Generally speaking it is your local authority’s responsibility to look after a road once the developer has commenced works, but the developer may be required to give the council confirmation of insurance by way of a surety bond, which would then give them the green light to go ahead.
The amount of security required is provided by the local council and is often higher than the developers contract works budget.
S38 Agreements cover new roads and S278 Agreements cover work being done on existing roads. Roads bonds insurance act as a guarantee for the council for any development where roads are being constructed and will be adopted by the council after completion.
Works that are carried out by the developer, will be required to be of a certain specification and certain timescale. If the works are not carried out to these standards then the local authority can call upon the bond money to complete the works of the road if for whatever reason it has been left incomplete.