## 4 Discussion
[49], which evaluated the variation of SAR in 15 human models of different sizes, considering a single-plane wave exposure from 300 to 5000 MHz. This latter study underlined that, under frontal exposure, the typical pSAR\({}_{\rm 10g}\) locations are more in the head/trunk region than in the limbs, particularly in the fingers, toes, nose, ears, chin, penis and testicles regions. This result was because the exposure field can effectively enter inside these body parts which have relatively small dimensions and irregular structures [49]. In all configurations, the highest pSAR\({}_{\rm 10g}\) values were observed in the skin, i.e., the most superficial tissue of the body, whereas in deeper tissues (e.g., the brain), the exposure level was 23% to 92% less than that in the skin. This result is in line with previous studies on RF human exposure assessment that evidenced how the highest peaks of exposure were always localized in the most superficial tissues (i.e., mainly the skin and eyes) because RF-waves penetrate only in the first millimeters of human tissues [24; 25; 26; 27; 28; 29; 30]. For the skin of the whole body and the head and for the brain tissues, the SAR\({}_{\rm 10g}\) distribution was skewed positively, meaning that most of the data were distributed towards the lower range of the exposure level. Additionally, from the analysis of the SAR\({}_{\rm 10g}\) distributions, we discovered that the values of SAR\({}_{\rm 10g}\) higher than 0.7 pSAR\({}_{\rm 10g}\) occupied only small areas over the skin of the whole body and the head and in the whole brain. Only in the eyes, which have smaller dimensions, SAR\({}_{\rm 10g}\) was more normally distributed, particularly for the frontal orientation of the phantom, and the values higher than 0.7 pSAR\({}_{\rm 10g}\) occupy a wider portion of the eyes, reaching up to 41% of the total volume in the frontal orientation of CONF 1, that is, the configuration where the eyes are most exposed to the field radiated by the windscreen antenna. We found the exact same trend in our previous study that dealt with the RF human exposure assessment in a possible future case of an indoor exposure scenario, where the presence of a 5G access point (AP) was simulated at a working frequency that was almost the same as that in this work (3.7 GHz vs. 3.5 GHz); also, in this study, in the tissues with a smaller extension (e.g., cerebellum and, in particular, the eye tissues), the SAR\({}_{\rm 10g}\) distributions become smoother and less skewed with respect to the SAR\({}_{\rm 10g}\) distributions over the skin on the whole body [25]. Since, in the present paper, a specific 5G-V2X exposure scenario was analyzed for the first time, with its peculiar characteristics (i.e., the use of the FR1 band, the new 5G-V2X array antenna with beamforming capability, the presence of the metallic body of the car), it is difficult to find a fair comparison with previous literature studies. It remains, however, interesting to discuss, at least from a qualitative point of view, similarities and differences with other studies that investigated the RF exposure outside or inside vehicles in the frequency range for mobile communication [32; 33; 34] and for V2V in the ITS 5.9 GHz band [38]. Table 5 gives an overview, comparing the exposure levels we obtained in terms of SAR from this study with respect to the ones found in these other literature studies [32; 33; 34; 38]. From Table 5, we can notice that, in the studies [32; 33; 34], different emitting devices (e.g., phones, UMTS, WiMax, Bluetooth devices) were placed inside the vehicle cabin, and the exposure levels were evaluated for the driver and the passengers. The peak SAR found in these studies is much greater than that in our present work, namely, up to 127 W/kg at 1800 MHz in [32], 3.77 W/kg at 900 MHz in [34] and 392.6 mW/kg for a WiMax device in [33], mainly due to the closer distance between the human models and the emitting devices. Furthermore, in the study of [PERSON] et al.