How visible does a mobile speed camera have to be ?

Question

i mean if i was coming over a hill how far does the speed camera have to be visable, because it cant just sit behind a hill can it?

Answer 1

if visibility is restricted then it makes sense not to drive to fast over the hill ,regardless of the presence of a speed camera.

Answer 2

Just hold out your arm in front of you....now imagine it's stretching longer and longer and longer. That's how close you have to be. You can use your leg, instead, if you want to.