Is there one? I was driving in the UK all week and encountered a bunch of average speed cameras (and static cameras too) and the volume of speeding on the roads was way way lower than it is here, with essentially no speeding in average speed camera zones.
So my question is - why don't we have them? The only argument against them I would subscribe though would be if they are used to track somebody's movements separate to them being used for speed enforcement (as in they could see that a certain car passed through a certain series of cameras and track somebody's movements that way), but assuming that was prevented, I'd be happy having the entire motorway network covered in these things.
I know that people will say that motorways are the safest place to drive, but you still see nutcases doing 150kph+ on the roads, and if the speed limits on the motorways were enforced then it's likely that when exiting motorways you are dropping from 120 to 100 and will actually stay there, rather than dropping from say 140 to 120/110 and be over the limit for N roads then.
Am I missing anything other than it prevents people from driving fast?