With the growing demands from smart city services, development of intelligent transportation systems has become a popular research field. In this work, we proposed a vision-based basic safety message (BSM) broadcasting system based on SAE J2735 through 3GPP 4G-LTE eMBMS broadcasting technique. Publicly available open government CCTV video data were firstly adopted as the detection source. Through a designed workflow, detection and tracking of the vehicles in the videos can be obtained by YOLOv5x and DeepSORT, respectively. Hence, the speed, location, and ID of each vehicle can be calculated by a BSM generation algorithm to obtain the content elements in SAE J2735 basic safety message. According to the experimental result, the speed and location information can be well transmitted and displayed on the mobile edge device. We expect that the proposed work can be widely applied in ITS applications, benefiting future smart city implementations.