Unadopted roads are the responsibility of the road owner, if they can be found, or the residents of properties fronting on to the unadopted road, often with no help from the local authority even though they pay full council tax. Unadopted roads, of course, can be adopted at the instigation of either a local authority or the frontages, but local authorities would normally expect the road to be of a proper standard before it can be adopted. Under section 236 of the Highways Act 1980, the local authority is permitted, but not required, to pay some or all of the cost of bringing a road up to an adoptable standard. The reality, of course, is that local authorities rarely instigate the process, and, in these austere times, it's seen as a liability that they can do without. The precise scale of the problem is not actually known. While local authorities are required by the Highways Act 1980 to maintain a register of the roads for which they are responsible, there is no such requirement to maintain a register of unadopted roads within their areas. Therefore, quantifying the scale of the problems is difficult. The data that is commonly quoted is generally sourced from a 2010 House of Commons library note on unadopted roads, which states that a Department for Transport survey in 1972 found that there were then approximately 40,000 unadopted roads in England and Wales, making up some 4,000 miles of road then. It's not just the roads that are neglected, but the stats are as well. 

The UK Government estimated in 2009 that it would cost £3 billion to make up these roads to an adoptable standard. The reality is that, as well as these historic unadopted roads surveyed in 1972, we have had a significant number of new estates being built in Wales, and we can all point to examples in our own areas where developers have either decided not to put forward roads for adoption, or have gone into liquidation, and where the roads in question remain unadopted for years on end and often in a state of disrepair.