SUPPLEMENTARY INFORMATION:

I. Public Participation and Request for Comments

FMCSA encourages interested persons to participate in this proceeding by submitting comments and related materials regarding Grote's supplemental information discussed in this notice.

A. Submitting Comments

If you submit a comment, please include the docket number for this ( printed page 66386) notice (FMCSA-2026-0100), indicate the specific section of this document to which the comment applies, and provide a reason for your suggestions or recommendations. You may submit your comments and material online or by fax, mail, or hand delivery, but please use only one of these means. FMCSA recommends that you include your name and a mailing address, an email address, or a phone number in the body of your document so the Agency can contact you if it has questions regarding your submission.

To submit your comment online, go to www.regulations.gov/​docket/​FMCSA-2026-0100/​document, click on this notice, click “Comment,” and type your comment into the text box on the following screen.

If you submit your comments by mail or hand delivery, submit them in an unbound format, no larger than 8 1/2 by 11 inches, suitable for copying and electronic filing.

FMCSA will consider all comments and material received during the comment period. Comments received after the comment closing date will be filed in the public docket and will be considered to the extent practicable.

B. Confidential Business Information (CBI)

CBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to the notice contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to the notice, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission that constitutes CBI as “PROPIN” to indicate it contains proprietary information. FMCSA will treat such marked submissions as confidential under the Freedom of Information Act, and they will not be placed in the public docket of the notice. Submissions containing CBI should be sent to Brian Dahlin, Chief, Regulatory Evaluation Division, Office of Policy, FMCSA, 1200 New Jersey Avenue SE, Washington, DC 20590-0001 or via email at brian.g.dahlin@dot.gov. At this time, you need not send a duplicate hardcopy of your electronic CBI submissions to FMCSA headquarters. Any comments FMCSA receives not specifically designated as CBI will be placed in the public docket for this notice.

C. Viewing Comments and Documents

To view comments, as well as any documents mentioned in this preamble as being available in the docket, go to www.regulations.gov, insert FMCSA-2026-0100 in the keyword box, select the document tab and choose the document to review. To view comments, click this notice, then click “Browse Comments.” If you do not have access to the internet, you may view the docket by visiting Dockets Operations in the DOT West Building, 1200 New Jersey Avenue SE, W58-213, Washington, DC 20590-0001, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

II. Legal Basis

FMCSA has authority under 49 U.S.C. 31136(e) and 31315(b) to grant exemptions from the Federal Motor Carrier Safety Regulations (FMCSRs). FMCSA must publish a notice of each exemption request in the Federal Register (49 CFR 381.315(a)). The Agency must provide the public an opportunity to inspect the information relevant to the application, including the applicant's safety analysis. The Agency must provide an opportunity for public comment on the request.

The Agency reviews the application, safety analyses, and public comments submitted and determines whether granting the exemption would likely achieve a level of safety equivalent to, or greater than, the level that would be achieved absent such exemption, pursuant to the standard set forth in 49 U.S.C. 31315(b)(1). The Agency must publish its decision in the Federal Register (49 CFR 381.315(b)). If granted, the notice will identify the regulatory provision(s) from which the exempted party will be exempt, the effective period, and all terms and conditions of the exemption (49 CFR 381.315(c)(1)). If the exemption is denied, the notice will explain the reason for the denial (49 CFR 381.315(c)(2)). The exemption may be renewed (49 CFR 381.300(b)).

III. Background

On December 10, 2025, Grote submitted an application for a five-year exemption from 49 CFR 393.25(e), which generally requires exterior lamps on CMVs to be steady-burning. Grote requested the exemption on behalf of motor carriers seeking to use auxiliary warning lamps in conjunction with Grote's RCW system. Grote's application described one or more auxiliary lamps positioned on the rear or sides of a CMV or trailer. The application described a rear-facing radar system that calculates the time-to-collision (TTC) of vehicles approaching from behind and also contemplated use of the system on the side of a CMV for side-impact protection during parking maneuvers.

In its application, Grote stated that the RCW signal circuit would activate when TTC was less than or equal to a threshold corresponding to a substantial risk of an impending collision, typically between 2.1 and 4.0 seconds. Grote proposed two possible auxiliary-lamp operating sequences. Under one sequence, red lamps would flash between four and sixteen times during a four-second period and then burn steady red while the RCW signal remained active. Under the alternative sequence, amber lamps would operate as SAE J595 Class 3 or Class 2 strobe lamps for up to four seconds and then burn steady red while the RCW signal remained active. Grote further stated that the auxiliary lamps could also be used in combination with brake and marker signal circuits.

