Norfolk Safety Camera Team

[993rsr]

Travelling back from Norwich towards Newmarket just before lunchtime today with the cruise on my RS6 set at indicated 80mph and the Origin B2 reading 77mph, just before the Snetterton turn off the origin laser warning went off and I hit the brakes. Camera van was parked under the bridge.
Question is - what is the tolerence they work on? Does it fall in with the Society of Chief Police Officers guidelines starting at 79mph? Roads were clear and weather good.