§ Mr. Dudley Smithasked the Secretary of State for Transport what comparison has been made of cost-benefit analysis ratios for programmed trunk road schemes under (a) cost-benefit analysis 9 and (b) earlier versions of cost-benefit analysis; what overall effect on estimated economic worth of schemes cost-benefit analysis 9 has had; what effect cost-benefit analysis 9 has had on the number and type of schemes in the programme; and if he will make a statement.
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§ Mrs. Lynda ChalkerComparisons were made, before the introduction of cost benefit analysis 9 in mid-1981, both with COBA 8 and with the interim version in general use since July 1980. Both the interim version and COBA 9 included preparation and supervision costs and used lower assumptions for economic growth that COBA 8. Both therefore gave substantially lower overall net economic benefits, but the degree to which this is so, varies between schemes and between the upper and lower ends of the range. As between COBA 9 and the interim version, there was no clear general trend, but charges varied from scheme to scheme because of the impact of detailed changes, including the more realistic representation of speeds in urban areas.
In our regular reviews of the road programme, and in deciding standards for individual roads, we make use of the latest available techniques of assessment—both economic and environmental. It is not possible, however, to identify precisely changes in the programme as a whole attributable to the introduction of COBA 9, though changes in planned standards—and even the dropping of some schemes—did follow the development of the interim COBA in several cases.