FMCSA grants a five-year exemption for cab-mounted warning beacons on Level 4 automated commercial vehicles

Where things stand on October 20, 2026: on October 9, 2026, FMCSA published a notice granting a limited five-year exemption to Aurora Operations, Inc. (Aurora) and to other motor carriers that operate commercial motor vehicles (CMVs) equipped with a Level 4 automated driving system (ADS), with prior notice to FMCSA. Subject to the exemption's terms and conditions, those carriers may use cab-mounted warning beacons in lieu of the warning devices specified in §393.95(f). The exemption covers the warning device placement requirements of §392.22(b), the steady-burning lamp requirement of §393.25(e) and the types and number of warning devices in §393.95(f). It is effective October 7, 2026 and expires October 7, 2031. It is an exemption, not a new rule, and it is limited to CMVs equipped with a Level 4 ADS.

What the regulations require, according to FMCSA

The notice describes the three provisions this way:

• Under §392.22(b), the driver of a CMV stopped on the traveled portion or shoulder of a road for any cause other than a necessary traffic stop must activate the hazard warning signal flashers and place the required warning devices as soon as possible, but within ten minutes, at specified locations behind and in front of the stopped CMV. The section also specifies placement in certain circumstances, such as during daylight hours or where the devices may be obstructed from view (for example, when stopped within 500 feet of a curve or the crest of a hill).
• §393.25(e) requires that all exterior lamps be steady burning, with exceptions the notice calls not relevant here.
• §393.95(f) specifies the types and number of warning devices for stopped vehicles: three bidirectional emergency reflective triangles or at least six fusees. Other warning devices may be used in addition to the required devices, as long as they do not reduce the effectiveness of the required devices.

What FMCSA granted

FMCSA grants an exemption from the warning device placement requirements in 49 CFR 392.22(b), the steady-burning lamp requirement in 49 CFR 393.25(e), and the requirements for the types and number of warning devices is 49 CFR 393.95(f). This exemption allows motor carriers operating under the exemption to use cab-mounted warning beacons, subject to the terms and conditions of the exemption, in lieu of the warning devices specified in 49 CFR 393.95(f).

Who it covers:

• Aurora, for its operation of CMVs, as defined in §390.5T, equipped with a Level 4 ADS as defined by SAE International in Table 1 of SAE J3016 (April 2021).
• Any other motor carrier operating CMVs equipped with a Level 4 ADS, only if it notifies FMCSA in writing before commencing operations covered by the exemption. The notification must include the carrier's legal name, USDOT number, principal place of business and point of contact; a statement that adequately demonstrates the carrier currently has cab-mounted warning beacons and the ability to comply with all terms and conditions; a statement affirming it will comply with them; and a certification under penalty of perjury that the information is true and correct.

The terms and conditions

Where it applies and what is excluded

• Operations may occur only on roadways that are part of the validated Operational Design Domain (ODD) for the specific ADS-equipped CMV.
• Operations are prohibited if they would otherwise require an H, X, P or S endorsement under §383.93 if a human driver were present.
• Longer combination vehicles, as defined in §380.105, are limited to doubles with two 28-foot trailers. The exemption must not be used with triples.
• While using the exemption, a carrier may not operate as a for-hire or private passenger carrier, or transport hazardous materials as defined in §383.5.

The beacons

• Forward- and rearward-facing flashing lights: at least one rearward-facing light on each side of the cab and at least one forward-facing light on the front of the cab, on mountings that provide stable support. The total width of the vehicle, including mountings and lights, may not exceed 122 inches.
• All lights mounted at least 100 inches from the ground, at or above the upper edge of the sideview mirrors but below the top edge of the cab.
• Amber in color and meeting the Class 1 photometric performance requirements of SAE J595.
• A flash rate different from that of the standard hazard warning signal flashers required under §392.22(a).
• Redundant power sources, to prevent failure due to a single-point power failure.

When they must activate

The beacons must activate as soon as possible, but in any event within five minutes, whenever the CMV is stopped on the traveled portion or the shoulder of a highway for any cause other than necessary traffic stops (i.e., whenever 49 CFR 392.22(b) would otherwise apply).

• The beacons must remain flashing for the entire duration of the stop, from the initial stop until the vehicle reinitiates movement or is recovered.
• The standard hazard warning signal flashers must also activate as required by §392.22(a) and continue flashing for the entire stop.

