(Note: Waymo submitted the request with Aurora back when it still had an active autonomous trucking unit. Waymo shifted focus away from self-driving trucks in June 2023, and isn’t as active in this fight.)

Almost two years later, the Federal Motor Safety Carrier Administration denied the application, stating that the solution does not provide an equal or greater level of safety than the existing requirement. In its denial, the agency referenced findings from Aurora and Waymo’s own limited studies, which show their proposed beacons actually performed worse than warning triangles in several key scenarios, including when the truck was stopped at a curve.

The FMCSA also suggested that cab-mounted beacons have their other shortcomings, namely that drivers might see the rear of a stopped truck before they see the beacons.