I wonder what the criteria is for setting speed limits on particular roads.
Some may not even classify what is after the sign as a road - being only one car wide and in places the gorse extends into the driving area; the tarmac surface has in many locations deteriorated to gravel; there are a lot of sharp bends - along the mile or so that we walked anyway.
I find it difficult to believe that any driver could get their car anyway near to 80km/hr and stay on the road.