Having seen a few people recently being flashed by these relatively new cameras on the M25 l wounder if the speed set has been reduced?
Anyway, here is some bedtime reading.
https://www.speedcamerasuk.com/hadecs-3.htm
REDFLEXhadecs3 or HADECS 3 which is short for Highway Agency Digital Enforcement Camera System 3 is one the newest speed cameras to be installed on UK roads. Current locations include the M1 in Derbyshire, M6 in Staffordshire, M25 in Surrey, M20 in Kent, M25 in Kent, M62 in West Yorkshire and M4/M5 in Somerset.
Following Home Office approval the first Redflex Hadecs 3 system went live on the M25 motorway between junctions 5 and 6/7 on the 22nd October 2014. Between the
22nd October and 25th November 2014 some 668 motorists had been caught speeding by the new speed camera, many of which are calling it a 'stealth camera'
The HADECS 3 speed cameras have so far been installed on the M25 in Kent between junctions 5 and 6/7. More locations are planned on a number of other motorways in the UK, including:
‣M1 in Derbyshire and South Yorkshire
‣M25 junctions 5 to 6/7 Kent
‣M3 in Surrey and Hampshire
‣M4/M5 in Somerset
‣M6 around Birmingham
‣M62 in West Yorkshire
These busy motorway locations all share one thing in common, they are all smart motorways. A smart motorway (formerly managed motorway) is a section of motorway which uses active traffic management (ATM) techniques to increase capacity by using variable speed limits and the use of the hard shoulder as an additional lane at times of congestion.
In the instance of the M25 smart motorway section in Kent, the speed limit is normally set to 70mph. However when the hard shoulder lane is in use, the speed limit can reduce down to 40mph, 50mph or 60mph. Any change in the speed limit is clearly communicated to motorists via overhead gantry signs. The HADECS speed enforcement cameras then adjust to the new speed limit