Resumen
We examines the effects of the change of toll system on the economic efficiency, focusing on a case of Tokyo Metropolitan Expressway, i.e., Shutoko, whose toll system had shifted from flat toll to distance-based toll. Drivers using the parallel general road are considered, and they are to pay the fuel tax to the government. We calculated the social surplus comprised of the consumers? surplus and the producers? surplus among both the highway company and the government. Furthermore, it is shown that the Ramsey pricing rule could increase the social surplus while toll receipts of the highway company being unchanged.