ID: Interpretation-ElectraMeccanica-May 22 2024

May 22, 2024

Mr. Isaac Moss
Chief Administration Officer
ElectraMeccanica
EMV Automotive USA, Inc.
11647 Ventura Blvd.
Studio City, CA 91604 

Dear Mr. Moss: 

This letter responds to your request, on behalf of the ElectraMeccanica Automotive USA, Inc., for guidance as to whether passenger car tires certified to meet Federal Motor Vehicle Safety Standard (FMVSS) No. 139 may be installed on new motorcycles. 

Your letter references a December 30, 1982 interpretation letter confirming that paragraph S5.1.1 of FMVSS No. 120 permitted a motorcycle to be equipped with passenger tires certified as complying with FMVSS No. 109, as long as the tires were fitted to rims listed as suitable for use with the equipped tires, and as long as those rims met the marking requirements of FMVSS No. 120.1 You note that since this 1982 interpretation letter, FMVSS No. 120 has been revised. Although you do not note this in your letter, since 1982, the National Highway Traffic Safety Administration (NHTSA) has substantially updated tire requirements and new passenger car tires are now required to meet FMVSS No. 139. You ask three questions in your letter, and I will address each in turn. 

First, you ask whether NHTSA can expand its December 30, 1982 interpretation letter to include passenger cars meeting the requirements of FMVSS No. 139. I can confirm for you that FMVSS No. 120 allows new motorcycles to be equipped with tires certified to meet FMVSS No. 139. This is explicitly stated in paragraph S5.1.1 of FMVSS No. 120. 

Second, you ask whether NHTSA can confirm that NHTSA would reference S4 of FMVSS No. 139, in lieu of the references to S4.4 of FMVSS No. 109 and S5.1 of FMVSS No. 119 

1 Letter to Anonymous (Confidential) (Dec. 30, 1982), available at https://www.nhtsa.gov/interpretations/1982-337  

Page 2
Mr. Isaac Moss 

contained in S5.1.1 of FMVSS No. 120. The answer to this question is yes. If tires certified to meet FMVSS No. 139 are installed on a new motorcycle, the tire manufacturer must list the rims as suitable for use with those tires in accordance with S4 of FMVSS No. 139. This requirement is consistent with the tire and rim matching information for tires certified with FMVSS Nos. 109 or 119. S4 of FMVSS No. 139, like S4.4 of FMVSS No. 109 and S5.1 of FMVSS No. 119, provides for disclosure of the rims that may be used with each tire a manufacturer produces. The tire’s manufacturer may make this disclosure either in a specific document provided to dealers of the manufacturers’ tires and to NHTSA, or in a yearbook published by one of several tire and rim standards organizations. 

Third, you ask whether NHTSA can provide guidance on whether compliance with FMVSS No. 110 is required in addition to FMVSS No. 120 when tires certified to meet FMVSS No. 139 are used on motorcycles. The answer to this question is no. FMVSS No. 110 is not applicable to motorcycles, even if tires meeting FMVSS No. 139 are installed on motorcycles. S2 of FMVSS No. 110 explicitly excludes motorcycles from the applicability of FMVSS No. 110. The only tire selection and rim standard applicable to motorcycles is in FMVSS No. 120. 

I hope this information is helpful. If you have any further questions, please feel free to contact David Jasinski of my office at (202) 366-2992. 

Sincerely,
Adam Raviv
Chief Counsel

Dated: 5/22/24
Ref: Standard No. 139

ID: aiam1102

Dear Mr. Mitchell: Thank you for your letter of March 27, 1973, requesting informatio concerning Federal Motor Vehicle Safety Standards with special emphasis on those standards pertaining to fuel systems.; Enclosure 1 is a brochure which gives a brief summary of all safet standards issued through June 1972, and a subscription Order Form, should you wish to purchase a complete edition of the standards from the Superintendent of Documents on a subscription basis.; Enclosure 2 is a copy of Federal Motor Vehicle Safety Standard No. 301 'Fuel Tanks, Fuel Tank Filler Pipes, and Fuel Tank Connections - Passenger Cars.' This standard is currently undergoing amendment that will include rollover and rear-end impact requirements in addition to the fixed barrier collision which is currently required.; The Bureau of Motor Carrier Safety regulates vehicular interstat commerce. Enclosure 3 is an Advanced Notice of Proposed Rule Making concerning plastic fuel tanks (*Federal Register,* Volume 36, No. 178, September 14, 1971) which was recently issued by this Bureau. Further information may be obtained by contacting this Bureau as follows:; >>>Director, Bureau of Motor Carrier Safety, Department o Transportation, 400 Seventh Street, S.W., Washington, D.C. 20590<<<; In response to your question: 'I particularly wish to know if th relevant Safety Standard in force in America requires the fuel tanks to be located outside the main body shell of the vehicles or if it is permissible under this Safety Standard for fuel tanks to be situated in the interior of the vehicles,' the standards as written do not specifically require that the fuel system be external to the passenger compartment. These standards, in accordance with Public Law 89-563 which authorized their development, emphasize performance rather than design considerations.; Another standard which may be of interest to you is Standard No. 302 'Flammability of Interior Materials in Passenger Cars, Multipurpose Passenger Vehicles, Trucks and Buses,' which was effective September 1, 1972. Enclosure 4 is a copy of this standard along with two proposed amendments.; We trust your inquiry has been satisfactorily answered. If there ar any other questions or we can be of further service, please do not hesitate to contact this office. I am also returning the amount you enclosed for postage, etc.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs;

ID: 571.209--Attachment hardware--Freedman--17-0328

Mr. David Klopp, Director

Quality, Testing & Compliance

Freedman Seating Company

4545 W. Augusta Blvd.

Chicago, IL 60651

Dear Mr. Klopp:

This responds to your request for an interpretation concerning the attachment hardware requirements in Federal Motor Vehicle Safety Standard (FMVSS) No. 209, Seat belt assemblies.  You ask whether it is acceptable to use attachment hardware smaller than that specified in the standard if the seating system complies with the strength requirements of FMVSS No. 210, Seat belt assembly anchorages.  As we explain below, under FMVSS No. 209 it is acceptable to provide attachment hardware other than the 7/16-20 UNF-2A or 1/2-13 UNC-2A attachment bolts specified in the standard if it meets 209’s S4.3(c) strength requirements [FD(1] when tested under the demonstration procedures of FMVSS No. 209’s S5.2(c).[JP2]   The agency will not use the FMVSS No. 210 demonstration procedures in place of those of S5.2(c).

Background

FMVSS No. 209 specifies a variety of requirements for seat belt assemblies, including S4.3(c), which specifies strength requirements for attachment hardware that must be met when tested to a procedure in S5.2(c).  [FD(3] Section S4.1(f) generally requires, among other things, that a seat belt assembly include all hardware necessary for installation in a motor vehicle.  However, S4.1(f) goes on to exempt certain seat belt assemblies from this requirement:

[S4.1](f) Attachment hardware.  *  *  *  However, seat belt assemblies designed for installation in motor vehicles equipped with seat belt assembly anchorages that do not require anchorage nuts, plates, or washers, need not have such hardware, but shall have 7/16-20 UNF-2A or 1/2-13 UNC-2A attachment bolts or equivalent metric hardware.[1]

Your question concerns the meaning of the phrase “equivalent metric hardware.”  You ask whether it is acceptable to use smaller (3/8” or M10 diameter) attachment hardware if the seating system (seat belts anchored to the seat structure) complies with the strength requirements of FMVSS No. 210. 

