Green de-restriction speed stripe

There are far too many deaths and accidents on rural roads and much time and energy and money goes into debates and changes in Communities and Councils all over the United Kingdom.
Meanwhile we have the same black on white stripe sign on hugely varying stretches of road which gives a 60 mile blanket de-restriction.
I am proposing a Green stripe replace the black on the sign on roads which have all or some of the following hazards, particularly prevalent in rural areas :- The road has many bends where vision is restricted, is too narrow in places for 2 cars to pass, has no pavement but is used regularly by walkers, cyclists and horse riders, particularly when part of a bridleway follows it on the ordinance Survey map, farmers drive sheep and cattle along it from field to field, the road is used heavily by farm vehicles of all sizes as well as all other types of road user. It is the main through-fare for communities.
I am proposing that the maximum speed limit would be dropped to 40 or 50, but this is for debate as well as a No Overtaking except of stationary vehicles rule.
Communities across the UK could then apply for this new category of driving limit in their area which would require no extra signs, just a very bright green rather than Black stripe and would be Nationally recogniseable.
I am sure that many people as in our community have their own stories of fatalities and near misses and would welcome a solution that would at least give drivers a slightly different rule and understanding of the road they find themselves on.