This paper presents OpenAirITS, an open-source Software-Defined Radio platform for DSRC (802.11p) technology. They extended the Linux 802.11 subsystem, developed a soft-modem and a dedicated driver for the OpenAirInterface Express-MIMO FPGA board. The low-layer PHY functions of DSRC have not been coded on the chipset, but instead as a soft-modem, which allows the SDR platform to be easily modified according to particular experimental objectives. The RF front-end and Express-MIMO board are reconfigurable to allow a wide range of options. In this paper, the authors configure the prototype for a 5Mhz channel bandwidth at 800MHz, and provide key performance metrics of the soft-modem, as well as the DSRC protocol stack.