Ranger1 is missing the important difference in scale between US and UK. The Peak Park of Derbyshire is surrounded by major conurbations and within an hour's drive of Manchester, Leeds, Sheffield, Nottingham, Derby, and Stoke, and only a little further from Birmingham, Leicester and Liverpool- a combined population of perhaps two or three US states. And most of that hour's drive is taken up in the city itself, and our bit of countryside would probably count as within the city boundaries in the USA.

There has also been increased damage due to the inflation of size of agricultural vehicles: the tractor of thirty years ago was a quarter of the size of a modern one. It doesn't only affect green lanes: just a few days ago a mediaeval bridge over the Warwickshire Avon at Bidford-on-Avon was damaged by a farm vehicle.

Add to that the fact that off-roaders' enjoyment requires precisely that the roads should be near- impassable, as there's little enjoyment in driving along a smooth track in good condition, and that they don't get their privileged and expensive moneysworth in their local city conditions, and you'll see that not only is the damage intentional (perhaps at an unconscious level, but don't bank on that), so is the denial of the use of the facilities to other users.