sustainability Article A Bus Subsidy Scheme Design Model Considering Competition between Bus Companies Shiqian Ji 1,2 , Jiaming Zhong 1,2 and Zhaocheng He 1,2,3,* 1 School of Intelligent Systems Engineering, Sun Yat-sen University, Guangzhou 510006, China; jishq@mail2.sysu.edu.cn (S.J.)...