Discussion

After examining the history of S4.1(f) regarding the phrase in question, we conclude that “equivalent” is referring to the alternate bolts’ meeting the strength requirements of S4.3(c) of FMVSS No. 209.  When the initial FMVSS No. 209 was promulgated in 1967 it incorporated by reference existing seat belt requirements codified at 15 CFR § 9.[2]  Section 9 required 7/16-20 UNF-2A or 1/2-13 UNC-2A fasteners; there was no provision for equivalent hardware.  The “equivalency” language was added later to FMVSS No. 209:

S3. Requirements.  Seat belt assemblies shall meet the requirements of [15 CFR §9] using the attachment hardware specified in paragraph (f) of 15 CFR 9.3 or approved equivalent hardware.”[3] 

NHTSA explained in the preamble to the final rule adding the equivalency language that the agency had “determined that other fasteners that meet or exceed the strength requirements of paragraph (c) of 15 CFR 9.5 may be suitable for use.  Therefore Standard No. 209 is being amended to provide for the use of an approved equivalent of equal or superior performance as an alternative to the fasteners specified.”[4]  The strength requirements in 15 CFR § 9.5(c) for attachment hardware were later re-codified at S4.3(c) of FMVSS No. 209.[5]  In sum, this history shows that the equivalency language was intended to allow the use of hardware other than 7/16-20 UNF-2A or 1/2-13 UNC-2A attachment bolts as long as the hardware meets or exceeds the strength requirements specified in S4.3(c).[6] 

These S4.3(c) strength requirements remain the same today.  They specify that attachment hardware must withstand specified forces when subjected to the test procedures in S5.2(c) of FMVSS No. 209.  This test involves applying a load to the bolt through attachment hardware from the seat belt assembly, or through a special fixture which simulates the loading applied by the attachment hardware. 

Note that S4.1(f) and S4.3 do not contemplate an FMVSS No. 210 strength test to assess the equivalency of alternate hardware.  Thus, to answer your question, NHTSA will not assess compliance with S4.3(c)’s strength requirements using the FMVSS No. 210 demonstration procedures.

“Equivalent Metric Hardware”

We recognize that the agency’s intent to state in FMVSS No. 209 that a manufacturer may provide equivalent hardware was somewhat obscured by a subsequent amendment.  The “equivalent hardware” language remained until 1998, when the standard was amended as part of a rulemaking that converted English system measurements in selected FMVSSs to the metric system.[7]  Section S4.1(f) of FMVSS No. 209 was amended by changing the phrase “equivalent hardware” to “equivalent metric hardware.”[8]  It was not the intent of the 1998 metric conversion rulemaking to make a substantive change to FMVSS No. 209.[9]  Instead, the intent was that “equivalent hardware” was still the rule.  Therefore, the agency interprets the S4.1(f) requirements to permit, as they have since 1967, fasteners other than 7/16-20 UNF-2A or 1/2-13 UNC-2A that meet or exceed the strength requirements in S4.3(c) when tested according to S5.2(c). 

If you have any further questions, please contact John Piazza of my staff at (202) 366-2992.

Sincerely,

Jonathan C. Morrison

Chief Counsel

Dated: 8/12/19

FMVSS No. 209

[1] (Emphasis and footnote added.)

[2] 32 FR 2408 (Feb. 3, 1967).

[3] 32 FR 3390-91 (Mar. 1, 1967) (emphasis and footnote added).

[4] Id. (emphasis added).

[5] 34 FR 115, 117 (Jan. 4, 1969) (recodification).  Also, NHTSA amended FMVSS No. 209 to remove the word “approved” from “approved equivalent hardware.” 

[6] See also NHTSA’s letter to Takata Kojyo Co, Ltd. (Apr. 9, 1973) (stating that “[u]nder the provisions of S4.1(f), ‘equivalent hardware’ is permissible in lieu of the 7/16" bolts.  In such a case, the tests required under S4.3(c), as prescribed under S5.2(c), would be performed on the entire equivalent hardware, rather than or the individual components (bolts).”).

[7] 62 FR 19253 (Apr. 21, 1997).

[8] 63 FR 28922, 28936 (May 27, 1998) (final rule).  See also letter from Paul Jackson Rice, Chief Counsel, to J.W. Lawrence, Volvo GM Heavy Truck Corporation (May 8, 1992) (stating that equivalent metric hardware is permitted).

[9] 63 FR 28922 (“The [metric] conversions are not intended to make any changes in the stringency of the affected FMVSS”).

ID: 571.226--Conversion of vans--M Johnson

Mr. Michael Johnson Black Hills Transfer Inc.

P.O. Box 9472

Rapid City, SD 57709

Dear Mr. Johnson:

This responds to your email forwarded to us by U.S. Senator John Thune’s office, and to your September 4 and September 12, 2020 telephone conversations with Deirdre Fujita of my staff, asking whether a motor vehicle dealer may make certain modifications to your used 2019 passenger vans to convert them to cargo vans. You explain that the work would involve, among other things, removing all passenger seats, seat brackets, and seat belts rearward of the driver’s seat, installing a full partition behind the driver’s seat and right front passenger seat to separate a cargo area, and replacing the side curtain air bag on the driver’s side of the vehicle with a side curtain air bag specially designed for only the driver’s seating position. As discussed below, our answer is the vehicles may be modified as you describe, subject to certain conditions.

By way of background, the National Traffic and Motor Vehicle Safety Act (Safety Act, 49 U.S.C. Chapter 301) authorizes NHTSA to issue Federal motor vehicle safety standards (FMVSSs) for new motor vehicles and items of motor vehicle equipment. Among other things, § 30112 of the Safety Act prohibits any person from selling any new motor vehicle or motor vehicle equipment that does not meet all applicable FMVSSs. This requirement applies until the first purchase of the vehicle or equipment other than for resale (first retail sale). Following such first purchase of the vehicle or equipment, § 30122 of the Safety Act prohibits a manufacturer, distributor, dealer, rental company, or motor vehicle repair business from knowingly making inoperative any part of a device or element of design installed on or in a motor vehicle or motor vehicle equipment in compliance with an applicable FMVSS. It is this latter provision, § 30122, that bears on the questions you ask.

You explain in your email and phone calls that you purchased two used passenger vans with the intent of converting them to carry cargo for your business. Both vehicles are equipped with side curtain air bags of different designs. You describe the driver’s side curtain as extending from the windshield into the cargo space, and that “[t]he passenger side already has separate airbags [sic] for the passenger’s front seat and the cargo space.” You would like to retain functioning side curtain air bags for the driver and right outboard passenger seats, but given the installation of the partition and creation of the new cargo area, you wish to replace the driver’s full length side curtain air bag (which you call the “long” side curtain air bag) with an air bag that protects only the driver’s seat (a “short” side curtain air bag). You would like to remove the curtain air bag from the cargo space on the right front outboard passenger side rearward of the partition, and retain just the original separate “short” side curtain air bag designed for the front right seat. You are in contact with a dealer who can modify the vehicle in this way, but the dealer requests a “letter of authorization” from NHTSA before it will modify the vehicles.

Discussion 

Section 30122 of the Safety Act limits the modification of vehicles by persons listed in § 30122. That section prohibits those persons, including dealers, from knowingly removing, disabling or otherwise “making inoperative” the performance of equipment or elements of design installed on a vehicle in compliance with an FMVSS. Removing safety equipment such as seat belts and a side curtain air bag, and not replacing them, is generally impermissible by dealers under § 30122, as those items were installed in the vehicles in compliance with applicable FMVSSs.1 However, modifications that change a vehicle from one type to another present a unique circumstance regarding § 30122.

The Safety Act does not prohibit persons from changing a used vehicle from one type to another, e.g., from a passenger van to a cargo van.2 In the situation involving modification of a used vehicle, NHTSA views the determinative standards for the make inoperative provision to be those that would have applied to the vehicle had the vehicle been originally manufactured as the vehicle type to which it has been converted.3 This means that your dealer may modify your used vans, provided that the modified vehicles will have working safety systems installed that would have met the applicable FMVSS for vehicles with partitions and no designated seating positions rearward of the partition, if the vehicles were new.

