. 1397 and 1410) by not installing safety belts in a vehicle when it installed the bench seat in the used van. Because the vehicle involved was a used vehicle at the time the rear bench seat was installed, the prohibitions of Section 108(a)(1)(A) against selling or otherwise introducing into interstate commerce a new vehicle that does not conform to all applicable Federal Motor Vehicle Safety Standards would not apply to your client. This is because Section 108(b)(1) of the Act specifically provides that the prohibitions of Section 108(a)(1)(A) do not apply after the first purchase of a vehicle for purposes other than resale.; Section 108(a)(2)(A) may have an effect on your client's action. Tha section prohibits any manufacturer, distributor, dealer or motor vehicle repair business from knowingly rendering inoperative any equipment or element of design installed on a vehicle in compliance with our standards. The prohibition of 108(a)(2)(A) applies whether the vehicle is a new or used vehicle. Thus if the used van had safety belts in it at the position where your client installed the bench seat and your client removed them, there may have been a violation of Section 108(a)(2)(A). If the used van did not have safety belts at that position, Section 108(a)(2)(A) does not create an affirmative duty under Federal law to install safety belts. However, there may be such a duty under State statutory or common law. The other prohibitions of Section 108 do not apply to the situation you have described. Likewise Section 125 of the Act, which sets forth limitations on the agency's rulemaking authority, does not apply to your client's situation.; Other than Section 108(a)(2)(A), there are no other provisions of th Act that apply to your client's installation of a bench seat on a used vehicle.; If you have further questions, Stephen Oesch of my staff (202-426-2992 would be glad to assist you.; Sincerely, Jeffrey R. Miller, Chief Counsel |
|
ID: aiam5196OpenMr. Ernest Farmer Director, Pupil Transportation Tennessee State Department of Education Office of Commissioner Nashville, TN 37243-0375; Mr. Ernest Farmer Director Pupil Transportation Tennessee State Department of Education Office of Commissioner Nashville TN 37243-0375; Dear Mr. Farmer: We have received your letter of June 25, 1993, wit respect to your plan to retrofit three school buses with strobe lights for 'the traditional incandescent lights currently used in the eight light overhead warning system on school buses.' You ask whether this equipment would 'conflict with the provisions of FMVSS 108.' Yes, the substitute system would not conform to S5.1.4 of Standard No. 108 because it is not a school bus signal lamp system meeting the requirements of SAE J887 School Bus Red Signal Lamps, July 1964. Moreover, section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1392(a)(2)(A)) prohibits a manufacturer, dealer, distributor, or motor vehicle repair business from knowingly rendering inoperative any device or element of design installed in accordance with a Federal motor vehicle safety standard. However, the prohibition does not extend to the vehicle owner. We assume for purposes of this interpretation that the State is the owner of the school buses, and owns the repair facilities where the conversion will occur. Under these circumstances, there is no Federal legal prohibition against the State's conversion to the strobe light system if the work is performed in its own repair shops. Sincerely, John Womack Acting Chief Counsel; |
|
ID: aiam2653OpenHonorable Lamar Gudger, House of Representatives, Washington, D.C. 20515; Honorable Lamar Gudger House of Representatives Washington D.C. 20515; Dear Mr. Gudger: Please excuse the delay in my response to your letter of June 15, 1977 addressed to Mr. Norman Sultan, with a copy to the National Highway Traffic Safety Administration (NHTSA) regarding the Federal requirement for registration of tires.; Mr. Sultan has reported a tire registration of 10 percent in his are of operation which is considerable less than the national figures of 30 percent for retreads and 70 percent for new tire replacements developed in our studies. Mr. Sultan is urging a change in the law to permit voluntary registration of all tires.; Mr. John Snow, my predecessor, reported to the Honorable Warren G Magnuson, Chairman of the Committee on Commerce, U.S. Senate, that consideration would be given to changing Regulation Part 574 allowing voluntary registration of retreaded tires in lieu of mandatory registration. Since taking office, I have devoted considerable attention to reviewing and analyzing the pertinent factors related to tire registration. I am convinced of the safety benefits of registering new tires and I consider the mandatory recordkeeping provision essential to the purpose of the Vehicle Safety Act. However, because retreaded tires are individually manufactured and therefore could