This appraisal method brings together large amounts of disparate information in a rational, comprehensive, but not necessarily quantified manner and allows interested members of the general public to be informed of the issues and to form and express their own views. Transport has a wide range of impacts on the economy and on different groups, most of which are relevant to decisions but not necessarily quantifiable . Expertise is required to prevent double counting of costs and benefits and to account correctly for such transfers as taxes, subsidies, tolls, and revenues. Where impacts can be quantified naturally, they should be, but the quantification of impacts is not an end in itself. Where quantification is inappropriate, a verbal description is sufficient.
Judgment is at the heart of the process.
The final choice of an option should come after all options and their effects have been compared. The U.K. report on trunk road assessment recommends comparing two options at a time until the best is found. Such an assessment should require only inexpensive administrative, financial, and human resources. The techniques should be well understood by the transport authorities and should be made understandable to the general public. Given the inherently judgmental nature of decisionmaking, the process should be open, transparent, and beyond the control of any single group.