On February 9, 2026, FMCSA published a notice of Grote's application and requested public comment (91 FR 5798). The notice described the RCW system as activating the auxiliary lamps when a TTC threshold was reached and stated that, following the initial flashing or strobing sequence, the lamps would burn steady red while the collision risk persisted.

On March 4, 2026, FMCSA extended the comment period by 60 days, through May 10, 2026, after the Commercial Vehicle Safety Alliance requested additional time to review the application (91 FR 10674).

During the comment period, interested parties raised questions and concerns regarding, among other issues, the relationship between the proposed RCW system and forward collision warning technology, the meaning conveyed to following motorists by the auxiliary warning lamps, and the proposed transition from flashing or strobing warning lamps to a steady-burning red indication. CVSA expressed concern that following motorists could interpret steady-burning red lamps as an indication that the CMV was braking and recommended that the RCW system not transition from flashing amber to steady-burning red for a warning condition unrelated to brake application.

IV. Supplemental Information Provided by Grote

Following the close of the comment period, FMCSA staff sought clarification from Grote regarding the design and operation of the RCW system. FMCSA's questions addressed the operation and sequencing of the auxiliary warning ( printed page 66387) lamps, the relationship between the RCW function and Grote's auxiliary brake-warning function, the priority between those functions when both are activated, installation on various CMV types and combinations, and operation of the radar detection system.

Grote subsequently provided the following supplemental information:

A. RCW Warning-Lamp Operation and Color

Grote clarified that when operating as part of the RCW system, the auxiliary warning lamps pulse in amber for up to four seconds with each activation of the RCW signal circuit and do not transition to a steady-burning red indication. Grote explained that the transition from amber pulsation to steady-burning red is associated with the brake-activated auxiliary pulsating lamp function, not the RCW warning function.

This supplemental information differs from the description in the original application and February 9, 2026, notice, which stated that after the initial flashing or strobing RCW warning sequence, the auxiliary lamps would transition to steady-burning red while the RCW signal remained active.

B. Functional Priority and Interaction With Auxiliary Brake-Activated Warning Lamps

Grote explained that the RCW system uses the same auxiliary lamps used by its brake-activated auxiliary pulsating lamp system.

When an RCW event and a braking event occur at the same time, Grote stated that the brake-activated function takes precedence over the RCW function. Thus, when the service brakes are applied during an RCW event, the auxiliary lamps would transition from the RCW warning sequence to the applicable brake-activated warning sequence. Any steady-burning red indication would therefore be associated with brake application rather than with the RCW warning function.

The original application stated generally that the RCW auxiliary lamps could be used in combination with brake and marker signal circuits but did not describe the operational priority between those functions. Grote's supplemental explanation provides additional information concerning that hierarchy.

C. Radar Detection and Activation

Grote stated that the RCW system uses a self-contained, rear-facing radar system capable of detecting approaching vehicles at distances of approximately 200 meters. The system continuously evaluates the relative motion of an approaching vehicle and calculates TTC. When the calculated TTC reaches the programmed activation threshold, the RCW system automatically activates the auxiliary amber warning lamps.

Grote further stated that the RCW system does not require the CMV driver to activate or otherwise interact with the system and that operation of the RCW radar would not interfere with other radar-based vehicle detection systems.

D. Scope and Combination Vehicles

Grote clarified that it intends the requested exemption to apply to all CMVs. For combination vehicles consisting of more than one trailing unit, including doubles and triples, Grote stated that the RCW system would be installed and operated on the rear-most unit of the combination.

E. Supplemental Materials

FMCSA has placed in the docket a memorandum summarizing the meeting between FMCSA staff and Grote during which Grote provided the operational clarifications described above. The memorandum also includes a chart provided by Grote illustrating the operation of the RCW system and its interaction with the brake-activated auxiliary lamp function.

The memorandum to the docket is titled “Ex Parte Communication with Grote Industries, LLC Regarding Rear-End Collision Warning Lamp System.”

V. Reopening of Comment Period and Request for Comments

FMCSA believes interested persons should have an opportunity to review and comment on this new information before the Agency makes a decision on Grote's exemption request. Comments submitted in response to this notice must be limited to addressing any relevant information summarized in this notice and in the Memorandum to the Docket identified above. Comments addressing other matters will not be considered by FMCSA.

91 FR 66385