Interesting video. Never encountered one of these on a highway where I live/drive. Does the radar usually cover only one lane? If not, how can a single driver know his speed if others in the next lane are going above/below his speed? And how effective are these signs (on multi-lane highways) at slowing traffic down to the posted speed limits? I would think not much.
I encounter these speed signs a lot on secondary roads where I drive and being on K or Ka band, they are a good test of one's RD sensitivity ( very low output power) as the signals are detected before the sign is in sight.
Sorry - duplicate reply post.