A computer is no substitute for a human.
No matter what environmentalists say, there are situations where a bit of speed is a good thing. I once overtook a car doing 50 in a 60 zone on a good quality road and, given that I'm fairly confident in my driving and I wanted to get back on my side ASAP, I sped up to about 80. Only, as I did that, I noticed there was a police speed radar stood behind a tree. He never gave me a ticket.
I can't believe that people want cameras to be hidden. They were originally supposed to be used at accident blackspots to slow people down, why would people slow down if they are hidden? Instead, they would just dish out fines and those people would carry on speeding through the blackspot.
At the end of the day, they lead to panic breaking, they only slow people down over a very short section of road, they only catch a small minority of law breakers and they never understand the whole situation. Scrap speed cameras, get traffic police back out there.
Only in a dictatorship will you find spies hidden in bushes catching you breaking the law, even if you haven't actually done any harm.
And whilst we're at it - remove the national speed limit!