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: aiam1600OpenMr. Roger J. Harris, President, Eagle Coach Company of Dallas, Inc., 5424 Gregg Street, Suite 109, Dallas, TX 75235; Mr. Roger J. Harris President Eagle Coach Company of Dallas Inc. 5424 Gregg Street Suite 109 Dallas TX 75235; Dear Mr. Harris: This is in reply to your letter of August 15, 1974, asking about 'thos requirements which presently exist for limited volume manufacturers.'; I enclose a copy of an information sheet that tells where you ma obtain the Federal motor vehicle safety standards and other regulations. No exceptions are automatically provided for limited volume manufacturers. Those whose total annual production is 10,000 units or less may petition for a temporary exemption from one or more standards upon the grounds that compliance would cause substantial economic hardship.; As a converter of production sedans into extended wheelbase vehicles and as a customizer of automobiles, your principal obligation is to insure that any new and previously untitled vehicle you sell and deliver to the ultimate purchaser conforms to all Federal motor vehicle safety standards applicable to passenger cars. This means that you should review the standards to determine whether your manufacturing operations affect conformity of any new vehicle as delivered to you that is certified by its manufacture as meeting Federal requirements. In any event, since your alterations consist of more than minor finishing operations you are required to attach the label described by Title 49, Code of Federal Regulations, Section 567.7, a copy of which I also enclose.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam0912OpenMr. Keitaro Nakajima, Factory Representative Office, Toyota Motor Sales, U.S.A., Inc., Lyndhurst Office Park, 1099 Wall Street West, Lyndhurst, NJ 07071; Mr. Keitaro Nakajima Factory Representative Office Toyota Motor Sales U.S.A. Inc. Lyndhurst Office Park 1099 Wall Street West Lyndhurst NJ 07071; Dear Mr. Nakajima: This is in reply to your letter of October 2, 1972, concerning th requirements applicable to a seat belt installed as part of a restraint system conforming to S4.1.2.3 of Standard 208.; You are correct in reading S4.1.2.3 to provide that a seat belt capabl of meeting the injury criteria of Standard 208 is not required to meet Standard 209 except as provided in S7.1 and S7.2 of Standard 208.; We have under consideration a petition from the Japan Automobil Manufacturers Association to amend Standard 209 to reflect the exemption made in Standard 208. The agency's response to the petition will be issued shortly.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3328OpenJames. R. Clifton, P.O. Box 237, Bessemer, AL 35021; James. R. Clifton P.O. Box 237 Bessemer AL 35021; Dear Mr. Clifton: This is in response to your telephone conversation with Kathy DeMete of my staff on Tuesday, September 2, 1980. You asked for the status of section 580.5(a)(1) of Title 49 of the Code of Federal Regulations. That section exempts from the odometer disclosure requirements anyone transferring a vehicle having a gross vehicle weight rating of more than 16,000 pounds. That exemption is part of the regulation, originally issued in January 1973, which prescribes rules requiring a transferor of a motor vehicle to make a written disclosure to the transferee concerning the odometer reading and its accuracy.; In January 1977, the exemption was declared void by the United State District Court for the District of Nebraska on the grounds that the National Highway Traffic Safety Administration (NHTSA) has exceeded its authority in fashioning the exemption. Notwithstanding the court's decision, the NHTSA believes that it has the authority to create exemptions for vehicles for which the odometer reading is not relevant. The exemption, consequently, remains a part of the odometer disclosure regulations.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1315OpenHonorable Jack Edwards, House of Representatives, Washington, DC 20515; Honorable Jack Edwards House of Representatives Washington DC 20515; Dear Mr. Edwards: Your request for information on the Federal Odometer Disclosur regulation on behalf of Mr. Charles J. Fleming has been referred to me for reply.; I am enclosing a copy of the regulation which includes an example of a acceptable format. Other formats are acceptable if all the required information is included.; We are unable to advise Mr. Fleming about the effect of a particula typographical error without knowing its nature, but as a general matter a typographical error would not give rise to liability unless it were deceptive in a way which misleads a purchaser.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam4117OpenMr. E. Brooks Harper, General Manager, Backstop, Inc., 240 Pegasus Avenue, Northvale, NJ 07647; Mr. E. Brooks Harper General Manager Backstop Inc. 240 Pegasus Avenue Northvale NJ 07647; Dear Mr. Harper: This responds to your letter asking whether installation of your touc sensitive reverse braking system called 'Backstop' on an air brake vehicle would conflict with any Federal motor vehicle safety standards or regulations. According to your letter, Backstop is plumbed into the vehicle air brake system and wired to the back up light circuit. The system is activated only when reverse gear is engaged and works by instantly applying the vehicle brakes when the rear bumper is touched while reversing. Shifting to neutral or a forward gear returns the system to normal braking.; By way of background information, the National Highway Traffic Safet Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. The National Traffic and Motor Vehicle Safety Act places the responsibility on the manufacturer to certify that its vehicles or equipment comply with applicable requirements. The following represents our opinion based on the facts provided in your letter and