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: nht73-5.10OpenDATE: 10/05/73 FROM: AUTHOR UNAVAILABLE; Ellwood T. Driver; NHTSA TO: United States Senate TITLE: FMVSR INTERPRETATION TEXT: This is in further reply to your letter of September 7, 1973, concerning correspondence you received from Mr. Alton R. Rau of Linton, North Dakota. Mr. Rau objects to Federal regulations which require him to purchase trucks with stronger axles and tires than those trucks which he formerly purchased. The National Highway Traffic Safety Administration Certification regulations (49 CFR Parts 567 and 568) require manufacturers to establish gross vehicle and gross axle weight ratings, and to equip new vehicles with components, including tires and axles, that are of sufficient capacity to carry intended loads. The regulations do not establish the relevant ratings, which are established solely by manufacturers. We feel the justification in terms of safety for such requirements is obvious. We believe situations such as that experienced by Mr. Rau where, according to manufacturer's figures, vehicles should have been equipped with stronger axles and tires, demonstrate the need for the Certification requirements rather than showing them to be unnecessary. The regulations apply only to new motor vehicles, and not to vehicles already in use. For Mr. Rau's information I have enclosed a copy of these requirements. 3 ENCLS. |
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ID: nht78-3.2OpenDATE: 01/25/78 FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA TO: Toyo Kogyo Co., Ltd. TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of December 14, 1977, inquiring whether attaching mirrors onto the backs of sun visors on the passenger's side would violate S3.4.1 of Motor Vehicle Safety Standard No. 201, Occupant Protection in Interior Impact -- Passenger Cars. The National Highway Traffic Safety Administration has determined that paragraph S3.4.1 of Standard No. 201 does not prohibit the installation by manufacturers of vanity mirrors on sun visors. Consequently, so long as the mirror does not cause the visor to be hazardous or to interfere with the energy-absorbing requirement of S3.4.1, manufacturers are free to incorporate such mirrors into or onto sun visors, including fitting mirrors onto the backs of the sun visors on the passenger's side as in the diagram you enclosed. SINCERELY, Toyo Kogyo Co., Ltd. December 14, 1977 Joseph J. Levin, Jr. Chief Counsel National Highway Traffic Safety Administration U.S. Department of Transportation Dear Mr. Levin: We are considering to attach a mirror to the sun visor for customers' convenience. However, since MVSS 201 provides for the following requirement, we would like to have your comment as to whether we can meet it by doing so. MVSS 201 "Occupant Protection in Interior Impact" S3.4 Sun visor S3.4.1 Two sun visor shall be provided that are constructed of or covered with energy-absorbing material. The mirror will be fitted into the back of the sun visor on passenger's side as shown in the attached sheet. We consider that this would be in compliance with the above requirement on the grounds that the sun visor made of energy-absorbing material would not contact the occupant under normal condition, thus would not produce an adverse effect on the safety of the occupant. We would appreciate hearing from you on this matter as soon as possible. Moriyuki Watanabe Director and Assistant General Manager Research and Development CC: TOYO KOGYO USA REP. OFC., DETROIT BRANCH (Graphics omitted) |
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ID: nht92-6.45OpenDATE: May 21, 1992 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA TO: Nathan W. Randall TITLE: None ATTACHMT: Attached to letter dated 3/2/92 from Nathan W. Randall to Chief Counsel, NHTSA (OCC 7067) TEXT: This responds to your letter of March 2, 1992, asking for confirmation that you will be a manufacturer of "used" motor vehicles under the fact situation that you outlined and a previous interpretation of this agency. You intend to assemble replica vehicles which will incorporate new items of motor vehicle equipment except for "previously used engine/transmission/drive axle/gearing combinations from previously certified configurations," in compliance with EPA emission requirements for rebuilt vehicles. Because "its running gear is not new", you believe that we would consider your vehicle "as 'used' even though its body and chassis are previously unused." You inform us that "these vehicles will be fully compliant with EPA regulations for rebuilt automobiles and the Colorado State Motor Vehicle code." In support you cite a 1980 interpretation of this Office under which the