Recently, technology development of self-driving cars has gradually expanded, and interest in Platooning has also increased, and system development has been taking part in the development of several automobile manufacturers. The existing method of Platooning falls short of the original goal of Platooning, which is to reduce the amount of road traffic and time due to delays in the process of reorganizing the cluster or joining another group. Thus, in this paper, the existing SAE J2735 Message Protocol has been improved to newly design the cluster-running algorithm, and the flexible cluster-running, which can be applied even in urban road, has been put forward.