asked the Secretary of State for Transport if he will list in the Official Report, in order of priority, all road schemes included in"Policy for Roads: England 1978"on which cost benefit analysis has been carried out, indicating, where available, their net present value to cost ratio according to cost benefit analysis.
Cost benefit analysis is carried out for all the schemes in the trunk road programme. For most of these the COBA system is used. At the early stages of design the COBA assessment is based on broad estimates of costs and benefits and its main value is to compare options. The assessment is refined as preparations of schemes proceed but is still likely to vary as modifications are made during the design process. A firm estimate is made at the public inquiry stage. A revised version of COBA has been introduced and schemes are being re-assessed on this basis. A complete list of net present value COBA ratios on a consistent basis is, therefore, not available at present. The figures will be published as schemes reach public inquiry.