then Chief Counsel stated that "the agency tends to view as 'used' a motor vehicle whose running gear is not new even though its body and chassis may be previously unused." That 1980 interpretation addressed a situation in which the vehicle was to be constructed from all new parts except for the front suspension and axle, engine, and transmission. You are correct that your situation appears analogous to the one in the 1980 letter, and that you will be viewed as a manufacturer of "used" motor vehicles. As you also correctly understand, you will be responsible for notification and remedy of any safety related defects occurring in your product. However, you should also be aware that our views relate only to the specific facts as you have related them. On April 22, 1991, we informed Memory Motors, another replica vehicle manufacturer, that its products would be considered "new" vehicles for purposes of compliance with the Federal motor vehicle safety standards where the previously used chassis was retained in modified form, and the only other used components retained included the rear axle assembly and front end components. Because the engine and other fuel system components were new, we assume that the Memory vehicle did not qualify as a "rebuilt" vehicle under EPA regulations. |
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ID: RMAmetric22869Open Mr. Steven Butcher Dear Mr. Butcher: This responds to your March 12, 2001 letter asking whether four labeling sample proposals, subject to Federal Motor Vehicle Safety Standard (FMVSS) No. 119, New pneumatic tires for vehicles other than passenger cars (571.119), are acceptable in terms of placement of the metric units under the Final Rule for the Metric Conversion of Tire Standards, Docket No. NHTSA-98-3837, Notice 1 ("Final Rule") (May 27, 1998, 63 FR 28912). The National Highway Traffic Safety Administration (NHTSA) does not issue advance approval of compliance by manufacturers with motor vehicle safety standards or regulations. The agency, however, will give an informal opinion as to whether your sample markings appear to comply with the requirements of FMVSS No. 119, as amended by the Final Rule. A review of the labeling illustrations you supplied indicates that you have used a different format than illustrated in our Final Rule of May 27, 1998. For example, the amended FMVSS No. 119 does not dictate repetition of the existing English measurement label after the metric measurement label, e.g. "MAX LOAD 1020 KG AT 350 KPA COLD (MAX LOAD 2250 LBS AT 50 PSI)" but, rather, the placement of the existing English measurement in parenthesis after the metric measurement, e.g. "MAX LOAD 1020 KG (2250 LBS) at 350 KPA (50 PSI) COLD". This specification resulted from comments by manufacturers that unnecessary words needlessly increase the amount of labeling required on the tires. The example of marking information shown in S5.6 of FMVSS No. 119 in the Final Rule is intended only as a guide to manufacturers. A manufacturer can vary the illustrated format somewhat as long as the requirements of S5.6, as amended, are satisfied. Since the additional words in your proposed labels do not obfuscate the required markings, the labels appear to comply with the requirements of FMVSS No. 119, as amended by the Final Rule. I hope this information is helpful. If you have any questions or need additional information, feel free to contact Nancy Bell of my staff at (202) 366-2992. Sincerely, John Womack ref:119 |
2001 |
ID: 09-001076asOpenMr. Scott Ault President/Dealer Developer Deceleration Technologies, LLC 5515 University Drive Grand Forks, ND 58203 Dear Mr. Ault: This responds to your letter, in which you ask about the permissible activation of stop lamps under Federal Motor Vehicle Safety Standard (FMVSS) No. 108, Lamps, Reflective Devices, and Associated Equipment. Specifically, you asked whether it would be permissible to activate the stop lamps when the vehicle reaches a certain rate of deceleration, regardless of whether the driver intended to activate a braking or engine retardation system. Our answer is that this would not be permissible under the standard. By way of background, the National Highway Traffic Safety Administration (NHTSA) is authorized to issue FMVSSs that set performance requirements for new motor vehicles and items of motor vehicle equipment (see 49 U.S.C. Chapter 301). NHTSA does not provide approvals of motor vehicles or motor vehicle equipment. Instead, manufacturers are required to self-certify that their products conform to all applicable safety standards that are in effect on the date of manufacture. NHTSA selects a sampling of new vehicles and equipment each year to determine their compliance with