The FMVSSs directly affected by installation of the partition and reconfiguration of the side curtain air bags are FMVSS No. 214, “Side impact protection,” and FMVSS No. 226, “Ejection mitigation.” In a passenger van that might be converted to a cargo van, the manufacturer likely installed side curtain air bags at the driver’s seating position and at the right front outboard seating position to meet FMVSS No. 214’s pole test requirement (S9). It is technically feasible

1 Presumably the seat belts were installed to meet FMVSS No. 208, and the side curtain air bags were installed in compliance with FMVSS No. 214 and/or No. 226.

2 While NHTSA does not have a definition for a “van,” passenger vans are considered “multipurpose passenger vehicles” (MPV) under NHTSA’s definitions (49 CFR § 571.3, Definitions).  An MPV is defined as “a motor vehicle with motive power, except a low-speed vehicle or trailer, designed to carry 10 persons or less which is constructed either on a truck chassis or with special features for occasional off-road operation.” A cargo van (commonly understood as a van with no designated seating positions rearward of the driver’s position) could be considered an MPV, but could be a truck. “Truck” is defined as “a motor vehicle with motive power, except a trailer, designed primarily for the transportation of property or special purpose equipment.” (Id.) Under NHTSA’s self-certification framework, manufacturers certify their vehicles as meeting all FMVSSs applicable to the vehicle type, and, in doing so, classify their vehicles for purposes of determining the applicability of the FMVSSs. NHTSA may take issue with that classification if the agency believes the manufacturer has misclassified the vehicle, and thus failed to certify the compliance of the vehicle with applicable FMVSSs.

3 See, e.g., August 17, 1979 letter to Mike Champagne, https://isearch.nhtsa.gov/aiam/aiam3072.html, April 21, 1993 letter to Jeffrey Kester, https://isearch.nhtsa.gov/files/8439.html (“we have not interpreted Section [30122] as forbidding modifications that result in the inapplicability of one or more of the FMVSS with which a vehicle originally complied”); May 21, 2003 letter to Teresa Stillwell, https://isearch.nhtsa.gov/files/001646drn.html. Please note that the Safety Act was amended in 2015 to include “rental companies” in the entities subject to the “make inoperative” provision.

for the pole test to be met by installing the short side curtain air bag at the driver’s seating position in place of the long air bag, and by retaining just the short side curtain air bag at the right front outboard seating position, which are modifications planned by your dealer. If the short side curtain air bags at the driver’s seating position and at the right front outboard seating position would deploy in a manner meeting the pole test requirement, the modification would not constitute a § 30122 violation as regards FMVSS No. 214.

FMVSS No. 226 has requirements for vehicles with a fixed partition behind which there are no designated seating positions (S5.2.1.2(c)). For such a vehicle, it is technically possible to meet FMVSS No. 226 with just a short side curtain air bag at the driver’s position and a short side curtain air bag at the right front outboard seating positions. Under S5.2.1.2(c), no ejection mitigation side curtain air bag is required rearward of the partition for such a vehicle.

Accordingly, this means--with regard to FMVSS No. 226 S5.2.1.2(c)--it is possible for your dealer to modify the side curtain air bags as you describe without violating § 30122, assuming the short air bags would continue to deploy in a rollover as contemplated by the standard, and in the manner meeting the ejection mitigation requirements for the seats forward of the partition.

We note that it may not necessarily be a simple matter of stripping the van, installing different side curtain air bags, and reinstalling a cut headliner and original side pillar trims. For example, the replacement short curtain air bag would need to fit the structure of the vans being modified and matched to the crash sensing system. The original manufacturer of your vehicles should be able to inform the dealer which additional components and modifications, if any, may be needed to avoid making inoperative the front row side curtain air bags.

Please keep in mind that the dealer also must not knowingly make inoperative devices or elements of design required by other FMVSS provisions not included in the above discussion. Thus, for example, the modification must not make inoperative the side curtain air bag monitoring system required by S4.2.2 of FMVSS No. 226, which informs the driver of the readiness of the side curtain air bag system.

As for removing the rear seats and accompanying belts, removing vehicle seats on a passenger van to convert it to a cargo van is not prohibited by § 30122. While FMVSS No. 2084 requires rear designated seating positions to have seat belts, if the designated seating position were removed, there would be no designated seating position to equip with the seat belt.5 Accordingly, your dealer’s removal of the rear seats and seat belts to convert the passenger van to a cargo van would not, by itself, violate § 30122.

In sum, your dealer may modify your vans as you describe, provided that the short air bags would deploy as specified by FMVSS No. 214 and 226, and that the work does not make inoperative devices or elements of design required by other provisions of the applicable FMVSS, such as the readiness indicator required by S4.2.2 of FMVSS No. 226.

4 FMVSS No. 208, “Occupant crash protection,” 49 CFR § 571.208.

5 See, e.g., December 22, 1995 letter to Fred Prizker, https://isearch.nhtsa.gov/files/11210.html. Removal of rear seat belts as part of converting a passenger van to a cargo van by removing the rear seat does not violate the make inoperative provision.

We trust this letter provides the information you need. Please contact us if you have further questions.

Sincerely,

JONATHAN CHARLES MORRISON

Digitally signed by JONATHAN CHARLES MORRISON

Date: 2020.10.23 19:11:26 -04'00'

Jonathan C. Morrison Chief Counsel

Signed: 10/23/20

Ref: FMVSS 226

ID: aiam5174

"Dear Mr. Gonzalez: This responds to your letter of March 25, 1993 regarding testing for Standard No. 208, Occupant Crash Protection. You are a manufacturer of seating products for the recreation vehicle industry. You propose to perform a baseline HYGE sled test using all OEM hardware and seats and then to perform a second test using OEM hardware and the seats you manufacture. You asked: If the results of the test using our seats are equal or better than those obtained values with the OEM seats and hardware, does this test prove that our seats are safe to use instead of OEM? Can these results and procedures be acceptable as do diligent (sic) and can our seats then be certified for use in these vehicles regarding FMVSS 208? Some background information may be helpful. The National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq., the Safety Act) authorizes this agency to issue motor vehicle safety standards for new motor vehicles and new items of motor vehicle equipment. We have exercised this authority to establish Standard No. 208, Occupant Crash Protection (49 CFR 571.208), which specifies performance requirements for the protection of vehicle occupants in crashes. (I note that a number of other safety standards also include requirements relevant to seats, including Standard No. 207, Seating Systems, Standard No. 209, Seat Belt Assemblies, Standard No. 210, Seat Belt Assembly Anchorages, and Standard No. 302, Flammability of Interior Materials.) The Safety Act establishes a 'self-certification' process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. Standard No. 208, the subject of your inquiry, is applicable to vehicles and not to individual items of equipment (except for pressure devices and explosive devices used in air bags). Therefore, if one of your seats is installed in a vehicle during manufacture, the vehicle manufacturer is responsible for certifying that the completed vehicle complies with all applicable standards, including Standard No. 208. If the seat is added to a new, previously certified, motor vehicle prior to its first sale, the person who modifies the vehicle would be an alterer. An alterer is required to certify that, as altered, the vehicle continues to comply with all of the safety standards affected by the alteration. Finally, if the seat is sold as aftermarket equipment to be installed in a used motor vehicle, the seat, as a piece of equipment, does not have to comply with any Federal standards. However, 108(a)(2)(A) of the Safety Act provides, in pertinent part: No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative, in whole or part, any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard. . . . Therefore, none of these entities could install one of your seats if it caused the vehicle to no longer comply with any of the safety standards. In all of these situations, you, as the seat manufacturer, would have no certification responsibilities under Standard No. 208. Therefore, with respect to that standard, the remainder of the discussion in this letter is applicable to vehicle manufacturers (including alterers). Each of this agency's safety standards specifies the test conditions and procedures that this agency will use to evaluate the performance of the vehicle or equipment being tested for compliance with the particular safety standard. The National Highway Traffic Safety Administration (NHTSA) precisely follows each of the specified test procedures and conditions when conducting its compliance testing. However, a manufacturer is not required to test its products only in the manner specified in the relevant safety standard, or even to test the products at all. A manufacturer may choose any means of evaluating its products to determine whether the vehicle complies with the requirements of the safety standards, provided, however, that the manufacturer assures that the vehicle will comply with the safety standards when tested by the agency according to the procedures specified in the standard. Under certain circumstances, particularly if the agency testing shows an apparent noncompliance exists in a vehicle, the manufacturer may be asked to show the basis for its certification that the vehicle complies with the relevant safety standard or standards. If in fact there is a noncompliance, the manufacturer is subject to civil penalties under the Safety Act unless it can establish that it exercised 'due care' in the design and manufacture of the product and in the evaluation (through actual testing, computer simulation, engineering analyses, or other means) to ensure compliance, but nevertheless did not have reason to know that the vehicle did not in fact comply with the safety standards. This agency has long said that it is unable to judge what efforts would constitute 'due care' in advance of the actual circumstances in which a noncompliance occurs. What constitutes 'due care' in a particular case depends on all relevant facts, including such things as the limitations of current technology, the availability of test equipment, the size of the manufacturer, and, above all, the diligence exercised by the manufacturer. You should also note that, while the exercise of 'due care' may relieve a manufacturer of liability for civil penalties in connection with the manufacture and sale of noncomplying vehicles, it does not relieve a manufacturer of the responsibility to notify purchasers of the noncompliance and remedy the noncompliance without charge to the purchasers, if either the manufacturer or this agency determines that vehicles do not comply with all applicable safety standards. I hope you find this information helpful. If you have any other questions, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel";

