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: nht79-3.48OpenDATE: 06/06/79 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Wayne Corporation TITLE: FMVSS INTERPRETATION TEXT: This responds to your May 18, 1979, letter asking to what extent the parallelepiped device required by Standard No. 217, Bus Window Retention and Release, must fit inside a school bus in order to provide the mandated "unobstructed passage." The agency responded to a request similar to yours in 1976. A copy of that interpretation is included for your information. The essence of that interpretation is that while conducting the test in accordance with S5.4.2.1(a) of the standard, the parallelepiped device must, at a minimum, fit inside a bus so that the device's outside edge is flush with the lower outside edge of the bus body. If your bus complies with this interpretation of the standard, it would be in compliance. SINCERELY, Wayne Corporation May 18, 1979 Joseph Levin, Jr. Chief Counsel U.S. Department of Transportation National Highway Traffic Safety Administration Dear Mr. Levin: Section S5.4.2.1(a) of FMVSS 217, Bus Retention and Release, requires that the rear emergency door opening of a school bus be large enough to provide the unobstructed passage of a rectangular parallelepiped. Will the condition illustrated on the enclosed sketch satisfy this requirement? The following applies to this sketch: The rectangular parallelepiped is of the prescribed dimensions, surface "A" is totally within the outline of the body except for the top portion where the body contour slopes forward. The forward side of the rectangular parallelepiped (the side opposite surface "A") is totally inside of the body and contacts the rearmost surface of the passenger seats. An early reply will be greatly appreciated. Robert B. Kurre Director of Engineering SURFACE 'A' Wayne Corporation An Indian Head Company Wayne Transportation Division Richmond, Indiana DATE: 5-11-79 SCHOOL BUS REAR EMERGENCY DOOR OPENING PASSAGE (Graphics omitted) |
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ID: nht81-2.50OpenDATE: 07/22/81 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: British Standards Institution TITLE: FMVSS INTERPRETATION TEXT: This responds to your letter of June 8, 1981, concerning Standard No. 209, Seat Belt Assemblies. You are correct that my letter of June 1, 1981, on the abrasion test procedure of the standard should have referred to section 5.1(d), instead of to section 5.2(d). You also suggested that in the process of clarifying the standard's abrasion requirements, the agency should consider possible modifications to sections 4.2(e) and (f) of the standard. In the process of reviewing the abrasion test requirements, the agency will also examine those other sections to determine what changes should be made. Finally, you raised the issue of whether the standard, as with other national and international standards, should have a requirement that conditioned webbing must retain a certain percentage of its unconditioned strength and must also meet the minimum strength requirement for unconditioned webbing. The agency is not aware of any data indicating that our current conditioned strength requirements are insufficient. Sincerely, ATTACH. JUNE 8, 1981 F Berndt -- U.S. Department Transportation, National Highway Traffic Administration Dear Mr Berndt Many thanks for your letter dated 1 June 1981 regarding abrasion testing to FMVSS 209. However, should Section 5.2 (d), when it occurs, read 5.1 (d)? I understand your reasoning for the clarification, however, should this be extended to cover Sections 4.2 (e) and 4.2 (f)? In most of the National and International specifications which we test to the strength after conditioning must be above a certain percentage of its unconditioned strength and also above the minimum required strength of the webbing. You are permitting the use of webbing that might, after abrasion, fall below your minimum strength requirement. Do you have any comments on this? I look forward to receiving a prompt reply to the first paragraph. Yours sincerely J E BINGHAM -- SENIOR TEST ENGINEER, MOTOR VEHICLE SAFETY COMPONENTS SECTION, BRITISH STANDARDS INSTITUTION |
