The highly anticipated era of Internet of Things (IoTs) expected to empower all aspects of Intelligent Transportation Systems (ITS) will undeniably improve transport safety and significantly reduce road accidents. To promote the communication of mobile vehicles (or IoVs), US FCC officially allocated a merger 75 MHz spectrum in the 5.9 GHz band to enable vehicular communication. In this paper, we studied the application of CR technology to IoVs in order to increase the spectrum resource opportunities especially when the officially allocated 75 MHz spectrum in 5.9 GHz band is not enough due to high demands as a result of increasing number of connected devices as already foreseen in the near era of IoTs. We proposed a novel CRAVNET framework which empowers CR assisted vehicles to make opportunistic usage of licensed spectrum bands on the highways, and developed a novel co-operative three-state spectrum sensing and allocation solution which makes CR vehicular SUs aware of additional spectrum resources opportunities on their current and future positions. Both the simulation and theoretical analysis have demonstrated that our solution can significantly improve the performance of a cooperative spectrum sensing and sharing schemes, and provide vehicles with additional spectrum opportunities with zero interference with the PUs activities.