ID: aiam3542

Dear Mr. Lawson: This responds to your letter of December 22, 1981, concerning Federa Motor Vehicle Safety Standard No. 218, *Motorcycle Helmets*, and its relationship to non-Federal standards.; FMVSS No. 218 is the helmet standard in the United States to whic manufacturers must certify compliance for all newly manufactured helmets to which the standard is applicable. Private standards, such as ANSI or Snell, are not legally enforceable. However, it is possible in cases of product liability that such private standards could be used as evidence in civil suits that a particular manufacturer was not designing its helmets to the state of the art.; Various states may also have requirements concerning motorcycl helmets. However, section 103(d) of the National Traffic and Motor Vehicle Safety Act provides that '(w)henever a Federal motor vehicle safety standard established under this title is in effect, no State or political subdivision of a State shall have any authority either to establish, or to continue in effect, with respect to any motor vehicle or item of motor vehicle equipment any safety standard applicable to the same aspect of performance of such vehicle or item of equipment which is not identical to the Federal standard....' Thus, a non-identical State safety standard covering the same aspect of performance as FMVSS No. 218 would be preempted by the National Traffic and Motor Vehicle Safety Act and therefore would be unenforceable.; The answers to your more specific questions are as follows. a) How are the two standards linked for compliance testing now tha their technical requirements are different?; As indicated above, there is no connection between FMVSS No. 218 an private standards.b) What procedure should helmet manufacturers follow in order to gain compliance?; The National Highway Traffic Safety Administration does not grant prio approvals of motor vehicles or motor vehicle equipment. Instead, section 114 of the National Traffic and Motor Vehicle Safety Act requires manufacturers to certify compliance of each motor vehicle and item of equipment with all applicable FMVSS's. The Act requires that manufacturers exercise 'due care' to ensure that their products conform to each applicable standard (section 108(b)(1)).; A manufacturer is not required to run the actual tests specified by safety standard. Instead, a manufacturer must take whatever steps are necessary to ensure that its products, if tested according to the requirements of a standard, would meet those requirements. Since FMVSS No. 218 includes a number of specific test requirements, it is likely that a manufacturer would find it necessary to do some testing in order to ensure that a helmet complied with the standard. For enforcement purposes, the agency would test a helmet according to the specific test requirements of FMVSS No. 218.; c) Who are the recognized Test Houses in the U.S. and elsewhere? The National Highway Traffic Safety Administration does not maintain list of qualified test laboratories. There may be many test laboratories, both here and abroad, who are qualified to do the testing necessary to ensure that a helmet meets the requirements of FMVSS No. 218. Southwest Research Institute and Dayton T. Brown, Inc., have been our compliance test contractors. Their addresses are:; >>>Southwest Research Institute, 6220 Culebra Road, San Antonio, T 78284; Dayton T. Brown, Inc., Church Street, Bohemia, Long Island, NY 11716<<< d) What part does the American Association of Motor Vehicl Administrators and the Safety Helmet Council of America have in compliance testing?; As indicated above, manufacturers are responsible for certifying thei compliance with FMVSS No. 218. The National Highway Traffic Safety Administration monitors compliance with FMVSS No. 218 and other safety standards through its enforcement program. The American Association of Motor Vehicle Administrators (AAMVA) is an association of State and provincial government officials who are involved in the administration and enforcement of motor vehicle and traffic laws in the United States and Canada. The Safety Helmet Council of America is a trade association of helmet manufacturers. We are uncertain what role these organizations currently play in either assisting manufacturers in meeting their certain responsibilities under FMVSS No. 218 or, in the case of the AAMVA, in the enforcement of State safety standards identical to FMVSS No. 218.; We have enclosed a copy of a recent interpretation issued by thi agency which concerns preemption and pre-sale State enforcement of safety standards. Among other things, the notice discusses this agency's interpretation of the effect of a State law which purports to require, as part of a pre-sale enforcement program of a State standard identical to FMVSS No. 218, that approval of helmets be obtained from the American Association of Motor Vehicle Administrators.; As the notice states, it is the opinion of the agency that the State are preempted under the National Traffic and Motor Vehicle Safety Act from engaging in activities involving the pre-sale enforcement of State standards identical to the FMVSS's where such activities involve procedures or impose burdens which differ in any significant respect from those of the Federal regulatory scheme under the Act.; Thus, any State requirement which necessitates that manufacturers pa fees in order to obtain approval under a State standard identical to a FMVSS, and any imposition of requirements for approval which has the effect of proscribing the sale of equipment certified under the Act to a standard such as FMVSS No. 218 is preempted by operation of the Act and of the agency's action in adopting the Federal standard in question.; States may, however, choose to enforce State standards identical t Federal standards through the purchase and testing of an item at State expense. Thus, a State might purchase a motorcycle helmet and test it according to the requirements of a State standard identical to FMVSS No. 218.; e) Can you advise me where I can purchase a magnesium alloy tes headform and support arm for the required shock absorption testing?; We are aware of two companies that market magnesium alloy tes headforms. Controlled Castings Corporation has recently been involved with contract work for the agency and has A, C and D sizes available. (Only the size C headform is currently required by the compliance tests of FMVSS No. 218). We are currently working with their headforms for research purposes. The United States Testing Company, Inc., also markets a version of the size C headform. It is the only company we are aware of that markets monorail drop equipment, which includes the support arm. We do not know if they sell the support arm by itself.; We would point out that the support arm marketed by the United State Testing Company, Inc., may be too heavy for the size C headform produced by Controlled Castings Corporation. It may, therefore, require some modification before it can be used for testing purposes with that headform.; The addresses of those two companies are: >>>Controlled Castings Corporation, 31 Commercial Court, Plainview, N 11803; United States Testing Company, Inc., Instrument Marketing Division 1415 Park Avenue, Hoboken, NJ 07030<<<; In regard to your questions (c) and (e), you may wish to contact th Safety Helmet Council of America. It may be able to give you additional information about qualified test laboratories and suppliers of testing equipment. The address of that organization is:; >>>Safety Helmet Council of America, 9841 Airport Boulevard, Suit 1208, Los Angeles, CA 90045<<<; Sincerely, Frank Berndt, Chief Counsel

ID: NCC-230308-001 NelsonMullinsParkingBrakeIndicatorInterp

October 31, 2024

Ms. Christie L. Iannetta
Nelson Mullins Riley & Scarborough LLP
101 Constitution Ave, NW, Suite 900
Washington, DC 20001

Dear Ms. Iannetta:

This interpretation responds to your letter regarding Federal Motor Vehicle Safety Standard (FMVSS) No. 135, Light vehicle brake systems. Specifically, you asked about paragraph S5.5.1 of FMVSS No. 135, which outlines the requirements for when certain brake indicators must be activated. Your question focuses on subparagraph (c), which requires that an indicator be activated when there is “[a]pplication of the parking brake.” You asked the agency to confirm that “a parking brake visual indicator that illuminates when a driver intentionally activates the electronic parking brake via the park brake control meets the requirements of FMVSS No. 135, S5.5.1(c), but that when the same electronic parking brake is automatically applied by the vehicle, the parking brake visual indicator may, but is not required, to illuminate to be considered compliant with this same provision.” Based on the information you have provided, our answer is that this requested confirmation does not provide an accurate understanding of FMVSS No. 135. To comply with FMVSS No. 135, a parking brake indicator must be activated whenever a parking brake is engaged, regardless of how the parking brake is applied.

