The Highway Design and Maintenance Standards Model (HDM) was developed by the World Bank’s Transportation Department to meet the needs of highway authorities, particularly in developing countries, for evaluating policies, standards, and programs of road construction and maintenance. The latest version is the 1995 HDM System, issued in 1995. The model simulates total life cycle conditions and costs for one road, a group of roads with similar characteristics, or an entire network of paved or unpaved roads, for a series of road agency construction or maintenance strategies, and provides the economic decision criteria for evaluating the strategies being analyzed. The primary cost set for the life cycle analysis includes the costs of road construction and maintenance and vehicle operating costs, to which travel time costs can be added. The costs of construction related traffic delays, accidents and environmental pollution can be entered in the model exogenously based on separate estimates. HDM can be coupled with the companion Expenditure Budgeting Model (EBM) to find the best way of using road agency funds under budgetary constraint.
Highway Design and Maintenance Standards Model: Model Capabilities and Applications