Something that I have yet to see in the automotive world is a radar detection system that also does direction finding… Sure, I'd like to know that a radar threat is out there, but I'd also like to know where it is. After all, a signal coming from your left or right isn't actually a threat, but one directly ahead or behind is... and if you even know exactly what frequency it's on, you might even be able to figure out if the signal generator belongs to a threat or the local automatic door opener... with a very good signal processing system, you could even possibly be able to differentiate individual transmitters.
However, because radar detectors are very common these days, police departments seem to be going to the use of LIDAR to detect speed instead of radar because it is a lot more specific and a lot more difficult to detect until it's too late.