抄録
In this paper, the methods of determining the optimum modal split between the mass transit and the car of passenger transport in a model city having ring and radial grid networks and in the transportation networks of an actual city are developed.
The optimum modal split in the model city gives the least total transport cost on the condition of the environmental standards and the capacity of the mass transportation. The total transport cost consists of the total transport time cost and the construction and operation cost for the mass transportation and the car traffic and is a function of the modal split, too. This method is applied to the planning of the passengers transportation in Nagoya Region. As a result the optimum modal split in Nagoya Region is found to be 70 percent for the mass transportation and 30 percent for the car traffic.
The method of determining the optimum modal split between the mass transit and the car of passenger transportation in the actual city gives the least total transport cost on the condition of the capacity of the transportation. The total transportation cost consists of the same items as the above case.
It is necessary to forecast transport demands of many functional alternative networks and to evaluate them in order to determine the optimum modal split in the optimum network, in the future. Relative to this, following three iterative methods are developed: a) the binary search method where links are increased and decreased according to their importances; b) the incremental method which adds the most necessary links step by step; c) the decremental method which takes off useless links. We can obtain the optimum network by using these iterative methods. The method c) is found to be most useful by applying these methods to some cases.
A combined model of trip distribution, modal split and traffic assignment is applied to forecasting transport demands. Transport demands are forecasted whenever the networks change. The transportation networks consist of car link, mass transit link, and park-and-ride system.
Finally after the usefulness of the combined model is proved in Nagoya City, these useful methods are applied in determining the optimum railway network and the optimal modal split of the transportation network in Nagoya City in 1980.