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ID: nht79-4.50OpenDATE: 03/28/79 FROM: D. J. ARNOLD -- VESELY COMPANY DIRECTOR OF PRODUCT DEVELOPMENT TO: FREDERIC SCHWARTZ -- OFFICE OF THE CHIEF COUNSEL NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION TITLE: NONE TEXT: Dear Mr. Schwartz: With issuance of Docket No. 1-22; Notice 8, relating to Vehicle Identification Numbers I must assume the NHTSA is getting closer to "finalizing" FMVSS No. 115 notwithstanding the VIN litigation upcoming in the U.S. Court of Appeals for the Fourth Circuit. As such, and in follow-up to my several letters and telephone conversation with you on January 9, 1979 I am again requesting official NHTSA written replies to these as soon as possible to enable our small company to try and comply with the Federal requirements. To date, I have not received approval of our requested first three digit assignments (letter of October 30, 1978) as required by the standard and I have not received written permission to utilize digits 12 and 13 for our own in-house use (letter of December 11, 1978). Further, I have never received an official answer to my letter to President Carter other than a post card from Secretary Adams saying he will be replying. All in all, not much action to help our company comply with these Federal mandates. If our company is going to be able to meet the effective date of September 1, 1980 we must have some answers now! Docket No. 1-22; Notice 8 has done nothing to alleviate or reduce this company's burden as I interpret the impact of it. Since we not only manufacture motor homes (MPV's) but recreational trailers as well, we must institute this 17 digit system even though the chassis manufacturer would assign his VIN. We cannot stay with our current VIN system for one product and change to a completely different VIN system for our other products. Your replies will be anxiously awaited to enable us to continue the necessary work to comply with FMVSS 115 as it now stands by the effective date of September 1, 1980. Very truly yours, |
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ID: nht78-3.21OpenDATE: 07/26/78 FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA TO: T. Iinuma - Nissan Motor Co., Ltd. TITLE: FMVSS INTERPRETATION TEXT: This responds to your May 25, 1978, question concerning the strength requirements of Safety Standard No. 210, Seat Belt Assembly Anchorages, as they would be applicable to the anchorage on a single diagonal passive belt system. You ask how many pounds of force should be applied to such a belt system for the anchorage strength test. The anchorage for a single diagonal passive seat belt should be tested with a 3,000 pound force for purposes of the Standard 210 requirements, the same force required for the upper torso portion of a Type 2 seat belt. Most vehicles with single diagonal passive belt will have knee bolters or some other method to restrain the legs in a crash, so the anchorage will not experience as much stress as would be placed on a lap belt without knee bolsters. Therefore, 3,000 pound test should ensure that the anchorage for a diagonal passive belt can withstand typical crash forces. SINCERELY, NISSAN MOTOR CO., LTD. May 25, 1978 Joseph J. Levin Chief Counsel NHTSA Department of Transportation Dear Mr. Levin: This letter is to request your interpretation regarding the test method of FMVSS 210 "Seat belt assembly anchorages". The force applied to the anchorage of Type 1 or Type 2 seat belt assembly is expressed clearly in that standard. (Type 1:5000 lbs., Type 2:lap portion 3000 lbs. and shoulder portion 3000 lbs. simultaneously). It seems, however, there is no specific description of the force for the anchorage of the single diagonal passive seat belt (so called VW Rabbit type passive seat belt). I would like to know how many pounds we should apply to the above mentioned passive seat belt for the anchorage strength test. I look forward to hearing from you as soon as possible Tokio Iinuma Staff, Safety cc: WILLIAM E. SMITH -- CRASHWORTHINESS DIV., NHTSA |
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ID: nht78-1.18OpenDATE: 06/19/78 FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA TO: Nissan Motor Co., Ltd. TITLE: FMVSS INTERPRETATION TEXT: This responds to your letter of May 1, 1978, to Mr. Tilton of this office requesting our interpretation of the requirement of Standard No. 110, Tire Selection and Rims, that a placard displaying specified information be "permanently affixed to the glove compartment door or an equally accessible location." (S4.3) Specifically, you inquire whether the back side of the lid of the center console box is an acceptable location for the placard within the meaning of S4.3. We have interpreted "equally accessible location" as requiring a location where the placard (1) can be referred to easily, as it can when located on the glove compartment door; and (2) will be relatively free from exposure to substances which may destroy it or render it illegible, as it is when located on the glove compartment door. The back side of the lid of the center console box as depicted in the diagram attached to your May 1 letter fulfills these two requirements, and is therefore an "equally accessible location" within the meaning of S4.3. Sincerely, ATTACH. NISSAN MOTOR CO., LTD. May 1, 1978 Roger S. Tilton -- Office of the Chief Counsel, NHTSA Dear Mr. Tilton: This letter is to request your interpretation concerning a location of the tire placard which is specified in S.4.3. of FMVSS 110 "Tire selection and rims". We are planning to affix the tire placard to the back side of the lid of the center console box in one of our future models as shown in the attachment. We would like to know whether this location is acceptable or not under the requirement of "A placard, permanently affixed to the glove box compartment door or an equally accessible locations" in S.4.3. We would appreciate your reply as soon as possible Thank you. Very truly yours, Tokio Iinuma Staff, Safety Enclosure (Graphic omitted) |
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ID: nht76-4.12OpenDATE: 08/04/76 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Blue Bird Body Company TITLE: FMVSS INTERPRETATION TEXT: This responds to Blue Bird Body Company's June 21, 1976, question whether S5.3.1 of Standard No. 121, Air Brake Systems, requires the installation of an antilock system, or whether the stopping distance and "no lockup" requirements may be met using modulation of the service brake control by the vehicle driver. Section S5.3.1 requires that vehicles subject to it must be capable of stopping under specified conditions, within the stopping distance set forth in Table II without leaving a 12-foot-wide lane and without "uncontrolled" lockup of certain wheels of the vehicle. There is no requirement for the installation of an antilock system. Also, there is no test condition that specifies a full brake application and modulation of the service brake may be used to reduce or eliminate lockup. Yours truly, ATTACH. BLUE BIRD BODY COMPANY June 21, 1976 Thomas Herlihy -- Office of Chief Counsel, National Highway Traffic Safety Administration Dear Mr. Herlihy: SUBJECT: FMVSS 121 - AIR BRAKE SYSTEMS It is our understanding that the subject standard does not currently specify maximum allowable stopping distances. We also understand that maximum allowable stopping distances are specified for future vehicles. Our question is, when and if the stopping distance requirements of Paragraphs S5.3.1 and Table 2 are reinstated for buses, will it be permissible to meet those stopping requirements without an anti-lock system, provided we can meet the requirements stated in S5.3.1 ". . . . without any part of the vehicle leaving the roadway and without lock up of any wheel at speeds above 10 MPH . . . .?" Obviously, the driver would have to modulate the braking force to prevent wheel lock up on a system not equipped with an automatic anti-lock system. We would appreciate your early reply. Thank you. Yours very truly, W. G. Milby -- Staff Engineer c Ben Newberry |
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ID: nht74-2.8OpenDATE: 11/06/74 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: Truck Body and Equipment Association, Inc. TITLE: FMVSS INTERPRETATION TEXT: This responds to your October 3, 1974, questions whether the exemption for 24,000-pound axle vehicles from Standard No. 121, Air brake systems, until September 1, 1976, applies to fire fighting vehicles, and whether a tandem axle assembly consits of two "axle systems" for purposes of our definition of "Gross axle weight rating." The answer to both of your questions is yes. A fire fighting vehicle would qualify for exemption until 1976 if any of its axles has a gross axle weight rating of 24,000 pounds or more. A tandem axle assembly, which we understand to mean a running rear assembly consisting of two axles and associated components, comprises two "axle systems." As we pointed out in the preamble to Notice 2 of Docket No. 74-10, the term "axle system" is used only to avoid confusion in situations where a suspension system does not employ an axle (39 FR 17550, May 17, 1974). Yours truly, ATTACH. TRUCK BODY AND EQUIPMENT ASSOCIATION, (Illegible Word) October 3, 1974 Richard Dyson -- Office of Chief Council, National Highway Traffic Safety Administration Dear Mr. Dyson: Recently several members of our Fire Apparatus Manufacturers Division have contacted us with questions concerning FMVSS 121 and its effective date. In order that we may accurately answer these questions, we would like the following clarified. (1) Does a fire apparatus qualify for the "Special Permit Vehicle" classification if it is equipped with an axle with a GAWR equal to or greater than twenty-four thousand pounds (24,000 lbs.)