SYSTEM OPTIMUM FRAMEWORK FOR EVALUATION AND EFFICIENCY OF ROAD NETWORK

Road network system development in Indonesia, until now, always constrain with available budget limit. This condition, investment on road network should be done efficiently using priority scale commitment, depend on problem urgent level and expectation of benefit value. Right now, generally, performance of road network analysis has been done using user equilibrium (UE) methods; with assume that in along time period a driver will make a best route choice depend on his perception where results his minimum cost. On road network optimality framework, equilibrium method was not capable to give description how efficient a plan of handling schema. Consequently, result of recommendation wasn't optimum solution for handle this problem. One alternative of assignment models that was capable to give indication of efficiency level for a road network use is a system optimum (SO) method. System optimum framework was based on assume that on road network, there is a route choice system solution with a minimum cost system. Using this method will find critical point and efficiency level of a road network use. System optimum procedures was tested and applied on artificial network and real network of freight transport in Java Island. In artificial case, it was found that SO method is more efficient than UE method. SO method gives efficiency of 8.69% compared to UE method. In real case of freight network in Java Island, it was found that rail expansion is more beneficial than road expansion. Network improvement through rail expansion gives benefit of 7.11% compared to the do-nothing case, while road only 0.5% relative to base condition. Recommendation and result of this study was useful for road network performance evaluation and to arrange step by step of problem solving of right now and tomorrow cases.