This Obscure Law Could Slow Autonomous Trucking To A Crawl

Autonomous driving is becoming increasingly widespread. Waymo self-driving cars are zipping passengers around more and more cities, while driverless AI trucks are hauling freight across Texas in trials. Yet one obscure law could bring any further advancement of this relatively new industry to a standstill.

Deep in the many pages of federal regulations governing the trucking industry lies Section 392.22 of Title 49, which outlines precisely what needs to happen when a commercial motor vehicle breaks down on the road. First, the vehicle's hazard warning signal flashers must be activated. The hazard lights must remain flashing until either three approved bidirectional emergency reflective triangles or at least six fusees/three liquid-burning flares are physically placed in very precise locations around the truck within 10 minutes. 

While enacting the hazard warning signal system can easily be accomplished by the onboard computer or a remote operator, physically setting down warning markers can't be done without the presence of humans — especially because one must be placed exactly four paces (about 10 feet) from the stopped rig on the traffic side, in the direction of approaching traffic. Plus, a second device must be dropped 40 paces (100 feet) away from the vehicle in the same direction as approaching traffic, but this time either in the center of the traffic lane or shoulder, depending on where the truck is located. Finally, a third needs to be placed 40 paces in the same lane or shoulder, this time away from approaching traffic.

While the testing phase has included observers physically sitting inside the trucks to take over in case of an emergency, the ultimate goal is for them to be devoid of any physical human presence at all. Besides perhaps a remote operator available to take control if needed, these trucks are supposed to be fully autonomous — which represents the crux of the problem.

Aurora, which began its self-driving trucking service in Texas in May 2025, applied for an exemption to Title 49, but was shot down by the Department of Transportation (DOT) in December 2024. Aurora even offered an alternative concept wherein they would attach brighter warning beacons to the front and back of the truck instead of using cones, warning triangles, and flares (which often get hit or burn out and become useless). Aurora fired back with a lawsuit in January 2025, alleging that the ruling was not only "arbitrary" and "capricious" but also "an abuse of federal regulators' discretion." 

Regulators agreed to conduct research that could help answer the question of whether the use of such technology could be just as safe as manually implementing warning signs. Meanwhile, Rep. Vince Fong (R–Calif.) introduced theAMERICA DRIVES Act, with the goal of creating a national framework for the autonomous trucking industry. This would in part allow driverless rigs to use warning beacons instead of physically placed devices. However, Title 49 remains unchanged and in limbo while further studies are conducted. As it stands, autonomous driving appears to have hit a troubling plateau — at least in the trucking industry.