城市蔓延
The extent of the practice around roads led to its problems becoming intense and recognition as an inefficient use of resources, requiring bypass roads to be built, and often a precursor to untrammelled urban sprawl, so a key aim for the United Kingdom's post-war planning system was to implement a presumption and convention that proposed new ribbon development is inappropriate. Urban sprawl/suburbanisation of large areas led to the introduction of green belt policies, new towns, planned suburbs and garden cities.