In a lot of European countries you have speed-control via section-control, means:
the avgerage speed is measured of a certain distance by taking picture of car when entering and leaving the measuring section.
Unfortunatly currently you can not warn other users of such controls.
On contrary, such controls are only posted as stationary speed-control when entering, which is very misleading

I drive every day Germany swiss...500+ miles track . ( I deliver pockets)
I dont know why but the waze app doesnt sows for you the speed cameras / radars in swiss ,also no option to add this to the map !
This section controlled track are not Fix! The speed limit changes according to the corrent situation. Thats mean if there is an accident or road works they reduce the speed limit ,from 120- to 80...Also the radars and cameras are swiched to the corrent speed limit...So its can be that yesterday the road was ok ,and good ,and was allowed 100 or 120 ,but next day there is road work so they cange the speed limit to 60...and also the rtadars shoothing at 60+ ...Its a mean thing. Other wazers need to be informed abouth this !