I use Waze for nav and it includes speed cameras - don't think I've ever seen one that it has missed, although being a social network it is susceptible to fake reports.
But, being completely honest here, I try and stay within +10% of the limit unless I'm going through residential areas or directly through a camera, in which case I'll make sure I'm under. 30mph in a 20mph zone is pretty uncool.
Otherwise you end up in situations where you're being pushed down the motorway by an angry dad, or stuck in the slow lane with the lorries. Having cruise control for the first time also made me realise how much people slow down when going up hills and speed up on the other side!
But, being completely honest here, I try and stay within +10% of the limit unless I'm going through residential areas or directly through a camera, in which case I'll make sure I'm under. 30mph in a 20mph zone is pretty uncool.
Otherwise you end up in situations where you're being pushed down the motorway by an angry dad, or stuck in the slow lane with the lorries. Having cruise control for the first time also made me realise how much people slow down when going up hills and speed up on the other side!