Autonomous trucks ditch triangles for beacons in 5-year US safety shift
US regulators grant Level 4 autonomous trucks permission to replace reflective triangles.
The US autonomous trucking industry has secured a landmark regulatory exemption, allowing Level 4 autonomous vehicles to replace traditional reflective triangles with cab-mounted warning beacons for the next five years. The Federal Motor Carrier Safety Administration (FMCSA) granted the exemption this week, setting a deadline of October 7, 2031, and covering operators like Aurora, Kodiak AI, and Waabi.
Federal rules currently require human drivers to place warning devices within 10 minutes of stopping, a task impossible for driverless vehicles. The new exemption allows beacons to activate within five minutes, a change FMCSA described as “a clear, verifiable safety improvement.".
“Going from a temporary waiver to a five-year exemption gives the industry a lot of confidence. As these companies scale, raise money in the capital markets and set up business partnerships, there are often questions about what they are going to do about the warning-triangle issue. Now there is a firm answer.”
Jeff Farrah·CEO, Autonomous Vehicle Industry Association
How the new beacon system works: Autonomous
The exemption outlines strict technical requirements for the warning beacons. They must be amber, meet SAE J595 Class 1 photometric standards, and be mounted at least 100 inches off the ground, at or above the top of the side mirrors. Each truck must have at least one rearward-facing light on each side of the cab and one forward-facing light on the front, all with redundant power to prevent single-point failures.
The beacons must activate within five minutes of a stop and continue flashing alongside standard hazard lights until the truck moves or is recovered. This replaces the current requirement for three bidirectional reflective triangles or at least six fusees, which autonomous trucks cannot deploy without a human driver.
“Now, with autonomous vehicles, we need to evolve some of these requirements, since with an autonomous truck there is not going to be somebody who can get out and put warning triangles behind the vehicle,” Farrah added.
Operational limits and industry impact
The exemption comes with several operational restrictions. Autonomous trucks may only operate within their validated operational design domain and cannot haul hazardous materials, passengers, or perform tasks requiring special endorsements (H, X, P, or S). Doubles are limited to two 28-foot trailers, and triples are barred entirely, though tankers are permitted.
Carriers must report any crashes involving the beacons within five calendar days and submit annual reports on beacon malfunctions and power issues by November 1. States are prohibited from enforcing conflicting rules on interstate operations covered by the exemption.
Bart Teeter, director of fleet and operational safety at Bot Auto, emphasized the exemption’s significance: “This will give the autonomous freight industry a key piece of regulatory certainty that will allow us to continue to scale safely.”
The exemption replaces a series of four three-month waivers Aurora has operated under since October 2023. Kodiak AI, Waabi, and Stack AV have since opted into the new rule, which also allows any other Level 4 carrier to participate after notifying FMCSA. The decision follows years of advocacy and testing.
The Owner-Operator Independent Drivers Association (OOIDA) and the Small Business in Transportation Coalition have also questioned the exemption’s scope, with the latter warning it “would open a can of worms.".
FMCSA Administrator Derek Barrs signed the exemption, noting that the issue “may be ripe for future regulatory action” to update warning device requirements for all commercial vehicles.
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