is limited to the standards and regulations administered by NHTSA. You may wish to contact the Bureau of Motor Carrier Safety (BMCS) concerning whether any of its regulations are relevant to the installation of Backstop.; NHTSA does not have any regulations covering a touch sensitive revers braking system such as Backstop. However, since installation of Backstop requires plumbing into the vehicle's air brake system and wiring into the vehicle's backup light circuit, it is possible that it could affect a vehicle's compliance with Federal Motor Vehicle Safety Standards (FMVSS) No. 121, *Air Brake Systems*, and No. 108, *Lamps, reflective devices, and associated equipment*. For example, your letter states that a delay of four milliseconds is introduced to the air brake system response by the insertion of the double check valve in the control line. While this delay is very small, it could conceivably affect a vehicle's compliance with the timing requirements of sections S5.3.3 and S5.3.4 of FMVSS No. 121 if the vehicle otherwise was at the edge of compliance. We suggest that you carefully consider whether installation of Backstop in the variety of current vehicles and vehicle configurations would affect compliance with the requirements of FMVSS No. 121 or any other Federal motor vehicle safety standard.; If your device is added to a new motor vehicle prior to its first sale the person who modifies the vehicle would be an alterer of a previously certified motor vehicle and would be required to certify that, as altered, the vehicle continues to comply with the safety standards affected by the alteration. The specific certification requirements for alterers are set forth at 49 CFR Part 567.7, *Certification*. On the other hand, you as the manufacturer of Backstop would have no certification responsibilities, because we have no safety standards applicable to your equipment. However, an alterer would probably require information from you in order to make the necessary certification.; If your device is installed on a used vehicle by a business such as garage, the installer would not be required to attach a certification label. However, it would have to make sure that it did not knowingly render inoperative the compliance of the vehicle with any safety standard. This is required by section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act.; Should a safety- related defect be discovered in your device, whethe by the agency or yourself, you as the manufacturer would be required under sections 151 *et* *seq*. of the Act to notify vehicle owners, purchasers, and dealers and provide a remedy for the defect.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam3778OpenCapt. Bill Perzinsky, President, TWI Inc., 14525 Bessemer Street, Van Nuys, CA 91411; Capt. Bill Perzinsky President TWI Inc. 14525 Bessemer Street Van Nuys CA 91411; Dear Capt. Perzinsky: This is in reply to your letter of October 14, 1983, to Mr. Vinson o my staff regarding your F-S- 700 A flasher. The device is essentially a slender bar of lights mounted on the rear panel shelf of a passenger car. The left and right sides blink to indicate turns in the appropriate direction. The entire bar lights up when the brake pedal is applied. You ask for our 'approval' of this device.; The Federal motor vehicle safety standard on lighting forbids th installation of motor vehicle equipment that impairs the effectiveness of lighting equipment required by the standard. Stop lamps are required by the standard. They must be red. They must go on when the brake pedal is applied. The stop signal put out by the F-S-700 flasher is amber, not red. Therefore, an amber signal coming on at the same time as a red one would impair the effectiveness of the red stop lamp by creating confusion.; The Federal lighting standard allows either amber or red turn signa lamps. There is obviously a potential for confusion if your amber light device is on a vehicle whose turn signals are red. But an even greater problem with interior-mounted lamps, whatever their color, is the reflection that they cause in the rear glass, particularly when it's raining or snowing, interfering with the rear vision of the vehicle's driver.; For the reasons given above the F-S-700 A flasher causes us som concern. Further, you should investigate whether the laws of the jurisdiction where you wish to sell this device will permit its installation and use.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1745OpenMr. Gerhard P. Reichel, Attorney, Volkswagen of America, Inc., Englewood Cliffs, New Jersey 07632; Mr. Gerhard P. Reichel Attorney Volkswagen of America Inc. Englewood Cliffs New Jersey 07632; Dear Mr. Reichel: This is in reply to your letter of December 4, 1974, to Michael Pesko of this office asking whether it is permissible under Standard No. 110 to refer to air conditioning and automatic transmission option in stating the 'vehicle capacity weight' on the placard required under S4.3 of the standard. The format you suggest would state a vehicle capacity weight, followed on a separate line by the statement: 'If air conditioning is installed, subtract 82 pounds.' you also ask whether basic vehicle body style may be similarly treated. Your request is based on your desire to standardize the placard required by Standard No. 110, to make the placarding requirements less expensive to meet.; We interpret Standard No. 110 to permit the use of a standardize placard that contains various vehicle capacity weights based on body style or the presence of various options. However, in such a case we believe that label should at least initially contain the lowest vehicle capacity weight for the vehicle, that is, a weight which presumes that the vehicle is equipped with those options having an effect on vehicle capacity weight. If the absence of these options increases the vehicle capacity weight, we believe this should be stated beneath the basic vehicle capacity weight, and by specifying the actual weight with the option omitted rather than asking the reader to perform a computation.