A vehicular ad-hoc network is a class of Mobile Ad-hoc Network (MANET), consisting of a network of vehicles, moving at a relatively high speed that communicate among themselves with different purposes. The wireless access in vehicular environment system has been developed to enhance driving safety and comfort of automotive users. The main drawback of VANET network is the network instability, which reduces the efficiency of the network. One of the major challenging issues in VANET is routing due to high mobility and dynamic topology change. Since the routing protocol decides how better the communication occurs among the vehicles, the design of the routing protocol is very important. There are some well-known VANET routing protocol like AODV (Ad hoc On-Demand Distance Vector Routing Protocol), DSR (Dynamic Source Routing (DSR) Protocol), OLSR (Optimized Link State Routing (OLSR) Protocol), GPSR (Greedy Perimeter Stateless Routing), etc. and those routing protocol have some advantages and disadvantages. No routing protocol is efficient alone for all the scenarios of VANET, so it is required to review the existing protocols and find out a hybrid routing protocol for VANET for better connectivity and better communication.