The HDM-III Model, released around 1987, stands for Highways Design and Maintenance Standards Model. HDM-III was designed to make comparative cost estimates and economic evaluations of different construction and maintenance options, either for a given road project or for a group of roads on the network, being used mostly at the project level.
Many of the technical models in HDM-4 also date back to the technical work underpinning HDM-III. The HDM-4 Model, released around 2000 kept the same structure as the HDM-III model and was used both as a technical tool for the economic appraisal of road projects and to perform road network economic strategic analysis.
The model will now be an update known as HrDM5 and will take into account the latest research in terms of roads appraisal, especially the impact of climate change on road infrastructure, the new vehicles and social aspects linked to mobility.
There will be 5 complimentary initiatives to inform the new HrDM5. HVT will work on three of them: Analysis of the current gaps in the model; Analysis of emissions and fuel consumption using updated models and taking into account new fleet; new models for tyre consumption taking into account the change in load and fleet especially in LICs.