? (2) Is a tandem axle assembly comprised of two "Axle Systems", per your GAWR definition? Your cooperation in this matter is greatly appreciated. Sincerely yours, Byron Crampton -- Manager of Engineering Services |
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ID: nht75-1.10OpenDATE: 12/17/75 FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA TO: British Leyland Motors Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in response to your October 20, 1975, letter concerning the status of amendments to Federal Motor Vehicle Safety Standard No. 101, Control Location, Identification and Illumination, that were proposed in Notice 10 (Docket 1-18, 38 FR 26940, September 27, 1973). Although a further proposal on this subject is being considered, no final decision has been made by the National Highway Traffic Safety Administration (NHTSA) concerning action on the outstanding proposal. You should be guided by the standard in its present form. The effective date of any amendments issued by the NHTSA will allow adequate lead time for compliance. YOURS TRULY, October 20, 1975 Office of General Counsel National Highway Traffic Safety Administration On 27 September, 1973, Docket 1-18, Notice 10 proposed several changes to FMVSS 101. One specific change proposed the use of ISO symbols in lieu of the current 101 symbols. Notice 11, issued 29 July, 1975, amended the Standard in respect of the ISO symbols alone. It made, however, no reference whatsoever to the remaining proposals of Notice 10. We are presently negotiating with our supplier for new instruments for 1977 model year vehicles. We propose to identify the fuel, oil pressure and temperature guages with ISO symbols rather than words, as this would allow commonization between European and USA guages. While the symbols we propose for these guages are not prohibited at the present time, we are concerned that the words proposed in Table 2, Notice 10 might be implemented. Are steps being taken on the Notice 10 proposals or may we proceed with ISO symbols with confidence that NHTSA will propose ISO symbols for all controls mentioned in Notice 10 at some future time. BRITISH LEYLAND MOTORS INC. Dianne Black Liaison Engineer |
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ID: nht88-2.68OpenTYPE: INTERPRETATION-NHTSA DATE: 07/12/88 FROM: WAYNE IVIE -- MANAGER, VEHICLE SUPPORT SERVICE SECTION, NHTSA TO: NHTSA, OFFICE OF SAFETY COMPLIANCE/ENFORCEMENT ATTACHMT: LETTER DATED DEC. 8, 1988 TO WAYNE IVIE, OREGON DEPT. OF TRANSPORTATION, FROM ERIKA Z. JONES, NHTSA TEXT: On June 16th of this year, Oregon enacted a mandatory helmet law. Anyone riding on a motorcycle or moped on our highways must wear "approved" protective headgear. Our agency adopted FMVSS 218, Motorcycle Helmets, as the minimum standard for helmets. Part S5.6.1 of the standard requires permanent and legible labeling of helmets, including the DOT symbol, to prove that a helmet meets that standard. Helmet manufactu rers apparently attach a sticker with the DOT symbol onto the back of the helmet. Our office is receiving inquiries from individuals and police officers, who advise that on many helmets, this DOT sticker has fallen off or been removed by someone in order to paint the helmet, etc. They add that often there is no other labeling in or o n the helmet, so they can not determine that it meets any standard. (Is considered "approved" for use in Oregon.) To complicate this further, there is no manufacturer or brand name anywhere on the helmet, so contacting a dealer or manufacturer for infor mation is not possible. Advising someone to dispose of such a helmet and get another with proper labeling doesn't seem an appropriate answer, and may be just an undue expense for the motorcycle rider. Are manufacturers allowed to use the DOT sticker only, with no other labeling, or is this being done in violation of FMVSS 218? (If the DOT sticker is now the only label used, we would definitely like to recommend that a permanently embossed DOT symbol somewhere in or on the helmet be also required.) Have you been advised of similar problems by other jurisdictions? Do you have suggestions on how we can resolve the situation of a helmet that appears to have been made in compliance with standard require ments, is in a good, undamaged condition, yet does not have any labeling? Thank you for your help in this matter. |
