FMCSA lets driverless trucks use cab-mounted beacons instead of warning triangles

Federal regulators will let driverless trucks use cab-mounted warning beacons instead of the reflective triangles drivers must set out when a truck is stopped on the road.

The Federal Motor Carrier Safety Administration's five-year, limited exemption took effect Oct. 7 and runs through Oct. 7, 2031, according to the agency's notice in the Federal Register, published Oct. 9.

What the exemption covers

The exemption applies to Level 4 autonomous trucks, which operate without a human driver, and waives rules on the type, number and placement of warning devices and on steady-burning lamps.

Aurora requested the exemption, and its application was published for public comment in April. Any other company running Level 4 trucks can use the exemption if it notifies FMCSA in writing before starting. Kodiak AI told Trucking Dive it will give FMCSA written notice that it plans to operate under the exemption.

The notice sets specific terms. Among them:

• The beacons must be amber, mounted on the cab at least 100 inches off the ground, and facing both forward and rearward, with redundant power so a single failure cannot knock them out.
• They must switch on within five minutes whenever the truck is stopped on the roadway or shoulder, and flash at a different rate than the standard hazard flashers, which must also stay on.
• Trucks may operate under the exemption only within their validated operating area, and not on loads that would require a hazmat, tank, passenger or school bus endorsement if a driver were present.
• Carriers must report to FMCSA within five calendar days any crash that happens while the beacons are on, or should have been, and file annual reports on malfunctions, power problems and other failures.

FMCSA reviewed 402 public comments.

A reversal for the agency

Aurora and Waymo jointly applied for similar relief in 2023, and FMCSA denied that request in December 2024, faulting it for covering unspecified carriers, equipment and vehicles without monitoring controls. FMCSA later granted Aurora a temporary, narrow waiver; Trucking Dive reported that the waiver followed a lawsuit Aurora filed against the agency.

According to the notice, Aurora reported using the beacons under that waiver from Oct. 10, 2025, through Jan. 9, 2026, on 34 trucks that traveled more than 500,000 miles, with no faults and no collisions while stopped with the beacons on. FMCSA said the new terms fix the problems it cited in 2024.

This time FMCSA concluded the beacons "would likely achieve a level of safety equivalent to, or greater than, the level of safety that would be achieved without exemption."

Industry split

The Autonomous Vehicle Industry Association and Volvo supported beacons for trucks with and without drivers. The American Trucking Associations backed the exemption and asked FMCSA to study the data for lessons that could apply to all trucks.

The Owner-Operator Independent Drivers Association opposed it, arguing that the two studies Aurora submitted did not account for the range of weather, road, lighting and traffic conditions trucks face.

"This corporate carve-out sets a troubling precedent," OOIDA President and CEO Todd Spencer said in a statement to Trucking Dive.

Aurora's senior vice president of government relations, Gerardo Interiano, said in an email to Trucking Dive that the beacons are "a critical, 21st-century solution that enhances roadside safety by immediately alerting other road users without ever needing to put a person in harm's way."

What it means for drivers and fleets

For drivers sharing interstates with autonomous trucks, the practical change is what they will see on the shoulder: a disabled driverless truck may display flashing beacons on the cab instead of triangles spread out behind it.

For autonomous truck developers, five years of regulatory certainty removes one barrier to running without a safety driver, and the required reporting will show whether beacons work as well as triangles.

The exemption does not change the rules for trucks with drivers, who must still set out triangles or flares as required.