The first one is installed after the road sign which says M25 B 172.6, the second one is after the sign M25 B 168.8 and the third one is immediately after the sign M25 B 164.8.
The Government’s stance is that these Automatic Number Plate Recognition (ANPR) cameras have been installed for the purpose of monitoring traffic flows and that this information will be used to set signals on roadside mobile message signs to harmonise speeds, to control congestion before it occurs. The stretch of M25 between Jn 30 and Jn 27 is always congested at 7AM and any problems on A12 and M11 southbound further elevate traffic congestion.
The installation of these cameras basically mean that you have to drive very very carefully between Jn 28 and Jn27 to avoid being caught by these cameras. This is definitely going to INCREASE traffic congestion between these two junctions.
But I think its a big nuisance!! These SPECS cameras capture the colour image of the front of the car and calculate the average travelling speed between the two camera locations. Speeding tickets can be automatically issued via this system. The initial trial of SPECS system was reported to have captured 4300 offenders in a single day. Potentially this single site installation can make the UK Government nearly Â£60 million!
UK Government’s Transport Minister Stephen Ladyman uses a speed camera detector in his car to detect fixed speed cameras, and yet the Government continues to install new speed cameras all over UK!