To pull this back on topic, if the camera in my example was not signed, I would not have braked unnecessarily. thus avoiding an uncomfortable road moment, so there is a two-way aspect to the "immediate correction" argument. That is not necessarily a good thing, but having said that, I know of no statistics as to incidents in the vicinity of a camera. I've not even heard on once case. I have seen a camera placed in a location that was really a bit braindead in terms of consideration of road users safety.
I would prefer them all to be marked not so I can see them coming, but because I think the visible presence is more effctive, and hiding them and doing it covertly I think is leaning more towards maximising revenue.
Perhaps a happy medium - less signage, but still must be marked, so less likely to induce a panic response, whether warranted or not, that might be safety issue, while still providing visible presence.
Ultimately I think we are barking up the wrong trees with respect to correcting widespread driver behaviour.
Sorry for the diversion, but it is one of this weeks road rules debate topics (3% or less margin) and I sort of bundled it in.
My OCD focus on speedo accuracy is born of two aspects :
(a) There is a fundamental wrongness in enforcing greater accuracy from users than the feedback they are provided. Yes, the usual bias is in their favour, but it feeds to "I have this margin" psychology, and that psychology is used by speedsters to gauge how many points they are going to lose, for the more law abiding is used to find close tolerances, and for timid drivers to justify looking at someone doing close to the limit and considering them just as much a crim as the driver who is actually over it.
And the bias is not always in the drivers favour, as a read of this thread should reveal.
(b) If the tech has improved so much for our enforcement to be this much more accurate, then the tech has improved enough for our instrumentation to be equally accurate, and that the enforcement margin mandates adjustment of the manufacturing instrumentation margin.