Shadows of dynamic objects in RAGE is still barely working on my RX 480 and one of our other systems with a R9 280X for the last few years, at least since 2016.
I have most of the few graphics settings enabled in the settings menu of the game. In addition, I am attaching a few screenshots to show the incomplete shadows (currently with radeon drivers 19.3.1).
I would have captured a video with Radeon ReLive as a better example, but AMD has not interfaced the Radeon Overlay with the OpenGl graphics API.
It would be kind if the driver team could investigate and hopefully improve on this.