Some road spend is on the bits you don't see.
Derbyshire County Council have accepted a Government ring-fenced grant of £4.85 Million to repair the walls supporting the A6 for the ~5 miles between Whatstandwell and Matlock.
The height of these walls are un-noticed unless you are a road engineer, or a footpath walker with an eye for, and appreciation of, these features.
For Genocache, as the road number implies, the A6 was a major long distance road. In this area it is a two lane road (in the UK that's one lane in each direction) and wide enough for the heaviest UK lorries to pass each other. It has a significant number of bends, meaning there are few overtaking opportunities because the required length of clear forward visibility doesn't exist.
I don't recall exactly (I rarely use it), but I suspect this stretch of road has a limit of 50mph, except where lower limits have been applied near junctions. This length of the A6 runs along the valley of the River Derwent, the road being built up to avoid flooding.
The outer face of the retaining walls are roughly dressed stone; I don't know exactly what's behind that, but I suspect the specialist repair will be to inject 'cement' grouting behind the outer wall, to both fill voids left by rainwater washing out the 'fines', and to more firmly lock the stones in place.
Regards.