Background
By way of background information, the National Highway Traffic Safety Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under 49 U.S.C. Chapter 301, manufacturers are required to ensure that their vehicles and equipment meet applicable requirements.

Please also note that our answer below is based on our understanding of the specific information provided in your letter. This interpretation letter does not have the force and effect of law and is not meant to bind the public in any way. This letter is intended only to provide clarity regarding existing requirements under the law and represents the opinion of the agency on the questions addressed in your letter at the time of signature.

FMVSS No. 135
FMVSS No. 135 establishes requirements for light vehicle braking systems. Paragraph S5.5.1 of FMVSS No. 135 requires indicators to be activated when the ignition (start) switch is in the “on” (“run”) position and one or more of seven scenarios occur. Paragraph (c) of S5.5.1 requires an indicator to be activated upon “application of the parking brake.” So if the parking brake is applied and the vehicle’s ignition is in the “on” position, a parking brake indicator must be activated.

Your Question and NHTSA’s Response
In your letter, you describe a manufacturer’s Electronic Parking Brake (EPB) system. You indicate the EPB system is integrated into the rear foundation brake calipers and is not separately serviceable. Your letter states that the EPB can be applied manually by the driver or automatically by the system. When the driver manually applies the parking brake control, upon successful confirmation of engagement of the EPB, a visual indicator appears on the user interface in plain view of the driver. You state that the EPB visual indicator remains illuminated while the EPB is engaged as a reminder to the driver to manually release the parking brake before driving.

In addition to the manual application of the parking brake, your letter indicates that there are scenarios when the EPB automatically engages, even when the driver does not manually activate the EPB, including when the vehicle is shifted into park. You explain that if a driver puts the vehicle in park and does not manually apply the parking brake, the vehicle will automatically apply the EPB. If the vehicle automatically applies the EPB, the parking brake indicator is not activated. Lastly, you indicate that when the driver shifts out of park, the EPB system is automatically deactivated.

In your letter, you assert the manufacturer’s view that this system is compliant with FMVSS No. 135 S5.5.1(c) because the regulation requires display of the parking brake only when the driver manually applies the parking brake. You point to previous interpretations that NHTSA has published, where we explain that the parking brake indicator requirement was promulgated to ensure drivers do not drive with the parking brake engaged. You assert that because the manufacturer’s EPB system eliminates this risk, the system should be considered compliant. Additionally, you assert that the regulatory history and language of the standard point to this system being compliant under paragraph S5.5.1.

After careful consideration of both the standard and the arguments made in your letter, the agency has concluded that the EPB system described in your letter would be considered noncompliant with FMVSS No. 135 S5.5.1(c). As discussed above, FMVSS No. 135 S5.5.1(c) requires that if a vehicle ignition is switched to the “on” position and the parking brake is applied, an indicator must activate to inform the driver of the status of the parking brake. From the details in your letter, there would be scenarios where the vehicle you described would have the ignition switched to the “on” position with the parking brake applied, but the parking brake indicator would not be activated. To use the example from your letter, if a driver puts the vehicle in the park position and does not activate the parking brake manually, the parking brake will automatically apply, but no parking brake indicator will be active. The system you describe in
your letter would be considered noncompliant under FMVSS No. 135 S5.5.1(c). Simply put, if the parking brake is applied, the parking brake indicator must be activated.

Your letter asserts that the phrase “application of the parking brake” in paragraph S5.5.1(c) refers to an action that the driver takes via the “parking brake control.” You state that a driver cannot “apply” a parking brake system, but only the control, meaning that the parking brake indicator requirement only applies when the driver manually applies the parking brake. We disagree with this reading, which is inconsistent with both the language and the intent of the standard. Had S5.5.1(c) been intended to cover only manual application of the parking brake control, it would say so. Other parts of FMVSS No. 135 refer to application and activation of the “parking brake control”1; by contrast, S5.5.1(c) refers more generally to the “parking brake.” Moreover, FMVSS No. 135 makes multiple references to manual application, actions, or controls, without doing so in S5.5.1(c).2

As you state in your letter, when FMVSS No. 135 was first promulgated, manual application of the parking brake was the only way a parking brake could be engaged. However, FMVSS No. 135 has been updated multiple times since it was first issued in 1995, including as recently as 2022,3 and it has never been amended to specify that S5.5.1(c) applies only to manual application of the “parking brake control.” This history, and the lack of a manual application requirement or reference to the parking brake control in S5.5.1(c), show the agency intended the parking brake indicator to be active whenever the parking brake is engaged, regardless of how the brake is engaged.

Moreover, if S5.5.1(c) covered only manual application of the parking brake control, then no indicator would be required when a vehicle automatically engages the parking brake, even if nothing prevents the vehicle from driving during this engagement—a circumstance when an indicator would be especially essential because the driver may not have consciously activated the parking brake. In fact, your letter’s description of the manufacturer’s EPB system suggests there may be circumstances where the parking brake in the manufacturer’s vehicle is automatically engaged other than when the driver shifts the vehicle to “Park.”

The distinction your letter makes between a vehicle’s “parking brake” and its “parking brake system” does not change this analysis. “Parking brake system” has no regulatory definition.4 “Parking brake,” which is the term used in S5.5.1(c), is defined as “a mechanism designed to prevent the movement of a stationary motor vehicle.”5 The definition does not distinguish between mechanisms that are activated by a designated manual control and mechanisms that are activated by other means. S5.5.1(c) simply requires activation of the indicator when the parking brake mechanism is engaged.

The agency has also considered the arguments you made in your letter regarding previous interpretations NHTSA has published on the parking brake indicator requirement. NHTSA has indicated in interpretations that the purpose of the parking brake indicator requirement is to prevent drivers from driving their vehicles with the parking brake activated. Doing so could potentially lead to excessive wear on the transmission and parking brake system, which could cause a variety of safety issues.6 However, just because a manufacturer has designed a system that purports to resolve, though other means, a safety concern addressed in an FMVSS does not mean that it is not bound by the requirements of the FMVSS or that it may introduce noncompliant motor vehicles or motor vehicle equipment to the market. If a manufacturer believes that it has developed technology that makes certain regulatory requirements unnecessary, it may petition the agency for a rulemaking to amend the relevant requirements. It may also request an exemption from an applicable standard if it has reason to believe it is eligible.7 Otherwise, the current requirements apply.

Accordingly, the plain meaning and intent of S5.5.1(c) is for the parking brake indicator to be active any time the parking brake is engaged and the vehicle’s ignition is in the “on” position. This requirement applies regardless of whether the parking brake is engaged through the manual application of the designated parking brake control or through other means.

I hope this letter answers all of your questions. If you have any further questions regarding this matter, please feel free to contact Mr. Matthew Filpi of my staff at (202) 366-2992.

