When big rigs pull to a highway shoulder, their drivers are required by federal regulations to place three reflective triangles behind the vehicle within 10 minutes of stopping.
In a self-driving world, there's nobody around to perform that task.
The two companies are seeking a five-year exemption from Federal Motor Carrier Safety Administration regulations that address the required placement of warning devices.
Their exemption request will be made public Friday when the administration, which provides safety oversight of commercial motor vehicles, is expected to publish it in the Federal Register. A copy of the application was available online Thursday night.
Instead of triangles or flares at night, Waymo and Aurora have requested their partner motor carriers be allowed to equip truck cabs with flashing warning beacons that would be activated when a truck stops along the side of the road.
The beacons would be mounted at a height above the upper edge of sideview mirrors, according to the exemption request.