There's a road near me where because of idiots messing around with the road over the years they've ended up with a situation where the speed limit goes from 30 to 50 and yes they also have a camera just before the 50 sign but in fairness to the council I think it's just a leftover from before the roads got messed around with.

It used to be a 40 to a 50, but then they decided to build some housing on the stretch of road that was 40 and decrease the speed limit to 30.