not be recalled as are mass produced items, I am considering proposing revocation of the mandatory recordkeeping requirements for retreaded tires.; For your information I am enclosing a copy of my recent letter t Senator Magnuson in response to his questions on this subject.; You may be interested to know that a recent meeting wit representatives of the National Tire Dealers and Retreaders Association (NTDRA) provided an opportunity to discuss basic clerical problems associated with registration. As a result, an interpretation of the regulation was reached which would permit the tire purchaser personally to complete the registration form. Although dealer responsibility remains, the interpretation is considered by NTDRA to provide considerable relief to dealers in time and cost. Hopefully this action will offset much of the objections to the current tire registration process.; Sincerely, Joan Claybrook |
|
ID: aiam0394OpenMr. J. A. Westphal, Senior Staff Engineer, FWD Corporation, Clintonville, WI 54929; Mr. J. A. Westphal Senior Staff Engineer FWD Corporation Clintonville WI 54929; Dear Mr. Westphal: This is in reply to your letter of July 1, 1971, concerning the Tir Identification and Record Keeping Regulation (49 CFR 574).; You are correct in your interpretation of the regulation, the vehicl manufacturer is not required to forward tire data to the tire manufacturer. The vehicle manufacturer's responsibilities are limited to maintaining a record of the tires on or in the vehicle when shipped along with a record of the names and addresses of first purchasers of the vehicles equipped with such tires. The method of complying with these requirements is left to the vehicle manufacturer. In the event of a defect notification, the tire manufacturer will be under an obligation to notify the vehicle manufacturer describing the suspect tires.; If we can be of further assistance, please feel free to write. Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
|
ID: aiam3412OpenMr. Carol Kirk, Robinson L. P. Gas Company, R. D. No. 1, Beaver Grade Road, Coraopolis, PA 15108; Mr. Carol Kirk Robinson L. P. Gas Company R. D. No. 1 Beaver Grade Road Coraopolis PA 15108; Dear Mr. Kirk: This responds to your recent letter requesting information regardin the conversion of school bus fuel systems to dual fuel carburetion running on propane gas. Specifically, you ask whether any regulations require that a protective cage be placed around a propane fuel tank, if propane carburetion is installed on a school bus.; The answer to your specific question is no. Federal motor vehicl safety standards and regulations do not require protective cages for propane fuel tanks. In fact, the Federal safety standard regarding fuel system integrity, Standard No. 301, is not directly applicable to propane fuel systems.; I am enclosing a fact sheet for your information which discusses th Federal implications of installing auxiliary fuel tanks and of converting fuel systems to use alternate fuels. From that fact sheet you will see that there may be certain responsibilities which must be met by persons converting school buses to use dual fuel systems. Please feel free to contact Hugh Oates of my staff if you have any further questions after reviewing this information (202-426-2992).; You will have to contact your State department of motor vehicles t determine if there are any local laws or regulations which would require the installation of a protective cage around propane fuel tanks.; Sincerely, Frank Berndt, Chief Counsel |
|
ID: aiam3042OpenMr. D.J. Schrum, Manager, Product Compliance, Subaru of America, Inc., 7040 Central Highway, Pennsauken, NJ 08109; Mr. D.J. Schrum Manager Product Compliance Subaru of America Inc. 7040 Central Highway Pennsauken NJ 08109; Dear Mr. Schrum: This is in response to your letter of June 4, 1979, concerning Subaru' obligation to provide to prospective motor vehicle purchasers an explanation of the Uniform Tire Quality Grading (UTOG) Standards (49 CFR 575.104(d)(1)(ii)). You ask whether Subaru must provide UTOG information to prospective purchasers prior to April 1, 1980, in view of the fact that all motor vehicles sold by your company are equipped with radial tires.; With respect to radial tires, the effective date for all requirement of the UTOG regulation, other than the molding requirement of paragraph (d)(1)(i)(A) and the first purchaser requirement of paragraph (d)(1)(iii), is April 1, 1980. Therefore, manufacturers, such as Subaru, which offer for sale only motor vehicles equipped with radial tires, need not provide UTOG information for examination by prospective purchasers prior to April 1, 1980.; Sincerely, Frank Berndt, Chief Counsel |
|
