How far away from a mobile speed camera van do you have to be to get caught speeding?

Question

If you were to slow down as soon as you saw it to below the legal limit, would you no longer be caught? Is there say a distance, say 5 metres away where they take your speed from?

Answer 1

I would say if it can see you, it can probably get your speed. So if you see it, and you know it can see you, slow down. I doubt there's really a set distance, but im sure its a lot more than 5 meters.

Answer 2

It snaps a photo when you enter the radar cross section if you are going too fast.  That radar cross section is generally 50 feet from the back of the van.