Chinanews, Shanghai, Dec. 14 – China should improve safety measures to prevent its metro systems against possible terrorist attacks, said Sun Jun, an academician of the Chinese Academy of Social Sciences, and Zhu Peigen, a professor at the PLA University of Science and Technology.They made the proposal when attending the Safe Use and Management of Underground Space Forum held in Shanghai on Thursday.There are lots of factors that will affect the safe use of metro system. These factors include accidents, fires, system problems, explosions, including explosions caused by terrorist attacks, and other accidental incidents and contingencies. All these factors are unpredictable and they will pose a potential danger to the safe operation of the subway. There is a need for us to take effective measures to prevent these potential dangers, Sun said.In addition to establishing an emergency rescue system in the subway, we should also take other things into consideration, including the line's arrangement above ground, the engineering geological features, the hydrographical geological features and meteorological conditions in areas near the subway, Sun said.In the designing stage, Chinese engineers had already applied various safety measures in subway construction However, the tactics employed by terrorists are usually well-concealed and difficult to predict, said Zhu. He suggested that China should set up a mode to simulate and analyze different cases, which might help engineers to better assess the safety of the metro systems and make correct decisions to handle the problem.