I certainly find that the radar controlled flashing speed limit reminders very effective
There's one in the village next to mine - 40 limit on SC road with pavement and traffic islands. It's extremely rare for it to stop flashing, except when there are no cars and lorries at all.
By contrast, there's one on the same road in the next village along (40 again), but there's also a camera at the other end of the village. I've never seen that one light up at all.