applicable FMVSSs. If our testing or examination reveals an apparent noncompliance, we may require the manufacturer to remedy the noncompliance, and may initiate an enforcement proceeding if necessary to ensure that the manufacturer takes appropriate action. With regard to the specific technology, called Slow-N-Tell, you are inquiring about, you state: My technology specifically reads vehicle speed and calculates rate of deceleration, when deceleration is detected. Based on the rate of deceleration, expressed as negative mph per second, stop lamps are activated when braking threshold is reached. As you note in your letter, deceleration can occur in a variety of situations, including upon application of the service brake, activation of an engine retarder, or simply by force of gravity if the vehicle is traveling up an incline. In the latter situation, because Slow-N-Tell works by sensing deceleration, it would activate the stop lamps even though the driver may not have intended the vehicle to decelerate. You state that it is your opinion that this does not violate paragraph S5.1.3 of FMVSS No. 108 (which states that no motor vehicle equipment shall be installed that impairs the effectiveness of lighting equipment required by this standard), because it signals to following drivers that the vehicle is slowing. We disagree with your suggested interpretation of the standard. The SAE Recommended Practices on stop lamps that are incorporated by reference into Standard No. 108, SAE J586 (May 1984) and SAE J1398 (May 1985), define stop lamps as [l]amps which indicate the intention of the operator of a vehicle to stop or diminish speed by braking. [emphasis added] As we have stated in several letters, including the April 10, 1992 letter to Mr. Lance Watt[1] that you cite: Activation of the stop lamps initiated by release of the accelerator pedal is permissible only when the intent of the driver is to reduce the speed of the vehicle by an immediate subsequent act of braking, whether that is achieved through his use of the service brake system, use of retarders, or a combination of the two. However, a configuration where the stop lamps operate in the absence of service brake application or activation of a retarder system (as appears to occur when a retarder cut off switch has been activated) would be subject to S5.1.3 of the standard. The situation you describe is analogous to the situation proscribed in the letter to Mr. Watt. If the vehicle experienced deceleration due to reasons other than the application of a braking or engine retardation system (e.g., the vehicle was traveling up an incline), it would be a violation of paragraph S5.1.3 for the stop lamps to activate. Finally, we do not agree with your assertion that activating the stop lamps in such a situation would actually enhance the effectiveness of the lighting equipment. The signal emitted by stop lamps is to alert other drivers of the vehicle operators intent to slow down or stop. If the vehicle is decelerating due to an incline, activation of the stop lamps would send an improper signal that could be confusing to other drivers. If you have any further questions, please contact Ari Scott of my staff at (202) 366-2992. Sincerely yours, Stephen P. Wood Acting Chief Counsel ref:108 d.7/24/09 |
2009 |
ID: nht76-1.8OpenDATE: 07/15/76 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Pacet International TITLE: FMVSS INTERPRETATION TEXT: This is in response to your June 15, 1976, question whether Arcoflex windshield wiper blades must be certified as being in compliance with Federal motor vehicle safety standards before they may be sold as aftermarket equipment through vehicle distributors' dealer parts programs. Standard No. 104, Windshield Wiping and Washing Systems, requires vehicles to be equipped with a power-driven windshield wiping system that meets specified performance requirements. It is up to vehicle manufacturers to certify that each vehicle they produce conforms to the requirements of Standard No. 104, in accordance with the certification procedures specified in 49 CFR Part 567. Standard No. 104 is not an equipment standard, however, and is not applicable to wiper blades sold in the aftermarket. Therefore, there is no requirement that Arcoflex windshield wiper blades be certified, so long as they are not installed on vehicles as part of the wiping system prior to the first sale of the vehicle. Sincerely, ATTACH. PACET INTERNATIONAL The Chief Counsel -- NHTSA Gentlemen This Company imports Arcoflex windshield wiper blades from Italy and sells them through the import aftermarket throughout the US. It is my understanding that your Department has no interest in this activity. Recently, however, we have