Public Lecture: The Highway Development and Management Model (HDM-4): Understanding the Importance of this Model to Road Management and Transport Economics

The Highway Development and Management Model (HDM-4) is the de-facto international decision-support tool for analysing road investment and maintenance choices at project and program levels. The main argument is that a road’s true cost is not what the road agency spends. The true cost is the total transport cost over the life of the asset: agency costs plus the much larger costs borne by road users. That idea links engineering-based road management to economic appraisal.