Be warned...SPECS cameras are now up and running on parts of the M4.
These are digital cameras (no flash) located in overhead signs that record your number plate and work out your average speed between cameras.
Triggered at 78 mph.
No radar beams for those of you with dashboard gadgets.
In operation now between J12 and the Membury Svcs (J14/15) and more to follow soon.
Beware and pass on.