Autonomous Truck Fleets Secure Five-Year Warning Beacon Exemption

AV truck fleets win 5-year exemption on warning beacons

The Federal Motor Carrier Safety Administration has granted a five-year exemption allowing qualifying autonomous trucks to use cab-mounted flashing amber beacons instead of the roadside warning triangles required for conventional trucks.

The exemption took effect Oct. 7, 2026, and runs through Oct. 7, 2031. It was originally requested by Aurora Operations, but it also applies to other carriers operating SAE Level 4 automated driving systems that notify FMCSA of their intent to use the exemption and comply with its conditions.

The decision addresses a practical problem for driverless trucks: There may be no person available to leave the cab and place warning devices around a disabled or stopped vehicle. Under existing federal rules, a truck driver must activate the hazard flashers and place warning devices in front of and behind the truck within 10 minutes. The required equipment generally consists of three bidirectional reflective triangles or at least six fusees.

Under the exemption, qualifying autonomous trucks must use amber beacons that meet Class 1 photometric requirements under SAE J595. The lights must be mounted at least 100 inches above the ground, at or above the top of the truck’s side mirrors. Each vehicle must have rearward-facing lights on both sides of the cab and a forward-facing light on the front. The system also must have redundant power to reduce the risk of a single-point electrical failure.

The beacons must activate within five minutes after the truck stops and continue flashing with the vehicle’s standard hazard lights until the truck moves or is recovered. FMCSA described the five-minute requirement as a “clear, verifiable safety improvement” compared with the 10-minute period allowed for a driver to deploy roadside warning devices.

The exemption replaces a series of shorter waivers that Aurora had operated under since October 2025. During one waiver period, Aurora reported using the beacons on 34 trucks that traveled more than 500,000 miles. The company said the lights were active for nearly 10 hours and that it recorded no faults, malfunctions or power issues. FMCSA also said the trucks were not involved in collisions while stopped with the beacons operating.

For carriers other than Aurora, participation is not automatic. Each company must notify FMCSA before beginning operations and certify, under penalty of perjury, that it has the required equipment and will follow the exemption’s terms. Carriers must report crashes that occur while the beacons are activated, or should have been activated, within five calendar days. Annual reports on beacon malfunctions and power problems are due by Nov. 1.

The exemption also limits where and how the trucks may operate. Vehicles must remain within their validated operational design domains, meaning the specific road, weather, traffic and operating conditions for which their automated systems have been designed and approved. The trucks may not carry hazardous materials or passengers, and they cannot perform operations that would require an H, X, P or S endorsement if a human driver were operating the vehicle.

Doubles are limited to two 28-foot trailers, while triples are prohibited. Tankers are allowed under the exemption. States may not enforce conflicting warning-device requirements on interstate operations covered by the federal exemption.

Autonomous trucking companies and their supporters welcomed the longer-term authorization. Jeff Farrah, CEO of the Autonomous Vehicle Industry Association, said the move gives companies greater certainty as they seek financing, build partnerships and expand their fleets. Bart Teeter, director of fleet and operational safety at Bot Auto, said the exemption provides a regulatory path for the autonomous freight industry to scale.

For professional drivers, the change concerns more than the technology itself. A stopped truck on a shoulder or roadway is a hazard regardless of whether it has a person in the cab. The warning system is intended to alert approaching motorists without requiring anyone to walk into traffic to set out triangles.

The exemption has also drawn substantial criticism. The Owner-Operator Independent Drivers Association called it a “corporate carve-out” and questioned whether the beacon system has been shown to provide equivalent protection under the range of conditions covered by federal warning-device rules.

OOIDA and other opponents raised concerns about curved roads, hills, poor weather, different trailer configurations and situations in which a truck is jackknifed or positioned at an angle. They also questioned whether cab-mounted lights could be blocked by a trailer or disabled by a power failure. The groups argued that the research supporting the exemption did not provide enough evidence for a five-year authorization and urged FMCSA to conduct a broader study of warning devices for stopped trucks.

FMCSA previously rejected a broader request from Aurora and Waymo in December 2024. At the time, the agency said the request involved unspecified carriers, equipment and vehicles, making it difficult to determine whether the proposed operations would provide an equivalent level of safety.

The new exemption is more specific. It identifies the beacon equipment and operating conditions and requires each participating carrier to identify itself to the agency. FMCSA also said available research does not establish that roadside triangles significantly improve driver reaction times, and that the broader safety benefit of warning devices remains an unresolved question.

The exemption gives autonomous trucking operators a clear federal framework through October 2031. It also places responsibility on carriers to maintain the beacon systems, remain within approved operating limits and report crashes or equipment problems as the technology is used in freight operations.