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam0857OpenMr. Bob Rauscher, Product Engineer, The Gates Rubber Company, Galesburg, IL, 61401; Mr. Bob Rauscher Product Engineer The Gates Rubber Company Galesburg IL 61401; Dear Mr. Rauscher: This is in reply to your letter of August 1, 1972, requesting a interpretation in regard to the application of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials', to hoses used in engine compartments and to hoses used in engine compartments that would also 'lead through the firewall into the passenger compartment'.; Hoses are not included in the list of motor vehicle interior component (Section S4.1) to which the Standard applies, and therefore they are not covered by the Standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3282OpenMr. Thomas E. Cole, Tire Division, Rubber Manufacturers Association, 1901 Pennsylvania Avenue, N.W., Washington, DC 20006; Mr. Thomas E. Cole Tire Division Rubber Manufacturers Association 1901 Pennsylvania Avenue N.W. Washington DC 20006; Dear Mr. Cole: This is in response to your letter of April 14, 1980, regarding tw apparent discrepancies in the revised Uniform Tire Quality Grading tread label format, published on November 29, 1979, in Docket 25, Notice 35 (44 FR 58475). As you note, the word 'Vehicle' was omitted from the term 'Federal Motor Vehicle Safety Standard No. 109' under the heading 'Temperature' in Figure 2, Part II, of the regulation as published. This was an inadvertent omission which the National Highway Traffic Safety Administration (NHTSA) plans to correct in a future notice.; You also point out that paragraph (d)(1)(i)(B)(1) of the regulation (4 CFR 575.104(d)(1)(i)(B)(1)), applicable to tires manufactured prior to October 1, 1980, provides for use of the heading 'DOT QUALITY GRADES' in capital letters, while Part I of Figure 2 of the regulation contains the heading 'DOT Quality Grades' using lower case letters. The label format specified in paragraph (d)(1)(i)(B)(1) parallels the label format originally announced in Docket 25, Notice 24 (43 FR 30542, July 17, 1978), the heading of which used all capital letters. Since Part I of Figure 2 is not required on labels printed in accordance with paragraph (d)(1)(i)(B)(1), the use of lower case letters in the heading of Part I does not affect the requirements of paragraph (d)(1)(i)(B)(1). NHTSA will permit, at the manufacturer's option, the use of all capital letters in the heading of Figure 2, Part I, in printing labels to comply with the new two-part label format.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4547OpenMr. George Ziolo DOT Paperwork Processor 234l7 Everett Place Ramona, CA 92065; Mr. George Ziolo DOT Paperwork Processor 234l7 Everett Place Ramona CA 92065; Dear Mr. Ziolo: This is in reply to your letter of April 20, 1988 asking about the acceptability under Safety Standard No. 108 of modifying imported vehicles so that they are equipped with two Type 2D1 and two Type 1C1 headlamps. You have been informed by the agency's Office of Vehicle Safety Compliance that this is impermissible 'because they are 'nonconforming' 'headlight systems'.' You disagree because you believe that the minimum requirements of the Standard are satisfied by the Type 2D1 lamps, and that 'S4.4 appears to permit such a combination.' Paragraph S4.4 is not applicable to the situation you present as it refers to combinations of lamps serving different functions, in your discussion, the lamps serve the identical function of headlighting. Given the fact that the Type 2D1 sealed beam 7' diameter headlamps fulfill the headlighting requirements of the Standard, your question must be viewed as whether a supplement to the headlighting system is permissible under Standard No. 108. Paragraph S4.l.3 of Standard No. 108 permits the addition of nonrequired lighting equipment provided it does not impair the effectiveness of the equipment that the standard requires. The two Type 1C1 5 3/4' diameter sealed beam lamps in a four lamp headlighting system form the major portion of an upper beam headlighting system. The two Type 2D1 lamps in a two lamp headlighting system form the whole of an upper beam headlighting system. Thus, a vehicle furnished with the systems you posit would be equipped with more than one upper beam headlighting system. The Type 2D1 system must be designed to conform to the photometric requirements of SAE Standard J579c DEC79 'Sealed Beam Headlamp Units for Motor Vehicles.' The SAE Standard establishes at two test points, H-V and 4 D-V, maximum allowable candela of 75,000 and 5,000 respectively for each Type 2D1 headlamp. This means that the maximum allowable candela for headlighting systems at these test points is 150,000 and l0,000 candela. The Type 1C1 headlamps will also be designed to conform to SAE J579c. Corresponding maxima at test points H-V and 4 D-V for Type 1C1 systems are 60,000 and 5,000. Thus, a vehicle equipped with the lamps you have described could emit a total of 270,000 candela at test point H-V (when only 150,000 is permitted), and 20,000 at 4D-V (when only l0,000 is allowable). Agency research has shown that candela readings in excess of 150,000 greatly increase the potential for glare with little increase in seeing ability. This glare would be visible both to the driver of an oncoming car, and the driver of the modified vehicle itself through creation of a 'veiling' glare. The addition of the Type 1C1 headlamps would therefore impair the effectiveness of the Type 2D1 headlighting system, and is forbidden by S4.1.3. We appreciate your interest in safety. Sincerely, Erika Z. Jones Chief Counsel; |
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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.