Reports to FMCSA

• Crashes: notice to FMCSA by email not later than five calendar days after any crash involving a CMV while the beacons are activated or should have been activated. "Crash" has the meaning in NHTSA's Third Amended Standing General Order 2021-01. The notice must include all available information, including the date and time, the city or town and State and geolocation, the VIN, any property damage, the number of people injured, the number of fatalities and the police-reported narrative, if available.
• Annual report: upon request, and annually by November 1 of each year the carrier operates under the exemption (or within 30 calendar days of ceasing operations under it). It covers the entire period of operation: the number of CMVs and vehicle miles traveled under the exemption; data on each malfunction, power issue or other instance where the beacons did not operate under the terms (frequency, duration, date, location including road type, vehicle configuration and reason); the mounting locations of all beacons; and any variations in beacon types, mounting or flash patterns, with any performance differences.
• Safety notification: not later than five calendar days after a carrier becomes aware, or otherwise determines, that continued use of the beacons is no longer likely to maintain a level of safety at least equivalent to the level without the exemption.
• Nonpublic information in the crash and annual reports will be treated as confidential business information if the carrier designates it as such.
• Each carrier must comply with all other applicable Federal Motor Carrier Safety Regulations and, at FMCSA's request, meet with FMCSA to answer questions about the data and information required.

Why FMCSA granted it

FMCSA determined that the exemption would likely achieve a level of safety equivalent to, or greater than, the level that would be achieved without it. According to the notice:

• A previous request was denied. Aurora first applied in 2023, and FMCSA denied that request in December 2024. FMCSA then granted Aurora a temporary, narrow waiver. The present application requests limitations similar to the waiver's, and FMCSA incorporated them into the terms: prior written notice by carriers other than Aurora, annual reports, the ban on operations that would require an H, X, P or S endorsement, and technical specifications for the beacons.
• Data under the waiver, according to Aurora. From October 10, 2025 through January 9, 2026, Aurora used the beacons on 34 CMVs that traveled over 500,000 miles. The beacons activated for a total of nearly 10 hours and, to the company's knowledge, operated without faults, malfunctions or power issues. The notice states that Aurora's CMVs under the waiver were not involved in, nor contributed to, any roadway collisions while stopped and using the beacons.
• Two studies. In Aurora's naturalistic study, motorists initiated their first evasive response further back from the trailer with the beacons than with the triangles in six of eight scenarios, and the average distance at response was 135.71 meters for the beacons versus 133.24 meters for the triangles. In a survey in the Virginia Tech Transportation Institute (VTTI) study, 78.26 percent of daytime participants and 83.33 percent of nighttime participants reported that the beacons were more noticeable and easier to see than the triangles.
• Five minutes instead of ten. The beacons must activate within five minutes; §392.22(b) allows a 10-minute window to place triangles.
• Doubles and tankers. In response to concerns about rear visibility of longer combinations, FMCSA limited them to two 28-foot trailers, which, as Aurora notes, add approximately only 9.5 feet to a standard CMV's length. The exemption may also be used with tankers.

FMCSA received 402 comments. Opponents raised, among other concerns, trailers blocking the beacons in a jackknife or at an angle, single-point electrical failures, the lack of performance standards for the beacons, and weather, road, lighting and traffic conditions not covered by the studies.

States, revocation and renewal

• States. Under §381.600, while the exemption is in effect, no State may enforce any law or regulation applicable to interstate commerce that conflicts with or is inconsistent with the exemption, with respect to a firm or person operating under it. States may, but are not required to, adopt the same exemption for intrastate operations.
• Renewal. The notice states that an exemption may be renewed (§381.300(b)).

Revocation. In the notice's words:

However, the exemption will be revoked as to all motor carriers or an individual motor carrier if: (1) the motor carrier or motor carriers operating under the exemption fail to comply with the terms and conditions of the exemption; (2) the exemption results in a lower level of safety than was maintained before it was granted; or (3) continuation of the exemption would not be consistent with the goals and objectives of Title 49, chapter 313 or section 31136.

What this notice does not do

The exemption is limited in scope to CMVs equipped with a Level 4 ADS. FMCSA writes that updating the warning device requirements for all CMVs, not just ADS-equipped CMVs, may be ripe for future regulatory action; the notice does not propose that change. As of October 20, 2026, nothing else has been published in docket FMCSA-2026-0958. We will update this article if that changes.

Sources

• FMCSA, Parts and Accessories Necessary for Safe Operation; Application for Exemption From Aurora Operations, Inc (USDOT #341156), notice of final disposition; grant of application for exemption, 91 FR 64736 (October 9, 2026).
• Docket FMCSA-2026-0958, regulations.gov.
• 49 CFR §392.22, hazard warning signal flashers and warning devices for stopped commercial motor vehicles.
• 49 CFR §393.25, requirements for lamps.
• 49 CFR §393.95, emergency equipment, including warning devices.