Excuse me, high-speed road that red twinkle like LED Blue beacon light what role

Excuse me, I often cotton to the high-speed (including other high-speed) (see high-speed roadside green belt and the roadside have) that has a square plate inclined to what sky below it led blue beacon light  is a flashing red light like LED Blue beacon light that the lamp is stem what use, I saw it had a put it when the speed limit LED Blue beacon light to feel, to the deceleration (with great care, because rotating beacon light  do not know the way electronic eye installation where there, high-speed electronic eyes there are signs suggest).