In some countries, to increase public support for speed cameras, they are only installed in areas with an established history of speed-related accidents. For example, downhill sections in winding country lanes with poor visibility. The cameras are very, very clearly signposted - and project success is measured by issuing fewer tickets, as that means fewer people are speeding. So you might also install clearer signage and other traffic calming measures at the same time.
On the other hand, if your aim is to maximise revenue, then project success means issuing as many tickets as possible. Installing clear speed limit signage? More profitable if we don't. Making the cameras clearly visible, so people can slow down in good time? More profitable if we don't. And if there's a wide, safe freeway with great visibility and no history of accidents? Well, that's going to be a profitable place for cameras, as people will feel safe going fast.
On the other hand, if your aim is to maximise revenue, then project success means issuing as many tickets as possible. Installing clear speed limit signage? More profitable if we don't. Making the cameras clearly visible, so people can slow down in good time? More profitable if we don't. And if there's a wide, safe freeway with great visibility and no history of accidents? Well, that's going to be a profitable place for cameras, as people will feel safe going fast.