Two model analyses of the urban structure of minimal transportation energy consumption

The transportation sector needs to reduce fuel consumption to deal with global warming because it depends on fossil fuels strongly and it seems to be difficult to substitute other fuels. This study aims at investigating an optimal land use in urban areas from the viewpoint of reducing energy consumption for transportation. For this purpose, the authors developed two kinds of models. One minimizes the total trip length under the condition of constant congestion. The other minimizes the fuel consumption directly where congestion is taken into account endogenously. The optimal structures calculated numerically illustrate that business areas are located around the center of a city while residential areas are on the suburbs, which is similar to the actual land use observed generally. These results are compared with the land use of the central business district (CBD) in Tokyo.