It's a red-light with a speed warning and a detector - if you go over the allowed speed, it turns red, otherwise stays green forever.
But we also have hidden radars which are not announced.
But we also have hidden radars which are not announced.
Of course some will still get as close to the light as they can and hammer the breaks last moment, but they'll do that at other lights too, and other unsafe things, so the danger is not caused by the light in that instance.