A WELL-DEVELOPED public transportation is “the only solution to traffic problems in a metropolis like Shanghai,” Mayor Yang Xiong said yesterday. “Compared to Metro, medium-capacity traffic is less developed in Shanghai,” he said. Chen Bizhuang, general engineer of Shanghai Urban-Rural Construction and Transportation Development Research Institute, said that “medium-capacity traffic projects should only be put into use on the premise of a comprehensive study of practical road situations and passengers' needs.”