Road Region of Savo-Karjala is one of nine regional road districts in Finland. According to region's long term plan pavement management strategies were enhanced as a separate project. The objective of the project was the management of the whole road network (length over 10 000 km) in order to keep up the balance of the available budget and the condition of the roads. Objective was very fruitful to take advantage of the HDM-4 software. Regional road network model was created as a basis of the study. One of the road feature types for network model was land use classification, which was established in the beginning of the project. Road sections with similar properties were combined to road types. Modelling was done in order to help and clarify the description of road network in the analysis phases performed later during the project. Review on the pavement history condition was run similarly. Study continued with the definition of different strategies for various pavement types. The base alternative for bituminous roads was to follow the condition criteria given in Finnish PMS. Other alternatives were "lighter version of PMS" (lower criteria), concentration on structure improvements, management with "Do minimum"-alternative and "downgrading" the road (replace the bituminous pavement with gravel). Base strategy for the gravel roads was the present road-keeping and the alternatives were to accept lower condition, upgrading to a sealed road, and frost heave section improvements. The main objectives for road management were to maintain the present condition on main roads and to improve the condition of less trafficked but otherwise important roads on regional key connections. As the work proceeded "less important" roads had to be moved to lower condition level while with the present budget there are no possibilities to maintain the present condition objectives. Study included impact assessments for different strategies. HDM-4 program was used to analyse road user costs, road maintenance costs and to forecast road condition (surface and structural condition). Impacts for traffic, environment, inhabitants and routine maintenance were also analysed. All pavement types could be analysed with HDM-4 program equally. HDM-4 models were calibrated similarly according to Finnish PMS-system. Study revealed that network strategy with present road condition criteria is too expensive for the road district. For less trafficked roads criteria has to be lowered. At the same time money is saved to improve regional key connections. Lower maintenance is acceptable for minor gravel roads in order to move funds to upgrade major gravel roads and to repair frost heave sections. HDM-4 was found to be a suitable tool for analysing road network in Finland. It could be used for network level analysis of both sealed and unsealed road in freezing conditions. However, a considerable amount of work had to be invested in adaptation and calibration of the model to Finnish circumstances. For the covering abstract see ITRD E135448.
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