ID: aiam4787OpenSamson Helfgott, Esq. Helfgott & Karas, P.C. 60th Floor Empire State Building New York, NY l0ll8-0ll0; Samson Helfgott Esq. Helfgott & Karas P.C. 60th Floor Empire State Building New York NY l0ll8-0ll0; Dear Mr. Helfgott: This is in reply to your letter of June ll, l99 (Your file CAIN 8877), with respect to the permissibility under Standard No. 108 of the use of amber lamps on the rear of motor vehicles. You have referenced our letter to you of March 30, l989, on the use of a single amber lamp adjacent to, but separate from, the center highmounted stop lamp. Your client wishes to utilize the amber center lamp in conjunction with rear amber turn signal lamps to provide an amber triangular array on the rear. The array would be activated when the ignition is turned on, and remain activated except when the stop lamps were activated (which, with the red center lamp, provide a red triangular array). With respect to the triangular amber lamp array you have asked the following four questions: 'l. The possibility of utilizing the amber turn signals as tail lights, instead of the red tail lamps. This is the same as is now in effect on the front of all vehicles.' Standard No. 108 requires that the color of taillamps be red. Therefore amber turn signal lamps could not serve as substitutes for taillamps. Your comment about frontal lighting is not exactly in point. A turn signal lamp may be combined with a parking lamp (provided the requirements for each are met) but Standard No. 108 requires that both be amber in color. '2. The possibility of supplementing existing tail lamps with the presence of the amber lamps.' We do not regard this as a true supplement because the color of the array differs from that of the taillamps required by Standard No. 108. However, like taillamps, the array is intended to indicate the presence of a vehicle. The question is, whether an array of three amber lamps would impair the effectiveness of the required two red taillamps. As we advised in our letter of March 30, l989, additional lighting equipment is permissible as long as it does not impair the effectiveness of the lighting equipment that the standard requires. We cautioned that you should consider whether steady-burning amber lamps might confuse following drivers, who would probably be unused to seeing steady burning amber lamps on the rear of a vehicle. Because you have not informed us as to the intended candela of the array, we cannot advise with any assurance whether the amber array would impair the effectiveness of the required red taillamps. Certainly if the candela of the triple amber arrray exceeded that of the red taillamps a basis would appear to exist for a judgment of impairment. '3. The possibility of using the amber lamps as daytime running lamps on the rear of a vehicle.' Under this scenario, the amber array would function as daytime presence lamps, a function not provided by any rear lighting system required by Standard No. 108. The question therefore is whether such a system would impair the effectiveness of the signal lamps required by Standard No. 108. These are hazard warning signals, turn signals, and stop lamps. With respect to the hazard warning signals, these operate through the turn signal lamps, and, although operable when the vehicle is in motion, they are designed to operate when the ignition is not on (i.e., when the triple array would be deactivated). Therefore, we do not believe that the triple array would impair the effectiveness of the hazard warning signals. As for impairment of the turn signals, we must distinguish between those that are amber and those that are red. Again, we raise the possibility that confusion could exist if the candela of the triple array exceeds that of an amber turn signal system. It is imperative that following drivers understand without hesitation the signals provided by other vehicles in front of them. Confusion may be less likely to exist if the required signal lamp and the triple array differ in color. Concerning the stop lamps, you have informed us that the triple array is deactivated when the stop lamps come on. In this event, there would be appear to be no impairment of the stop signals. '4. The possibility of utilizing the 'amber triangular array' as described above.' In our view, no specific Federal rulemaking appears required for your client to offer its system for installation on motor vehicles, subject to the constraints expressed in this letter and the letter of March 30, l989. As the earlier letter explains, the determination of whether there is impairment is initially made by a manufacturer who wishes to offer the system as new vehicle equipment. In the aftermarket, installation of the system must not, in effect, result in impairment of required lighting equipment, but nevertheless the system is subject to State and local lighting laws. We have forwarded a copy of your letter and our response to the agency's Office of Research and Development for their information. We appreciate your client's interest in motor vehicle safety. Sincerely, Paul Jackson Rice 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.