Peak District National Park
The latest proposal for a Traffic Regulation Order in the Peak District makes the main reason for a TRO abundantly clear:
The amenity of the area in this context, is considered to be a combination of the benefits derived from open air recreation, tranquillity, and the landscape. It is considered that if these are being affected by use of motorised vehicles, then the implementation of the proposed order would preserve and work towards improving the amenity of the route.
Yorkshire Dales National Park
The Yorkshire Dales NPA policy document says:
In all cases where a TRO is being proposed the reason is to preserve both the “amenity” and the “natural beauty” of the National Park under S1(1)(f) and S22(2) of the RTRA:
(s1(1)(f) RTRA84) enables a TRO to be made when it is expedient for preserving or improving the amenities of the area through which the road runs, and
(s22(2) RTRA84) enables a TRO to be made for the purpose of conserving or enhancing the natural beauty of the area, or of affording better opportunities for the public to enjoy the amenities of the area, or recreation or the study of nature in the area.
There are restrictions on a number of routes in the Yorkshire Dales National Park. These are for the purposes of preserving the amenity, conserving the natural beauty of the area, or for the prevention of damage.