Incidentally I was using a bus lane out of hours (in readiness to take a left at some lights) while approaching a fixed speed camera, a woman in a Micra whizzed past using the normal lane & set off the camera. She DID slam on her brakes & stopped dead in the road. As I trundled past smirking at her she engaged reverse & backed up over the speed camera markings on the road, then moved forward over them again but slowly this time
I can only imagine she thought she could somehow undo the speeding offence she had just committed