Typically, a vehicle uses On Bus Unit (OBU) to connect to Road Side Unit (RSU) in vehicular networks. When a Corresponding Node (CN) communicates with a MN (Mobile Node, i.e., a vehicle) in vehicular networks, packets are transmitted through both the wired and wireless links. The link between OBU and RSU is a wireless link, while the link between RSU and CN is a wired link. The wireless link is known with a high packet loss rate. Many packet losses in the wireless link are caused by error loss. If the retransmission is made by CN, CN needs to retransmit packets through both the wired and wireless links. Thus, in this paper, we proposed to use the relay gateway approach for having SCTP (RG-SCTP ) in vehicular networks. The relay gateway is able to retransmit packets caused by error loss in the wireless link. The retransmission need not be made by CN. As a result, retransmission made by the relay gateway is much faster than that made by CN. The simulation results show that RG-SCTP can have faster transmission speed and less wasted bandwidth in the wired link than the basic SCTP can.