A roadside detection system (100), a roadside unit (104) and a roadside communication method are provided. The roadside unit (104) receives a positioning signal from a satellite positioning system and obtains roadside latitude and longitude coordinates and an initialization parameter coordinate. The roadside unit (104) receives object information of the object. The roadside unit (104) obtains object latitude and longitude coordinates, an object speed, an object acceleration, an object length, and an object heading/direction based on the roadside latitude and longitude coordinates, the initialization parameter coordinate, and the object information. The roadside unit (104) converts the object latitude and longitude coordinates, the object speed, the object acceleration, the object length, and the object heading/direction into a V2V Basic Safety Message format.