The sites are chosen because of a combination of PIC (personal injury Collisions) and KSI's. That means that if someone has had a collision which resulted in even a slight bruise or cut, if it was then reported to the police within 30 days it would count towards the siting of the camera. The baseline for selection is three years, but then a count of all PIC's over a five year perios is taken to make sure the cameras are going in the right places.
Fixed cameras have to have had 3 KSI's on the site per km in the 36 month baseline period; mobile cameras have to have had 1.
When the site does not meet the PIC requirements, or the requirements for visibility etc. the force can still operate it as an "exceptional site" for 15% of the total hours that a core site is in operation - Translation: Police can put cameras wherever they damn well please!
Police can also operate covert sites (meaning that the camera can be totally hidden from view) at their discretion, and the siting of these cameras does not necessarily need to be at places where injuries have occurred. They only need to be at sites where there have been a few too many reports (or complaints) of high speeds.
I once had to swerve into the middle of the road to avoid one police car because whilst he was hiding behind a wall recording my speed he'd left his car sticking out a foot or so into the narrow country lane we were in. So if anything had rounded the bend coming the other way I would have been lucky to miss it.
The "Rules" also say that non-compliance of the "Rules" does not mitigate or provide a defence against prosecution... so I ask you what is the point of having these rules? The only penalty that Forces endure for not following the rules is that their costs cannot be reclaimed if it can be shown that they didn't. Sounds more and more like the only reason they bother to put yellow stickers on the boxes these days is that they won't get paid if they don't! And they say it isn't about money? Don't make me laugh!
See:
http://www.dft.gov.uk/stellent/groups/dft_rdsafety/documents/page/dft_rdsafety_611087.pdf for further details.
Happy reading!
