Although always keen to weigh in on the cynical side myself on this sore topic, I do think there is a genuine safety and funding concern these councils are addressing (or at least a very plausible line ).

Under an intense and constant severe financial squeeze from central government while trying to provide reasonable local services, LAs are additionally paying a lot of potentially useful money into central government from these cameras, while being expeted to shell out scarce money in local partnerships. So they are not getting the benefit of that revenue to either (a) cover their maintenance, etc costs; or (b) use in alternative road safety/improvement schemes.

If they were getting that money (and really DID use it for safety schemes) then they might actually put up more cameras, which perhaps WOULD then have a greater deterrent effect. Or they could site them in more important, possibly less lucrative, locations, thus increasing genuine safety, as they would at least be covering their costs). I don't think that fixed cameras are necessarily a pointless safety exercise in themselves - it's the way they're being used.

But both these councils seem to be looking mainly to mobiles - whether they will be 'safer' I doubt, as drivers are going to get more of a shock when they encounter one hidden in a layby, etc than they do with fixed ones, which is not going to improve safety! Possibly this might be being looked at simply as a more effective revenue gatherer, rather than a genuine alternative.

David
(Navigon 70 Live, Nuvi 360)