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ID: 11348Open Jane Thornton Mastrucci, Esq. Dear Ms. Mastrucci: This responds to your request for an interpretation as to which passenger vehicles and which multipurpose passenger vehicles (MPVs) meet the Federal Motor Vehicle Safety Standards (FMVSSs). You ask this since Florida law allows transportation of pupils in MPVs that meet "all federal motor vehicle safety standards for passenger cars." As explained below, in recent years many of the FMVSSs have been amended to have the same requirements for passenger cars and MPVs. However where differences exist, the only way your client, Dade County School Board, will be able to determine that a specific MPV meets the FMVSSs applicable to passenger cars would be to contact the vehicle's manufacturer. NHTSA is authorized under 49 U.S.C. Chapter 301 Motor Vehicle Safety to issue FMVSSs for new motor vehicles and new items of motor vehicle equipment. The FMVSSs are codified at Title 49 of the Code of Federal Regulations (CFR), Part 571. There are presently 53 FMVSSs. Each FMVSS's applicability section specifies the motor vehicles and/or equipment to which it applies. Under 49 U.S.C. section 30112, a person may not manufacture or sell any motor vehicle unless the vehicle meets all applicable FMVSSs and is so certified. Section 30115 establishes a self-certification system whereby the vehicle manufacturer is responsible for certifying that the vehicle meets the safety requirements in the standards applicable to the vehicle. In the certification, the manufacturer must specify the vehicle type (e.g., passenger car, MPV, truck, bus) of the vehicle. Each vehicle type's definition is found at 49 CFR Part 571.3 Definitions. Thus, a new passenger car sold in the U.S. must be certified by the manufacturer as meeting the FMVSSs applicable to passenger cars, and a new MPV must be certified as meeting the standards applicable to MPVs. In recent years, many FMVSSs have been amended to specify the same requirements for passenger cars and MPVs. For example, for model year 1998 vehicles, Standard No. 208, Occupant crash protection will specify identical requirements for passenger cars and MPVs. For Standard No. 214, Side impact protection, in July 1995, NHTSA issued a final rule in which MPVs manufactured after September 1, 1998 would be required to meet the same dynamic testing requirements as passenger cars. However, some safety standards that apply to both passenger cars and MPVs do not specify identical requirements for each vehicle type. For example, Standard No. 103 Windshield defrosting and defogging systems applies to passenger cars and MPVs, but specifies different requirements for each vehicle type. There is no easy way to determine whether a particular MPV meets the passenger car safety standards. Because of differences in FMVSS requirements for passenger cars and MPVs, for information whether a particular MPV meets the passenger car standards, you should contact the MPV's manufacturer. Please note that for some safety standards such as Standard No. 208, a manufacturer may have phased-in the compliance of its MPVs with the safety standard over several years. Therefore, some MPVs manufactured in a particular year may meet the newer standard but other MPVs may not. For information about whether a specific MPV meets the passenger car standards, the manufacturer should be provided with the MPV's seventeen digit vehicle identification number (VIN), which can be found on the vehicle's certification label on the hinge pillar, the door-latch post, or the door edge that meets the door-latch post, next to the driver's seating position. I hope this information is helpful. If you need any further information, please contact Dorothy Nakama of my staff at (202) 366-2992. Sincerely,
Samuel J. Dubbin Chief Counsel ref:vsa#571 d:12/26/95
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1995 |
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.