Sincerely,
ADAM RAVIV
Adam Raviv Chief Counsel
 

Dated: 10/31/24
Ref: Standard No. 135

1 See FMVSS 135 S.7.12.2(b), (i), (l).
2 See FMVSS 135 S5.3.2, S6.3.5, S6.3.11.2.
3 See 87 FR 34810 (Jun. 8, 2022).
4 The only published definition your letter provides for “parking brake system” is a proposed definition, never implemented, in FMVSS No. 121, which is a separate standard for air brake systems in trucks, buses, and trailers. Your letter also argues that “[t]he driver cannot ‘apply’ the parking brake system, only the control (e.g., using a lever or button).” In fact, FMVSS No. 135 indicates otherwise: it discusses how to test the parking brake “[i]n the case of a parking brake system that does not allow application of the specified force in a single application.” S7.12.2(j).
5 49 C.F.R. § 3(b).
6 See Letter to Headley, May 30, 2002, available at https://www.nhtsa.gov/interpretations/23871jeg#:~:text=We%20noted%20that%20the%20purpose%20of%20the,wa s%20applied%20(and%20hence%20should%20be%20released; see also Letter to Selander, Apr. 29, 2002, available at https://www.nhtsa.gov/interpretations/6992.
7 See, e.g., 49 C.F.R. § 556.

ID: aiam4837

"Dear Mr. Jones: This responds to your letters of December 11, l990 and January 22, l99l, to Clive Van Orden of this agency, enclosing copies of your letters to Representative Blaz, dated July 6 and October 11, 1990, and to our Office of Enforcement dated July 5, l990. You have also enclosed a copy of a letter that Governor Guerrero of the Commonwealth of the Northern Mariana Islands (CNMI) wrote on your behalf on October 11, l990, to Representative Blaz. Your letter to us of July 5, l990, expresses your understanding that the Federal motor vehicle safety standards (FMVSS) apply in the CNMI, and that you, as an importer, have imported only vehicles that are certified as conforming to the FMVSS, however, certain of your competitors have not. You asked 'Will I get compliance enforcement? Or should I join the competition and bring in the vehicles that do not comply?' To similar effect is your letter of the next day to Representative Blaz. Governor Guerrero's letter to Mr. Blaz expresses his opinion that the FMVSS do not apply in the CNMI. The Governor explains: By our Covenant with the United States, we were obliged to except NHTSA believes he means 'accept' federal laws that applied to Guam and the several states as of January 9, 1978. Federal enabling legislation behind the FMVSS has been on the books since l966. The legislation applied to Guam and the states on January 9, 1979 sic . It looks like we get the law. But that is not the end of the analysis. We would accept application of the FMVSS here only if such federal law did not deny us our guaranteed right of local self-government with respect to internal affairs. It is my view that automobile safety is an internal affair. It is the subject for self- government. The Federal Motor Vehicle Safety Standards do not apply in the CNMI. These federal safety standards are imposed on the states by virtue of the Commerce clause of the Federal Constitution. The federal Commerce clause does not apply in the CNMI, it cannot carry the FMVSS into our islands. I t is our position that the FMVSS does sic apply here and will not be enforced by my Administration. We cannot agree with the Governor's conclusion. The National Traffic and Motor Vehicle Safety Act of l966 (l5 U.S.C. 1381 et seq.), does apply in the CNMI, as do all regulations such as the FMVSS that are issued under the authority of that law. The Governor believes that 'automobile safety is an internal affair'. For the most part we agree, but not with respect to the primacy of the FMVSS. We agree that vehicle registration, taxation, and use of the roads in the CNMI are matters properly under the jurisdiction of the CNMI. Further, the Act permits local jurisdictions to enact or continue in effect their own vehicle safety standards provided that they do not differ from the FMVSS (except as may apply to their own official vehicles). The FMVSS are manufacturing standards that apply when the vehicles are built, imported, and sold. We are sorry that your observance of the law may have put you at a competitive disadvantage. If you have specific information regarding possible violations of the importation provisions of the Act in the CNMI including the names and addresses of specific businesses or individuals, please communicate that information to Mr. Van Orden. Our sources of information are kept confidential. Although the FMVSS apply in the CNMI, it is obvious that enforcement of them by this agency is made more difficult by the absence of agency staff in the CNMI. If local government would 'move for immediate adoption of those standards ... by local law', then they may be enforced locally. I cannot think of a single one of the FMVSS that would not be of benefit. Although speeds may be low on the roads of the CNMI, many of the FMVSS are intended to provide crash protection at 30 m.p.h. Obviously, FMVSS that pertain to vehicle lighting, windshield wiping and washing, etc. provide protection at any speed. We appreciate your bringing this matter to our attention. Sincerely, Paul Jackson Rice Chief Counsel cc: Thomas Rabago Highway Safety Coordinator";

ID: NCC-230607-001 571.108 Automatic Activation of Hazard Warning Signal for Nonresponsive Driver Frooshani signed 7.22.25

U.S. Department of Transportation
National Highway Traffic Safety Administration
Office of the Chief Counsel
1200 New Jersey Avenue SE. Washington, DC 20590

July 22, 2025

Mr. John Frooshani 

Vehicle Regulatory Manager, Government Relations  

North American Subaru, Inc. 

One Subaru Drive Camden NJ 08103 

Dear Mr. Frooshani,

I write in response to your letter dated February 5, 2020, requesting an interpretation on whether identified advanced driver assistance system (ADAS) features would comply with the hazard warning signal requirements in Federal Motor Vehicle Safety Standard (FMVSS) No. 108; Lamps, reflective devices, and associated equipment. You also spoke with staff from the National Highway Traffic and Safety Administration's (NHTSA) Office of the Chief Counsel on October 29, 2024. You ask whether your system, after determining a driver is non-responsive, could automatically activate the vehicular hazard warning signal while decelerating the vehicle and bringing it to a stop. Our conclusion is that such a system is permissible in the circumstances described in your letter. 

The contents of this interpretation letter do not have the force and effect of law and are not meant to bind the public in any way. This letter is only intended to provide clarity regarding existing requirements under the law at the time of signature. 

Background 

NHTSA is authorized by the National Traffic and Motor Vehicle Safety Act (Safety Act, 49 U.S.C. Chapter 301) to issue FMVSS setting performance requirements for new motor vehicles and new items of motor vehicle equipment. NHTSA does not pre-approve new motor vehicles, new motor vehicle equipment, or new motor vehicle technologies. In addition, NHTSA does not prohibit the introduction of new motor vehicles or motor vehicle technologies such as Automated Driving Systems (ADS) into the vehicle fleet, provided those vehicles and technologies meet applicable FMVSS and do not present a safety defect. The Safety Act requires manufacturers to self-certify that their vehicles and equipment conform to all applicable FMVSS in effect on the date of manufacture. 

Two provisions of FMVSS No. 108 bear on the issue raised in your letter. First, the standard requires vehicles, except trailers and motorcycles, to be equipped with a vehicular hazard warning signal operating unit and a vehicular hazard warning signal flasher.1 A vehicular hazard warning signal operating unit is defined as a driver-controlled device which causes all required tum signal lamps to flash simultaneously to indicate to approaching drivers the presence of a vehicular hazard.2,3 Second, FMVSS No. 108 S6.2.1 states that no additional lamp, reflective device, or other motor vehicle equipment is permitted to be installed that impairs the effectiveness of lighting equipment required by FMVSS No. 108.4 

Your letter states that Subaru is exploring deploying an ADAS with a feature intended to prevent a crash if a human driver has become nonresponsive, with the system assuming vehicular control when a driver is inattentive and non-responsive to system warnings. In the described scenario, the vehicle would be brought to a stop and would "activate the hazard warning lamps as the vehicle is decelerating and continue to activate the hazard lamps after the vehicle has been brought to a stop." You state that, in your opinion, the scenario described in your letter is like the one in our 2016 letter to Brian Latouf of General Motors, which allowed automatic activation of the hazard signal following detection of a nonresponsive driver and after the vehicle has been brought to a stop by advanced vehicle systems, and you seek our concurrence. 

