Research interest has been focused on vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication systems, known as V2X technologies, namely in road safety and traffic ergonomics. The evaluation of their performance is crucial before their potential integration and deployment in real systems. The present work aims at investigating the correspondences between two sets of scenarios of a simulation and an experimental model pertaining to the performance of IEEE 802.11p communication standard, and confronting their results. Concerning the first set, it pertains to the simulation of the physical layer PHY IEEE 802.11p standard, involving the implementation of V2X PHY transmission model, in a vehicle-to-vehicle V2V and vehicle-to-infrastructure V2I, according to different scenarios. The simulation series also involved data exchange between high-speed vehicles over Rice Race channel. This paper highlights several main parameters that may affect the physical layer network performance and the quality of transmission QoT. In this paper, the Bit Error Rate BER according to the Signal to Noise Ratio SNR was used to assess the performance of the V2X communication standard using all modulation types. Regarding the second set of evaluation scenarios, it includes the development of real-case measurements using the Arada LocoMate OBU transmission system to test the effects of the transmission range on V2X communications. V2I and V2V communications are evaluated in terms of real low and high mobility effects with transmission being taken into account.