I didnt know this not sure if anyone else does,
But those speed camera vans, are actually occupied.
they'll sit in the one spot for 4 hrs and the coppers gotta sit in their the whole time and watch the screen, as they are automated.
I know this because i was working on one the other day and the copper said to me he's sure some police have dozed off or even ****ed off in one once and a while to pass the time.

I didnt know what to think, as he was the one picking it up.