The IEEE 802.11p/1609 standards specify a suite of communication protocols for vehicular communication networks. A new operational mode, called theWAVE (Wireless Access in Vehicular Environments) mode, is defined to enable communication among high-speed vehicles or between a vehicle and a roadside infrastructure network. In the WAVE mode, a mobile/stationary station uses a combined FDMA/TDMA channel access scheme to switch its channel between the control channel and a service channel every 50 ms. The primary purpose of this design is to detect new services announced by other stations. However, if a station would like to use all of its service channel bandwidth to transmit a large volume of data to another station, switching back to the control channel every 50 ms without doing anything useful only unnecessarily reduces the maximum possible transmission throughput by a half. To overcome this problem, in this paper we propose an improved channel access scheme to allow a station to stay on a service channel as long as it requires before returning to the control channel. Our simulation results show that the proposed scheme significantly improves the service channel utilization under various network conditions.