We present a hardware vehicular channel emulator aimed at assessing the performance of IEEE 802.11p transceivers in realistic scenarios. Contrarily to commercial emulators, which are usually very expensive and not quite flexible, we have developed an FPGA-based solution that is cheap, flexible and reconfigurable. In this paper we outline its design, implementation and basic operation. To show its capabilities, we present two examples of performance evaluation: we measure the bit error rate and packet error rate of an IEEE 802.11p system when performing transmissions between two vehicles that are approaching at high speeds in a highway and in an urban canyon.