Feeling argumentative this morning so:
I recently did advanced driving course (a requirement from work) and the instructor said that if you change lanes in an average zone then the cameras cant get you. i:e enter in the inside lane and exit in the outside lane.
Advanced driving instruction fail.
Your speedo inaccuracy will not be constant. Might be showing 56-57mph on the speedo at a true 50mph on worn tyres, but put new tyres on and a true 50mph will drop down to 52-53mph on new tyres. An extra 8mm or more on the radius equals a big change in rolling circumference
True, but the variation is not that great. In reality you never have 8mm change – tyres usually come with 8 and people change them at around 2. I recently went down from a 55 to a 50 on my tyres (nearly 10mm sidewall difference) and it's a 2mph change in overall speed.
I understand that you are timed between the first and last camera in the sequence (the others aren't cameras, they just record a vehicle passing by) – they haven't deployed the ones that get you between any pair in the sequence yet. The switching lanes trick should still work.
Makes no sense, switching lanes does not work (verified by someone having been caught) and why would they install the inbetween cameras in relatively short-term works locations if they didn't have the ability to use them yet? Depending on the day I travel different pairs of cameras are turned on in a set of 6, some days it's 1 and 3, some days its 1 and 2, some days its 1, 2, 3 and 5 etc. They're obviously all active, although which ones work in pairs it's impossible to know.