抄録
Today, environmental issues, such as global warming caused by greenhouse gases, has been emerged as globally emergent issues and governments are expected to take measures to solve these issues. Greening of the automobile tax system, environmental tax, and changes in car tax rate are examples of these measures studied recently. In this study, we propose Co-Creative Institutional Design that creates effective institution resulting from interaction between the institutional designer and the whole system. The emergence of car tax rates considering the reduction of carbon-dioxide emissions by applying Co-Creative Institutional Design to the car tax system is confirmed from the result of computer simulation.