Discussion 

NHTSA's interpretations of "vehicular hazard warning signal operating unit" read FMVSS No. 108 as broadly restricting automatic activation of the hazard signal.5 However, NHTSA historically has read FMVSS No. 108 to allow automatic activation on a case-by-case basis under limited circumstances consistent with the purpose of the hazard warning signal stated in
the standard. FMVSS No. 108 does not permit automatic hazard signal activations that lack any relationship to the original purpose of a hazard warning signal or could create confusion about the signal's meaning.6 

1 49 C.F.R. § 571.108.
2 Id. When activated, sufficient turn signals must flash to meet the minimum photometric requirements in FMVSS No. 108 applicable to turn signals. For the purposes of this letter, we refer to these systems collectively as activating the "hazard signal."
3 Id. The standard also defines the vehicular hazard warning signal flasher as a device which, as long as it is turned on, causes all the required turn signal lamps to flash. This system must flash when actuated by the operating unit. See id Table I-a.
4 49 C.F.R. § 571.108 S6.2. l. Under the impairment analysis NHTSA typically considers four aspects of supplemental lighting: activation pattern, brightness, color, and lamp location. In addition, the impairment analysis is applicable to supplemental lighting (i.e., lighting not required by the standard) and is closely related to the requirement that a manufacturer not "knowingly make inoperative" a compliant device or element of design. 49
U.S.C. § 30122(b). See, e.g. Letter to Paul Schaye, Feb. 9, 2019, available at
https://www.nhtsa.gov/inter.pretations/571108-ama-schaye-front-color-changing-light.
5 In letters to Mark Steele and Eric Reed in 1999 and 2000, NHTSA interpreted "a driver controlled device," to mean that that the hazard signal may not automatically activate. See Letter to Mark Steele, Feb. 25, 2000, available at https://www.nhtsa.gov/inter.pretations/2ll7lztv : and Letter to Eric Reed, Feb. 29, 2000, available at https://www.nhtsa.gov/inter.pretations/reedztv. 
6 Letter to Sen. Orrin G. Hatch, Aug. 5, 1999, available at https://www.nhtsa.gov/inter.pretations/20l80ztv. 

Per FMVSS No. 108, the purpose of the hazard warning system is "to indicate to approaching drivers the presence of a vehicular hazard." Recent interpretations have noted that "the purpose of the hazard warning is to indicate to approaching drivers that the vehicle is stopped or is proceeding at a slower rate than surrounding traffic."7 Several previous agency interpretations referenced FMVSS No. 108 S6.2.1 and emphasized that there is no ambiguity about the meaning or purpose of the hazard signal following a crash.8 Although S6.2.1 applies only to equipment not required by FMVSS No. 108, in our 2016 letter to Mr. Latouf, we clarified that the same analysis applies to automatic activation of the hazard signal.9,10 

Several letters of interpretation have discussed situations in which we believe automatic activation of the hazard signal would be inconsistent with FMVSS No. 108, such as during braking events,11 after "sudden release of the accelerator pedal,"12 or as a "deceleration warning system"13 where it would conflict with the purpose of the stop lamps.14 Most recently, on March 22, 2023, NHTSA denied a petition for decision of inconsequential noncompliance filed by

7 Letter to Brian Latouf, Nov. 18, 2016. https://www.nhtsa.gov/interpretations/16-1289-gm-hazard-innovative-28-apr-16-rsy. This statement is based on a previous statement made in our letter to Sen. Richard Lugar on May 9, 2000, that drivers in general activate the hazard signal to "indicate either that [they are] proceeding at a slower rate than surrounding traffic, or that the vehicle is stopped on or off a roadway." https://www.nhtsa.gov/interpretations/21478ztv. This was a description of typical hazard signal use and was not intended to state the purpose of the hazard warning. The letter stated the activation should depend on the driver's evaluation of the driving environment and should not occur involuntarily simply because the vehicle is decelerating. 8 Letter to Mark Steele, Feb. 25, 2000, available at https://www.nhtsa.gov/interpretations/2ll71ztv ; Letter to Timothy Bartlett, Jan. 28, 2002, available at https://www.nhtsa.gov/interpretations/23695ztv; Letter to Stephen Powers, Jan. 19, 2021, available at https://www.nhtsa.gov/interpretations/571108-help-system-powers.
9 Letter to Brian Latouf, Nov. 18, 2016, available at https://www.nhtsa.gov/interpretations/16-1289-gm-hazard­ innovative-28-apr-16-rsy. This conclusion is based in part on our longstanding position that the "use of required lighting equipment for other than its original purpose" constitutes equipment not required by the standard such that it can result in impairment. See, e.g. Letter to Sen. Orrin G. Hatch, Aug. 5, 1999, available at https://www.nhtsa.gov/interpretations/20180ztv. Automatic activation could be understood as allowed supplemental lighting (in addition to the manually controlled hazard signal) if the specific system does not impair the effectiveness of any required lighting. Because it does not influence our conclusion in this letter, we do not determine whether automatic activation of the hazard signal in the manner you describe is or is not supplemental lighting or other motor vehicle equipment.
10 NHTSA interprets FMVSS No. 108 to require that all auxiliary lamps be "steady burning," with the sole exception being auxiliary lamps that supplement required lamps that flash, such as turn signals. Letter to Donald Lane, Nov. 6 2024, available at https://www.nhtsa.gov/interpretations/ncc-230120-001-571108-peterson-trailer­ auxiliary-door-light-110624-signed. To the extent that the lighting described here could be considered supplemental lighting, NHTSA would view it as supplementing required lights that flash.
11 Daimler Trucks North America, LLC, Denial of Petition for Decision of Inconsequential Noncompliance, 88 Fed. Reg. 17291 (Mar. 22, 2023).
12 Letter to David Coburn, Aug. 6, 1999, available at https://www.nhtsa.gov/interpretations/19886ztv.
13 Letter to Jeffrey Echt, incoming received Mar. 10, 1995, available at https://www.nhtsa.gov/interpretations/aiam552l. Automatically activating the hazard signal can also interfere with other required lighting, such as the turn signals. We have also addressed cases in which other vehicle systems were activated. See, e.g. Letter to Sen. Orrin G. Hatch, Aug. 5, 1999, available at https://www.nhtsa.gov/interpretations/20l80ztv (finding activating the hazard warning system when the horn is sounded would impair the hazard warning system).
14 See Letter to Stephen Powers, Jan. 19, 2021, available at https://www.nhtsa.gov/interpretations/571108-help ­
system-powers (limiting the automatic activation of the specified system to after a crash in part because it activated the turn signals up to three times faster than the required flash rate under FMVSS No. 108). 

Daimler Trucks North America, LLC (DTNA), regarding certain Model Year 2020-2021 Freightliner Cascadia heavy trucks.15 These trucks contained a system that automatically activated the hazard signal during a brake assist application, when the brake system applies maximum braking force to assist the driver in bringing the truck to a complete stop. 

In contrast to these scenarios, our 2016 letter to Mr. Latouf addressed a similar situation to the one described in your letter. There, we stated that under FMVSS No. 108 a system could, after finding a driver unresponsive and bringing the vehicle to a stop, automatically activate the hazard signal.16 We analogized the situation to the one after a crash and noted that being at a complete stop "is the prototypical situation in which the hazard lights are intended to be used, and it is one of the situations that other motorists have come to expect when they see the hazard signal."17 However, we also stated that "the purpose of the hazard warning is to indicate to approaching drivers that the vehicle is stopped or is proceeding at a slower rate than surrounding traffic."18 We also declined to state that such activations could occur only when stopped, finding that future approaches for automatic activation of the hazard signal would be handled on a case­ by-case basis.19 

Based on our understanding of the specific circumstances described in your letter, the automatic activation of the hazard warning signal you describe is permissible under FMVSS No. 108. As an initial matter, because FMVSS No. 108 does not specify in what situations the hazard warning signal may or may not be activated, we decline to state categorically that the hazard warning signal can be automatically activated only after a vehicle has come to a complete stop. Indeed, in the letter to Mr. Latouf, we acknowledged that "proceeding at a slower rate than traffic" is a situation in which drivers typically activate the hazard warning system. 

