## 4 Discussion  
To the best of the authors' knowledge, this is the first study on the assessment of human RF exposure in a realistic 5G-V2X communication scenario. Specifically, in the present study, we assessed the dose of RF absorbed by people (e.g., a pedestrian) in the vicinity of a car equipped with two 5G-V2X antennas. To conduct this exposure assessment, first, model of a 5G-V2X antenna was implemented based on the last technical specifications released by 3 GPP (Release 16 and 17 [11; 12]), resulting in an array antenna of eight elements at the working frequency of 3.5 GHz in the FR1 range for 5G wireless communications. Then, two exemplars of this antenna model were mounted on a 3D realistic model of a city car, according to the typical antenna mounting position, i.e., on the windscreen and on the roof at the back of the car [43; 44]. Lastly, the human exposure levels induced by the two antennas were assessed using the Ella model from the Virtual Population by considering different configurations between the car body and the human model to better characterize the impact of the position of the person near the car on the exposure levels. The assessment of the exposure levels was based on the analysis of the SAR\({}_{10g}\) distribution and pSAR\({}_{10g}\) values, focusing on the typical tissues of interest for the exposure assessment in the GHz frequency band, which are the skin, the brain and eyes tissues, in line with the analysis conducted in other studies on RF human exposure assessment considering the forthcoming 5G networks deployment [24; 25; 26; 27; 28; 29; 30]. Firstly, and most importantly, in the considered 5G-V2X scenario, the exposure in the different configurations was well below the SAR\({}_{10g}\) limit of 2 W/kg for the head and torso, as indicated by the ICNIRP guidelines [39]. If the input power of the two 5G-V2X antennas is further scaled to a realistic value of 23 dBm, i.e., 200 mW, as indicated in the technical specification of 3 GPP [11; 12]), the level of exposure due to a V2X communication scenario is even more significantly reduced. Our study evidenced that the highest SAR\({}_{10g}\) values were localized mostly in the head area in both orientations and all examined configurations, except in CONF 2 in the frontal orientation and in CONF 4 in the orthogonal orientation, where pSAR\({}_{10g}\) was localized in the arm, that is, the part of the body in closer proximity to the 5G-V2X antennas. Furthermore, in all cases, the legs showed values of exposure almost equal to zero. This result was expected because the head and arms are the regions of the human model closest to the 5G-V2X antennas, whereas the legs, being more distant from the antennas, are consequently less exposed. Moreover, it was noticed that the exposure level depended on the position of the human model near the car. Among all configurations, CONF 1, where [PERSON] stands in front of the car hood, showed the highest pSAR\({}_{10g}\); in the remaining configurations, pSAR\({}_{10g}\) was 84% to 98% less than that in CONF 1. This is probably due to the position of the frontal 5G-V2X antenna, it being mounted on the inclined surface of the windshield with a tilt of 37\({}^{\circ}\) degrees in the forward direction, thus directing the main beam of radiation more towards the human model than the rear antenna. On the contrary, the rear antenna, being placed on the horizontal plane of the car roof, directs the main beam in the upward direction; consequently, when the human model stands at the back of the car, it is reachedalmost exclusively by the side lobes of the radiation. The orientation of the human model with respect to the car has only a marginal effect on pSAR\({}_{\rm 10g}\) values. Regarding CONF 1, for both orientations of the human model, the highest exposure levels are focused on the head area--specifically, at the nose and eyes in the frontal orientation and at the ears in the orthogonal one. This is in line with the study of [PERSON] et al.