Speed signs

Not so long ago one of those signs appeared at the side of Weston Road that tells you how fast you're going.  Originally they put it up in the middle of some trees so it was really hard to see your speed let alone feel prompted to slow down if you were going too fast.  Recently tho, someone has turned it around so that it faces the other way and is not obscured by the trees.  I find it very useful; when I went past on my bike the other day it told me I was going 10mph, and when I walked past it, it told me I was going 3 miles an hour.  

It is much better than the one they have in Shardlow.  I drive past that one, speedometer dead on 30, and it flashes 30 at me like I'm going too fast.  Considering that most car speedometers are set 3mph too fast to help avoid speeding, I think this sign must be set wrongly.  The fact that when I go through Aston at dead on 30, the sign says I'm doing 27 seems to back this up.  So in other words they want people to drive at 25mph through Shardlow despite it having a 30mph limit.