To solve problems confronting the realization of light, short-distance transportation of street cars etc., which improves inner-city environments, convenience, and comfortability and reduce construction costs, problems of stopping places and intersections, operational expenses, etc. while securing users' convenience.

At the formation of an inner-city, short-distance, and areal public transportation network, ring lines which go around and travel in one direction in small areas are provided for zones of higher necessity and profitability. Similar ring lines are provided in such a way as to be partially adjacent to the existing lines in adjacent zones according to a heightened degree of necessity with the development of urban areas. By their repetitions and linkages, the inner-city public transportation network is gradually widened.