摘要: |
The Highway Design and Maintenance Standards Model (HDM-III), developed by the World Bank, has been used for over two decades to combine technical and economic appraisal of road investment projects, standards, and strategies. The International Study of Highway Development and Management has extended the scope of the HDM-III to provide a harmonized systems approach to road management, with adaptable and user-friendly software tools. The new Highway Development and Management Tool (HDM-4) now caters to strategic planning, work programming, and project preparation. Strategic planning involves the analysis of the road system as a whole, typically requiring the preparation of short- or long-term estimates of expenditure for road development and preservation under various budgetary and economic scenarios. Work programming involves the preparation, under budget constraints, of multiyear road work and expenditure programs in which sections of the network likely to require improvement are identified and listed by priority. Project preparation is the final stage in which the economic benefits of road schemes are analyzed before implementation. The optimization methods developed for the strategy and program applications of HDM-4, which use incremental benefit-cost ratios in the prioritization process, are described. |