A Road Transport Investment Model for Developing Countries

The report describes the development of a model which can be used to aid investment decisions within the roads sector in developing countries. The report is aimed at senior administrators, engineers and planners and at those responsible for developing improved techniques for road investment appraisal. The model calculates the construction cost of a road and predicts the condition of the road as time passes and vehicles travel along it. Having predicted the condition of the road, the model estimates the costs of road maintenance and the cost of operation of the vehicles for each year. All these costs are then discounted back to the base year and summed over the life of the road to obtain the total cost. All estimates are made in terms of physical quantities and costs are obtained by applying unit rates to these. The model is very flexible and can be used to study the economics of varying stage construction alternatives such as upgrading an earth road to a gravel or paved road at any time during the design life. The report describes the construction, road deterioration, road user cost and road maintenance sub-models and then looks at a case study of a road in Kenya.