endeavored to sell our product to the import car manufacturers' US distributors for marketing through their dealer parts programs. The representatives of some of these companies have expressed the concern that, since they are wholly owned by the car manufacturers, your Department may wish for our product to be certified, even though it will not be used as original equipment on their cars. Please be kind enough to clarify, therefore, whether or not Arcoflex wiper blades need to be certified by your Department before they may be sold through import car distributors' dealer parts programs. Your immediate attention to this matter would be greatly appreciated, since important sales decisions depend upon your reply. Yours very truly, Peter W Mole |
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ID: nht72-3.9OpenDATE: 09/01/72 FROM: AUTHOR UNAVAILABLE; Robert L. Carter; NHTSA TO: Rolls-Royce, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of May 19, 1971, concerning the placement of vanity mirrors in sun visors. We apologize for our delay in responding to your letter. The issues it raised, however, are of consequence to manufacturers other than Rolls-Royce, and concerned basic matters of interpretation of Standard No. 201 which have only recently been resolved. The National Highway Traffic Safety Administration has determined that paragraph S3.4.1 of Standard No. 201 does not prohibit the installation by manufacturers of vanity mirrors on sun visors. Consequently, manufacturers are free to incorporate such mirrors into or onto sun visors, including mirrors that are recessed into the surface of the visor as in the sample you enclosed. SINCERELY, ROLLS-ROYCE, INC. May 19, 1971 National Highway Traffic Safety Administration U.S. Department of Transportation attention: Ref. FMVSS 201 Mr. Risteen Gentlemen: F.M.V.S.S. 201 OCCUPANT PROTECTION, INTERIOR IMPACT -- SUNVISOR, VANITY MIRRORS The mirror was deleted from visors at the introduction of the Safety Standard. Customer criticism of the deletion of the mirror, however, has prompted us to seek the following interpretation, if in fact they would be regarded as acceptable: We are aware that a Notice of Proposed Rule Making to Amend F.M.V.S.S. 205 - Docket 71-1; Notice 1 - glazing materials exist, where mirrors should meet the requirements of items 1 to 13 of ANS-Z26. With (Illegible Word) proposed effective date of January, 1972, however, it is hoped we will have material for the mirrors, but we are still not certain that it would qualify as energy absorbing. The method of fitting mirrors to sunvisors to markets other than North America is: 1. 4-DOOR VEHICLES A plain glass mirror, backed with adhesive tape, so that should it fracture fragments adhere to the tape. The glass plus the tape is in a recess in the foam which makes up the body of the visor. A thin gauge soft aluminum frame is used to tidy up the leather cover around the aperature. 2. 2-DOOR VEHICLES A semi-rigid plastic mirror is used in a shallow recess in the foam. Again a frame is used to tidy up the trim around the aperature. In other respects the construction is the same. In order to help in your interpretation, a sunvisor with the glass mirror and a sample of the plastic mirror is enclosed. If necessary, you may strip them down and break them if it will assist in arriving at a decision. May we request an early response. Trevor Williams Service Manager |
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ID: nht93-8.25OpenDATE: November 22, 1993 FROM: John Womack -- Acting Chief Counsel, NHTSA TO: Bob Carver -- Wayne Wheeled Vehicles TITLE: None ATTACHMT: Attached to letter dated 10/01/93 Est. from Bob Carver (OCC-9218) TEXT: This responds to your letter in which you referred to this agency's final rule amending Federal Motor Vehicle Safety Standard (FMVSS) No. 217, Bus Emergency Exits and Window Retention and Release, dated November 2, 1992 (57 FR 49413). Specifically, you referred to S5.5.3(c) of FMVSS 217, as amended, and asked whether it was necessary to outline an emergency roof exit with retroreflective tape even though the tape would not be visible unless the bus is tilted on its side. You also asked whether the tape width requirement will be changed to 1 inch. As you correctly quoted in your letter, S5.5.3(c) of FMVSS 217, as amended by our final rule of November 2, 1992, provides: Each opening for a required emergency exit shall be outlined around its outside perimeter with a minimum 3 centimeters wide retroreflective tape, either red, white, or yellow in color, that when tested under the conditions specified in S6.1 of 571.131, meets the criteria specified in Table 1. The plain language of this provision requires every school bus