One of the shower thoughts I've had is why don't we start equipping cars with UWB tech. UWB can identify itself, two UWB nodes can measure short range distances between each other (around 30m) with fairly decent accuracy and directionality.

Sure, it wouldn't replace any other sensing tech, but if my car has UWB and another car has UWB, they can telegraph where they are and what their intentions are a lot faster and in a "cleaner" manner than using a camera to watch the rear indicator for illumination