Multi-source traffic information application and optimization is one of the hottest topics in the field of intelligent transportation systems and is important in improving the efficiency and safety of transportation systems, which attracts extensive attentions and in-depth investigations from scholars and experts around the world. In order to better serve transportation system management in China and promote the application of multi-source traffic information in transportation systems, the editorial office of Traffic Information and Safety is organizing a special column of Multi-source Traffic Information Application and Optimization. This column aims to introduce the research findings and practical applications in the field of multi-source traffic information application and optimization in China. Professor Jianhua Guo from Southeast University, Professor Ge Guo from Northeastern University, and Professor Weibin Zhang from Nanjing University of Science and Technology are invited as chief guest editors of this column.