Vehicular ad-hoc Network (VANET) is fundamentally a collection of vehicles and keen access points for communication, transmission and gathering information of nodes and environment for managing traffic loads. Thus the steering of destination, supervise speed and track of vehicles becomes a critical issue in VANETs. Previous researchers only focus on individually. VANETs will enhance driver safety and reduce traffic deaths and injuries by implementing collision avoidance and warning systems. In this paper, I am going to describe the importance of clustering in VANET and also subcategories of clustering and its protocols.