Where past agency interpretations have opined negatively about in-motion activations, it was because the use in question was not consistent with the purpose of the hazard warning system or it impaired the effectiveness of required lighting in violation of FMVSS No. 108.20 However, your system does not appear to activate the hazard warning system in a way that we have previously found unacceptable. Instead, we view the conditions described in your letter as largely similar to those described in our letter to Mr. Latouf. 

This letter does not mean that NHTSA views FMVSS No. 108 as generally allowing the automatic use of the hazard warning signal while in motion or to indicate that a vehicle's ADAS 

15 88 Fed. Reg. 17291. We believe the circumstances of the petition are distinguishable under FMVSS No. 108. First, Subaru's system does not adjust the flash rate. Second, it activates only in the rare event of a nonresponsive driver. Third, DTNA's system specifically activated during brake events. FMVSS No. 108 states that the stop lights communicate that a vehicle is stopping or diminishing speed by braking. Therefore, the instant circumstance presents much lower risk of confusion than activation during a brake assist.
16 Letter to Brian Latouf, Nov. 18, 2016, available at https://www.nhtsa.gov/intei:pretations/16-1289-gm-hazard ­
innovative-28-apr-16-rsy.
17 Id
18 Id See Supra, note 9, for clarification regarding this quote.
19 Id
20 This letter does not rescind prior NHTSA letters of interpretation on the topic of automatic activation of the hazard warning system. 

or ADS systems are active. The presence of a nonresponsive driver creates a situation where vehicle operation and driving maneuvers are largely disabled and will be for an unknown duration, as is often true following a crash or if there is a health or mechanical issue. In such a circumstance, even if the vehicle is being decelerated to a stop, the hazard warning is not being used to communicate deceleration, activation of the stop lamps, or another action that may be the purview of a lamp required by FMVSS No. 108. Instead, the activation occurs only upon the detection of a separate hazard: a nonresponsive driver. Therefore, the risk of ambiguity or confusion of the signals is low. 

Conclusion 

Based on the information presented in your letter, the system described above would not violate FMVSS No. 108's requirements applicable to the vehicular hazard warning signal operating unit or vehicular hazard warning signal flasher. It would also not impair the effectiveness of required lighting. This interpretation is specific to the circumstances described above.

We note that Subaru indicates that when the driver is unable or unwilling to take control of the vehicle, the system will bring the vehicle to a stop. A vehicle system that stops a vehicle directly in a roadway might, depending on the circumstances, be considered to contain a safety-related defect, i.e., it may present an unreasonable risk of an accident occurring or of death and injury in an accident.21 Federal law requires the recall of a vehicle that contains a safety-related defect.22 We urge Subaru to fully consider the likely operation of the system it is contemplating and ensure that it will not present such a risk. 

Finally, activation of the hazard signal is subject to State laws, which may control when a hazard signal may be used. Nothing in this interpretation should be read to preempt State law regarding when it is appropriate for a hazard warning system to be used. We are unable to advise you on those laws, but you should ensure your system complies with any and all State laws regarding when a hazard warning system may be activated.
If you have any further questions, please contact Eli Wachtel of my staff at interpretations.NHTSA@dot.gov. 

Sincerely,

Peter Simshauser 

Chief Counsel

Dated: 7/22/25
Ref: Standard No. 108

2149 u.s.c. §§ 30102, 30118.
22 49 U.S.C. § 30118.

ID: aiam5631

"Dear Mr. Bode: This responds to your letter concerning whether 4 U.S.C. 30101 et seq. (formerly the National Traffic and Motor Vehicle Safety Act) requires a motor vehicle manufacturer to ensure that its vehicle continues to comply with applicable Federal motor vehicle safety standards (FMVSSs) after the first retail purchase of the vehicle. You specifically ask about FMVSS No. 124, 'Accelerator Control Systems,' and its application to a 1988 Dodge Ram 50 pickup truck. It appears from the questions you ask that corrosion developed inside the carburetor of the pickup truck at some point during the life of the vehicle, such that the carburetor would not return to idle in accordance with the requirements of Standard No. 124. You asked us to 'confirm the accuracy' of a number of statements. Your first statement, concerning the application of the FMVSSs generally, is as follows: As we understand it, former 108(a)(1)(A) of the National Traffic and Motor Vehicle Safety Act, 49 U.S.C. 30112(a), prohibits any person from manufacturing, selling or introducing into commerce any new motor vehicle unless the vehicle is in conformity with all applicable FMVSS. However, the Safety Act further provides that the requirement that a vehicle comply with all applicable FMVSS does not apply after the first purchase for purposes other than resale, i.e., the first retail sale of the vehicle. Safety Act former 108(b)(1), 49 U.S.C. 30112(b)(1). After the first retail sale, the only provision in the Safety Act that affects a vehicle's continuing compliance with an applicable FMVSS is set forth in former 108(a)(2)(A), 49 U.S.C. 30122(b), which prohibits certain persons from knowingly rendering inoperative a device installed in a motor vehicle in compliance with an applicable FMVSS. Your general understanding is correct. However, a manufacturer has responsibilities in addition to those in 30112, that may bear upon on 'continuing compliance' of its vehicle. Under 30118-30122 of our statute, each motor vehicle manufacturer must ensure that its vehicles are free of safety-related defects. If NHTSA or the manufacturer of a vehicle determines that the vehicle contains a safety-related defect, the manufacturer must notify purchasers of the defective vehicle and remedy the problem free of charge. This is not to say that the development of the corrosion in the carburetor necessarily constitutes a safety-related defect. Rather, we acknowledge the possibility of such a finding in certain circumstances, such as where the corrosion developed unreasonably quickly in the vehicle and the problem was such that it could lead to crashes involving injuries or fatalities. State law could also be relevant to this issue. For example, as part of its vehicle inspection requirements, a State could require that the accelerator control systems on vehicles 'continue to comply' with the requirements of Standard No. 124. With the above discussion in mind, I will now address your other four questions on Standard No. 124. Question 1. We ask that NHTSA confirm that FMVSS 124 is a standard that a given vehicle must comply with only at the time of the first retail sale of the vehicle. As explained in our answer above, your understanding is correct with regard to our requirements (49 U.S.C. 30112). There may be State requirements that apply. Question 2. We ask NHTSA to confirm that if a carburetor installed in a 1988 Dodge Ram 50 pickup truck met all the requirements of FMVSS 124 at the time of the truck's first retail sale, but, after the sale, due to in-service conditions, corrosion developed inside the carburetor so the carburetor would not return to idle in accordance with the requirements of S5.1, S5.2, and S5.3 of FMVSS 124, that circumstance would not render the vehicle in violation of FMVSS 124. Your understanding is essentially correct. As permitted by Federal law, Chrysler sold the truck based upon its own certification of compliance with FMVSS No. 124. That corrosion developed in the system may or may not be relevant with respect to the existence of a safety-related defect. Question 3. We ask NHTSA to confirm that all of the performance standards imposed by FMVSS 124 are contained in S5.1, S5.2 and S5.3 of FMVSS 124 and that S2 headed PURPOSE does not impose any separate regulatory obligation beyond those contained in S5. While your understanding is essentially correct, note that Standard No. 124 and other motor vehicle safety standards are minimum performance standards. Question 4. We ask you to confirm that the performance standard set forth in FMVSS 124 does not contain any requirement relating to durability or corrosion resistance. Standard No. 124 does not specify a test for corrosion resistance. It is unclear what you mean by 'durability.' The requirements of the standard must be met when the engine 'is running under any load condition, and at any ambient temperature between -40 F. and +125 F. ....' (S5) In addition to the performance regulated by Standard No. 124, each manufacturer must ensure that its motor vehicle does not have a safety-related defect. If you have any questions about the information provided above, please contact Dorothy Nakama of my staff at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel";