This weekend I made a test with a radar warning device named Coyote. It is legal and not only shows fixed and mobile speed controls, but also accidents, traffic jams or obstructions on the road ahead. I positioned it fairly in my field of view and it is quite pleasant to drive this way. My +300km trip through Luxembourg went without any major issue. I let her cool down before I stored her in the garage until the next blat.
Cheers.