emergency exit required by the standard to be outlined by the retroreflective tape, including required roof exits. No exceptions are provided in the standard. I note that the November 1992 final rule required additional emergency exits for school buses, but provided manufacturers various options from which to choose. Roof exits were specified as one option because of their potential safety benefits in rollover situations where the bus comes to rest on its side. Further, roof exits could also serve as potential exit routes where other exit routes were either unavailable or inoperative. The retroreflective tape requirement was intended to increase the conspicuity of emergency exits in low-light situations. In a situation where a bus is resting on its side, the increased conspicuity of a roof exit could be critical for safety. With regard to the width of the tape, we proposed a 1-inch retroreflective tape in the NPRM. However, in the final rule that 1 inch measurement was inadvertently converted to 3 cm rather than the correct 2.5 cm. We are in the process of issuing a technical amendment to the final rule which will specify that the tape must be not less than 2.5 cm (1 inch) in width rather than 3 cm. I hope this information will be of assistance to you. Should you have any further questions or need any additional information, please feel free to contact Walter Myers of my staff at this address or at (202) 366-2992. |
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ID: nht92-5.34OpenDATE: 07/01/92 EST FROM: Bob Bullard TO: Walter Myers TITLE: None ATTACHMT: Attached to letter dated 9/4/92 from Paul Jackson Rice to Bob Bullard (A39; Std. 120) TEXT: In regards to our telephone conversation on Monday, July 20 concerning used tires being installed as standard equipment on new utility trailers. There are over 200,000 utility trailers manufactured annually. Of this number, approximately 185,000 are mounted with used tires and shipped to the dealers. The dealers sell these trailers to the general public. This situation presents a problem in that every trailer has a rated load weight allowable. With used tires being used-the rated load weight is totally inaccurate, because no one knows what kind of weight a used tires can carry. Because of this problem, it is not uncommon to see a new trailer have a blow-out on our highways. In many instances, these accidents cause major fatalities. The NHTSA has had the foresight to asses the situation and now has a regulation pertaining to used tires on trailers,--reference #49CFR Ch.V,571.120,S5.1.3. The drawback to this regulation is that no trailer manufacturer or dealer knows about this law. If they are aware of it's existence- they do not full understand it. Although this regulation speaks for itself, some of those dealing with the requirements may not have an extensive educational background. For this reason, I desperately need an interpretation from your office that spells out exactly what a manufacturer and dealer can and cannot do in regards to this law. Please include in this interpretation, a simplified version of the regulation, penalty for violations, and who to contact for enforcement. This version will be sent to dealers around the country. If only one life can be saved on our highways by bringing utility trailers to your already existing standards, the time on this issue will have been well spent. Please forward the requested information to: Bob Bullard 12400 West I-20 E Odessa, Texas 79766 (915) 563-0300 |
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ID: nht91-5.27OpenDATE: August 19, 1991 FROM: Phil Lanam -- Engineer, Ukiah Fire Department TO: Taylor Vinson -- DOT/OCC TITLE: None ATTACHMT: Attached to letter dated 10-23-91 from Paul Jackson Rice to Phil Lanam (A38; Std. 121); Also attached to letter dated 3-4-80 from Frank Berndt to Joe Cain TEXT: I have been referred to you by Engineer Blane Laubis of Vehicle Safety Compliance. My question to him was in regards to a piece of equipment we just purchased. This piece of equipment is a 1978 F700 Ford truck, 24500 GVW, VIN N75FVB89042. The problem we are having with it is the Eaton anti-skid brake system. Part of the anti-skid system has been removed. In my research, I have found this system was plagued with problems. We would like to install standard S cam air brakes on this vehicle. I have talked with several agencies and they have made this change. My question to you concerns the legality of this change. I have been told there is a clause in the anti-skid law that allows this on some problem plagued systems. I would greatly appreciate any information you could give me to help resolve this problem. |
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.